Brakes pulling hard left (sometimes)

[zuburg]

I am having a pretty scary problem with the brakes pulling VERY hard left when braking especially with hard braking on my 1956 Thunderbird.. I swear if I didn’t hold the steering wheel it would make a left turn.

The trick is it doesn’t always do it. Last Monday I drove it around running several errands. It was a very hot/humid day, and it pulled every time. Today, I drove it just a few miles both directions at 7:00am when it was just in the 70’s and it didn’t pull at all. Is it possible that hot/humid days (over 90 degrees) or driving longer distances or longer time could cause something to cause the brakes to pull hard left?

Background: The drums were turned and all the brake lines, wheel cylinders, shoes, master cylinder and brake booster have been replaced or rebuilt. Also, all the front suspension parts (except the control arms and idler arm) have been replaced and new bushings everywhere.

[oldbugger]

Did it pull left before you did all the work?

[zuburg]

To be honest, I don’t remember. There were so many problems with the car when I bought it, I didn’t trust to drive it. I ended up rebuilding nearly everything mechanical including new engine, rebuilt transmission and carb, new starter, alternator, water pump, fuel pump, radiator, brakes, front suspension, etc., etc.

[dmsfrr]

You might double check that the shoes were installed correctly, with the smaller shoe of each pair at the front.
Since the brakes were semi-recently redone, it may be time for readjusting the brake shoes, as they've likely settled in by now.

[miker98038]

I’m just finishing up a brake job on a buddy’s car. It was pulling left, not quite as bad as yours sounds. Turned out it wasn’t the left front, it was the right front with a sticking piston in a caliper. Your’s is drums, but it just might be adjustment on the right.

Dmsfrr is right about checking all the brake adjustments. I know from when I had the 4 drums, one being out can cause funny things to happen. I also had a rear brake that didn’t quite release on the parking brake. Not enough drag to notice, but enough to put that wheel out of adjustment real quick.

Were the shoes fitted to the turned drums? That’s kind of a lost art, but it not you’ll have wear on the shoe center and not the ends until they “wear to fit”. That makes for a rapid need for adjustment too.

Ambient temperatures will affect brake cooling, so maybe there’s a little drag causing fade in there on a hot day. Seems unlikely, but…….

[Flathead Fever]

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That is a little strange that it doesn't always do it. Bad wheel cylinder, broken spring, fluid on the lining on one side (check fluid level), collapsed brake hose or something installed incorrectly. Maybe when the wheel cylinder heats up the piston is not returning. The flathead guys are having all kinds of problems. with bad new wheel cylinders. Just because it came out a of new box does not mean it's good. Make sure you didn't break something like a suspension control arm. Have someone turn the wheel back and forth while you watch all of the steering and suspension parts for play. You'll probably need to pull the drums and inspect the brakes. Check the wheel bearing play first and rotate the tires to make sure they are not separating. Drums should be machined to within .010" each other on the same axle to avoid pulling but I don't think it would cause a drastic pull like you have. That used to be a question on the brake adjuster license and ASE brake certification here in CA.

[zuburg]

I agree with your comments about most things would not be intermittent, but think your idea that the wheel cylinder is not returning when hot (if so, I believe that would indicate the front left?). The suspension and alignment are good and it tracks straight down the road with no hands on the wheel. Also the tires are new with less than 1,000 miles.

[Daves55Sedan]

Food for thought:
On the backside, at the top of the brake backplate there is a giant hex-bolt holding down a coil spring. That hex bolt, if turned, changes the centering of your brake shoes. When I got my backplates back from sandblasting, that bolt had been turned (probably to get the sand out). After I had and assembled and adjusted the brake shoes initially, there was a pull to one side. I finally discovered that the shoes were off center on one side. So I had to play with that bolt to get the shoes re-centered. Then you need to re-adjust the star-wheel at the bottom to get the shoes adjusted near the drums.

[zuburg]

Thanks, that’s good to know, wasn’t aware of that. Again, I would guess if that was the problem, the brakes would always pull rather than working perfectly at times. I’ll look for those bolts when I remove the wheel and drum to inspect. I’m going to try to determine if the wheel cylinder on the left front looks sketchy or is stuck the next time it pulls.

[dmsfrr]

Originally Posted by Daves55Sedan

Food for thought:
On the backside, at the top of the brake backplate there is a giant hex-bolt holding down a coil spring. That hex bolt, if turned, changes the centering of your brake shoes. When I got my backplates back from sandblasting, that bolt had been turned (probably to get the sand out). After I had and assembled and adjusted the brake shoes initially, there was a pull to one side. I finally discovered that the shoes were off center on one side. So I had to play with that bolt to get the shoes re-centered. Then you need to re-adjust the star-wheel at the bottom to get the shoes adjusted near the drums.

Zuburg,
I think I read somewhere that '55 was the last year for those large upper anchor pin / shoe centering bolts on T-Birds, so if you don't find them on your '56 don't be confused.
.

[Gene F]

A pull can be the front brake, or the rear. Don't discount that something can go wrong on either.

[ventport]

The right front wheel cylinder could be sticking and not applying the right brake, thus pulling to the left.

[Daves55Sedan]

Originally Posted by dmsfrr

Zuburg,
I think I read somewhere that '55 was the last year for those large upper anchor pin / shoe centering bolts on T-Birds, so if you don't find them on your '56 don't be confused.

The '56 full-size cars had them. Don't know about T-birds. Interestingly, '54 had a different system for centering the shoes which might have been easier to adjust, but too many little parts to it. That's probably why they got rid of it. Using the big bolt/spring/cam system is a slow slog to get them centered perfect via trial-and-error.
The '55/56 centering cam was never meant to be adjusted from the factory setting no matter how many times you changed shoes.