VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 Brakes locking up

Working on my 1936. I have replaced all wheel cylinders. Rebuilt the Master cylinder. And installed all new brake lines.

When I try to drive the car in my driveway, the right front wheel locks up and leaves a long patch of rubber. And it only does this going forward. In reverse all of the brakes seem to engage fairly evenly.

I took the front hub off yesterday.

• The return spring is good.
• The brakes are like new - but when I ran my fingernail across them I got a small amount of black goo on them.
• I cleaned the shoes with brake cleaner.
• I cleaned the drum although it was very bright and clean.
• Then sanded the shoes with 200 grit - and cleaned them with brake cleaner again.
• Last step was to back off the adjustments about 4 clicks.

When I installed the brake cylinders and lines, naturally I bled them all.

What are the possible causes?
--- Oily shoes?
--- Air in the line?
--- Adjustment still bad?

Thanks for any ideas.

It sounds to me like the wheel cylinder is hanging up. When you push the peddle there is enough pressure to push it out but it is tight enough to not return.
With drum off,push the shoes back and forth to see if they move free.

I would also check the lh side. Possibly something on that side is keeping it from getting equal braking force-such as an internally collapsed hose or air in the line.

replace the oil socked shoes as they cannot be cleaned successfully.
Al

At this stage of the problem, adjust the brake for full contact with the shoes. Adjust them very tight, now back them off until you can turn the wheel by hand. Press on the brake pedal and check the adjustment again. Sometimes the obvious (loosening the shoe adjustment) is not the correct thing to do.

Okay... I'm reading your comments...

I think calling them "oil soaked" linings is a little harsh. None of the four hubs had any noticeable oil on them... the brake shoes "feel" dry to touch. But I was able to scrape my fingernail across one and got some minor gunk that way.

When I installed and filled the new brake lines for the first time, I adjusted them just as Ray suggested.

But I have a question, since the '36 brake cylinders have TWO adjustments, how you do you know when you've got the front and rear shafts equally adjusted? Without taking all of the hubs off again?

I don't know if this is the approved method, but I adjust the front adjuster until it drags on the drum then back it off until it doesn't. Then do the rear adjuster the same way.

I still say the fault is with the linings. All the other things mentioned could cause a pull but not a lock-up.

You may, however, try riding the brakes for a while and see it the heat will take care of whatever is on or in the shoes to dissipate. Not a good solution, I know, but the alternative is new shoes.

My 41 coupe was doing the same thing. Burn out didn't work. Got new shoes from Advance Auto Parts and it fixed the problem.

Charlie

BTW: You can stack a lot of stuff in that bed. Gather some of those free range chickens (not yours) and haul them to the parts store. Parts guys and gals love to eat chicken. They'll likely trade shoes for some chicken. Saves some money. Will too!

I go through the same thing every Spring with my '39. For two or three years they will "burn-off".....when it gets so that dosen't work I pull the right front wheel/drum and sand the linings with a real coarse sand paper. I also dress all the edges with a file. Have tried different shoes and had the same problem. The linings always look OK.

I just went outside to put the tractor away and lock up the shop when I saw the skidmarks. Just had to show you what I'm seeing.




I guess the good news is that each time I sped towards the shop, the car stopped BEFORE the door. Ha! But I'm sure my neighbors across the street are wondering "What the heck?" each time that they heard the tires squeal.

I have had to do that with my 37, ride the brakes for a little way and they always got better. Have new shoes to put on this summer, hope that helps.

That does look pretty severe. Does it release OK when you let off the brake pedal?

Yesterday when I let off it wouldn't release. I had to back it up a tad.

But today, as soon as I let off the pedal, it releases the brake. But the slightest pressure, locks it up again.

I had brake lock problems on my 39 sedan once. It has stainless steel sleeves and pistons in all the wheel cylinders. Turns out when i bled the brakes , all the crud in the brake fluid ended up in the bottom of the first wheel cylinder i bled.It would not allow the pistons to retract , and so locked up at the slightest touch of the brake pedal. I had to pull the pistons out and give the cylinder a good clean to fix the problem.

Is it the wheel with the longest brake line which you have bled first , that is locking up.?

Like I said, The wheel cylinder is hanging up!!!

Have you taken the wheel cylinder apart? As you probably remember there are the two boots, two pistons, two metal cups which the spring seats in presumably to protect the rubber, etc. It is easy to get one or more of these items in backwards which might cause your problem. Take the wheel cylinder apart and take a peak. Also you probably know that the dimensions of the front and rear cylinders is differenct. Make sure you have the right diameter kit for the front wheel. Jim

Re: debris in lines, Jack you make a good point restorers of vintage brakes should remember. When replacing brake parts the lines should be flushed with denatured alcohol and blow dried before connecting to the slave cylinders. It is also important to replace the rubber hoses with NEW when replacing the cylinders as that is where most moisture can enter. I would select newly made over NOS or NORS because rubber deteriorates over time.

Bill,

I doubt you got the wheel cylinder parts in basackards or anything like that. You would have brake fluid squirting everywhere.

You said you put new hoses on so there is little likelihood that you have an internal flap allowing fluid one way but not another (one way gate).

As to adjusting each wheel cylinder. Start off with the same amount of threads screwed in to the adjustors fron and rear of the cylinder. Adjust then by doing a little from front to rear or visa-versa. When they wheel locks down to where you can't turn it. Back off five clicks or notches. Front or rear or some of both ends. Won't matter. It is not critical that you end up with the very same length of threads. It just means that one cup and piston will be a tad farther into the cylinder, that's all.

Facing the adjuster it is clockwise to tighten. That is looking forward for the rear facing ones and rearward for the front facing ones. Of course you know that.

Good luck.

Charlie

BTW: Are you sure those are not "burn out" marks? And, if as you say a lock-up problem how many times did you have to flat-spot the tire before you realized something was amiss?

I had this once...I put the springs on wrong... I did this by putting the springs on the shoe before attaching the shoe to the back plate. Thought I would save time that way. They were binding and caused lock up. Check spring location.

My black marks are on the garage floor. One time I had to drive it into the garage with the wheel locked up.

I sent you a PM...Lets talk...

Terrill -- haven't received a PM yet... ??

More progress today. Dick Olson came over and assisted me. We went back to basics.

1) Bled the brakes - in the order the Shop Manual recommends. LR, LF, RR, RF.
--Didn't hear or see any air. Just lots of fluid.

2) Adjusted all wheels again. Turned until tight, then backed off 5 clicks.
--Some adjustments needed 20-24 clicks before they stopped the wheel.

3) Drove car.

NOW - BOTH FRONT WHEELS LOCKED UP EACH TIME!!!!

And that DOUBLED the skid marks!!! ha ha....


Finally got my nerve up and drove the car down the block while lightly pressing the pedal. By the time I got to the end of the block (1/4 mile), the grabbing stopped.

Did this two or three times and got the brakes to work a lot smoother. Then let the car sit for an hour - drove it, and the right front grabbed AGAIN!!!! Dang it.

But the good news is that I'm now able to drive out of my driveway and down the block.

FYI -- New brake lines. New wheel cylinders. Everything is clean and "properly" installed.

I think my next step is to REPLACE the brake shoes... I looked them up at TFS and I can't believe how inexpensive they are.... what the heck... that's too cheap NOT to try it.

Thanks for all of the suggestions. More later -- after I get additional nerve up to go all the way down my hill. (approx 1.5 miles - 800 feet elevation drop).

--Bill

Looks like you gotta regular "drag strip" going there... But, since I didn't hear you mention it I gotta ask...Bill...? Did you have the new shoes "arched to the drums"...? I know it is hard to get done these days...but...geez...Bill

The crud that was is the wheel cylinder on my 39 sedan was like a extremely fine silt layer, The brake tube lines were all new , the master cylinder was brass sleeved , and re sealed, and the wheel cylinders were stainless steel sleeved with stainless steel pistons. The car stopped great for a couple of years. Then duing some maintenance on the car , i bled the brakes to replace the old brake fluid, and then the wheel lock problem started.
The problem with wheel cylinders is that the inlet pipe for the brake fluid is in the centre of the cylinder. The bleed screw is placed at the top portion of the cylinder, because every knows that air in a fluid rises. So bleeding the brakes will expel the air in the lines and wheel cylinders. The fluid looks new and every thing is thought to be ok. But any of the finest particles in the brake fluid will settle to the bottom of the wheel cylinder and not be removed during the bleeding process ,because heavy particles sink, and then gets caked on hard at the bottom. The rubber cups then jamb on the crud and doesn't return to the fully retracted position.

A piece of scotch brite scourer can be used to removed the caked on particles , followed by a thorough cleaning with denatured alcohol or methylated spirits.

Good one... Yes, there is a place locally that does that. And I just ordered NEW shoes yesterday. So I'll look into getting them done. Thanks for the suggestion.
---Bill

Followed this thread from the beginning as I had the same problem with my '31. Put in new brake linings 5 yrs ago while getting it ready for the road. Brakes worked great for the first 3 yrs and then last year they started to lock up bad just before I put it away for the winter. Took it out of storage last month and as I was driving it to the garage I noticed it was the left rear one locking up the worst. Then one more month of snow. Sunday I took it out and put 10 miles on it and rode the brakes to see if that would help. Problem solved. Now I have to readjust the left rear brake and I think I'll be OK.

I one had an issue on my 36 with the Master cylinder. One of the 2 holes (compensator hole),from the master cylinder Reservoir to the piston was clogged. The pressure in the system was not releaseing and after driving a short while the brakes would lock. After a littel while they would then release.

UPDATE: I installed new brake shoes on all four wheels. During testing, I removed my hands from the steering wheel and jammed on the brakes. The car stopped in a straight line with an even force. SUCCESS!!!

Apparently one shoe on the right front previously had brake fluid which leaked on to it. That was causing the grabbing.

Next step. Drive a hundred miles, then remove the drums again and see how "even" the shoes are wearing against the drums.

Thanks for everyones comments and suggestions.

You will find after 100 miles there will be next to NO wear on the linings unless you drive 99 of the miles with a foot on the brake and one on the gas.
It takes perhaps 2000 miles or more to begin to have the linings wear in enough to make full contact with the drum.

Gene is right, at 100 miles there wont be any noticeable wear but there will be witness marks on the linings of contact with the drum which will give an indication of correct lining to drum radius.
Tony

The best way to do it is take the drums down to get turned and have the shoes arced to them. That way you start out with full surface contact. If you can find someone who knows how to do it any more...

'Glad you got it going your way. Brakes are so simple. They should be easy to fix and always the same. Trouble is, too many times they can drive us a bit crazy.

Having the linings matched to the drums is a very good idea.

You don't have to get the drums turned (unless needed) to have the shoes/linings matched to the drums. All you need is to find someone that still has the machine to do it ( and is willing to do it), take the shoes/linings and drums to 'em and pay your money. Gives much better lining-to-drum contact and, as a result, a much better brake to start with. Hard to find those little machines these days.