57 Tbird power assisted brakes.

[Clif57]

57 power assisted brakes swerve to right. I have checked the air pressure in the tires to assure the pressure is even in both front tires, adjusted brakes on both sides and both wheels rotate a half turn, removed both wheels to see if there were any fluid leaks, checked master brake level for fluid, checked to see if there was any grease/oil on shoes/wheels and they are clean, both sides of shoes have plenty of ware left. I’m at my wits end. Any suggestions?

 

[jack-in-sac]

57 power assisted brakes swerve to right. I have checked the air pressure in the tires to assure the pressure is even in both front tires, adjusted brakes on both sides and both wheels rotate a half turn, removed both wheels to see if there were any fluid leaks, checked master brake level for fluid, checked to see if there was any grease/oil on shoes/wheels and they are clean, both sides of shoes have plenty of ware left. I’m at my wits end. Any suggestions?

Have you had a look at the wheel cylinders? In a car seldom used this can become a problem where a wheel cylinder "hangs up". The result can be anything from a slight pull to a violent lurch to one side.

 

[Robert Evans]

57 power assisted brakes swerve to right. I have checked the air pressure in the tires to assure the pressure is even in both front tires, adjusted brakes on both sides and both wheels rotate a half turn, removed both wheels to see if there were any fluid leaks, checked master brake level for fluid, checked to see if there was any grease/oil on shoes/wheels and they are clean, both sides of shoes have plenty of ware left. I’m at my wits end. Any suggestions?

You may have a bit of air in the brake system and the one side of the brakes may be applying more pressure than on the other side. You may want to try bleeding the brakes again one thd side that is not working.

 

[Critterpainer]

If its pulling right, check the LEFT brake hose and wheel cylinder. Hose may be swollen closed (has happened to me) or cylinder frozen not allowing left brake to work properly.

 

[Clif57]

Checked the wheel cylinders, bled the brakes. Every thing seems to work OK. Don’t know which one of the suggestions worked, but all is a go! Thanks to all for taking the time to help. Much appreciated.

 

[jack-in-sac]

57 power assisted brakes swerve to right. I have checked the air pressure in the tires to assure the pressure is even in both front tires, adjusted brakes on both sides and both wheels rotate a half turn, removed both wheels to see if there were any fluid leaks, checked master brake level for fluid, checked to see if there was any grease/oil on shoes/wheels and they are clean, both sides of shoes have plenty of ware left. I’m at my wits end. Any suggestions?

More than anything I am glad you are safely back on the road, Happy Motoring!

 

[Pink T-Bird]

I'm going to resurrect this thread as I have the same problem, violent lurch to the right when braking that suddenly appeared. The degree of pull is proportional to how fast/firm I hit the brake pedal. Some moron cut me off and I partially changed lanes onto the shoulder it pulled so hard.

If I ease on the brakes and apply more pressure after the initial pull there is no additional pull. So the first thing I thought was brake adjustment or sticking wheel cylinder. Nope.

I have checked all the things mentioned here already to no avail.

I have also swapped the front drums and wheels left to right, and replaced all 8 control arm bushings (they looked like they could have been 63 years old) and had a wheel alignment. Still pulls.

What is left? I suggested rubber brake hoses to mechanic, and he assured me he got "good pressure" out of all 4 wheels while bleeding.

 

[Critterpainer]

Pressure and volume are not the same thing. Left hose could be restricted or one piston on the cyl could be stuck, That would give you normal brake feel until you jammed the brake hard. After you released the pedal after hitting the brake hard did both wheels turn freely and even?

 

[Ward 57]

It could even be a rear brake problem. I would find a gravel road or parking lot, go about 10-15 mph and hit the brakes By the skid marks you might be able to track down the offending wheel. Happened to me before. If one locks up more than another you will be able to see or if one doesn't skid at all you may have a frozen wheel cylinder.

 

[Pink T-Bird]

After you released the pedal after hitting the brake hard did both wheels turn freely and even?

After that it drove normally, no pull, until the next time I hit the brakes, then pulled again just like before.

Before throwing in the towel and taking to a mechanic I adjusted and bled the brakes. Old fluid looked like coffee. The LF seemed to freewheel/ less friction before the brake adjustment, after the adjustment they were equal, but that didn't fix it. I inspected the suspension and noted dry rot in the control arm bushings, all else looked and tested normal to me (I grew up working in my dad's service station in 60s and 70s and we did a fair amount of brakes, bearing repacking, idler arms, tie rods, ball joints, and wheel alignments).

The mechanic replaced the control arm bushings with parts I supplied from CASCO, did the alignment, swapped the drums side to side, and insisted on bleeding it again. nothing changed. Then we got 8" of snow. Car is still at the shop and it should be clear enough tomorrow to get back to road testing.

I'm still thinking hoses. Those are at least 31 years old, from when the car was originally restored.

 

[Ward 57]

After that it drove normally, no pull, until the next time I hit the brakes, then pulled again just like before.

Before throwing in the towel and taking to a mechanic I adjusted and bled the brakes. Old fluid looked like coffee. The LF seemed to freewheel/ less friction before the brake adjustment, after the adjustment they were equal, but that didn't fix it. I inspected the suspension and noted dry rot in the control arm bushings, all else looked and tested normal to me (I grew up working in my dad's service station in 60s and 70s and we did a fair amount of brakes, bearing repacking, idler arms, tie rods, ball joints, and wheel alignments).

The mechanic replaced the control arm bushings with parts I supplied from CASCO, did the alignment, swapped the drums side to side, and insisted on bleeding it again. nothing changed. Then we got 8" of snow. Car is still at the shop and it should be clear enough tomorrow to get back to road testing.

I'm still thinking hoses. Those are at least 31 years old, from when the car was originally restored.

Something is sticking. I'd still look towards the rear. If it pulls towards the right I'd focus on the left rear not engaging.

 

[Critterpainer]

If a hard braking yanks the steering wheel out of your grip, its front brakes, if the car swerves the rears

 

[Pink T-Bird]

Yep, yanks the steering wheel, it's in the front.
I'm leaning towards the left front rubber brake line despite what the mechanic says, but I'm guessing it would not hurt to rebuild the wheel cylinders either since from what I can tell there has been little attention to the brakes in the last 31 years except replacing the RR wheel cylinder just before I bought it... I'm going to get all flex lines and the wheel cylinder kits from CASCO and just go for it.

 

[Critterpainer]

Kits? The wheel cylinders should be fairly cheap and if they have not been messed with in 30 years you can pretty much bet on pitted cylinders.

 

[Pink T-Bird]

Update if anyone is interested....
The mechanic had done all sorts of brake adjustments to set right bias, rear bias, moved tires and drums around, still pulled hard right. I took the car back from the shop. Replaced all 4 flex brake lines, rebuilt front wheel cylinders. I found both hold down pins on LF were bent like arthritic fingers... (Put a straight pin from RF in picture for reference). LF wheel cylinder also had just a bit of evidence of weeping and the weeped fluid was syrupy and rust colored. So I'm guessing the LF brakes weren't coming on or only slightly coming on due to bent pins restricting movement. The leaking WC didn't help either.

The 3 front flex lines all had DOT codes and dates from the mid and late 90s. Sighting through them against a light source they did not appear collapsed internally. Rear flex hose was likely from 1957, no DOT makings or codes, and very stiff, and different type of rubber compared to front hoses. And it was a bear to loosen the fittings. I believe it was internally restricted as I could not get light from end to end like the front hoses.
Bled the brakes, readjusted them to undo the mechanics attempts at differential biasing. Took a test drive. Still pulls right, but much less violently and not through the steering wheel at all now. And miracle of miracles, the RR wheel locks up now. It never did that before. The prior owner stated his mechanic replaced the RR wheel cylinder in preparation for the sale.

Want to bet I'll find he didn't replace the fluid soaked brake shoes?

 

[Ward 57]

Could be, also the leading shoe and trailing shoe could be reversed. Easy mistake but nobody is perfect. I'll bet your diagnostic skill set is exploding.

 

[Pink T-Bird]

And the fun never ends....
Replaced the rear shoes even though they seemed fine. I thought the retracting springs looked "stretched" on the right side so maybe the shoes were closer to the drum than on the left. NAPA had springs in stock for me to do both sides rear retracting springs to keep the same tension on the shoes.
Took a test drive - In a controlled, panned, normal stop no real pull so that's a win. with moderate or hard braking still pulls maybe a bit less, hard to say. From fast stop at 20 mph now it locks up both fronts and the RR, but the RR locks up first (longest rubber trail). LR must be the culprit??

Thinking replacing both rear wheel cylinders so it's a known matched pair is next. It's an outlier that's bugging me. In my dad's shop we always either rebuilt or replaced Wheel Cylinders in pairs on an axle. But I'm open to suggestions

 

[Pink T-Bird]

For anyone still keeping track - with matching rear wheel cylinders and the retracting springs mounted correctly it still pulls. Not "jerk the wheel out of you hand"/"change lanes" pull like when this started, so there was some progress.
Panic stop from 15 mph both right wheels lock up, nether left wheel does. I've bled the brakes like crazy - no air.
I bought the car over the summer, so it's new to me. The prior owner had RR wheel cylinder replaced in May. He did not change shoes, did not change or rebuild LR cylinder...
The brakes did not pull when I bought the car, or if they did it was so mild I did not notice. So it was fine for the first couple hundred miles.

It did have an issue with vibration above 55 mph which the prior owner disclosed before sale. I had the 30+ year old tires & tubes, and one K-H wire wheel replaced to address the vibration issue. I checked the brakes while the wheels were off and found the RR shoes and drum surface felt oily. Cleaned with Brake cleaner, reassembled. Adjusted brakes on all 4 wheels. This is about when the trouble started.... didn't notice anything right away, but shortly thereafter I had to make a panic deceleration because someone changed lanes in front on me and then slowed quickly to make a right turn. My car changed lanes to the right all by itself! From that point on the car pulled strongly to the right when braking but no issues when accelerating, cruising, or coasting.

the work so far:
- all 4 flexible brake lines replaced. line to rear axle was likely from 1957.
- front wheel cylinders rebuilt (LF has a little weeping under the dust boot towards the primary shoe) - there was no pitting in the bore and I had rebuild kits on hand
- retaining pins on LF brakes shoes bent over like arthritic fingers - replaced both
- replaced all 4 rear brake shoes in case RR was damaged by the prior leaking of the wheel cylinder
- replaced both rear wheel cylinders so they match, corrected retaining spring attachment, bled rear brakes
- replaced upper and lower control arm bushings as they also appeared to be 63 years old and cracked/dry rotted
- replaced sway bar bushings
- Mechanic says eveyting else in the front suspension is good
- Wheel alignment
- moved wheels around to different location on car

One other odd thing likely not related - even with the 4 brand new American Classic 'bias look' radial tires, if the road surface is the grooved concrete the front tires want to follow the grooves like bias ply tires.

Ever see anything like this?

 

[Ward 57]

Wow. You have looked at everything where murphy's law would apply. You have gone from the outside in tracing the problem. You said the right brakes work well but the left don't. Seeing as these are single system brakes the only place left to look is at the source. The junction from the master cylinder to the distribution block. Not sure if it's distributed left to right or front to rear. Happy hunting..

 

[Pink T-Bird]

Funny you mention the distribution block - I was thinking the same thing... However I found there are really three blocks: 1 booster to frame; 2 split to both front wheels; 3 rear axle distribution block. So block 2 & 3 would need to have issues for the right to be lame. Alternately both new LF flex hose in the front and original(?) LR steel line in the back would have to have issues. Also seems unlikely given the sudden onset of the problem. I'm really baffled here.