[elefantrider]

Still chasing uneven braking problems on hard braking. Back brakes work great. All wheels/drums will get very hot except for the front passenger side. Have tried everything on that one.... re-bleeding, adjusting tighter..... still stays cold and the car will pull hard to the left when you hit the brakes hard.......so need to hold the steering wheel tight!

Could the a bad wheel cylinder cause this...... even if it doesn't leak?

I find it really strange that the back brakes will always lock up before the fronts.... am thinking of putting in an in-line adjustable proportioning valve to the rear.

[421 S/Stocker]

Possible problem with the brake hose on the right front causing a restriction (internal failure) or a kinked/crushed line

[elefantrider]

Had not thought of that because it bleeds correctly.

[421 S/Stocker]

Single or dual reservoir master cylinder?

[elefantrider]

Single round one. It's still got a lot of braking power for drums.. Just front passenger side not working correctly, and rears are working too good.

Steering wheel literally wants to jump out of our hands if it is held loosely and car wants to veer to the left.

Scary stuff. Will probably just begin replacing parts until I find the problem.

No amount of adjusting fixes the problem.

Looking for new front drums.

Also need new bleeder nipples.......looks like I got two different types up front.....might try the spring loaded speed bleeders as I often have no helpers around.

Gravity bleed does not want to work on this car.

[63Banshee]

Toe out misalignment, worn out idler arm/pitman arm/tie rods?

[c5farmer]

Look for any kind of restriction in the lines, both hard and rubber. If there is no restriction, look closely at the brake shoes. Make sure they are not glazed over and move freely. You can take the drum off and wrap an expandable band around the shoes. Have someone slowly apply the brakes while you observe the movement at the mounting points and wheel cylinder.

Did you have the drum turned? Are they within the diameter tolerance? Check the drum's surface for scoring or heat. Are the brake shoes on correctly--primary side and secondary side?

Since all the other brakes are doing their job, I don't think the Master Cylinder is to blame. Just take your time and eliminate each potentional problem one at a time. Then adjust both front brakes the same. Mechanic Keith posted his technique that has worked for thousands of miles, try it.

[elefantrider]

Originally Posted by 63Banshee

Toe out misalignment, worn out idler arm/pitman arm/tie rods?

I don't believe so.......alignment looks right. Didn't think those things could affect braking. Just replaced Pitman arm last year for a new one..... Everything else seems pretty tight.

[mechanickeith]

Pistons siezed in the slave cylinder.

[63Banshee]

Originally Posted by elefantrider

I don't believe so.......alignment looks right. Didn't think those things could affect braking.

They can and do. It's a matter of physics. Slave cylinder, like Keith said.

[elefantrider]

Ok, Will tackle wheel cyl. tomorrow. Should probably be changing the fluid more often. Anyone have a part number handy for new bleeder screws.....one of mine has a broken top.

[Radman]

I use the bleeders from NAPA that have a check valve in them. That way you can bleed the brakes by yourself if you need to. Also no back draw of air into the system.

[c5farmer]

I use this $5.99 one man bleeder kit from Harbor Frieght. Item #37201 worked great on our cars.
http://www.harborfreight.com/catalog...=brake+bleeder

[elefantrider]

Ding ding ding.... .we have a stuck slave piston..... and these were rebuilt only about 7 years ago. Removed the pistons, used some steel wool on them to get rid of the crud. Put some silicone spray (actually motorcycle o-ring chain lubricant.....safe for rubber) on the pistons and bores and slapped them back in. Rebled that side and the car brakes straight now.

Will check the other side soon.

Back drums are still much more powerful and get hotter than the fronts......do not expect that to change much until I get new front drums/shoes.

HF Brake bleeder kit looks good as do the speed bleeders...... looks like the correct part number is SB51624?

[Peter Serio]

The pistons for these old GM cars are cast out of aluminum or at least some sort of an aluminum alloy. They corrode over time especially if the car sits. They will fuse solid to the cast iron cylinder. I would replace both front wheel cylinders with brand new ones. You can get a new seal kit and pistons if you want and try to rebuild the cyls but I would error on the side of caution and just replace with new.

While you are at it check all your steel brake lines and replace all of the rubber ones. If they are original to the car I would replace everything rubber and steel that has to do with the braking system. The old drum brakes are a single system so if you pop a leak anywhere in your system you have no brakes!!

[elefantrider]

What about stainless pistons, wouldn't that prevent the problem?

[elefantrider]

Would like to find a set of NOS front wheel cyls for my '62 but they are not easy to find. '63 are a different story, have a few.

[elefantrider]

I think a pressure bleeder is best for these cars. The round master cyl will spit up fluid if the cap is not on. Makes for a messy experience when bleeding, and the reservoir is not a large capacity one so there is a lot of back and forth to prevent it from going dry. If I can find a cheap good one I will try it.

[FrankieT/A]

All masters spit fluid on while bleeding, just leave the cover on loose. Ok now that you have the wheel cylinders under control, check this to try and get better proportioning: all friction surfaces come in different grades whether it be pads or shoes. Here's how to tell the difference; on the side of the lining there will a two letter grading scale. You will usually see DD, EE or FF. DD will be the lowest and FF will be the highest. Make sure you have FF in the front. Secondly, even though the brake shoes are identical front to rear (within the same wheel) the rear lining is longer. Our older GM cars have servo brakes meaning when you step on the brake the whole assembly cocks within the drum, wedging the shoes against the drum friction surface adding additional force to reduce effort. (This is also how the self adjusting feature works when you back up. It cocks in the opposite direction which hits the starwheel and tightens the shoes). Point is make sure you have the correct shoe in the correct location and use the best lining grade in front. Hope this helps.

[elefantrider]

Shoes are in the right direction. After changing the fluid out and re-adjusting the front brakes tighter (I like a maximum of 3 tire revolutions after a good flick), my pedal is where it should be and the brakes are working pretty darn good. The passenger seat will flip forward if you hit the brakes now! Never did that before!

Next step, I will try swapping in some "Praise" Ceramic shoes in the front and new Drums. But for the time being, is a huge improvement. Car is braking straight and I will try it again with the weight of a full tank of gas in (is currently empty) and see if that helps the braking distribution front to rear. The brake section of the workshop manual is pretty good but beware of stuck pistons and one should remember to test ones brakes thoroughly and change the brake fluid regularly.

Next time, I might try Sta-lube synthetic brake grease on the piston bores to prevent corrosion and stuck pistons. Actually, I will try various brands until I find one that doesn't break down when it comes in contact with DOT3 fluid.