stuck rear brake drum

[nevets]

The right rear brake drum on my BN6 seems to be stuck, even with the adjuster turned counterclockwise all the way. I am guessing it could be a bad brake cylinder. In an attempt to free up the brake, with the car up on jack stands, I started the engine and put it into 2nd gear. The left rear wheel turned but the right wheel, with the stuck brake, did not. Is this normal? Did I break something? I know that the diff enables wheels to turn at different speeds, but one wheel not turning? Thanks.

 

[Marvin Gruber]

Brake shoes stuck to drum. Not that uncommon if car has sat for a while. Jack up, remove wheel. Whack the drum sharply with a big hammer to shock the drum and hopefully make the brake shoes come loose. You may to the use sometime like WD40 sprayed all over, then whack again.

Marv

 

[nevets]

Thanks Marv
I removed the drum and here's what I see. There is wetness in there plus some crystalline coating on the wheel cylinder (see attached photos). I'm wondering if the wetness is brake fluid or bearing grease? or both? You can see that the shoes also show some contamination. The shoe lining thickness measures 0.158", not sure if they should be replaced. If the thickness is good, can they be cleaned with brake cleaner? If they need to be replaced, are the replacement parts any good? Can I have them relined?

Thanks.

 

[Bob_Spidell]

Looks like brake fluid to me; can't tell if your hub seal is leaking, but it's possible. I'm afraid you'll need to rebuild, or possibly replace, your slave cylinder and get new shoes. I've tried cleaning brake shoes using brake cleaner and sanding, and after many attempts the shoes would still ooze fluid; they're almost sponge-like in their ability to absorb fluid.

Your linings appear to be bonded, not riveted, to the shoes. Dunno if they can be relined or not; new ones are available and AFAIK they are OK.

 

[nevets]

The wetness is clear and about the same viscosity as brake fluid so must be brake fluid.

 

[Keoke]

Acid Test:

Put finger in wetness then touch tongue if it tastes nasty it is Brake fluid!----:glee:

 

[johnea]

To determine if the wheel cylinder is leaking simply lift up the dust cap. It must be wet inside.

 

[nevets]

Think I'll check under the dust cap before doing a taste test. I pulled the opposite drum and there is also a fair amount of wetness inside the drum plus contaminated linings so I ordered a new set of shoes and replacement wheel cylinders along with the installation fitting kit. I'm not convinced that the hub isn't leaking as well. Is there a way to tell? I believe diff oil has a distinctive smell, which I am not detecting. Thanks.

 

[nevets]

One more question. I searched the forum for threads about rear hub leaks and found an informative one by Dave Russell. He uses the term 'amp' quite often. Anyone know what amp stands for? thanks

 

[SimsBJ8]

Not related to the leak, but I noticed something in your pictures that might help me.
On the fourth picture where is shows the wheel cylinder and both brake shoes, the right brake shoe end has a different profile than the left brake shoe end (where they contact the wheel cylinder). Is it possible that the right shoe is installed 180 degrees off and should be reversed, or in one of my brakes installed 180 degrees off?
Thanks in advance for your help.

 

[John Turney]

To answer one of your original questions: Yes, if one wheel is stuck, the differential will turn the other wheel. That's what it's suppose to do.

Differential oil does have a distinctive smell, it isn't clear and it is much more viscous than brake fluid. Don't do the taste test.

 

[nevets]

SimsBJ8

I did not install the brake shoes so I can't say whether the orientation is correct. I attached photos of L and R sides, which may be of some help to you. Back to the potential hub leak vs wheel cylinder leak...any additional thoughts would be appreciated, thanks. Oh, and can anyone decode 'amp'?

 

[dcarlg]

1. Send a sample to Keoke for a taste test.
2. "Amp" occurs often in the theads. I think it's a computer translation issue without real meaning.
3. I had a spun rear bearing/ruined oil seal problem last year. It smelled like gear oil. So did the garage. I replaced seals, bearings, shoes and springs both sides. Used RTV instead of paper gaskets, which we re too thick and caused the bearings to spin to begin with.
Good luck.
Douglas

 

[Bob_Spidell]

Check the backside of the backing plates; often, hub leaks will be evident there. Based on your photos--minus shots of the backsides--I think you're OK. I can't tell from your photos, but hub seal leaks usually cause a dribble straight down the backing plates under the axle disk. If you see some, wipe with a Q-Tip and smell (or send to Keoke for analysis as suggested).

Note that synthetic gear oil doesn't have the 'distinctive' smell due to the EP (extreme pressure), sulfur-based additives in 'standard' gear oil (if the oil says 'Extreme Pressure' on the label it most likely has the sulfur compounds, which may or may not cause damage to brass components, but that's another thread).

 

[TimK]

Not related to the leak, but I noticed something in your pictures that might help me.
On the fourth picture where is shows the wheel cylinder and both brake shoes, the right brake shoe end has a different profile than the left brake shoe end (where they contact the wheel cylinder). Is it possible that the right shoe is installed 180 degrees off and should be reversed, or in one of my brakes installed 180 degrees off?
Thanks in advance for your help.

After 35 years of incorrect brake shoe orientation, I learned from this forum that the correct orientation is as shown on Nevets photo post. The cutout section is for the adjuster, but the other side should have the cutout at the top -- they are shaped to self-energize in a continuous circlular direction.

 

[nevets]

Thanks again everyone for the valuable information. I could not survive Healey ownership without all of you in my corner. I'm well on my way to completing the brake work. BTW, a real treat removing those wheel cylinder retaining spring plates.

 

[nevets]

Making good progress with the rear brakes.
Two questions: Anyone know the torque value for the 5 nuts that retain the splined wheel hub?
Also, after reconnecting the brake pipe to the new wheel cylinder, a small drip developed at the connection. Not from the threads but between the union and the pipe. I tightened it a bit and the drip slowed down, but after a few minutes I see a drop forming. I'm reluctant to over tighten this union for fear of damaging the threads on the alloy body of the brake cylinder. It there some kind of sealant to use? Or perhaps a tool to deform the brake pipe so it makes a better connection? Any help with these questions will be greatly appreciated. Thanks!

 

[John Turney]

...
Also, after reconnecting the brake pipe to the new wheel cylinder, a small drip developed at the connection. Not from the threads but between the union and the pipe. I tightened it a bit and the drip slowed down, but after a few minutes I see a drop forming. I'm reluctant to over tighten this union for fear of damaging the threads on the alloy body of the brake cylinder. It there some kind of sealant to use? Or perhaps a tool to deform the brake pipe so it makes a better connection? Any help with these questions will be greatly appreciated. Thanks!

You will probably need to replace that section of brake line, or at least cut off the end and redo the flair. There is a brake flaring tool. I think I got mine from Northern Tool, but it's not the greatest.

 

[nevets]

Thanks. I ordered a new section of brake line from British Car Specialists in Stockton, CA. They carry pre-bent stainless steel pipes.