VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 31 Brake Adjustment

The brakes on my 31 sport coupe work very well. The car was completely rebuilt three years ago so all brake pads were new. I have no oil leaks near the brakes. Had good pedal height when stopping until my last drive. Pedal is now close to the floor when braking normally. Seems time for an adjustment. I have not done any adjustments to the brakes since the rebuild. I have the repair manual and the instructions are straight forward. My questions are:
1. Do I have to jack up all four wheels at one time to do this, as per the manual? Seems like doing both front or both back at one time works well (I have already done some adjusting).
2. How much drag is 'slight drag' as stated in the manual? I give each of the front wheels a good spin and the brake shoes create enough drag that each wheel will not turn more than two times before stopping (with both front wheels off the ground). The back wheels had no contact between the shoes and the drum until after I adjusted them.
3. Are there any tips or rules of thumb that would help here?

Thank you for any suggestions.

Jim.

I'll give you a short response. Hope that it helps.

Place a hydraulic jack under the front axle in the middle. Then you can adjust both fronts at the same time. Then when you're done with the front, place it under the rear banjo housing and you can do both rears at the same time.

My technique is to turn the adjustment screw until the tire won't turn at all. That way I know for sure that I've reached the "end of travel". Now back off about 5 half turns. Enough so that there is freewheeling. But it is okay if there is just a LITTLE bit of drag noise still present. The wheel should turn 3 or 4 times with a single spin.

Now do the same with the rear. Try to adjust them with the same number of turns when you back off. If you need to , I would always have the FRONT brakes engage a little bit sooner than the rear ones. So maybe the fronts would be backed off 4 half turns while the rears are backed off 5 half turns.

Now the number of half turns may vary depending upon the condition of the shoes and the amount of slack in the entire system. So let your ear be your judge. The first wheel that you adjust should be backed off so that it spins freely, with only a small amount of scraping noise. By the time that you get to the 4th wheel, you might have to modify your target number of half turns a little bit if the rears end up being too tight.

When you're done, you should have all four brakes engaging at the same time. Stopping quickly on a gravel road is a good way to test this.

If the pedal is still too low, then you need to adjust the pedal just under the floorboard. A single bolt there will do the trick.

Good luck.

--Bill B

Jim,
My first question is "Did you centralize the brake shoes when the shoes were first installed?" The reason I ask is that centralizing is commonly not done unless you follow the procedure in the repair manual. Also I have never found all centralizers on a used '31 or '32 to be free and adjustable. Centralizing is critical as it positions the shoes to both contact the drum simultaneously. Both shoes working together are far better than only one. Rapid loss of pedal height can be due to only one shoe contact.

If you have riveted woven linings they tend to wear down fairly fast until the high spots are level with the major part of the lining. It is also common for the linings to not be completely flat against the shoe. Heat and pressure will correct that fairly quickly but loss of pedal height will occur. So it is not uncommon to have to readjust each wheel and also the brake rods.

Bill:
Thank you for the details in your response. That is the type of information I had hoped was out there. I have not had to adjust these brakes before so it is great to have input from someone who has.

Chipper:
The brakes were centralized when the car was rebuilt (from the ground up). I have only used the car on short rides, like around 10 or so miles, over the past two years. It was on the most recent ride, which was closer to 30 miles, that the low brake pedal developed. After reading your response, it makes sense as to why it happened. I do have the riveted woven linings, which were new when the car was reassembled.

I thank both of you. Your responses have been a great help in understanding the problem. I hope to work on the brakes this weekend.

Jim.

When a person has owned and driven '31 & '32 Chevrolets for over 40 years some knowledge creeps into the brain. Trying to understand what happens can be a challenge but discussing the problems and fixes with others and reading the volumes of literature helps a bunch. VCCA tours are a prime educational experience. That is if you don't hide in your motel room each evening or don't even go on a tour. Try it you just might like it.