11 inch Manual Drum Brake Problems......

Agree it may be a L/R problem with the adjusters. I guess it could be a MC problem.

Also maybe a problem with an old flex line from chassis to axle (if your's is old). They can collapse internally and hold pressure even when the pedal is released.

If it does it again, try cracking open the bleeder on the offending wheel(s). If that releases the pressure, its a hydraulic problem with the flex line, master or maybe prop valve.

OE drum prop masters have (I believe) a residual pressure function to hold slight pressure against the wheel cylinders when the brake is released. If that were stuck, it could be causing your problem.

You have auto adjusters on your 11" brakes?

Thanks fellas... good info

Are you referring to the prop valve or the master cylinder holding a bit of residual pressure?

The brake hoses, lines, wheel cylinders are all new. The prop valve is the original piece off the car. I have a spare that came off a 318 manual drum brake car that I am tempted to try. It looks exactly the same and I assume that it is at this point. The master cylinder is an OEM type that I rebuilt. All seemed fine with it however I did notice that the flow of fluid coming out of the rear wheel cylinders seemed slow during the bleed process.

It is strange. I think it is set off when I get on the brake pedal hard. In both instances it seems that could have been the case. Does that raise any questions? Like I said once I got it home and on jacks I would remove the drums and have to back off the adjustors... once having done that and running some checks, everything seemed to operate as one would expect.

If it does it tomorrow, I will immediately open the wheel cylinder bleeds to see if there is residual pressure.... good idea.

Yes, auto adustors on '70 cuda with 11 inchers. My 68 11" power drum brake Charger is manual adjust.

I have to agree, sounds like your starwheel adjusters are in the wrong side.

did you verify that too?

I'm not sure I can picture a scenario where "wrong side" adjusters would tighten the brakes; in normal operation the self-adjusters only work when the brakes are applied while backing up, on forward application there is no action from the self-adjusters.

Man.. this issue is more of a PITA than the tranny.. at least with it I saw what the problem was right away and fixed it.

Today I worked on the brakes again with less than worthy results. I made sure the adjustors were correct - which they are. I went ahead and put the drums on and then bolted the drums down without the wheels. It went from good rotation to binding with the lugs tightened. I hand sanded the whole inner ridge to smooth out that area since it appeared from the wear marks on the shoes, that area was suspect. It got better, I set the adjustors for optimum rotational feel and put the wheels back on.

I took it out for a test hop and they began to get tight again. When I came back I put it up and checked the bleeds on the wheel cylinders.. no pressure there. Drums were not bound up but they were tight. I removed the drums and everything was seated and as it should be - the shoes that is.... confounding.

When I rotated the RH wheel, 180 degrees of rotation was as expected and the other half tight.... similar but less so on the LH side.

With that I thought I may have potentially out of round drums so I took them to my local guys and then cleaned them up. Not much to clean, RH side was a bit more non concentric. When I got them home, I put them on and they rotated and sounded perfect... just as you would expect. I thought I was golden. Adusted shoes, took it out and wouldn't you know it, they got tight AGAIN!

This is getting old. I put it up on jacks and put it in gear and watched the wheels spin to see if there was any wobble or any other visual that might indicate something is amiss. I hit the brakes a bunch of times, engaged and disengaged the e-brake and it essentially ends up with the scenario where half the rotation is bound and half is not.

I ran out of time tonight so I am wondering about the next plan. I have manual adjust hardware that I was going to substitute and see how that goes. I also was going to put it up and take the wheels and drums off and rotate the axles with the engine running and trans engaged to see if there is any kind of strangeness there. It almost seems as thought the axle could be tweaked....

That's the latest.

I put in a new Raybestos brand set of adjusters front and rear on my 11" drums. New spring kit also. Just as the top springs were freshly painted, and when stretched into position, the override springs of the adjuster cables also had to be overstretched to get the paint to pop so the adjuster lever would line up correctly with the star wheel. The top lip should contact below the centerline of the star. Pull the cable and the lever should rotate the star wheel upwards one click at a time. If your adjusters are on the correct side for their thread the rod will lengthen. This action will only occur while reversing when setup properly and will not overtighten. That's what the override spring is there for. Post a pic with the drum off. Also I had to reuse the adjuster thrust washers as the new kit did not have them. They go on the free spinning side of the shaft, and never seize is better to lube the threads and free spinning side. Hope this helps.

I will get some pix later. Cannot get to that at the moment. It is setup correctly. Adjustors are below centerline and the tang moves upward and catches the star wheel and rotates it when moving the cable by hand. I have gone over the build time and time again.. trying to find that one stupid thing I did wrong or missed but so far, everything seems as it should. That is what makes it so frustrating.

The spring kits I got from Raybestos also had the wrong length shoe retaining pins for the front 3" shoes. I had to order them seperately. Did you put a light film of grease on the backing plate contact points and shoe webs? Adjuster cables also? It also helps to have the parking brake cable lubed and adjusted so that you get drag on first click of the pedal, do this first, release the P brake, then do your wheel adjustment. The P brake will keep the front shoe where it should be, it doesn't move the rear shoe. Wheel adjuster will then push the rear shoe into alignment. And this is a pain in the a$$, did you arc the shoes?

Similar experience I had a few years ago involved the placement of the brake lining on the shoes. Fronts kept binding, couldn't understand why until I compared the new shoes to the originals. Went back to NAPA & went through gobs of boxes until we found shoes that the linings were same as the originals. Not clear on whether you replaced your shoes, but even if you didn't could you have switched sides? just my

To eliminate the self adjuster simply remove the cable and give it a try..

Then look at other possibilies...

Another very likely cause the the parking brake hanging up, when fully assembled the shoes must both touch the center anchor pin.

Eliminate the autoadjusters

The problem is likely the position of the e brake lever because the e brake cables are too tight-even though they may not appear to be too tight.

Be sure the the e brake cables work and are loose
set up your rear brakes. After you are sure the brakes work properly then adjust the e brake.

Relighting this post to pass along findings.

The problem to the original brake issue and also the wump, wump noise coming off the rear end was the axle housing. It is bent. So bent that it could be seen with the naked eye. It was not easy to notice when in the car but once out it was. Somewhere between 5 and 10 degrees out would be my guess.