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Problem Bleeding rebuilt original Master Cylinder power Vacuum Booster - 1956 Century Riviera 60 series


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Hello,

 

I had another post about fluid types but I think this is a new topic and I could really use some help please if any one is knowledgeable on this. No one in my town is.

 

I just had my power brake unit rebuilt but I have no idea how to bleed it. The company I used, White Post Restorations, said that it didn't need bench bled. So I installed the unit and filled it with fluid. I cracked the wheel cylinder bleeder at the furthest wheel cylinder which is the rear passenger, but pumping the brakes isn't doing anything. No pressure at all.

 

My first worry was that the rebuild was faulty, but then I started reading that some sort of bleeding of the master cylinder itself does needs done prior to bleeding the full system with lines and all. Alas, apparently I should've bench bled.

 

Can this be done with the unit in the car? It's all put together with the steering gearbox locking it in, but the inlet and filler can both be accessed just fine. What's the best and easiest way to get this done? Does this sound like I just need to bleed the unit? Or does it sound like the unit isn't working?

 

 

 

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Edited by killy_4_u (see edit history)
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I have never had to bench bleed a displacement system like this.  If the fluid in the reservoir does not go down 2 ounces after 5 slow cycles (quit pumping :D) of the brake pedal, then the linkage is not adjusted correctly or the check valve is defective or installed wrong.

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Have just been through the same problem myself.

 

Mine is a 1955 Super and the unit has a remote reservoir so you really can't bench bleed it.

The other problem is that the master cylinder itself is not like most master cylinders which rely on rubber buckets on the end of a rod to pressurise the system and pump fluid out into the lines.

This master cylinder displaces the brake fluid when a stainless rod enters the master cylinder through a hydraulic seal but there is no bucket on the end to actually push fluid. If your line has a lot of air the normal pumping procedure just doesn't cut it. Study the workshop manual diagram and you will see what I mean about no bucket on the end of the push rod.

To bleed my system I borrowed a vacuum operated brake bleeder which literally sucks the fluid right through the system from the master cylinder reservoir. This unit is used on the wheel cylinder nipples ( which we use the normal tube on ) and sucks the fluid through to each wheel cylinder.

The other method I was told of was to use a pressure pump on the master cylinder reservoir. These consist of a hand operated hydraulic pump connected to your reservoir via a screw cap - fluid/air tight and used to push the fluid through the system.

 

At the end of the day it didn't matter how much I pumped the brake peddle in the normal procedure I didn't get any resistance.

 

You need a vacuum bleeder unit and your problem will be cured, well at least the brakes will be bled!!  

 

This is the unit I used to bleed mine

 http://www.ebay.com.au/itm/T-E-Tools-QS-2113-Vacuum-Air-Brake-Bleeder/281922863947?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D0887fa37c5084ba39dc3482220834d1d%26pid%3D100338%26rk%3D20%26rkt%3D27%26sd%3D141547516884     

Edited by 50jetback (see edit history)
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2 hours ago, old-tank said:

I have never had to bench bleed a displacement system like this.  If the fluid in the reservoir does not go down 2 ounces after 5 slow cycles (quit pumping :D) of the brake pedal, then the linkage is not adjusted correctly or the check valve is defective or installed wrong.

 

Where is the check valve? Is that inside the unit? What linkage are you referring to? The pedal linkage?

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2 hours ago, 50jetback said:

Have just been through the same problem myself.

 

Mine is a 1955 Super and the unit has a remote reservoir so you really can't bench bleed it.

The other problem is that the master cylinder itself is not like most master cylinders which rely on rubber buckets on the end of a rod to pressurise the system and pump fluid out into the lines.

This master cylinder displaces the brake fluid when a stainless rod enters the master cylinder through a hydraulic seal but there is no bucket on the end to actually push fluid. If your line has a lot of air the normal pumping procedure just doesn't cut it. Study the workshop manual diagram and you will see what I mean about no bucket on the end of the push rod.

To bleed my system I borrowed a vacuum operated brake bleeder which literally sucks the fluid right through the system from the master cylinder reservoir. This unit is used on the wheel cylinder nipples ( which we use the normal tube on ) and sucks the fluid through to each wheel cylinder.

The other method I was told of was to use a pressure pump on the master cylinder reservoir. These consist of a hand operated hydraulic pump connected to your reservoir via a screw cap - fluid/air tight and used to push the fluid through the system.

 

At the end of the day it didn't matter how much I pumped the brake peddle in the normal procedure I didn't get any resistance.

 

You need a vacuum bleeder unit and your problem will be cured, well at least the brakes will be bled!!  

 

This is the unit I used to bleed mine

 http://www.ebay.com.au/itm/T-E-Tools-QS-2113-Vacuum-Air-Brake-Bleeder/281922863947?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D0887fa37c5084ba39dc3482220834d1d%26pid%3D100338%26rk%3D20%26rkt%3D27%26sd%3D141547516884     

 

Awesome, thank you! Unfortunately I don't have a workshop manual. I'm going to give this a try! There's definitely a lot of air because the fluid drained out of the line for a long time when I removed the unit.

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I don't mean to be rude and apologize if this sounds abrasive, but did you just open a wheel cylinder bleeder valve, and then start pumping the brake pedal with the valve open the whole time?  Cause that's what your post reads like.  If so, that is the incorrect procedure.

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Yes good advice.  The Moraine and the Bendix system needs to have a static fluid status to begin displacing the fluid.  To create this the fluid needs to be persuaded to move and fill the system until a adequate static fluid level is achieved.  Kinda like priming a bilge pump or sump pump.  To draw the fluid through the system as suggested one can also use a large diaphragm hand suction pump starting at the farthest point and working around in the usual manner.  Once primed properly and air out bubbles out the internal rod plunger will displace the fluid as designed but remember the plunger is not creating suction and pushing the fluid lie in a newer rubber/sleeved cylinder pump.

 

This system was and still is really quite a good remarkably long term dependable system unlike traditional high maintenance rubber cylinder/plunger setups of today.  It has no typical plunger rubber cup that is constantly submersed in brake fluid which is needed to physically draw and push the fluid against a sleeved wall in a bored piston/cylinder format thereby exposing itself to constant fluid deterioration and constant wear. The Moraine/Bendix system on the other hand has a stacked series of fitted inset rubber seals that ride along the base of the shaft behind the plunger displacement metal head. This series seals configuration keeps the fluid contained  and away from the next proceeding set of inner seals.  They are not submersed in constant brake fluid itself like the rubber plunger setup.  Yes the seals eventually wear and the clearance between the seal face and the shaft increases until the unit internally leaks but rarely resulting in complete pedal failure unlike the sleeved cylinder rubber cup system that is prevalent today,  but this leaking takes much longer to develop.   In fact in a way, this Moraine / Bendix system sorta works much in design and functions like a caliper system works.  The caliper piston is end sealed and the caliper piston cylinder is like the shaft and fluid is contained by these outer seals  thereby limiting wear.

 

If one is very good at replacing their fluid annually and the system not allowed to sit around for months or years rotting on end the Moraine or Bendix continues to out perform on a longevity basis today's typical rubber plunger system.  The only real weathering weaknesses this Morian/Bendix system is exposed to is in the rubber flex brake lines found though out the brake line system itself which eventually deteriorate and rupture or leak long before the M.C. gives up the battle. But both type systems share this blithe. 

 

What we think eventually put this type of M.C. system out to pasture was not the functionality or safety of the system itself, as explained it worked very well and was dependable, but rather the eventual perceived need for introducing a proportioning valve braking system setup which would allow for more pedal & fluid psi allotment differential control between the now separated front and rear brake lines.  Also this necessitated the use of dual cylinders to separate the lines between front and rear in case of a M.C. failure which was and still is a very real threat because rubber plunger/sleeve cylinder systems render increased wear in the critical sealing area within the bore sleeved fluid reservoir itself and once gone the system fails quickly and one needs that extra dedicated and other separated cylinder in the M.C. to continue feeding the other split line system be it the front or rear lines, hoping  however, that both cylinders will not fail at the same time.

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I literally just did this last night before going to bed, I was up until 3 am in the driveway and had the same issues as you. Before I tore into my system, it lasted 5 minutes after sitting on the shelf and I had to completely redo the inside. The brakes work great now!

 

The issue you're having is a very large air pocket that is formed by filling the reservoir with air in the system. At the brake proportioning block, there is a rubber diaphragm check valve that keeps the fluid primed in the lines since the master cylinder is below the wheel cylinders. I started at the wheel cylinder closest to the master and attached a piece of surgical tubing to the bleed nut, which ended in a glass bottle. I opened the nut and waited until fluid began to pass and bubbles stopped coming out. I closed the bleeder and did this to all four wheels until I was the rear farthest from the master. What I then did was I kept the bleeder on the farthest open and got in the car and just started pumping the brake pedal all the way to the toe board. After 5 pumps, I would check the fluid reservoir and fill if required. It took maybe 30 minutes to get the first burp out and it was a huge air pocket. You'll know when you get close to the big bubble because the pedal gets almost ridiculously hard to go to the floor and then a sudden release in pressure as the line clears. After the large air bubble passes, and there were probably about three large bubbles, I kept bleeding the line until the foam stopped appearing. I then closed the bleeder and went to the driver rear cylinder and did the same thing. So on and so forth. When you get back to the front driver side wheel cylinder and finish pumping the fluid out, I then went back to the passenger rear cylinder and did it all over again until there were no traces of foam or bubbles in the line.

 

It's a lot of patience, but the bubble eventually works its way out. All in all it took me an hour and a half to get the brakes properly bled. I used a large bottle of the Valvoline 3+4. I also have a 1956 Buick Century, but mines a 2 door.

 

Also word of advice and ditch that pushrod boot. If you still have the original one, use that. Those narrow neck pushrod boots will be sucked inwards by internal vacuum of the unit and close off the power piston operation cycle. When I had a boot like that, it would create a seal around the power piston and constantly pull the brake pedal down to the applied position. When I switched back to the original boot, the booster operated as it should and I have been happy since. I initially adjusted the brakes to five clicks out on the adjuster per the shop manual but this is too much because the manual says the applied position should be an inch from the toe board and the applied position for me is almost at the toe board. So when you adjust the brakes, try to set it initially at 3-4 clicks out from their fully extended position (adjust shoes out until you can't rotate the wheel by hand then adjust back in).

 

Hope this helps! Let me tell you I went to a modern setup and the original blows the socks off any modern system you can fit down there. The car stops like any modern car, just don't get crazy with it and downshift down the big hills.

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12 hours ago, killy_4_u said:

 

.....Unfortunately I don't have a workshop manual.....

Get one.  I don't have a manual for your car either so all I can offer is just generic tips.

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On ‎5‎/‎29‎/‎2016 at 7:53 PM, JohnD1956 said:

I don't mean to be rude and apologize if this sounds abrasive, but did you just open a wheel cylinder bleeder valve, and then start pumping the brake pedal with the valve open the whole time?  Cause that's what your post reads like.  If so, that is the incorrect procedure.

 

Sweet, then what is the proper procedure? No offense taken; admittedly I don't know brake systems very well.

 

But I'm not a complete idiot either, and I've enjoyed a lot of success undertaking other projects with little experience, input from others, and trial and error.

 

I was hoping the same in this case when the actual rebuilder told me to perform a standard bleeding procedure.

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On ‎5‎/‎29‎/‎2016 at 10:18 PM, buick man said:

Yes good advice.  The Moraine and the Bendix system needs to have a static fluid status to begin displacing the fluid.  To create this the fluid needs to be persuaded to move and fill the system until a adequate static fluid level is achieved.  Kinda like priming a bilge pump or sump pump.  To draw the fluid through the system as suggested one can also use a large diaphragm hand suction pump starting at the farthest point and working around in the usual manner.  Once primed properly and air out bubbles out the internal rod plunger will displace the fluid as designed but remember the plunger is not creating suction and pushing the fluid lie in a newer rubber/sleeved cylinder pump.

 

This system was and still is really quite a good remarkably long term dependable system unlike traditional high maintenance rubber cylinder/plunger setups of today.  It has no typical plunger rubber cup that is constantly submersed in brake fluid which is needed to physically draw and push the fluid against a sleeved wall in a bored piston/cylinder format thereby exposing itself to constant fluid deterioration and constant wear. The Moraine/Bendix system on the other hand has a stacked series of fitted inset rubber seals that ride along the base of the shaft behind the plunger displacement metal head. This series seals configuration keeps the fluid contained  and away from the next proceeding set of inner seals.  They are not submersed in constant brake fluid itself like the rubber plunger setup.  Yes the seals eventually wear and the clearance between the seal face and the shaft increases until the unit internally leaks but rarely resulting in complete pedal failure unlike the sleeved cylinder rubber cup system that is prevalent today,  but this leaking takes much longer to develop.   In fact in a way, this Moraine / Bendix system sorta works much in design and functions like a caliper system works.  The caliper piston is end sealed and the caliper piston cylinder is like the shaft and fluid is contained by these outer seals  thereby limiting wear.

 

If one is very good at replacing their fluid annually and the system not allowed to sit around for months or years rotting on end the Moraine or Bendix continues to out perform on a longevity basis today's typical rubber plunger system.  The only real weathering weaknesses this Morian/Bendix system is exposed to is in the rubber flex brake lines found though out the brake line system itself which eventually deteriorate and rupture or leak long before the M.C. gives up the battle. But both type systems share this blithe. 

 

What we think eventually put this type of M.C. system out to pasture was not the functionality or safety of the system itself, as explained it worked very well and was dependable, but rather the eventual perceived need for introducing a proportioning valve braking system setup which would allow for more pedal & fluid psi allotment differential control between the now separated front and rear brake lines.  Also this necessitated the use of dual cylinders to separate the lines between front and rear in case of a M.C. failure which was and still is a very real threat because rubber plunger/sleeve cylinder systems render increased wear in the critical sealing area within the bore sleeved fluid reservoir itself and once gone the system fails quickly and one needs that extra dedicated and other separated cylinder in the M.C. to continue feeding the other split line system be it the front or rear lines, hoping  however, that both cylinders will not fail at the same time.

 

That's some excellent info and the caliper analogy helps me understand. I have seen inside of this unit and this all makes sense. I often worry about the single cylinder setup and going downhill towards the Oregon coast for a car show and losing all brakes on my 2-ton beauty. :)

Edited by killy_4_u (see edit history)
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On ‎5‎/‎30‎/‎2016 at 0:35 AM, Beemon said:

I literally just did this last night before going to bed, I was up until 3 am in the driveway and had the same issues as you. Before I tore into my system, it lasted 5 minutes after sitting on the shelf and I had to completely redo the inside. The brakes work great now!

 

The issue you're having is a very large air pocket that is formed by filling the reservoir with air in the system. At the brake proportioning block, there is a rubber diaphragm check valve that keeps the fluid primed in the lines since the master cylinder is below the wheel cylinders. I started at the wheel cylinder closest to the master and attached a piece of surgical tubing to the bleed nut, which ended in a glass bottle. I opened the nut and waited until fluid began to pass and bubbles stopped coming out. I closed the bleeder and did this to all four wheels until I was the rear farthest from the master. What I then did was I kept the bleeder on the farthest open and got in the car and just started pumping the brake pedal all the way to the toe board. After 5 pumps, I would check the fluid reservoir and fill if required. It took maybe 30 minutes to get the first burp out and it was a huge air pocket. You'll know when you get close to the big bubble because the pedal gets almost ridiculously hard to go to the floor and then a sudden release in pressure as the line clears. After the large air bubble passes, and there were probably about three large bubbles, I kept bleeding the line until the foam stopped appearing. I then closed the bleeder and went to the driver rear cylinder and did the same thing. So on and so forth. When you get back to the front driver side wheel cylinder and finish pumping the fluid out, I then went back to the passenger rear cylinder and did it all over again until there were no traces of foam or bubbles in the line.

 

It's a lot of patience, but the bubble eventually works its way out. All in all it took me an hour and a half to get the brakes properly bled. I used a large bottle of the Valvoline 3+4. I also have a 1956 Buick Century, but mines a 2 door.

 

Also word of advice and ditch that pushrod boot. If you still have the original one, use that. Those narrow neck pushrod boots will be sucked inwards by internal vacuum of the unit and close off the power piston operation cycle. When I had a boot like that, it would create a seal around the power piston and constantly pull the brake pedal down to the applied position. When I switched back to the original boot, the booster operated as it should and I have been happy since. I initially adjusted the brakes to five clicks out on the adjuster per the shop manual but this is too much because the manual says the applied position should be an inch from the toe board and the applied position for me is almost at the toe board. So when you adjust the brakes, try to set it initially at 3-4 clicks out from their fully extended position (adjust shoes out until you can't rotate the wheel by hand then adjust back in).

 

Hope this helps! Let me tell you I went to a modern setup and the original blows the socks off any modern system you can fit down there. The car stops like any modern car, just don't get crazy with it and downshift down the big hills.

 

Awesome story! I actually have a friend with an auto shop who is going to loan me the vacuum bleeder today. Do you think that will still work fine or do you think your method is better? I don't mind how much time it takes (although I'd like it to be quick if possible) I just want to go with the best method.

 

The boot you're seeing in the above photo actually has holes all through out it. They're difficult to see but they're there. I believe these holes are meant to alleviate the issue you're explaining. Is it because the newer boots are solid unlike this one?

 

I'm glad to hear your take on the system though. I've heard nothing except the same. The PSI out of that old thing seems incredible as it was meant to stop that big beast. Others have said converting to a newer system is good for the safety benefit of the dual-circuit but that the PSI just isn't as good. I'm also contemplating high-friction material to reline my pads with. I know they eat up the drums a little quicker but I think it might be worth it. What do you think?

 

I'd be happy to stock up on a couple extra set of drums in the next few pay days if it makes me stop better with high friction material. I don't hot rod this thing, but quite the opposite. I don't think it could drive fast if I wanted it to anyway. And I often start and stop with low gear. Trying to make it a habit. I think it might even be better on the transmission than starting off with such sluggish torque in Drive.

 

 

Edited by killy_4_u (see edit history)
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On ‎5‎/‎30‎/‎2016 at 6:52 AM, old-tank said:

Get one.  I don't have a manual for your car either so all I can offer is just generic tips.

 

Yes sir! Will do. Luckily this thing was in pretty amazing condition when I picked it up for a steal and I've only owned her for a couple years so it's only now that I'm starting to start maintaining some of the old systems that the previous owner maintained fairly well too. The master cylinder and steering gear rebuilds were kind of forced so I haven't taken the time to get a manual YET, but I definitely intended to already.

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There are differing opinions on what is the correct procedure to bleed brakes.  Some say to start at the nearest wheel to the master cylinder, I say start at the furthest wheel ( usually the passenger side rear) .  In either case, if you have a helper who is tall enough to push the pedal all the way to the floor board, then one person opens the bleeder valve at the wheel, and tells the other to push the pedal down to the floor.  The 2nd person pushes the pedal to the floor, and announces when it is there AND holds it to the floor till the first person closes the bleeder valve.  Once that is closed the first person announces that and then the 2nd person lets off the brake pedal.

 

There is more I'd like to type but I have an appointment right this minute.  Will try to fill in later.

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2 hours ago, killy_4_u said:

Others have said converting to a newer system is good for the safety benefit of the dual-circuit but that the PSI just isn't as good.

 

There is no safety benefit to a dual-circuit master cylinder, in my experience that claim is a myth. I had a front rubber hose blow on my 2002 Jeep Liberty that has a dual circuit master cylinder and I had zero brakes. Dual circuit master cylinders work on the same principles as a single circuit and still require primed fluid in order for the system to work. If one system fails and drains fluid from a reservoir, then you're still pushing against air and you have zero brakes. For the logic of a dual circuit to make sense, you would need two separate, enclosed master cylinders that work in tandem with each other. That's why I scrapped the crap and put the original one back in.

 

The newer boot I had bought was solid. Yours may work, but it may cause a vacuum leak.

 

I don't have a vacuum bleeder so I can't comment, but I did bleed the system without a helper. I just left the bleed nut open with a piece of surgical tubing immersed in brake fluid and would do four or five pumps and check to fill the reservoir and check the bottle for bubbles.

 

As for brake linings, the bonded ones from NAPA seem to work fine for me.

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Beemon's procedure can work provided the tubing is tight enough that it does not come off the end of the bleeder valve and that the system does not pull air from around the tube or the area of the threads of the bleeder valve.

 

The first thing I do is allow the system to bleed itself by gravity.  This works only if the reservoir is higher than the wheel cylinders themselves. That is the case in a 56.  For this segment I fill the reservoir and then open one or more bleeders and just wait for the brake fluid to flow out.  It may take a few minutes for this to happen but I cannot remember that ever failing.  As the fluid flows from the bleeder valves then I just close them off.  I keep the lid off the reservoir so I can keep an eye on the fluid level.  You do not want to let the reservoir run dry at any point.

Once I have flow at each wheel cylinder and all of them are closed,  I'll lay the cap on the reservoir,  then I follow the procedure I mentioned in the earlier post.  I use a helper because my personal preference is to close the bleeder valve when the brake pedal is being pushed. Right or wrong I figure when the system is pressurized from the insides, it is impossible for it to suck air unless there is a loose connection somewhere.  I usually bleed each wheel cylinder several times, and just watch for air bubbles being expelled. I also put a disposable rag in front of the opening of the bleeder valve and watch the flow as the pedal is being pumped.  If the flow does not seem forceful enough, or if I keep getting air bubbles,  I'll go back and look for loose connections in the system.  Sometimes it only takes that last little crunch to set the lines in the fittings. Fill the reservoir often. 

Some folks will say that you should pump the brake pedal between cycles of opening  the bleeders.  I have not found this to be necessary unless I do not get flow in the gravity feed cycle.  Even then, I never pump the pedal when one or more bleeders are open.

 

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5 hours ago, killy_4_u said:

I'm also contemplating high-friction material to reline my pads with. I know they eat up the drums a little quicker but I think it might be worth it. What do you think?

I may be wrong, but I think of brake shoes being lined with soft or hard linings. Softer linings will wear out the shoes faster, but are preferable.  The harder linings may generate more heat and heat can lead to fading. Further, multiple people have complained about todays relined shoes not stopping as well, and the response of the community is to have the shoes relined with softer material.

In addition, even if softer linings wear faster, chances are the reduced mileage a collectible car is used will more than offset the reduced number of miles the brakes will last. 

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7 hours ago, killy_4_u said:

That's some excellent info and the caliper analogy helps me understand. I have seen inside of this unit and this all makes sense. I often worry about the single cylinder setup and going downhill towards the Oregon coast for a car show and losing all brakes on my 1-ton beauty.

… Well first one would have to stop and think rationally of how this could even happen in the first place with your Moraine or Bendix setup of which we have been referring.  The only way one of these units which is and has been well maintained would fail and fail completely in the real world would be for one of the front rubber brake hose lines to suddenly burst or the rear center rubber axle hose bursting. Installation of steel braided lines would drop this possibility down to a low statistical marginal point.  Balance and counter this with the very real and more probable chances of losing your conventional M.C. setup completely and suddenly due to a number of possible reasons from a rubber piston failure or internal M.C. malfunction which is nearly impossible with the Moraine or Bendix units due to their design and construction as explained above as no sudden failure could occur as is not the case with the conventional cup setup we see today.

 

Yes as discussed earlier, the new conventional setups have dual cylinders serving as a sort of back-up for each other; the separation of hard lines between front and back and the proportioning valves that this setup requires. They need all of this because of their innate design weaknesses, not because it is a better design in terms of longevity and reduced possibilities of complete and sudden brake failure. But at the end of the day, driving your well maintained Moraine or Bendix unit down a lengthy coastal grade should be of little concern in terms of duty reliability.  More concern should really be focused on controlling heat buildup on brake shoe systems which however, if properly and diligently applied, should pose no real world threat as well.

Edited by buick man (see edit history)
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"Also word of advice and ditch that pushrod boot. If you still have the original one, use that. Those narrow neck pushrod boots will be sucked inwards by internal vacuum of the unit and close off the power piston operation cycle."

You can also create a small hole in the boot to let air escape and the boot will still keep the dust out!

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15 hours ago, killy_4_u said:

That's some excellent info and the caliper analogy helps me understand. I have seen inside of this unit and this all makes sense. I often worry about the single cylinder setup and going downhill towards the Oregon coast for a car show and losing all brakes on my 1-ton beauty

Not to scare you more, but if your 56 is one ton, you might be missing half of it.

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14 hours ago, JohnD1956 said:

Beemon's procedure can work provided the tubing is tight enough that it does not come off the end of the bleeder valve and that the system does not pull air from around the tube or the area of the threads of the bleeder valve.

 

I have developed a variation of the 'tube in a bottle of fluid' procedure.  Instead of a bottle I use a 2 oz (60cc) syringe attached to the tube front down and suspended above the bleeder.  Five cycles of the pedal fills the syringe.  Only fluid (if anything) will be pulled back into the system.  I never need assistance to bleed or flush.

Vacuum bleeder have never worked on my 55's.

Edited by old-tank (see edit history)
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18 hours ago, JohnD1956 said:

There are differing opinions on what is the correct procedure to bleed brakes.  Some say to start at the nearest wheel to the master cylinder, I say start at the furthest wheel ( usually the passenger side rear) .  In either case, if you have a helper who is tall enough to push the pedal all the way to the floor board, then one person opens the bleeder valve at the wheel, and tells the other to push the pedal down to the floor.  The 2nd person pushes the pedal to the floor, and announces when it is there AND holds it to the floor till the first person closes the bleeder valve.  Once that is closed the first person announces that and then the 2nd person lets off the brake pedal.

 

There is more I'd like to type but I have an appointment right this minute.  Will try to fill in later.

 

Copy. So this is the exact same procedure I was mentioning above that you said was incorrect. Not to be rude or abrasive.

 

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29 minutes ago, old-tank said:

I have developed a variation of the 'tube in a bottle of fluid' procedure.  Instead of a bottle I use a 2 oz (60cc) syringe attached to the tube front down and suspended above the bleeder.  Five cycles of the pedal fills the syringe.  Only fluid (if anything) will be pulled back into the system.  I never need assistance to bleed or flush.

Vacuum bleeder have never worked on my 55's.

 

So you've tried the vacuum bleeder and it didn't work? I've been told that they're the best way to do it bleed the master. My '56 is a different unit, but the negative experience with the vacuum bleeder is a bad sign.

 

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On ‎6‎/‎1‎/‎2016 at 9:48 PM, buick man said:

… Well first one would have to stop and think rationally of how this could even happen in the first place with your Moraine or Bendix setup of which we have been referring.  The only way one of these units which is and has been well maintained would fail and fail completely in the real world would be for one of the front rubber brake hose lines to suddenly burst or the rear center rubber axle hose bursting. Installation of steel braided lines would drop this possibility down to a low statistical marginal point.  Balance and counter this with the very real and more probable chances of losing your conventional M.C. setup completely and suddenly due to a number of possible reasons from a rubber piston failure or internal M.C. malfunction which is nearly impossible with the Moraine or Bendix units due to their design and construction as explained above as no sudden failure could occur as is not the case with the conventional cup setup we see today.

 

Yes as discussed earlier, the new conventional setups have dual cylinders serving as a sort of back-up for each other; the separation of hard lines between front and back and the proportioning valves that this setup requires. They need all of this because of their innate design weaknesses, not because it is a better design in terms of longevity and reduced possibilities of complete and sudden brake failure. But at the end of the day, driving your well maintained Moraine or Bendix unit down a lengthy coastal grade should be of little concern in terms of duty reliability.  More concern should really be focused on controlling heat buildup on brake shoe systems which however, if properly and diligently applied, should pose no real world threat as well.

 

It's the heat on the shoe system that I'm worried about as well. I'm trying to choose a good shoe at the moment. I think I'm not going to go with the hard aggressive relining of my stock shoes. Any recommendations for a good all-around shoe that will brake well with my original drums and act best with the heat issue? I experienced a lot of fade with my stock asbestos shoes. Is this something that I just won't be able to get around no matter what I do short of a front disc conversion? I'm trying not to go disc for the sheer cost. What is your opinion on the disc conversion? This one claims to go on the stock setup just fine and clears the stock steel wheel too. They claim all I need to add is a proportioning valve to adjust pressure between fronts & rears.

 

http://www.ebay.com/itm/WILWOOD-DISC-BRAKE-KIT-FRONT-41-56-BUICK-11-88-ROTORS-BLACK-CALIPERS-/270973461235?hash=item3f1746e2f3:m:mOWYtbZDFUl4gSG_HroE5aQ&vxp=mtr

Edited by killy_4_u (see edit history)
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On ‎5‎/‎29‎/‎2016 at 2:55 PM, old-tank said:

I have never had to bench bleed a displacement system like this.  If the fluid in the reservoir does not go down 2 ounces after 5 slow cycles (quit pumping :D) of the brake pedal, then the linkage is not adjusted correctly or the check valve is defective or installed wrong.

 

I haven't touched the check valve. The linkage is just as it was before. I'm hoping the vacuum bleeder will help. The fluid has not gone down. Only the reservoir is full.

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9 minutes ago, killy_4_u said:

Copy. So this is the exact same procedure I was mentioning above that you said was incorrect. Not to be rude or abrasive.

So, now I see where you are going.  No offense taken, but that's not what you put in your original post.  Good luck.

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7 hours ago, lancemb said:

"Also word of advice and ditch that pushrod boot. If you still have the original one, use that. Those narrow neck pushrod boots will be sucked inwards by internal vacuum of the unit and close off the power piston operation cycle."

You can also create a small hole in the boot to let air escape and the boot will still keep the dust out!

This creates a vacuum leak and exposes the internal vacuum circuit to the external vacuum where the dust is. The reason why the brake pedal comes back up is because the power piston by spring force is then seated to the vacuum diaphragm and vacuum escapes from the power piston around the pushrod. If the boot seals around the power piston, it won't let the brake pedal release and it will suck the power piston down into the bore. The vacuum must flow out of the power piston and back through the vacuum diaphragm until the vacuum diaphragm seals against the top of the vacuum canister, shutting off the vacuum circuit. If you vent the vacuum from the dust boot, then you have less vacuum. In general it obviously works, but you have poorer economy due to the vented vacuum. I have yet to see a distributor sell a correct power piston dust boot.

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8 hours ago, buick man said:

Wille:  Then the syringe plunger is obviously removed and it is only the syringe cylinder itself you are talking about ?

No. The plunger pushes out as the pedal is pressed. He has wanted me to take a video of me using mine. The worst part of his way is that occasionally the hose pops off the nipple. I HAVE used a vacuum pump and the pressure method with success before, as well as the pump with a friend method.

They will all work, and they all can cause problems at times. I don't like bleeding brakes.

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Leaving the plunger in gives a visual of not only fluid, but air in the system.  I first tried to use it as a vacuum bleeder with no success...nothing came out except air from around the bleeder threads.  I have a second one to suck brake fluid out of the container and add to the reservoir...eliminates the mess on 55's with power brake where the reservoir fill is under the steering column.

 I never worry about the order of bleeding.  My father did aircraft hydraulics and said there is no logical reason to bleed in any particular order.

Willie

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Any advice on shoe material? The only ones I can find are the cheap ones. I'm told they work fine, but is there any thing better I can reline them with? Here are the ones I bought for now. It's too bad the roadmaster shoes aren't the correct size for Century. There are plenty of options for Roadmaster and Super. It's a 12" x 2.25" shoe for Century but a 12" x 2.5" shoe for Roadmaster.

 

http://www.ebay.com/itm/271677964956?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

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3 hours ago, killy_4_u said:

Any advice on shoe material? The only ones I can find are the cheap ones. I'm told they work fine, but is there any thing better I can reline them with? Here are the ones I bought for now. It's too bad the roadmaster shoes aren't the correct size for Century. There are plenty of options for Roadmaster and Super. It's a 12" x 2.25" shoe for Century but a 12" x 2.5" shoe for Roadmaster.

 

http://www.ebay.com/itm/271677964956?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Shoe material?  All over the counter shoes are too hard and will not stop the car:  BRAKES

Willie

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killy…. try and find rivet type shoe material.  Then go and have the shoes arched to your drums at a good old well established brake company that does trucks and such.  Also buy a few and various type shop manuals.  Then try and practice the art of not comparing today's technology with yesterday's technology.  Yes it is tempting and an easy fall back.  The basic mantra in this the restoration crowd is not to recreate the wheel but to simply put the exiting wheel back in motion.  Cool ?

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I have found that the vacuum bleeders are a mixed blessing.  They do work as advertised most of the time, but they can be frustrating on some systems. I  have found that  many new cylinders (china made) have very sloppy threads on the bleeder valve and when opened they allow air to draw in around the threads instead of drawing the air out of the lines.  Check valves in the braking system increase this problem as they add resistance to the suction increasing the probability of air getting around the bleeder valve threads. I found that greasing the bleeder valve threads improves the operation of the vacuum bleeder.

 

I have built a pressure bleeder that is much more reliable on the old system with a screw cap on the master cylinder.  I take a scrap cap and tap the top for an airline quick disconnect and plug the vent hole in the cap.  I took and old canister oil filter assembly and added a flex line with an airline quick disconnect on the end of the line.  I tapped into the canister and installed a pressure gauge and schrader valve.  I fill the canister with brake fluid,  put the modified cap on the MC and hook up the flex line.  By applying about 2-4 PSi air, I can then go to each wheel cylinder and bleed the brakes very quickly.  Just put a rag around the modified cap when removing the system to catch the excess fluid in the cylinder.  

 

Bob Engle

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The old asbestos brake lining worked great, these new synthetics are too hard and take greater pedal effort and create more heat than the softer linings.  In the 50's 20,000 miles was great lining life.  People with a nervous brake pedal foot got about 10,000 miles.  Seek out a shops that has the softer linings to reline your shoes and you will be happy with the old systems.

 

Bob Engle

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