Asking for a friend on this forum because of all the braintrust..Not a Vette but a 67 Camaro with all drum brakes. Has power brakes. Car pulls hard to left when brakes are applied. Complete brake system has been replaced. ,springs hold downs, drums resurfaced,shoes,rubber and steel lines. Wheel bearings replaced. System bleeds good. With adjustment backed off drum will still get very hot. Only thing not replaced is brake distribution blocki, but it should not cause a problem. Right? I hope you guys can do better than the Camaro forum brains. Thanks.

 

I would do a search on how to size the shoes to the drums. Jerry

 

Sounds like a failed suspension component. Probably a bad bushing or ball joint but a cracked a-arm is also a possibility. Issue could be with the front or rear suspension.

 

Was anything done with the wheel cylinders? You mentioned rubber? Hoses or boots?

 

I would check the pads on the backing plates where the shoes ride. On lots of old cars these pads get a groove worn in them and it needs to be flat and smooth.

 

Does it continue to pull hard left for as long as the brakes are applied, or does it jerk left briefly and then brake in a straight line?

Live well,

SJW

 

 

Our 68RS has standard drums all around.
Put the car up on stands, all four wheels off the ground. Run the engine to spin the rear wheels and then hit the brakes. See if either wheel is locked up after releasing the brakes. Also, spin both front wheels and then hit the brakes. Check them to identify is one is not releasing. If any wheel is not releasing, check to see if the pressure releases by opening the bleeder. That tells you if it is a bad hose (even if new).
If it is pulling to one side, it is because A. One side has more clearance between the shoes and the drum than the opposite side. It takes more fluid and time to engage the shoes with the excessive clearance. You might be able to find the one that is grabbing first by spinning the wheels by hand while slowly applying the brakes. All 4 wheels must be adjusted equally. Tighten them up to meet the drum, and hit the brakes, then try tightening them again. Once you are sure they are all contacting the drums, back them off an equal number of turns of the star adjustment wheel. Then try again.
Another possible cause is the backing plate and hinge pins get worn and grooved and the shoes hang up and don't react as fast as the other side. I weld up the groove and grind them smooth and the keep a light coat of high temperature wheel bearing grease on the contact points - not too much to get on the shoes.
The star adjustment wheel and the pawl that moves it become worn and will not hold an adjustment. If one wheel is not maintaining good adjustment it will pull to the other side.
I have a Bendix brake manual in garage somewhere, I will try to find it and give you the words from the experts. I am still a learning amateur at only age 72.

 

After 20 years in the brake business I've seen, in rare cases, where a "burned" shoe (from miss-adjustment or what have you) can change it's coefficient of friction. While I doubt this is the case and lean toward hydraulics, as a last ditch effort you can swap shoes side to side to see if the problem follows the shoes. That said, I've seen so many brake issues that could cause this its pretty tough to diagnose third person.

 

When you say that when the brakes are backed off the "drum" still gets hot, do you mean just one? Or both/all? If it's just one, that's likely where your problem lies. But if the heat is even side-to-side, I think Mark is on the right track.

 

Here is one page of the 7 pages of troubleshooting from the Raybestos brake manual for the 70s. Maybe it will help.
I don't know how to attach it as an open document even though I opened it on my computer. Still have a lot to learn.
Ron
Found another page that may help.

 

Thanks for the replies. Upon pulling both front brake drums it was evident the shoes were only making contact on their ends and not in the center. Both sides. Apparently the resurface job on the drums was not good. Installing new drums and shoes today. I will let you all know if it is fixed.

 

If it is a rear getting hot, make sure that the e.brake is completely backed off before adjusting the brakes, this often causes problems and is part of the start of the brake job but is often over looked.

Also make sure that all four drums match in diameter from left to right. A drum turned to .050 on the left and .025 on the right can cause pulling. They should always be matched left to right. You either replace the big one or machine the small one to match it.

Just my thoughts.

 

New brake drums solved the problem. Either the person resurfacing the brake drums erred or the machine was operating inproperly. Thanks again for all the input. People on Corvette Forum rock!

 

You end up with a much better brake job if each drum is measured and the new shoes are arc ground to match the drum, if this is not done more times than not you will end up not having full shoe to drum contact.

Bill

 

Bill is right, but in our area you will not find a shop to grind and match the shoes to the drum let alone the calipers and dividers . As that is the

 

Great news. What happened was, the original drums were cut oversize to clean them up. This is normal procedure. What didn't happen is the shoes getting arced to the new drum oversize. Shoes are not arced anymore, so you would need to drive thousands of miles for them to wear into the new drum oversize. Or, you can 'hammer arc' the shoes by standing them on their ends with the lining facing up and smacking the center of the lining with a hammer to slightly flatten the curve of the shoe. I have done this more than once, and it works. You need to be careful, though. When you replaced the drums with new, standard size drums, they fit your new shoes, as all new shoes are made to match standard, un-cut drums.

 

I have heard of people "hammer arcing" brake shoes, however I still measure my drums and arc grind the shoes that way I am sure I have the proper radius and haven't changed the distance between the anchor pin and adjuster of the shoe, arc grinding poses no danger as it has been quite a while since brake shoes contained asbestos.

Bill

 

Just as a point of interest (and reminder to those that have dealt with it), arc fitting brake shoes is even more critical when dealing with the parking brake on C2-C3 disc brake equipped cars and often overlooked.

Good luck... GUSTO

 

Interesting! Careful would seem to be an understatement. How do you do that without damaging the lining itself?

Not sure I understand “standing them on their end” Does that mean on one end of the shoe with the shoe being vertical and hammer on the other end so as to strike only on steel? Or, when you say “hammer in the center of the lining” that sounds more like resting the shoe on it’s back (inner side) with the shoe being horizontal and hammering directly on the lining material.

How do you protect the lining material from being damaged by hammering on it? Wouldn’t a direct hit from a steel hammer dent, chip, or maybe even shatter the lining?

Does this work for both riveted and bonded linings?

I am confused by this process. Thanks for clarifying!