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Need HELP!! Brakes on '57 BelAir lock up #2856697
12/07/20 06:24 PM
12/07/20 06:24 PM
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Tri-Cities, Washington
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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!!!

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2856710
12/07/20 06:41 PM
12/07/20 06:41 PM
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Andrewh Offline
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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.

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: Andrewh] #2856713
12/07/20 06:51 PM
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Originally Posted by Andrewh
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?

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2856776
12/07/20 08:40 PM
12/07/20 08:40 PM
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North Dakota
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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.


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Re: Need HELP!! Brakes on '57 BelAir lock up [Re: 6PakBee] #2856785
12/07/20 08:53 PM
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Originally Posted by 6PakBee
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!!

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2856855
12/07/20 11:06 PM
12/07/20 11:06 PM
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Freeport IL USA
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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

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: poorboy] #2856896
12/08/20 01:30 AM
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Originally Posted by poorboy
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?

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2856897
12/08/20 01:45 AM
12/08/20 01:45 AM
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N.E. OHIO, USA
A12 Offline
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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?

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: A12] #2856961
12/08/20 10:25 AM
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Originally Posted by A12
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????

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2857060
12/08/20 01:36 PM
12/08/20 01:36 PM
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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.

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: second 70] #2857107
12/08/20 03:01 PM
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Originally Posted by second 70
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.

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2857121
12/08/20 03:16 PM
12/08/20 03:16 PM
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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?


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Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2857155
12/08/20 04:11 PM
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Originally Posted by VITC_GTX
Originally Posted by second 70
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.


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.

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: 6PakBee] #2857213
12/08/20 05:45 PM
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Originally Posted by 6PakBee
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?


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.

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: Andrewh] #2857215
12/08/20 05:48 PM
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Originally Posted by Andrewh
Originally Posted by VITC_GTX
Originally Posted by second 70
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.


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'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!!!

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2857220
12/08/20 05:55 PM
12/08/20 05:55 PM
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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.

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: topside] #2857253
12/08/20 06:58 PM
12/08/20 06:58 PM
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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.

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: Ramrod39] #2857263
12/08/20 07:14 PM
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Originally Posted by Ramrod39
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.

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: topside] #2857265
12/08/20 07:16 PM
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Originally Posted by topside
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.


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...

Re: Need HELP!! Brakes on '57 BelAir lock up [Re: VITC_GTX] #2857268
12/08/20 07:19 PM
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verify the pressure is the same is the first step.
prove that then you can dig further, otherwise you are just guessing.

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