Need HELP!! Brakes on '57 BelAir lock up

I really need help with my brakes on my ’57 BelAir. This has been my daily driver for the past three years and since I’ve had it the brakes have been “iffy” (soft). Also, the back-left wheel locked up very easily. The car is original with factory power brakes. This summer I had the master cylinder (single pot) and vacuum assist rebuild professionally. At that time I replaced the brake shoes, shoe return springs, drums, rubber hoses, wheel cylinders and I adjusted the brakes per service manual (just dragging when you spin the drum). When I finished the same back-left brake locks up REALLY EASY now (even worse due to new pads/drums). Just touching the brake pedal at 20 mph locks up the wheel. I backed off the adjustment on the back-left brake, still happens. I switch drums with the other side, still happens. Checked the axle and bearing on that corner and it seems fine There are no fluid leaks and I cleaned everything multiple times with brake cleaner.

I’ve been fighting this for months and I have no idea where to go now, please help!!!

so you replaced everything but the hard lines and distribution blocks.
I would probably get a pressure tester and start at the rear wheel cylinders and see what the pressure difference is per side. start working my way back to the master.

Exactly.

I thought about placing four gauges, one on each corner, to test pressure but I just didn't understand how one could be that far off from the others when there is only one line feeding them all (and it's a stock line). I'll have to put that on the list of things to check. Thanks!

Any other suggestions/thoughts?

Hmm. Since you replaced everything and the problem is still there, the problem wasn't caused by what you replaced. Is your parking brake adjusted too tight? Sometimes that will do it.

Good thought! I have checked that as well. The "crossbar" between the actuating lever and the front shoe is loose (there is a gap between it and the shoe). I've crossed that off the list.

Please keep the ideas coming. I'm at my wits end and I know someone out there will come up with the right answer!!

Are the brake shoes clean? Doesn't take much axle grease from a leaking seal, or a much brake fluid from a leaking wheel cylinder to cause a wheel to lock up. I understand that you have replaced the wheel cylinder, but these days, something being new does not mean its good.

Another thought is what condition are both of the backing plates are in. The brake shoes rest against the backing plate on 3 contact pads for each shoe. Those pads need to be perfectly flat. If there is a dip in any of them, the shoe will sit in the dip and could easily cause the wheel to lock up. It wouldn't return as far as the other side of the axle, and therefore makes contact with the drum faster, or it could be on the other side and may be keeping the shoe away from fully contacting the drum and it may not be functioning at full capacity, or may not be functioning at all. If there is a dip in any of the 6 pads on either side, you can weld them up, and grind them flat again. If you find any wear, check both the front backing plates as well. Gene

Good thoughts.

Everything was cleaned mulitple times and I've found no leaks.

I've heard about the pads on the backing plates. I checked both sides on the back and I couldn't see any difference between the two but I'm not sure how much wear on the tabs would make a difference. If I can't see a difference could that still be the issue or do they have to worn to point where you can tell by looking?

This is a far reach but I always thought that some brake shoe systems had specific "leading and trailing" brake shoes and if not in the correct position they could cause lockup or poor braking?

You're exactly right! I've checked and the shoes are on correctly (smaller shoe is the leading shoe).

Now I think you guys see my confusion/frustration. What can be causing this????

Any time I had only one brake that would lock it was because there was some type of blockage going to the opposite brake causing too much fluid going to what is the good brake that locks up. It sounds like the line from master cylinder to rear is fine and it's probably the block or line to the right rear brake.

Good thought. It generally is the weak brake that is the problem but I don't think so in this case.

I've removed the "tees" from the system to ensure they were clean. I also blew out the metal lines prior to putting everything back together. Remember, this is a single pot master cylinder so it only has one line that feeds all four corners.

It sounds like you've exhausted all the 'usual suspects'. All I can think of is that something was assembled incorrectly on that wheel and when you went back together, you duplicated the original incorrect assembly. Have you compared the other side to the problem child?

but the fact it is a single line says that it has to be something in that line.
rear's only have that single rubber to the hard line to the t.
so if you get different pressure it is a line.
if both are the same pressure, it is something on that side mechanical.

I have compared, removed and inspected all parts and reassembled a couple of times. It did this prior to me working on the brakes as well so I don't believe it's something that I have done. I just exacerbated the problem when I put a new components in.

I've verified all the lines and tees were clean and not crimped. I was thinking that since three of the four brakes are working normally that it's probably not an increased pressure issue but mechanical. I'm just not sure what's left to check!!!

If fluid is equal (volume & pressure) LR & RR, I'm thinking it's in the brakes themselves:
Wheel cylinder binding/not releasing
Springs or mounting not allowing shoes to back off drums.
Could even be the order in which the springs are installed, had that happen once.
I have a '57 Chevy FSM from when I had one in the '70s, if that helps.

Tip of the hat for someone dailying a Tri-five, BTW.
But to be honest I'd want to upgrade the braking system.

I once replaced all the components in a brake system and had a rear that kept locking up. Took me a while but I finally figured out that the rear wheel cylinders I bought were different bore diameters.

I know I sound like a broken record but I did check that as well. I checked the AC Delco part numbers I ordered against Tri-Five experts/distributors. Everything is in stock configuration.

Thanks, the car is a blast to drive. The only problem with it is I have to talk to everyone at the gas station and stop lights.

I should have updated the braking system but now that everything is new I hate to do it all over again...

verify the pressure is the same is the first step.
prove that then you can dig further, otherwise you are just guessing.

This is only a wild guess, but have you considered that the other side may not be applying as it should, something out of place in the assembly, and the locking side is trying to do all the work, and the front is working normally?

Just a shot in the dark ... years ago had something similar, but on the front, that turned out to be a collapsed rubber hose, internally, stopping the flow to one wheel, and making the other do all the work.

Have you tried tightening the adjustment on the problem wheel? Too loose can allow the shoes to overtravel and jam against the drum rather then apply smoothly.

Are the drums the correct diameter? An oversized drum has the same effect as loose adjustment.

You will have eliminated a lot of questions by doing so and can then move onto the assemblies themselves

Another thought crossed my mind, actually 3:
1. Are you 100 % sure the brake cables between the backing plates and main cable are free and not sticky
2. Possibly try swapping springs side to side. A long shot, but if the one side has weaker springs it will apply sooner.
3. One could try a thin layer of contact cement and thin sandpaper on the inside of the drum. Spay a very light coat of lacquer paint or machinists dye on the shoes, install the drum and see if there is a pattern difference side to side.

I believe you said you swapped the shoes so that would eliminate the friction compound.
Keep us posted

With the shoes off, run your finger across each pad. If you can feel anything except a smooth flat surface, it could be your problem. Sometimes it really doesn't take much surface difference at all to cause a problem, but I have also had the pads feel and look like they have Grand Cannon grooves that don't seem to make much difference.

Does the car have self adjusting brakes? We had a customer once that lived on a one way street, they backed out of their driveway in the same direction every time they went someplace. The self adjuster on one side would tighten the brakes more then the other side, and the first few stops would cause one wheel to lock up. After a few brake applications, it was good until the next time they left home. It just happened the boss was driving by one day when they backed out of their driveway. We removed the self adjusting cable for a week, and the problem went away. After we reinstalled the adjusting cable, the problem came back. I think the boss suggested they change how they back out of the driveway. Anyway, just another possibility, since your looking for strange stuff. Gene

Are the wheel cylinders the same on the rear, left and right? If so try switching wheel cylinders. If you still have the problem at the same wheel (left rear I think you said) then back the shoe adjustment off and see if you can get the right side to lock with it adjusted correctly? If not the you would have a line restriction from the single flex line distribution block on the axle housing.

I’ll try and answer all questions.

All rubber hoses (two up front, one in the rear) were replaced with new.

I did tighten the adjuster on the problem wheel, then I loosened it significantly and about 20 different spots in between. No joy.

The drums are correct for the vehicle and all are matching. I’ve also switched drums around and the same wheel locks up.

The e-brake assembly was loose but I will have to completely disconnect and remove the e-brake lever from inside the drum to rule it 100% out.

I did swap brake shoe return springs from side to side, didn’t work.

The shoes seem to be wearing smooth and there are no self-adjusters on this car.

Wheel cylinders are different for each corner of the car.

Try bleeding each wheel cylinder especially opposite the problem corner by removing one drum, pumping the brake pedal until the wheel cylinder pistons are out as far as possible (without falling out of course) then have someone hold the brake pedal down on the last pump, open the wheel cylinder bleeder, push the wheel cylinder pistons back in to purge any air out of the entire wheel cylinder. You might only need to do that with the wheel cylinder opposite the locking brake drum,........hopefully.

Starting to seem to me that the locking drum is actually free of air in the line and taking all of the master cylinder pressure and working correctly. While the other side still has some air in the system and just spongy??? Just throwing stuff out there to see what sticks.......besides the one brake drum Sorry not funny, apologize good luck

Mike

There is the old, tried and true method....vice grip one brake line shut. LOL. Sorry..that was the old 'fix' when we had a bad wheel cylinder back when I was in high-school.

Trust me, that has crossed my mind!!!

OK....so I'm not the only one that got creative in their youth when money was tight!

I had a similar issue on my 49 International truck. I'd hit the brakes, and the truck would turn left. I tried adjusting the brakes to no effect. As these brakes were old drums, and many of the parts were unobtanium, I put a disc brake kit in. Couldn't get the front to bleed. Finally out of frustration I pumped the crap out of the brake pedal. Found a tiny rust hole in the hard line. Not enough to show a leak normally, but enough to not allow the right brake to apply. Something to look for...

This is going to be difficult to explain, but this has cured a similar issue for me. On the top and bottom of the shoe material where the material meets the shoe itself on the upper and lower edges is it 90 degrees or beveled? I had to bevel some shoes before because they were really grabby. I smoothed the radius out because that sharp edge would grab and cock the shoes. Be careful as they may be asbestos.

But the bore on the fronts are the same and the bore on the rears are the same? You don't have wheel cylinders with different bore sizes on the same axle?

If you do not want to do the above

Did you move the drums with the shoes ???

One could also move the backing plates side to side ( except for the ebrake cables being hooked up)
.
You appear to have done everything but the pressure test and the backing plate swap. So I might just consider swapping the entire assemblies side to side.

A long shot but make sure the RE bushings , spring mounts U bolts etc. are all in good consition. I had one several years back that had a brake pull to the right. It had been to several shops and the customer wanted disc brakes. When the car came in the front cross-member was rotted 3/4 of the way around on the right side. I had him drive 60 miles to see it for himself. It was baltantly obvious yet 4 or 5 shops did not see it. You might need someone else to take a look at it.

"Just touching the brake pedal at 20 mph locks up the wheel." I call that grabbing more so than locking. When that happens, it's almost always the self energizing characteristic of drum brakes malfunctioning. One way to know is if it only happens going forward. If it doesn't grab in reverse, it is the a self energizing malfunction. If the anchor pin is mispositioned rearward, or especially if it is low due to a bent backing plate, or a junk chinese repop backing plate, it will cause grabbing. Or if the anchor pin is worn, allowing the top of the front shoe to retract too much. I would try a different backing plate and/or anchor pin. Also, grinding the top of the lining of the front shoe to a bevel could help, but it is a crutch, not fixing the cause. Good luck, Joel

Brake systems of that era can be different than later stuff, I daily drive a 51 Plymouth so I understand.

I also understand the hacks prior owners can inflict on old cars. You say the brakes have always bee iffy and the one wheel has always locked up.

You say that you've pretty much replaced everything, except hard lines.

I know nothing about the braking system on a 57 Chevy so I started googling. Lots of disc brake swap kits came up, damn near zero "how to rebuild the stock rear drum" info though.

The problem I see is how do you know it's put together correctly? If you put it together the way it came apart you may have just reinstalled the problem only with new parts.

Here's a shot of the rear brakes from trifive.com for reference. Key thing to remember that the parts are installed in reference to the front of the car, not your left or right. For example, the ebrake lever will be on the rear of the assembly which means on one side it will be on your right, but on the other it'll be on your left. All parts will be like that. Sorry to be so basic but that will sometimes bite even the best of us.

Exactly. The front wheel cylinders are larger bores than the rears but each axle has identical size bores.

Good ideas. I have not moved the backing plate or drum w/shoes to another wheel. I'll try that, and the pressure test.

I have checked the spring mounts, etc, decent shape. I have had a couple of friends to bebuild cars look at it and they are stumped too.

Great idea, I've never tried it in reverse. I'll go out and do that.

I believe the shoes were beveled from the factory but I'll have to check and make sure.

Not a problem!!!! Right now I need to get back to basics!! I'll check my work.

I want to thank all of you for the good ideas and help.

I have some homework to do:

Pressure test
Test brakes in reverse
Check condition of backing plates (pads)
Swap backing plates and shoes to another wheel
Check spring mounts/u-bolts
Verifiy that e-brake is properly adjusted

I'll go out and try these over the next few weeks (it's busy around here) and report back.

Thank again!

On the pressure test, it would be nice if you could do both rear wheels at the same time. They sell adapters that replace the bleeder screws. Have a helper depress the pedal as you record the readings on both sides. I would encourage doing so while appling and holding various pressures.

When swapping backing plates shoes etc, doe the drums as well.

On the e-brake MAKE SURE BOTH cables move freely

One last thought, check the run out on the axle flanges to make sure they not bent.
Good luck and keep us posted

I finally got enough energy to go out and battle the brakes in the '57 again (I've been working this for a year now and I'm getting tired of it). So here's what I did and what I discovered:

I completely removed the e-brake from the rear drums
I filled the very small groves in the three pads on the backing plates with mig welder and ground them smooth
I verified everything is put together correctly
There is no axle shaft run-out
Rear springs/u-bolts/shackles in good shape

No big change after this work and when I get back from the test drive the rear brake drums (especially the left one) are very hot but the front drums are just warm.

Now, I also did something else. I put a brake valve inline to reduce pressure to the rear brakes. When I start to close it the rear brake will not lock up as easy but the pedal starts getting pretty hard. So I put a pair of vice grips on the rear rubber brake line to remove both rear brakes from the equation. When I did that the brake pedal got VERY HARD with minimal travel and it took 30 yards to slow to stop from 25 mph. It was take me 1/4 mile to stop on the highway.

Am I fighting the wrong problem? I wondering if both front brakes are doing enough? Again, everything there is new as well...

I'm wondering if the master cylinder is plumbed correctly.

Does this have a modern, dual-circuit master cylinder or the original single outlet??

If it's a dual circuit, it almost sounds like you have the rear brakes plumbed to the front circuit, and the front brakes plumbed to the rear circuit.

This would cause the issues you're having as the front circuit has a residual pressure valve built-in that not only holds 3lbs of pressure in the line, but activates a split second AFTER the rear.

If you have the rears hooked up to the front circuit, this will cause them to both drag, but activate at the wrong time as well.

Doesn't sound as though you're fronts are doing much and they typically doe 80% or so of the braking.

I'll repeat one more time PRESSURE TEST
1st. at the master preferably, Dual master? buy two gauges, you'll need them at the wheels as well
2nd. At the front
3rd. At the rear
The numbers will confirm or eliminate the hydraulics, air, leverage ratios etc.
Not trying to be a jerk but,

Or continue to chase your tail

I know it was stated that front and rear cylinders are different, could they be swapped front to rear? I imagine the front should have a larger bore.

One would think so but not necessarily, shoe sizes, contact area, and a buttload of other things can come into play.

All origninal single pot master cylinder with one line going to all four corners.

Pressure test is on my list of to-dos I just haven't gotten the equipment (gauges/adapters) yet. I was trying everything else first. In theory it shouldn't be a pressure issue since it has one line but I've seemed to have exhausted most all other options.

The front and rear wheel cylinders cannot be swapped. They are completely different animals (wont' physically fit).

I went back to your original post and read it again and this jumped out at me:



Seems up to that point you only had one issue with the left rear brake locking up. Now you seem to have issues front and rear at all four corners. Have you discussed the issues you have now with the "professional re-builder" and asked what they think might be the issue? Have you found one of the hundreds of '55, '56 and '57 Chevy websites and Facebook pages that had to have had this issue in the past 56 years? To me the "professional re-builder" created something that was before the rebuild a single wheel lock up issue into what seems to be a nightmare or NO BRAKES! and a situation that could hurt you, someone else and your '57 BelAir. If you haven't gone back to the re-builder I would throw everything out the window and (re-) start there. If they are truly professional brake people you would hope they can help with a solution? Can they take a look at the situation or are they just a component shop or not nearby? Just thinking and typing on the keyboard.

Mike

Good thoughts.

The more I think about it the more I believe the car was this way since the beginning (at lease since I've had it). I believe there is a chance that the rear locks up so quickly because the fronts may not be doing their job well enough.

Karps Braks Service out of California did the work on the master cylinder. From what I understand they come highly recommended in the Tri-Five world. I haven't spoken with them about this yet as I struggled to see how a single pot MC could cause the issue (but I've been wrong before).

I would contact them and send them the link to this thread and they can see all of the issues you have been dealing with since the rebuild.

http://www.karpspb.com/

Mike

Having chased many a brake problem to resolution on many different vehicles I always start with an overall underside inspection, bushings, lines, hoses, frame etc. If all appears well,
# 1 Pressure check at master
#2 Pressure Check at both rear cylinders
#3 Pressure check at both fronts.|

In your case with a single reservoir master all numbers should be the same. If not find out why

Next step is linings, drums. cylinder diameter's etc.
You mentioned Power brakes, some MFR's change MC as well as wheel cylinder piston sizes to compensate for power vs non power.
keep us posted

I must've missed the part where it said the car has power brakes.

Here's something to look into.... it might be related.

A few years back, I had a '74 AMC Hornet with Power Brakes. A shotgun mechanic had been at it for the old lady owner, so many thing were done incorrectly or on the cheap. One issue I had with it from Day 1, and took me MONTHS to figure out was this: the brake pedal was mush for about half it's travel, and would accomplish diddly squat. But as soon as you'd hit that halfway point, the pedal would get a little stiffer, but you now had ALL THE BRAKES. Usually front right would lockup first. The car was virtually undriveable like that.

Anyway, after rebuilding all four corners, changing rubber and hard lines.... it still did it. So, that only left two pieces of the puzzle. A new-looking master, and the booster. I wrote off the master since it looked new! Well, the instant I removed the master, I'd found the problem. The pushrod from the power booster came out with the master!! Whoever did the master last, didn't know the difference between a power or manual master and had left the manual style pushrod locking clip in the master. This caused the pushrod to jam inside the master, not sit inside the cup in the booster like it's supposed to!

Well, after fixing that, the car had perfect brakes.

If that's possible to do on your '57, I'd suggest checking that out.