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Power Brake problem on '62 Le Sabre


Guest COMPACTBC

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Guest COMPACTBC

90% of the brake problem has been SOLVED, see my 10/8 reply at the end of this thread for what I did to make the brakes work better.

I just put new brake shoes on the front of my son's '62 Le Sabre and now the brake pedal is very hard and the brakes are terrible. Before replacing the front shoes the brakes were a lot better. When I reinspected them, the left front was not working at all because the wheel cylinder rods had slipped in behind the brake shoes where they are supposed fit and when I put them back where they are supposed to go and tested the action before putting the brake drum back on, the front half of the wheel cylinder did not move very much but the back half seemed to move normally. Any ideas why the brakes are worse now that they have new shoes??? confused.gif 10/1/02 STILL WOULD LIKE SOME MORE IDEAS ON WHAT THE PROBLEM MIGHT BE.

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Either you put something back wrong or a strange thing happened with the wheel cylinder. I replaced the rear shoes

on my 73 and ended up having to get a new wheel cylinder and bleed the system. The old one did not leak brake fluid - strange.

I would re-inspect again to make sure you have all the hardware back correctly - if that does not work - replace the wheel

cylinders - if that does not work, I give up.

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A hard pedal would indicate a frozen wheel cylinder. Had one freeze on the Toronado several years back, and what it did was finally break loose and then wouldn't retract so the LF brake locked. And early drum brake Toro are aggravating to change out front wheel cylinders tongue.gifmad.gif as you have to take the upper ball joint loose to remove the brake hose.

Sometimes brake linings are made of different materials than original and that may be part of the hard pedal feel.

On a car this old, I'm inclined to replace all the brake hydraulics just for safety. I've also put my old cars on a biannual brake fluid flush and I don't have near the brake problems I used to have with them. My Pontiac bud and I take a day every fall (coming up this Friday actually) and flush half our combined fleet of 8 cars. Up this year? Toro, Regency, a 64 Grand Prix and a newly acquired 66 Bonneville Brougham cool.gif .

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Guest 53and61

I have all new wheel cylinders, new linings, and rebuilt master cylinder/booster on my '61 Invicta. The pedal is hard and braking is terrible. Yesterday I had a mechaninc who has specialized in brakes for 40 years look at the linings. He claims that they were probably cut from rolls of material intended for non-automotive use. He is certain that the bad linings are the cause of the poor braking and thinks that asbestos linings or at least a better substitute would cure the problem. He said that good lining material for old drum brakes has become very difficult to find. Anyone know where one can get shoes with linings that are both legal and work well? Or how about just work well? The engine doesn't run right and the brakes don't work right -- so the car won't go or stop. Other than that, it's fine.

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I had the shoes installed at a local shop and did not buy them myself. All 8 linings are the same dark grey color and are bonded to the shoes without rivets. There is writing on the edges of the linings but no manufacturer's name that I can see.

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Two quick thoughts - I'm assuming you have all the correct springs and holders assembled properly onto the backing plate:

- Is the larger brake shoe mounted toward the rear side of the car on the backing plate, smaller brake shoe in front - consistent on all 4 wheels?

- I agree with Rocket Raider - a hard pedal is usually a sign of a hung wheel cylinder or brakes that are overadjusted too tight - too much drag on the drum. How old are the wheel clyinders? Can you look inside to see if they are corroded - maybe you can clean up with a few passes of a cylinder hone. My thought here is if you overextended the piston past its normal operational travel when the rods slipped off the shoes, the piston may have picked up some sludge, gum, dirt or debris, pulled it back into the cylinder when you reseated the push rod. This could cause some binding on one side of the wheel cylinder, as well as eventually causing the seal to fail. As I recall, you said you saw one side of the piston move more than the other.

Lastly (okay, 3 suggestions) if you have an open vent brake system I would reccommend flushing it every few years as they are notoroius for absorbing moisture.

Just some ideas - hope it helps and good luck.

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Guest COMPACTBC

Hi KAD36, I like your diagnosis. I have no idea how old the wheel cylinders are, and the brake fluid does look rusty. I just couldn't understand why after I put on the new shoes (yes, the large lining shoes are on the back side)that the brakes are worse that they were with the old worn out lining. With the hard pedal and no ability to skid the wheels at all, I was wondering if the power brake unit is also faulty, but why would that happen all of a sudden when I changed the lining? confused.gif

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I don't think your power brake unit is faulty - the brake linings were changed and the rods came off the cylinders, and if you hit the brakes while the rods were off the shoes, it is likely you overtravelled the wheel cylinder piston, so I would advise to focus in that area until I was sure everything was proper before I would add more variables to the situation.

A few more ideas:

Can you measure the diameter of the front brake drum and check against spec? Maybe your drum may have been cut down numerous times and is a wider diameter than the new shoes can match with adequate contact patch, therefore only the center part of your shoes would contact the drum. The older shoes would have eventually worn into the correct diameter over time and the full shoe would contact the drum after it wore in. If memory serves correctly, I think you can go about .060 over nominal diameter before the drum is shot, but check the numbers in the manual for your car to be sure - the stamping on the drum is probably long gone. Take a new shoe off and sit it inside the drum and get an idea of how it fits and how much lining hits the drum compared to an old worn shoe.

Drum brake hardware is tricky, especially if you only do a job every couple of years on the family fleet. You can always check it against the back set if they are still undisturbed just to make sure everything up front is proper.

How is the drag on the drum? Let it sit overnight and lift a wheel and spin it to check, then start it up, hit the brakes and release and recheck - see if the drag is the same as initial test or not. I once had a bad spring in the LR of the car that released the shoes really slow. Would have never found it until I smelt the new paint getting warm on the rim and listened to the spring still clicking after I let go of the pedal and walked around the car.

One last thought - so all of us trying to help have the same point of reference - how are you defining a hard pedal (shorter than normal travel, brakes come on, no grabbing or rumbling or pulling).

Let us know what you find out.

Anyone else?

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Guest COMPACTBC

Hard pedal = like stepping on a brick, not a little soft like most brake pedals. I can stand on the pedal as hard as I can and the car will not skid any wheel, front or rear. Pedal has never had much of a travel and has always been very close to the floor. Brakes do not grab and they pull a little bit sometimes. They just do not stop the car like they used to or should. frown.gif

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Guest COMPACTBC

Thanks to everyone who offered info and advice on the brake problem I was having. I broke down today and took it to an old timer in the brake business (40+ years)and $310.00 later the brakes are much improved. The things that he did were as follows:

1. He tossed the Bendix "cereal" brake material that was on the new shoes that I bought at the local parts store and installed some real original type EDF (asbestos)brake lining on all 4 wheels. What a find!!!

2. Rebuilt all 4 wheel cylinders, they were full of crud.

3. Flushed out the entire hydraulic system, to get rid of the rusty brake fluid that we inherited, at no extra charge, from the previous owner.

4. Turned the front drums a little bit to make them round again.

5. Repacked the front wheel bearings, and of course adjusted the brakes.

The power brake booster is operating at about a 50% efficientcy, and will have to be addressed after I recover from the $$$$ drain. tongue.gif

Thanks again for all the BCA input! smile.gif

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Guest 53and61

I managed to find some asbestos-lined shoes and just got done installing them. My brakes now work perfectly -- no more hard pedal. The shoes that were installed by the shop were making good contact, but they apparently just didn't have nearly enough friction.

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