Hey fellas, My '56 Pontiac pulls to the left when braking. It was all good for about 5 years then all of a sudden one day it pulled hard left and the steering wheel turned left as well. All stock brake system, not boosted. Since the problem began I've changed the master cylinder, bled everything, freed up the parking brake cables, adjusted wheel bearings, checked tire pressures, changed brake hoses, adjusted parking brake cable tensions, adjusted all 4 brakes for wear, and checked the entire system for leaks all to no avail. Speed, direction, how hard I brake all seem to have the same affect. Weird thing is it doesn't happen all the time and it seems to get slightly better the longer I drive. Anybody have any ideas? Also the brake shoe with the smaller surface should be forward, right? I did find one rear brake that wasn't arranged that way, but it was like that before the problems started. Any advice (other than upgrade to modern brakes) would be appreciated! Johnny
One of the cylinders is sticking then.... if it pulls to the right the left cylinder is stuck and vice versa.... kinda like a tank, you turn by braking only one side.... get it? Or it needs new rubber lines cause they can collapse.
Make sure if you buy new wheel cylinders that they are made in USA the others are junk. So much so IMO that I tend to hone and rebuild mine
Just changed the hoses.....How can they collapse under pressure? I can understand if the hoses were for a vacuum or suction type of pressure. I've heard of that before and never understood how it could happen. Is there anyway to test the wheel cylinders without driving? Like actuate the brake pedal with drums off or something? JohnEvans.....thinking right front?
The hose are multi layered and the fluid is forced between the layers and then collapses the inner layer thus closing off the hose .
Yea trust me it defies all the laws... but it can happen!!! Probably just a stuck cylinder thought, pull it and hone it a bit and put it back together... easy as that!
I would not actuate the brakes with the drums off, it may blow the cylinders out and get fluid all over the brakes. Keep the drums on and have someone step on the brakes and see if the rf brake is stopping as opposed to the left. I would suspect wheel cylinders as well. When brake hoses come apart internally , they can either have a total blockage and not let any fluid thru, or act as a check valve and not release pressure. In that case the brake would be stuck on and opening the bleeder screw would relieve the pressure caused by the "check valve " in the hose.
Rebuilt all the cylinders about 5 years ago, is it time for rebuild kits or hone and re-use? Also up in my original post I slipped a question in regarding how the shoes are arranged. Should the shoes with the smaller surface be leading (facing forward)?
For the couple of bucks for a rebuild kit I always hone and use a new kit . And I had a 56 T-bird that drove and braked fine before winter then in the spring I had your same problem...wound up rebuilding the wheel cylinders
Hmmmm.....Might be lazy, but if I remove the shoes, can I rebuild the cylinders on the car? Sort of worried about rounding off fittings and breaking bolts.
No No No. The cylinders need to be flushed of residue from honing. Many cylinders have to be removed to get the pistons out. If the fittings are in bad shape, then the lines need to be rejplaced also.
Just realized that after I posted!!! Just thought, man that would be quick! I guess it wouldn't pull to the left anymore if all the cylinders were full of debris and the brakes wouldn't work at all! My worries on the fittings are based on the over-tightening I'm sure I did in my earlier days of wrenching. Can't remember for sure but I probably used anti-seize on everything that doesn't come in contact with fluid. The lines all still look nice though.
I just chased the same problem for 2 months. New kingpins,tie-rod ends,adjusted braked 12 times. Found the wheel bearing was bad.
proportioning valve? dont think older cars have them, but my '74 chevy pickup had a problem with its proportioning valve. changed it and it steers fine. =Pete
And I have a kid that depends on Daddy for everything! It'll be done right! I'm one of those guys that uses a torque wrench for everything with a value listed in the manual. Very detail oriented and everything, but lacking in the time to work on the car department. I always have "good" ideas like that till I think about things in the weeks it takes before I have time to do any wrenching!
Forgot to mention the front wheel bearings are brand new too. Seem to be all good with no noise, discoloration, grinding feel or anything else. And no proportioning valve on this one!
Stuck wheel cylinder or a bad hose. I have seen old, grabby shoes too. Could also be a worn lower A frame bushing that when the brakes are applied, slop gets taken up and steers the car one way or the other.
Think I got it! Still a spongy pedal so I need to bleed it better, but seems to stop straight ahead now! I rebuilt both front wheel cylinders and found the right one all full of crud! Regarding adjustment, does it matter if you adjust the shoes before or after bleeding the system? Thanks, Johnny
I also just chased this problem, and the shoes were separating from the pad. Not off, but about 50-percent of the area was no longer bonded. It was pulling REAL hard to the opposite side. I'm now hunting for riveted shoes, because this isn't the first time it's happened. -Brad
it is easier to bleed your brakes after you adjust them, you get the maximum amount of fluid movement with a full pedal.
I had a similar brake issue on the caddy. On the way to bulletproof florida last year, it got to the point only the right front was working, and this was after they had just been adjusted. Took it to another shop, and they mic'd the shoes and drums, and matched them best they could. Been good for 600+ miles now. Leaving for bulletproof florida 2011 tomorrow. Let's hope i don't need to use the e-brake this year to get home!
In your case, yes. Yours are the Bendix brake, and they are all similar. The shorter lining shoe is the 'servo shoe', longer lining shoe is the 'working shoe'. The way to 'mastermind' the positions of 'servo' vs. 'working' is this: When brakes are applied, the wheel cylinder will expand both shoes, causing a 'rolling' reaction to the direction the drum is turning, as the expanded shoes contact the drum. The 'Anchor pin' at the top of the backing plate is literally what stops the car, as the working shoe is blocked against it. The smaller 'servo' shoe is assisting with friction, but in a lesser amount. Whichever shoe contacts the anchor pin is the 'working' shoe. (in pre-'48 Ford brakes, it is the leading shoe. The wheel cylinder also has a larger piston in front, for added hydraulic advantage)
I'm coming in late on this one but yes the shoe with the least lining always goes to the front. five years is a long time for a car that probably sits a lot more than it gets driven. The trouble with almost any enthusiast car or vehicle of any genre is that they almost always have to sit waiting to be driven way too much and that allows the brake cylinders to stick among other things. You and the others have covered most of the things that cause brakes to pull. the off side cylinder or caliper sticking . Grease or other contamination on the lining. One side not adjusted correctly. Usually due to the automatic adjuster sticking on that side or parts missing from the automatic adjuster. Shoes installed wrong on one side. Springs installed wrong on one side. Or broken or missing One drum worn or turned a lot more than it's mate. .Tire pressure uneven between sides. Mismatched tires either by, size, make or style. Try to get a car to drive and stop right after some clown decided that he wanted to run four different brands of tires on the car to see which gave the best service some time. Been there, done that and he wouldn't listen when I told him his problem was due to mismatched tires. Bias on one end and radials on the other can cause a rash of problems as far as handling and braking go. What ever you do on the brakes, do it right and buy quality pieces for it. Cut corners somewhere else but not on the brake system.
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