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#507004 - 05/02/08 10:42 PM
Re: Brakes locking up on my 60 Electra
[Re: Pete O]
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JoelsBuicks
Member
Registered: 03/10/08
Posts: 23
Loc: OK
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On the single circuit drawing, what is the purpose of the "inlet valve?" I'm also confused on why I cannot pull the brake pedal up to its normal position when the locking condition occurs?
Thanks again for the help. I'm on the road and slow to respond so please be patient.
Joel
_________________________
Joel Wilson
BCA #43854
36 Limited
36 Roadmaster
37 Special
47 Sedanet
60 Electra
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#507488 - 05/05/08 08:34 AM
Re: Brakes locking up on my 60 Electra
[Re: JoelsBuicks]
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Pete O
Member
Registered: 09/28/04
Posts: 130
Loc: Long Island
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As Simplyconnected said, there is no actual connection between the push rod that leads back to the pedal and the piston in the master cylinder. The push rod just presses against the piston. This is why the push rod clearance is a critical adjustment after a master cylinder rebuild. If you pull up on the brake pedal and find it's already completely at the top of its travel, I'd suspect the push rod clearance. But if you find that the pedal is not at the top of its travel, I'd look elsewhere first.
You wrote that you had a thorough brake job including master cyclinder kit. Did it also include rebuilt wheel cylinders, new brake shoe springs, new hoses and a flush, refill and bleed of the whole system? Again, as Simplyconnected said, the pedal return is dependant upon the brake shoes completely retracting, and any binding due to weak springs, crud in the lines, etc. could be contribute to the problem.
_________________________
Pete
1951 Buick 56C
BCA 38880
1929 Ford 40A
1930 Ford 170B
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#507740 - 05/06/08 09:08 AM
Re: Brakes locking up on my 60 Electra
[Re: simplyconnected]
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JoelsBuicks
Member
Registered: 03/10/08
Posts: 23
Loc: OK
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First, thank you all very much for the input and discussion. This sticking problem was the reason I decided to do the brake job in the first place. I honed and polished all wheel cylinders and the master cylinder and all recieved new kits. The drums were all turned and the brake lines flushed with the new fluid. I did my best to keep things oil and water free. However, I did not replace any brake shoe springs.
To me, the mystery is why I cannot pull up the pedal when this locking occurs. Indeed there is no connection between the cylinder piston and the push rod and I don't see why I can't pull it up. Does this mean the rod is binding somewhere? And if so, why would relieving the pressure remedy this? Keep in mind that normal driving and braking is fine, it's just when I have to get on the brakes that this lockup occurs. Thanks again and I'm back in the saddle for a while now.
_________________________
Joel Wilson
BCA #43854
36 Limited
36 Roadmaster
37 Special
47 Sedanet
60 Electra
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#507776 - 05/06/08 11:53 AM
Re: Brakes locking up on my 60 Electra
[Re: brh]
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JoelsBuicks
Member
Registered: 03/10/08
Posts: 23
Loc: OK
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Good question. I bought the car last year with 57K miles on it. It had been stored in dry dark storage for 31 years. The previous owner inhereted the car but didn't drive it. I called him and asked him about the brakes sticking and he wasn't aware of the problem. He did a little work on the car to prepare it for sale. The work included a new water pump, battery, fresh gas, and new exhaust. He did tell me that he would not drive the car very far because he felt that it needed brake work and that a person could lose all brakes if something failed.
I noticed the problem on the second day that I had the car. It took a while to figure out to relieve the pressure to get it unstuck. The car seemed to be only braking on one or two wheels and so I quickly put the car on blocks and did the brake work.
The master cylinder had nearly a half-inch of sludge in the bottom and I removed and cleaned it all up with solvent followed by compressed air drying. I will go out on a limb here and say that the brake system looked original to me. That is, the wear on the shoes and the overall crudiness of the system was consistent with 57K miles. All but two wheel cylinder pistons were stuck with a whitish material resembling cement. I made a wooden dowel to hammer these loose. Of course, all of that was thoroughly cleaned before assembly.
After the brake job, I tested it by stepping hard on the brakes and the problem was still there as if I had done nothing. Except for this, the car brakes evenly just as I'd expect.
I did not dismantle any of the power booster portion of the brakes.
I hope this helps, thanks again!
_________________________
Joel Wilson
BCA #43854
36 Limited
36 Roadmaster
37 Special
47 Sedanet
60 Electra
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#507817 - 05/06/08 03:29 PM
Re: Brakes locking up on my 60 Electra
[Re: brh]
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JoelsBuicks
Member
Registered: 03/10/08
Posts: 23
Loc: OK
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I did hone the wheel cylinders and the master cylinder. They all appeared to be in excellent condition with only minor staining. I used a standard brake hone with brake fluid as the honing fluid. I followed this honing with a polishing step using 800 grit sand paper wrapped about 1-1/2 times around the brake hone. They all looked great. The pistons looked to be some sort of alloy and I think you are right about the whiteish stuff being a salt derived from the corrosion of the pistons - perhaps something like magnesium oxide. I did check the fit of the wheel pistons after cleaning them but I don't recall checking the fit of the master cylinder piston - which did not have any of the white stuff.
One thing to add, on a couple occaisions, I could release the brake pedal by striking it soundly with my foot. This technique no longer is effective in getting it to release. Another thing I noticed was that the brake light switch must have been change because the wire connectors looked to be some aftermarket job.
I'm not smart enough to be easily insulted, learning stuff the hard way seems to be my mode of operation. So please, keep the questions coming and thank you for your help.
_________________________
Joel Wilson
BCA #43854
36 Limited
36 Roadmaster
37 Special
47 Sedanet
60 Electra
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#507829 - 05/06/08 03:45 PM
Re: Brakes locking up on my 60 Electra
[Re: JoelsBuicks]
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JoelsBuicks
Member
Registered: 03/10/08
Posts: 23
Loc: OK
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Here's something else I thought of. When the brakes are locked and the pedal is down, I try very hard to pull the pedal up. It feels like I am pulling against a very stiff spring. That is, I'm able to pull it up about a 1/2" or less against an opposing force pulling it back down.
_________________________
Joel Wilson
BCA #43854
36 Limited
36 Roadmaster
37 Special
47 Sedanet
60 Electra
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