VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 1933 Chevy Master - rear brake lockup

When I am backing off my car hauler the left rear brake will lockup on the ramp. I can pull forward and brake unlocks. Then backing off again I touch the brakes and it locks up immediately with a bang. You can apply power in reverse and the right wheel will spin. I eventually get it off the ramps by letting it roll off. Once it is on the road I get up some speed and apply the brakes and everything is normal again both forward and reverse. What might be causing this?

I had a similar problem with my 33 Eagle. Took the drum off and found a small nut. Removed the nut, and no more problem.

I had one do something similar & it had a broken return spring...Joe

Thanks for the responses. I was hoping not to have to get into the brake because as you know on the '33 you have to drain and open the differential and pull the axles to get at the rear brakes. But, it can be done. Anyone else have ideas before I do this? Gene

Check the tension on the cables to be sure that when the rear end gets a twist on it like one wheel slightly higher than the other the cable has enough room for the twist with out appling pressure on the brake. I had that problem when I went through a dip in the road...the rear brakes would apply automatic. I had to back off a little. (May be on your's, too. May be not.)

Do a search on this site as there have been numerous discussions of this problem.

Ray and Joe have a possibility and a third is oil leaking from the differential and contaminating the brake linings.
Tony

I see that one at work from time to time Tony....Joe

So have I Joe, another 1 today on a Toyota 4wd totally locked up on 1 wheel wouldnt drive at all.
Tony

Tracking down a lockup problem can be really tricky, especially if nothing is obvious on opening the brakes. After 40 years of trouble free brakes, I developed a really severe RR lockup going forward problem on my '33 Master RR after winter storage and had someone open the rear and check it out. Car came back pulling hard to the left and rear brakes could not be adjusted. I have just spent six weeks going through all 4 wheels myself and have not been able to road test yet. I tried to note every possible problem and found a lot of possibilities. The front brakes were really crudded up and required complete disassembly and cleaning. Possibly due to clean rears the fronts would not apply. I found the front return springs to be longer than the rears and the part number is same for all 4. Based on the '29-'34 parts manual photos I determined that the longer 40 coil spring was for the Master model and the shorter 34 coil spring is for the Standard model (assuming they did not mix the photos). I found the RR short shoe yoke to be extremely tight at the pivot point. Opened it up in a vice with a big hammer. That may have been the real problem. How the spread on the yoke tightened up is a mystery. Heat? Studied the Filling Station article on seizing due to old bushes and ordered them but found that work had to be done in the car because rear cam housings cannot be removed from the car. Fronts can. Wear was not great enough to warrant rebushing anyway. Probably due to the number of times I experienced the problem forcing the car to go forward and reverse to release the RR brake I also noticed car sagging on the RR. I took the rear springs to a spring shop for reaching and should have them back tomorrow.

Tom

Thanks, Guys. I guess I'm going to have to pull all 4 wheels to see what is hanging up. (bah humbug) I'm thinking that the springs are weak from age. I will report my findings when I get to it.

I had a 33 Eagle sport coupe several years ago that developed a similar lockup problem on the front wheels. One or the other would lock up when applying the brakes at slow speed, as when approaching a stop sign. Often I had to back up slightly to release the locked up brake. I tried readjusting the brakes many times with no change to the lockup problem. I finally pulled all the drums and discovered the brake lining material was a soft woven canvas-like material. I obtained some NORS riveted type conventional asbestos brake linings, and after installing the new linings at all four corners, the brakes worked perfectly.

Mark

I had a similar problem with both lock up and brake squeal. I tried every mechanical adjustment to no avail. Finally I tried a spray product by Kimball Midwest and it has solved both problems. Its called Complete Brake Finishing Treatment part number 80-1096. www.kimballmidwest.com for more info.

One other point. After completely cleaning and reassembling the brake assemblies and before installing the drums, I used a fish scale to see what the pulling effort would be at the end of the brake rods to the rear wheels and end of the brake rods that connect to the cables for the front wheels. I knew that they should be about equal left to right. For the record it took about 6 pounds to actuate the rear wheels and 12 pounds to actuate the front wheels. It makes sense that the fronts would require more force due to the additional friction in the cables (New from the Filling Station and lubed with 140 weight Gear oil). I still don't understand the operation of these brakes when it has been said that the fronts should apply before the rears.

Actually the back brakes are engineered to activate before the fronts. That is to attempt to not loose steering and stability if the fronts come on first. That is particularly the case on wet or icy roads.

Well, I have all four brake drums off and everything looks perfect just as I finished rebuilding them. OEM type woven brake linings look good, no oil leaking on the linings or drum surfaces, springs are all the same length, all pins,and contact point lubricated. I guess I could investigate stronger springs and try the Kimball Midwest Complete finishing treatment recommended by Steve D. I just wonder what this product is and how it works. Gene

Click on the link above and you can get all the information on the Kimball/Midwest product. It's my opinion that some of the soft woven lining is too aggressive. I can't guarantee that it will cure your problem but it did for me and I went thru all the same steps you noted above. Also had a friend that worked in a restoration shop check everything and we could not find a mechanical fault.

My only question is that if I change the lining material to some modern type will it have similar friction qualities to the woven type that I now have? My mechanical brakes at 50 MPH are pretty scary as it is. Gene

I don't know how you got from wondering about the product I mentioned to changing the brake lining. Did you review the information contained in the link for Kimball/Midwest? If your lining is not worn out then I see no reason to change it. When you posted you had rebuilt them I assumed that meant you had the shoes relined with modern non-asbestos lining. If not could you advise what exactly you did to "rebuild' them.

Gene,

I am curious as to the number of coils in your return springs.

You might try the pull test with a scale on the rears to see that they are about equal right to left. If not one of the shoes may be binding at the pivot point,

Chipper,

Thank you very much for clarifying the brake application front to rear. It makes complete sense. From cycling days in my youth it was always necessary to apply the rear hand brake prior to the front or you could have nasty spill.

The lining type is 3/16" woven as I understand is like OEM. All is in good condition. Before going to another lining type I will try the Kimball/Midwest product. The reason I thought about another lining type is that when I had my first '33 Master in the 50's the linings I had were a Johns Manville product (probably asbestos type) and never had any sort of problem such as I am having now. When I get time I will do a pull test and count the number of coils on the springs - and respond. Gene