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Bleeding Brakes - 55 Special


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I had a thought, which is sometimes dangerous.  If I am using a vacuum pump to bleed my wheel cylinders do I have to have the shoes and drums mounted?  Seems like it would be more convenient to bleed before everything else is in place.  Since the brake pedal won't be used in the bleeding process, there shouldn't be any pressure against the wheel cylinder pistons to force them out of the cylinder.  Am I missing anything in my thinking here?

 

Mark

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2 hours ago, M1842 said:

Thanks, Old Tank!  I will post my experience.  I wonder if it is due to the master cylinder being essentially at the same level as the wheel cylinders?

 

If the Buick is lifted in the air the axles drop putting the wheel cylinders below the master cylinder.  I have been able to gravity bleed my 54 and 60.  I do however use a vacuum brake bleeder without issue.   

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3 hours ago, avgwarhawk said:

 

If the Buick is lifted in the air the axles drop putting the wheel cylinders below the master cylinder.  I have been able to gravity bleed my 54 and 60.  I do however use a vacuum brake bleeder without issue.   

"Lifted in the air"...maybe that is where I went wrong.  I drive the car over my service pit and stand at each wheel.  I gave away my Mityvac before I destroyed it with a hammer.  But I have developed a method that is just as easy and no spills to attack painted parts.  Write your request for this info on a $50 bill.:D

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1 hour ago, FireballV8 said:

Hi Guys

I saw this bleeder system Gunson Eezi Bleed, where it pressurizes the brake cylinder reservoir and forces the fluid out. Not sure how this would work on our Buicks either.

 

Any thoughts?

 

Thanks

Steve

Just find a way to seal at the filler.

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21 hours ago, avgwarhawk said:

I have been able to gravity bleed my 54 and 60.

 

When I replaced the booster and master cylinder on my '60 I gravity bled the brakes by oversight, worked pretty good.

 

I flush them with a hand vacuum.

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The secret to Mighty-Vac success is to seal the bleeder screws so air does not get sucked in. I use (horror, GASP, HORROR, the world will end.....) PTFE tape! Just wrap at the "air" end, one wrap, leaving the first few threads next to the bleed hole IN THE wheel cylinder clear of tape. That way none of the shards of PTFE tape will make their way into the wheel cylinder/brake system, where, yes, things can go wrong.....  Tape on threads, vacuum at end of bleeder, where are the tape shards going? Yes, into the Mighty-Vac or other vacuum source.

 

Been using a Mighty-Vac to bleed brakes on all sorts of cars for 35 years. Everytime I get the "this isn't working right" feeling, I put tape on the bleed screw (see, I try it dry first!) and all is well.

 

YMMV

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  • 2 weeks later...

Grumble grumble.  I installed the new wheel cylinder and went to top off the master cylinder and the filler plug won't move.  I had it off last year to check the fluid level and reinstalled.  My socket just wants to round off the square plug.  Is it worth while to get some pipe plug sockets to improve my purchase on the head of the cap??

 

Thanks,

 

Mark

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Square plug means 4 sides. 4 sides does not work with 6 or 12 point sockets. Those are made for 6 or 12 sided fasteners.

 

You need 4 point or 8 point socket. 8 points are available at most auto parts or Sears stores.😉

 

Or the correct size open end wrench/adjustable wrench.

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I got my set of 8pt sockets today and with an 18" breaker bar, the filler plug started unscrewing.  I couldn't get a good angle on the square head to use adjustable wrenches.  The 8 pt 3/4" socket did the job!  Thanks for the tip.

 

Mark

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I thought I was finally in the clear till I hooked up my vacuum pump to the bleeder valve and started pumping.  First I tried building up vacuum and then opening the bleeder valve.  Then I tried opening the valve and pumping for quite awhile.  Neither method produced any brake fluid in the collection jar.  I am starting to think I have a internal blockage in the right rear brake line.  I have done this before on a 51 Chevy and not had this problem.

 

I bought a set of 4 wheel cylinders off eBay a year ago and I am starting to think that was a mistake.  The RR cylinder has a 10mm bleeder valve and the LR has a 3/8' bleeder.  I am also having problems reinstalling the parking brake strut, it is like there is not enough space between the bottom of the wheel cylinder and the axle. The cylinders are made in China.

 

 

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It is not unusual to see a set of wheel cylinders come with different sized - metric/imperial bleeder valves, so I wouldn't be too stressed about that.

 

Re the park brake strut, it is a tight fit but it should all fit ... there is usually quite a bit if wiggly around when putting everything together and a wish for a third hand!

The strut has the bend or cutaway that kinda sits around the wheel cylinder.

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The secret to Mighty-Vac success is to seal the bleeder screws so air does not get sucked in.

 

My solution was to buy a new bleeder screw for the wheel cylinders.......take the old one and drill a hole thru the end so you can screw it in and seat it, then attach the vacuum hose, no leaking...BUT when you feel

a wheel is bled, you must remove the one with the drilled thru hold and install a good bleeder....   of course this gives you a chance to put some anti-seize or grease on the threads so it will not rust in place.

My vacuum pump gathers dust because I made a one man bleeder....... glass pickle jar with two copper tubes soldered in the lid.    Attach a section of hose to one that reaches the bottom of the jar.

Then another section from that same tube will go the  wheel bleeder.   I usually put a little new brake fluid in the jar to start.   With this setup it doesn't matter if you get a little suck back because the hose inside the jar

will always be in fluid and no air can get sucked back into the line.

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2 hours ago, old-tank said:

Did you rebuild or replace the master cylinder? 

Tank,

 

I have not yet rebuilt/replaced the master cylinder.  It seemed to be working without any leaking.  though I am rethinking my decision to not mess with it.  On my 51 Chevy, I replaced everything except the brake pedal and the MightyVac started pulling fluid through the system to the wheel cylinders right away.   I was somewhat concerned when I disconnected the brake line there was no trace of fluid at the connection or in the cylinder.

 

Mark

 

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7 hours ago, 56 Buick said:

It is not unusual to see a set of wheel cylinders come with different sized - metric/imperial bleeder valves, so I wouldn't be too stressed about that.

 

Re the park brake strut, it is a tight fit but it should all fit ... there is usually quite a bit if wiggly around when putting everything together and a wish for a third hand!

The strut has the bend or cutaway that kinda sits around the wheel cylinder.

 

I ended up tapping the strut in with a rubber hammer.  Seems like there are a dozen ways (that look the same) to put the brakes together but only one where everything works!  :)

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On 10/11/2019 at 1:15 PM, Frank DuVal said:

The secret to Mighty-Vac success is to seal the bleeder screws so air does not get sucked in. I use (horror, GASP, HORROR, the world will end.....) PTFE tape! Just wrap at the "air" end, one wrap, leaving the first few threads next to the bleed hole IN THE wheel cylinder clear of tape. That way none of the shards of PTFE tape will make their way into the wheel cylinder/brake system, where, yes, things can go wrong.....  Tape on threads, vacuum at end of bleeder, where are the tape shards going? Yes, into the Mighty-Vac or other vacuum source.

 

Been using a Mighty-Vac to bleed brakes on all sorts of cars for 35 years. Everytime I get the "this isn't working right" feeling, I put tape on the bleed screw (see, I try it dry first!) and all is well.

 

YMMV

 

Going to look for my PTFE tape, it's on the work bench..... somewhere.

Edited by M1842
Correct spelling (see edit history)
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OK, I taped the threads on the bleeder valve and it certainly tightened up the vacuum.  I can build up 8 PSI but nothing comes out the hose, the hose "pops" when I disconnect it.  I think I will go ahead and disconnect the pipe and pressure test that.  Is it possible the bleeder valve is made incorrectly?  I try and test that too.

 

Mark

Edited by M1842
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31 minutes ago, M1842 said:

  Is it possible the bleeder valve is made incorrectly?  

 

Mark

 

Probably not as it is not an overly engineered product.  I recommend  the pressure bleeder be put away and the trusted right foot method be employed.  

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5 minutes ago, avgwarhawk said:

 

Probably not as it is not an overly engineered product.  I recommend  the pressure bleeder be put away and the trusted right foot method be employed.  

yes, just checked the valve, no problem there.

 

 

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These cars come from the factory with residual pressure valves installed since the master cylinder is generally the lowest point in the system. It might be enough to cause a restriction. Check it with your foot to confirm its not a clogged brake line.

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  • 2 weeks later...
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On ‎10‎/‎10‎/‎2019 at 11:59 PM, Bill Stoneberg said:

I have used a pressure bleeder on my old Buicks for a while and it works well ONCE you find the right adapter so seal the top.

 

I use my wife to step on the brake pedal when I bleed brakes.

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I have been redirected to doing inside tasks by SWMBO so have not been able to follow through on all the helpful suggestions on the bleed process.  I did buy a new master cylinder that is still sitting in its box.  It's tempting to go ahead and replace the brake lines as they appear to be original or if replaced it was done several decades ago.

 

Merry Christmas!

 

Mark

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