Technical Rear brake shoes hanging up

The rear shoes on My 1954 Buick ( the two with the parking brake levers) are not seating against the anchor pins.Brakes are fully bled (did it again today to be sure) I disconnected the main cable at the equalizer, and it made no change. What could be causing them to hang up like that?

I have good pedal, although sometimes it takes more pressure to get the car to stop

 

post pic - ever had drums turned/trued?

 

I'll have to pull the wheels tomorrow, Yes the drums were turned

 

Have you ever changed the rear flexible hose,if it's old it could have deteriorated with age and is collapsing internally,over a long period of time this is common and is often overlooked.

This could be the problem. HRP

 

HRP could well be on to something here. I had a similar problem with an OT DD a while back. I replaced the hose Danny mentioned , bled the rear brakes and the problem went away.

 

besides the hose might be collapsed , also check the backing plate for any burrs that might have worn in on them and also is the backing plate lubed at the wear pads and how old are the springs?? , as I have had one the springs were dead and the backing plate rusted at the pads and one burred and were locking the shoes in the outward position causing them to drag because they reused the return springs and used new hold down springs

 

My first question did you do the work ?
If so did you leave one side complete while you did the other ? Leaving one side together you have something to double check your work.

Only reason I ask it is REAL easy to mix up parts on drum brakes.

You may have done this a dozen times I do not know. But if drum brakes are reassembled wrong .. you can chase your tail ..

 

And chase ..just to find out you have one spring in the wrong place or clip or ..?

 

X2 on the rubber hose replacement. I had the exact same problem on my 54 Buick convert I used to have. Go for a ride and come back with the rear brakes smoking hot. Replaced the rubber hose at the front of the torque tube and problem gone.

 

Agree, replace rear rubber hose in brake line, smoked the rear brakes on our 51 Buick last summer, allowed fluid to go, but not return. Was in process of fixing brakes and trying to figure out the why ?, a mechanic friend mentioned, check the rear rubber hose, from external inspection, it looked good, junk when cut open.

 

Def replace the rear hose. If it looks old just change it. Its a safety thing. But look close at the backing plates. I have seen and fixed at least 5 or 6 sets of backing plates that were worn from the shoes rubbing the backing plate with no lube and put grooves in them that would hold the shoes out.

 

Hose was replaced today. I did the brakes Myself, one side at a time. it seems like the park brake lever is not moving, maybe cables are stuck? I never did try the parking brake since I've had it

 

I temp removed park brake lever, did not make difference. Cracked bleeder screw, and could push them back together. Replaced drum and pumped brake, and it did same thing. Attached is a pront view of the brakes, and a top view, looking down at the anchor pin, showing the issue. Everything was correctly lubricated where shoes conctated the backing plate.

 

I've had that problem several time in several different cars. In all cases, it was a combination of a semi-collapsed rubber hose as already mentioned, AND crap in the master cylinder ports that was preventing the fluid from returning. The buildup can happen if the car has been sitting for a while or if the MC is just plain old. In both cases, a new MC and rubber lines solved the problem, although I also replaced all of the brake lines while I was at it.

Good luck.

Chris

 

I thoroughly cleaned the master cylinder before rebuilding it, and replaced the rear hose with a brand new one. Will keep looking into it

 

The spring on the right side doesn't look like its got any tension on it.
See picture of another 54 buick spring.

 

If (great big if) releasing the bleeder is the only way to get the shoe to return, there certainly is a problem with fluid exiting the wheel cylinder and returning to the master cylinder. That problem can be anywhere between the wheel cylinders internals and the master's reservoir. That's going to require going over everything again. One little piece of crap in the line can act like check valve anyplace. A malfunctioning residual valve or too much valve can do it too. Your master probably has residual pressure valves in the ports of the master.

Here's why that's such a big if- once you crack the bleeder the shoe should go back to home position 100% all by itself- no touching by you at all. You said that you could push it back. That's a big clue there's not enough spring to do it, or a mechanical catch.

However, try to imagine how many hands have been into the brake system over the years. There's much potential for a variant or a stack of them.
The spring on the right looks like there's little tension on it. If it is for a different set up it won't work in yours. If the residual pressure is stronger than the springs return force the shoes won't return. I've seen backing plate tabs worn to the point that the shoes only slide one way- those needed built up weld an ground back into plane. I've found narrow drums, changed out backing plates, all sorts of Frankenstein parts that do work together but the application is something entirely different than what we've been working on. It's an automotive forensic investigation to get the right parts.

 

I bet you need more free play at the master cylinder to brake pedal. Adjust the rod shorter. Not letting the fluid back into the master after braking.

 

A sticking wheel cylinder will cause the same problem. Also, remove the park brakes struts (not the levers) to rule out any cable issues.

 

I can't see it and it may be there cut what about the bottom spring where the adjuster is located. HRP

 

And maybe while you're in there looking for wear and making those repairs, clean everything and put some while lithium grease at all points where there is metal to metal contact. And get a new spring kit for both sides if you can find a set.

 

Rear wheel cylinders are brand new.. BJR, I was wondering about the free play at the pedal too, note the way My brake pedal pad looks, I am not sure if ti should be cocked as it is now I can check the free play measurement. I looked down into the master cylinder with the cap off, could see the piston thru the compensating port, and there was no play, when I pressed the pedal, the piston moved.

 

A little update: I disconnected the line at each rear wheel cyl (one at a time) and put a hose into a jar, it moved about an inch and a half of fluid after pumping pedal 4 times. Also, this is affecting the left rear wheel, right rear wheel seems to be working ok

 

You might want to replace the shoe return springs. If they've been overheated at some point (usually indicated by badly discolored paint on them), they can lose tension and not pull the shoes back.

 

Does your brake pedal have a return spring? You should have some free play before the piston in the master cylinder starts to move, even 1/8" is enough.

 

are the leading shoes supposed to be that short or is it a optical illusion , to me it looks only to be 2/3 length of the shoe and them springs look old , when doing drum brakes always pitch the springs when renewing the lining , because of the heat and the corrosive shoe material ( holds water and causues rustout ) only other thing I can think of is how old are the steel tubing ?? you can have internal rust build up and its plugging the lines ( if the fluid is dark brown the lines are corroding )

 

Can you move the emergency brake spreader bar side to side or is it tight? Emergency brake or shoes hanging up on the backing plates are the most likely spots. If they won't go back with the bleeder open

 

They have no discoloration, and good tension in them yet

I always have put the shorter shoe toward the front on all the drum brakes I've done before.

Yes I can move it back and forth a small amount

 

We must be looking at different pictures then.

 

You could change the springs from left to right one at a time and see if the problem moves as well, if not you rule the springs out. JW