Smartin

57 Power Brakes still poor

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So I am still working on trying to improve the feel of the brakes on the Roadmaster.  Yes, the car is sold, but I am trying to help the new owner out with these brakes.  It acts like there is no/very little initial braking power.  There should be good pedal feel when using average braking pressure, but it really takes some stomp to get the car to slow down enough to make a turn.  I can lock the wheels up if I really try.  I am on the second mastery cylinder/booster combo with no change in feel.  Both have rebuild kits in them.  Dare I try to find a 3rd setup and rebuild that one?  These things don't grow on  trees.  The previous owner said he could never get the brakes to feel good, either.

 

One thing of note is that when the car isn't running, I can push the pedal about halfway down before it feels like a rock.  Shouldn't I have that "rock" feeling right at the top of the pedal travel?  This is assuming all vacuum has left the tank, and there is no power assist.

 

These parts are new:

Wheel cylinders

Flex hoses

All shoes

 

These parts have been rebuilt/repaired/replaced:

Drums turned

Master Cyl/booster rebuilt, then replaced with two separate units from another car and rebuilt, with no change in feel

 

Literally the only things that I have not touched are the hard brake lines and the brake pedal assembly.

 

I can feel the booster working when I have my foot on the pedal when I start the car. 

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Benefits of AACA Membership.

Are the shoes relined like old tank says to do, or over the counter units?

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Shoes are new, and I made sure they match the contour of the drums.  They are also the riveted style.  Springs and hardware are not new to me, but have been replaced.  If the brakes were dragging, I would be more concerned about worn out brake hardware, but I don't see any issues with it.

 

It really feels like a master cylinder issue...I have access to a free one, I just have to rebuild it.  I think this is going to be my next step. 

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The shoe friction material is semi-metallic?   Had semi-metallic on my 1960.  Terrible fade, braking was so-so, cracked from overheating.   I purchased organic friction material shoes for the front drums. Helped quite a bit with braking.   

Edited by avgwarhawk (see edit history)

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From personal experience with my '56 I can report:

I used over the counter new shoes.  Imported from China.

I sourced a spring kit from NAPA which was listed for a '63 Buick.  The new springs were visibly  thicker than the current ones on my 56, however they were all the same lengths. 

 

The results were as follows:

I immediately noticed stiffer pedal action. 

The initial use resulted in extreme panic as the car did not seem to want to stop with application of the system.

Subsequently ( I'd say within 100 miles with a lot of braking action) the brakes improved 100%  HOWEVER even after several thousand miles ( At least 2K+)  I still feel the resistance in the brake pedal.  I attribute that to the new springs.

 

When I apply the brakes it's as though there is a short pedal travel ( maybe a 1/4") where it does not feel like any braking action but then the brakes apply smoothly and effectively.  Without looking it up I believe the manual says the pedal should be 1 1/2" bottom space before the pedal hits the floor board.  This is roughly the toe section of my sneakers.  I was well within that spec.  Like you indicate,  locking the wheels is not a problem.  

 

I know you replaced a lot of parts.  Perhaps one of the hard metal brake lines is compromised internally?  Perhaps at some point one was bent at a bracket for access and crimped?  Or maybe one is the incorrect diameter?  

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1 hour ago, avgwarhawk said:

The shoe friction material is semi-metallic?   Had semi-metallic on my 1960.  Terrible fade, braking was so-so, cracked from overheating.   I purchased organic friction material shoes for the front drums. Helped quite a bit with braking.   

Look at the linings before more rebuilding on the hydraulic section!

Take some shoes to a rebuilder and specify aggressive linings that will stop 2+ tons of Buick.  Organic will fit the bill.  Then have them arced to fit the individual drums.  I had the same problem in 2007 and the replacement linings are still stopping after 70,000 miles with negligible  wear and only adjusted twice.

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Interesting.  I have a pair of organic Raybestos shoes on the shelf.  The ones I just put on the back are for sure semi-metallic.  Not sure about the fronts.  They don't appear to be semi-metallic.  I just have never heard of anyone around town here that does that kind of work.

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4 hours ago, Smartin said:

Interesting.  I have a pair of organic Raybestos shoes on the shelf.  The ones I just put on the back are for sure semi-metallic.  Not sure about the fronts.  They don't appear to be semi-metallic.  I just have never heard of anyone around town here that does that kind of work.

 

The  organic shoes I purchased are Raybestos.  I purchased from Rock Auto.  These shoes were arched quite well out of the box. I installed without any fanfare.  I can not say that for the semi-metallic that I removed.  Poor contact area.  Cracked from excessive heating.    The organic were a bit grabby but settled in quickly.   Overall I feel braking action is improved.   

 

My  only other thought is the power brake booster.  Is there any internal rod adjustments?  Is the booster slow to react?  

 

 

Edited by avgwarhawk (see edit history)
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After replacing the master 2x, I echo the sentiment about checking the shoes and springs, especially the fronts.  Weak springs can definitely be contributing to pedal feel, and drum/shoe issues can definitely contribute to poor braking.

 

In addition to checking the ID of the drums, I'd definitely try conditioning the cut surface to aid in the shoes seating.  Depending on the skill and care of the machinist, the surface may not be cut fine enough for proper seating.  In any case, it's always a good idea to scuff up the surface after it is machined before installing new shoes; this can make a huge difference.  Take some very heavy grit sandpaper and scuff in opposite direction that it was machined along the entire machined surface.  It should then seat pretty well after a driving and stopping a bit.

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Thanks for the suggestions guys.  I’ll order the front raybestos organics.  Will also check to make sure shoes are arc’ed with drums.  I’ll see if I can find new hardware.

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Front raybestos shoes ordered...and brake hardware also ordered.  Crossing fingers.

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Had the same problem.

Wrestled with it for years. Had the booster rebuilt by the guy in Florida and sent it back to him  (that was a whole nother can of worms). Still no joy. Changed linings. Better but still not good. 

Finally sent the shoes for new linings to an outfit in Texas recommended by Mike from Austin.

Put them on and the car stops on a dime, straight ahead with lite toe pressure, right out of the box.

Years of dicking around for no good reason............Bob

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On 2/7/2020 at 4:09 PM, Bhigdog said:

Years of dicking around for no good reason.

 

72 years for me, kind of fits me like a well worn flannel shirt.

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On 2/7/2020 at 3:09 PM, Bhigdog said:

Had the same problem.

Wrestled with it for years. Had the booster rebuilt by the guy in Florida and sent it back to him  (that was a whole nother can of worms). Still no joy. Changed linings. Better but still not good. 

Finally sent the shoes for new linings to an outfit in Texas recommended by Mike from Austin.

Put them on and the car stops on a dime, straight ahead with lite toe pressure, right out of the box.

Years of dicking around for no good reason............Bob

 

 Bob, care to mention the outfit in Tx?

 

  Thanks

  Ben

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2 hours ago, Ben Bruce aka First Born said:

 

 Bob, care to mention the outfit in Tx?

 

  Thanks

  Ben

 

Hi Ben. As the world's most disorganized person I lost the paper work from who did the shoes for me. The outfit was recommended to me by Mike M.,  forum name Buick5563. If you can ping him he should be able to help. Willy, Old Tank, likely can help you too with the name or getting in contact with Mike. Sorry I can't be of more help. If you do find them please let me know. I think I want to do my 55 Olds. ...............Bob

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3 hours ago, Ben Bruce aka First Born said:

 

 Bob, care to mention the outfit in Tx?

 

  Thanks

  Ben

San Antonio Brake and Clutch.  WEB

I might be able to find the specs on the lining material if needed...otherwise I just ask for aggressive linings that will stop 2 tons of Buick!

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what is your vacuum source?  engine or vacuum pump . a good vacuum source is necessary for proper  booster operation . 

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Full manifold vacuum.  Booster is working well.

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Just my opinions here... Adam in all practical probability it is not the brake shoes and it is not the master cylinder itself as it is just a hollow block as it essentially serves as a hollow metal reservoir ... but wit this system it is all about the rubber seals, metal ring positions, amount and type of lube used upon reassembly.  Also you may through no fault of your own have a crappy rebuild kit to begin with ( think type of materials used and the finished tolerances they are molded from )  or possibly you are creating something in how you are reassembling the components .... When you rebuilt the vacuum diaphragm did you apply any thing to the rubber comports that the rod slides through and/or how much did you use ? Did you apply anything to the walls of the plunger tank as shown in pic 7 ?   What type of plunger material are you using leather or plastic compound provided in the rebuild kit as shown in pic 3 ?   The bleeder line can leak internally new or old so take off and test it pic 1 & 2 .  If you did apply something to the either the leather or plastic plunger how much of it did you apply and did you make sue the internal ring spring was not walking out of the leather or plastic when you inserted it into the plunger drum ? One can easily reverse the reassembly of the satellite clip rings  pic 8 & 9. The cinch brass plug can be too loose or too tight when re-installed pic 6 If completed correctly and your reservoir vacuum tank and associated vacuum lines are all sealed and not leading, then if the car sits for ever you should still be able to get a hard pedal at about 1/4 of the way down and continue to do so even after multiple pumps.  If not then some area, item/component, lube  is either not installed right, overly lubed, reversed or is not sealing correctly or leaking or as stated you have a kit that has loosy goosy spec tolerances made of cheap component material.  

M.B. Rbld 2.JPG

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M.B. Rbld 20.JPG

M.B. Rbld 21.JPG

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Here are some more component photos to consider :  As for the master cylinder itself as stated above is a metal reservoir chamber but the plunger head rides and seals via multiple rubber and metal components all riding on the just the plunger rod itself as the head is metal not rubber and plunges into the reservoir as a mass of displacement to cause the brake fluid to seek an opposite dynamic in response to the metal plunger rod.  This then allows for greater displacement to occur with minimal counter force concentrated on the circumference to the small plunger shaft itself rather than conventional master cylinders that rely on the larger sealing areas needed and integrity of a cylinder wall of a rubber plunger/metal wall cylinder scenario.  With that said, the shaft however needs to have it's rubber components located correctly and the spec clearances of the replacement rubber components have to be tight and the material used of solid integrity.  If not this area of the master cylinder is going to give one problems on a rebuild pics 8 & 9.  Placement of the metal strainer spacer as shown at the end of the wooden handle as being removed has to be non corroded and placed and seated correctly into the master cylinder on rebuild  pic 6 & 9.  If the both the master and plunger cylinder are correctly reassembled, lube and rebuilt with solid close tolerance quality components, with correct toque sealing the you should have a solid pedal upon driving and almost instant brake response at about 1/4 deflection of the pedal.  If one wants to improve upon what is already a solid pedal feel, then the installation of metal braided DOT 4 flexible lines can be installed on both fronts and rear over axle line.  

 

Edit:  The metal braided lines will dramatically reduce the psi reflex rebound that rubber only lines experience upon braking.  In short rubber lines bulge out and this increases drop foot pedal travel where as metal braided teflon lines prevent this and contribute by reversing this rebound dynamic thereby assuring a more solid pedal and thereby reducing drop foot pedal travel.

 

 

M.B. Rbld 24.JPG

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M.B. Rbld 43.JPG

Edited by buick man (see edit history)
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Ok...lots to process there LOL

 

I’ve done a bunch of these without any adverse issues like I’m experiencing here now.  Oddly enough, I experienced the same pedal feel with the original one, the rebuilt original one, and the rebuilt one from the parts car.  And I know the one on the parts car was working on it before I pulled it off of there. 

 

All I have done with either of those vacuum cylinders and plungers is just clean and lube them.  I believe I also replaced the rubber vacuum line because it seemed a bit loose at the connections.  And I believe I used trans fluid on the plunger and wiped some all over the inside of the cylinder.

 

So my hesitation to believe that this stems from the master cylinder is what I explained above.  Literally no change in pedal feel from 3 different iterations of master/booster combo.

 

When I start the car with my foot on the pedal, I can feel the booster suck the pedal down...so I know it’s getting assist.

 

Its so frustrating, because I feel like I have been through every piece of this thing...and I’ve always been able to figure it out....except now.

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I do have an additional MC/booster that a local member brought over the other day.  The parts car isn't here anymore.

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Chris .... I just detailed and explained what a proper 57 Buick pedal should feel like ... what did you miss ? 

 

Adam ...  Yeah it is a lot to process and perhaps you were just lucking in the past.  Like I said it is either the parts original, cleaned and reused, or  new and funky spec or something your doing, missing or over looking.  Most likely the master cylinder and rod shaft interface.  It is all about the sealing around the shaft at the master cylinder.   But if you confidentially feel it has nothing to do with you or the components, go turn up the shoes into the drums up almost tight and see how your pedal feels ... if that cures pedal feel issues then it is most likely not your mc and while under vacuum the pedal rebounds properly as explained then it is something past the mc components and is either your brake lines themselves that although appear o.k. have an existing internal unseen failure problem.  By snugging up the shoes into the drum to a certain extent you can isolate the shoe drum interplay to determine if that is the problem.  🤒

 

Edit:  btw the photos shown above are from a tear down I did some years ago.  The entire brake system was working just fine like all the 57 Buicks I had before, just removed, disassembled, cleaned the parts up and reassembled so the photos depict what the parts look like.  Any cracking or dry parts which most likely won't occur unless the unit sat for years dry, then just clean up the parts and reinstall paying attention to how the shaft seals are doing their job.  Doubly inspect how the seals look upon contact along the shaft/piston.  Regarding the piston, make sure it is slightly just damp with ATF not soaked.  No need to butter up the inside of the tank.  Make sure the spring stays in position as you insert and pull back on the piston to check for binding or uneven retraction as you withdraw the piston and then pushing back in .... 

Edited by buick man (see edit history)

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