Rear brake adjustment
 

After re-lining the service brakes on the LHS rear wheel of my roadster pickup I went for a drive to check the adjustment. I gradually rotated the wedge adjusting screw in until the shoe just started to contact the drum.

I was surprised to find that the drum became very hot before there was any braking action. That seems illogical because, if the new lining is contacting the drum sufficiently to generate heat, surely any pressure on the brake pedal must instantly expand the shoe fully onto the drum? What am I missing here?

Re: Rear brake adjustment
 

After adjusting till contact, back the adjuster off a click or two.

Re: Rear brake adjustment
 

Need more information. You only relined the left rear? You relined all but the left rear is the only one giving you a problem? Did you do the ebrake band as well? How well did the drum turn before any adjustment? Did you do adjustment with wheel & tire mounted to the drum?

Re: Rear brake adjustment
 

Reply to Bobbader:
I reconditioned only the service brakes on the left rear wheel, as all other brakes are working well including the e-brake which was not re-lined. After the service brake shoes on that wheel were re-lined, the wheel and tyre rotated freely when it was jacked up. Then I tested the brakes by skidding gently (at low speed) on a gravel road and observing the skid marks. The wheel with the re-lined shoes is the only one not showing a skid mark, so definitely not working. And that being so, - it should not be heating up!

Reply to J Franklin:
Yes, after the drum heated up I backed the adjuster off until I could drive without it heating, but there is still no braking action.

Re: Rear brake adjustment
 

You will need to work with a helper pushing the brake pedal while you watch the action of the linkage and brake shoes. Did you forget a clevis pin?

Re: Rear brake adjustment
 

After major work like that, some of the adjustment is the adjusting screw. Some of it is in the brake rod clevis.

If you shorten a brake rod at the clevis to get it to brake more in time with the other wheels, you will probably have to back out that adjusting screw a bit, too. They work together.

Re: Rear brake adjustment
 

Reply to J Franklin: - No I didn't forget a clevis pin - they are all there.

Reply to Jim/GA: - Thanks, I will check whether any of the clevises need adjusting.

Regardless of all your helpful comments, I am still left with the inescapable fact that the drum starts to heat up before there is any braking action. How can that possibly occur?

I have followed Les Andrews' recommendations all the way.

Re: Rear brake adjustment
 

On further reflection, I guess there is one way that it could possibly occur: The adjuster wedge is turned in sufficiently for the newly-lined shoes to contact the drum and generate heat, but the clevis adjustment suits the action of the old brake linings, which might delay the braking action. Comment?

Re: Rear brake adjustment
 

That is what it sounds like to me.

Many people will really bang the table "do not adjust the brake rod lengths" but I have found that sometimes that is what you need to get the 4 wheels braking the same amount without having the lining drag when the brakes are not applied.

Having said that, I have always replaced both left and right shoes/linings on an axle at the same time, never just one wheel. You may be making it harder on yourself than it needs to be.

Re: Rear brake adjustment
 

Thanks Jim:
The reason I replaced the linings on one wheel only, was because the lining on that wheel got covered in grease. I think I must not have used high temp grease when I did it a few years ago. I used high-temp grease this time.

Re: Rear brake adjustment
 

You may know all of this, but just in case:

Your hub may be fretting on the axle.

The axle key is in the axle, correct???

You had to use a wheel puller to get the rear wheel off originally, correct?

You washed until clean and dry, the tapered section of the hub and the tapered portion of the axle, cleaned and repacked the roller bearing, reinstalled with a new seal and the bearing retaining clip, then torqued to a least a minimum of 75 - 95 foot pounds, the axle nut, with the heavy, thick washer and its gasket, correct?

Some drive around the block and remove the wheel and tire to recheck that the nut is still tight.

The hub and the axle tapers are supposed to be smooth, clean and dry, no grease, oil or anti-sieze when assembled. When properly torqued at the nut, they act as a single unit to carry the torque of the axle to the wheel. If the axle nut is not adequately tightened, the key will wear and the key way will become loose. If the key carries too much load, the axle will eventually crack. If not discovered soon enough, the axle sometimes fails in such a way that the wheel, hub and drum leaves the car. Not good.

Re: Rear brake adjustment
 

Good Afternoon...Can anyone show a brake adjustment board with dimensions for Mad Mac? Then he can follow the directions in Les Andrews red book, or Paul Shinn's, either one will work, and start with the brake rods loose and then do the work to get the shoes to hit the drumbs at the same time on all for wheels. Ernie in Arizona

Re: Rear brake adjustment
 

Years ago we had a worn bearing surface on the rearend housing. We ran with 3 wheel brakes. Not recommend!! Dont ask how I know.

Re: Rear brake adjustment
 

I suggest that all Model A Brake mechanics, especially the DIYer types, watch this video 10 times and then revisit it often. It is clear, concise and thorough. There is no stammering, stuttering or wasted words.

https://www.youtube.com/watch?v=3GFMJ7iiWiI&t=8s

Re: Rear brake adjustment
 

Thanks Rob Doe,
Thats a great video - the best I have seen on the subject. Plenty to think about there, especially the last bit where he talks about adjusting the clevices on the brake rods. I will adjust the clevis on that rear LHS wheel, but not the others, as they are all working OK.

Re: Rear brake adjustment
 

Acting on Jim's advice, I have now tried adjusting the clevis on the brake rod. Unfortunately there is not enough adjustment available before the threaded rod bottoms inside the clevis. Even after tightening the clevis up to its fullest extent, the shoes don’t expand fully onto the drum, so there is still no braking action. This is very strange, as the re-lined shoes must be thicker than the old shoes which used less of the available clevis adjustment. I must be almost there, because pulling the service brake lever slightly forward stops the wheel when rotated by hand.

Re: Rear brake adjustment
 

Are the shoes actually expanding when you step on the pedal? I may have missed it but did anyone mention the key (#12 in drawing) in the brake lever. Maybe it fell out during assembly? Easy enough to do.

https://www.fordbarn.com/forum/attac...7&d=1736898479

Re: Rear brake adjustment
 

I think the Woodruff key you refer to is on the e-brake shaft, not the service brake shaft. Its the service brake shaft that I am concerned with, and that does not have a Woodruff key, as it is secured by a steel pin.

Re: Rear brake adjustment
 

Mac, reading your last post, I wondered if you had left the cam out of the camshaft.

But your last comment that forward movement of the lever with the hand was stopping the wheel makes me wonder if your service brake rod is connected to the cross shaft. You should not be able to operate the service brake lever by hand if both ends of the rod are hooked up properly?????

As I recall, the rear brake rod clevis is supposed to be at the cross shaft. The fixed end goes at the backing plate. Is that where you are adjusting the clevis?

How many clicks from completely backed off is your adjusting wedge?

Re: Rear brake adjustment
 

[QUOTE=Rob Doe;2362384]Mac, reading your last post, I wondered if you had left the cam out of the camshaft.
Answer# 1
Thanks Rob, no the cam is on its shaft

But your last comment that forward movement of the lever with the hand was stopping the wheel makes me wonder if your service brake rod is connected to the cross shaft.
Answer #2:
Yes it is connected.

You should not be able to operate the service brake lever by hand if both ends of the rod are hooked up properly?????
Answer#3
I disconnected the brake rod clevis from the service brake lever when testing to see if pushing the lever forward expands the shoes onto the drum properly. It does.

As I recall, the rear brake rod clevis is supposed to be at the cross shaft. The fixed end goes at the backing plate. Is that where you are adjusting the clevis?
Answer#4: Yes, the clevis at the cross shaft, in the center of the car.

How many clicks from completely backed off is your adjusting wedge?
Answer #5:
Not sure but it is screwed in until driving the car starts to generate heat on the brake drum, then backed off one or two clicks.

The mystery deepens - I am at a loss what to try next.

Re: Rear brake adjustment
 

My suggestion is to have a second set of eyes look at your brakes. Or maybe several more sets of eyes. In my Model T club we would have Tech Sessions where the club members would be invited to a members house to work out a technical problem. The member with the problem would supply lunch. This worked well and we all learned from these sessions.

Mad Mac, That is a really good video, thanks.

Re: Rear brake adjustment
 

Make a brake adjusting board with the steps in it, like in Les Andrews' book, if you don't already have one, so that you can place the brake pedal in the same 3 reproducible spots time after time. A lot of guys poo-poo this board, but its reproducibility helps when sorting out problems.

One of the unfortunate characteristics of mechanical brakes is that 1 or 2 or 3 brakes that are adjusted too tightly can prevent that amount of brake rod movement from engaging the other wheel(s) properly.

The 4 brake rods are all mechanically bound to each other. They are all forced to move together, and if one wheel stops that movement prematurely, the other rods can't move as far as they need to for proper braking.

The solution, once you identify which wheel(s) are too tight, is to actually loosen the tight wheel(s) a bit. This allows the other brake rods to move a bit further and actuate their brakes more.

With all 4 wheels off the floor, see what amount of braking you have at the 3 "good wheels" when on just the first step of the board. We know there will be none on the 4th wheel. Then do the same at the 2nd and 3rd step of the board. It should be getting progressively tighter. You should not have a wheel lock up on the first step (that's too tight).

If the above does not point you to a wheel that is too tight... After noting the braking force at each wheel for each step on the board, start applying the board in steps with each one of the 3 "good brakes" disconnected. See if that helps get better progressive braking action on the other 3 wheels (including the one that is not braking now). Do this for each of the 3 good wheels, one at a time. This may help you identify which wheel(s) need loosening of braking adjustment. It might be more than one.

The loosening of a tight wheel might be done one of two ways: 1) by lengthening the brake rod a bit at the tight wheel. Make very small changes each time (like 1/2 turn of a clevis) and test again. See if directionally it seems to help. Keep a record of your changes, in case you need to go back.

Or 2) the loosening can be done at the brake adjuster screw at the tight wheel.

Since you have 2 things that you can change at each of the 4 wheels, it can get a bit complicated fast. Take your time, make small changes, and record exactly what you are doing on each wheel at each change. An assistant note-taker helps there.

With the brakes not applied, the shoes should not rub inside the drum. A light brushing touch in one or two spots as the wheel goes around is OK, especially on a wheel with new shoes, but they should not rub all the way around.

Changes to the clevis by 1/2 turn are much finer than changing the adjuster screw. So if you find yourself where one adjuster screw click is too much, go back and take 1/2 clevis turn on that wheel instead.

Good luck. Keep us posted on what you find.

Re: Rear brake adjustment
 

Thanks Jim, - some good suggestions there. If one or more of the other 3 brakes are too tight, would they not heat the drum even when disengaged?

Re: Rear brake adjustment
 

One more thing to contemplate would be how much play might there be due to worn rear hub bearing components. I've seen some badly worn journals on the axle housings that allow excessive movement of the hub & drum. Combine that with wear on the other parts and it might rub the drum when the wheel is on the ground but not with the wheel off ground.

Re: Rear brake adjustment
 

No, not unless they were adjusted out to rub against the drum when disengaged.

When I say "too tight", I really mean "adjusted too close". So the shoes get firmly against the drum right away, but are not touching at rest.

I would also recommend you pull the drum off of the "bad wheel" and inspect how the parts were all put together. It is possible that something has been accidentally assembled incorrectly. I can't predict what off the top of my head. A photo of everything with the drum off might help us spot it. (My apologies if you have already done that, posted a picture; I don't remember seeing it.)

Re: Rear brake adjustment
 

A photo might solve it all right.

Re: Rear brake adjustment
 

The fact that only the left rear brakes "didn't work" before you relined them begs the question ................... "Why is that the only one that didn't work?"

The other question is, if you run out of adjustment on the L/R brake rod, has that brake rod been shortened (CUT).

Your check list doesn't appear to have any holes in it. You've checked off and seemed to eliminate anything to do with how you did your repair and re-assembly. That suggests there was something wrong aside from a need to reline the shoes on that wheel while none of the others needed attention. As others have suggested, another set of eyes could be very helpful. Good luck as you continue to find a culprit.

Re: Rear brake adjustment
 

Thank you, Excellent tutorial

Re: Rear brake adjustment
 

Thanks everyone, especially Jim/GA whose suggestions demonstrate considerable experience with Model A brake issues.

In answer to Bobbader: No the brake rod has not been shortened. The only reason why I re-lined the service brakes on that wheel was because it was the only one with grease on the brake linings. All the others are OK.

Attached are two photos, taken after assembling everything onto the backing plate but before attaching the brake drum. I don't want to remove the brake drum to check it again, as I am sure that everything was assembled correctly on the backing plate, as per Les Andrews' book. Please note that I temporarily disconnected the "C" from the e-brake shaft to more easily attach its return-spring (this is not relevant to the service brake issue).

I have now made the brake-adjusting board as suggested, and my next move will be to use it to try to solve the service-brake problem.

Re: Rear brake adjustment
 

Mac,

I've one more idea for you. I've had this issue bite me more than once and learned to be careful about falling victim to it.

The video "How to Stop on a Dime" shows the narrator installing the rear shoes and springs in a specific order. He installs them by hand and it looks easy. It is not so easy for a 74 year old with skinny, bony hands.

When I use the $22.00??? pistol grip leveraging tool, it is fairly easy, but you have to be absolutely certain that you get the head of the roller pin seated on the roller track, and pushed all the way back, (toward the backing plate) else your shoes will not be in position to function correctly. They can look right to the non professional as we work on the brakes infrequently, but still not be fully seated in the correct position.

This leaves the shoes off center for sure.

Re: Rear brake adjustment
 

Thanks for clarification on why you relined just one wheel. Assuming you have hooked up the "C" horseshoe link for the emergency brake since you're not anxious to pull the drum again. If so, is it possible the ebrake lining is too thick? It's hard o tell from the pictures, but it looks to be the same 3/16" thickness as the service brake linings. It's supposed to be 5/32". Perhaps this is causing the drum to heat up as opposed to the service brake adjustment?

Otherwise, Rob Doe's supposition about the roller pins not being properly seated is definitely worthy of inspection.

Re: Rear brake adjustment
 

I think you might have a bad wheel bearing that is seized or ready to seize.

Re: Rear brake adjustment
 

I will predict you will pull that drum. When you do, remove the rod and work the lever by hand and see what is not working.

Re: Rear brake adjustment
 

Did you arch the shoes to the drum? If the new lining is thicker or thinner than the old lining it is possible that the shoe will contact the drum in only one spot. If you adjust the shoes to contact the drum they will rub on that one spot and heat up the drum. But you will not have much stopping power because there will not be full contact.


Bob

Re: Rear brake adjustment
 

This is very true. I have had this problem several times.

Here is the tool that Rob Doe references. It is $19 from Bratton's.

You hook up all of the brake springs without having the rollers engaged yet, pull the shoe away at the bottom/front, stretching the smaller brake spring out, and get the head of the roller clevis pin up on the track. Then let the spring pull the rollers back in against the wedge (front) or cam (rear) to fully seat.

Re: Rear brake adjustment
 

Thanks Bob: The e-brake was not re-lined - it still has the old lining, which didn't need replacing.

Re: Rear brake adjustment
 

Thanks Rob,
I hope you are wrong about that, as I want to avoid removing the drum again if possible. I used a jack to lift the upper shoe onto the roller after the springs were installed. An unusual method, but it gave precise and effortless control as the spring-loaded shoe was lifted up and over. I saw and heard the shoe click into place and it was not off-center.

Re: Rear brake adjustment
 

The bearing was removed, checked and replaced. It is perfect.

Re: Rear brake adjustment
 

Thanks J Franklin,
During assembly I worked the service brake lever back and forth several times to confirm that the cam was expanding and contracting the shoes properly (it was). And after installing the drum I temporarily disconnected the brake rod and worked the lever again. This got excellent brake action with the lever pulled forward. But the clevis has insufficient adjustment to achieve the same result when the brake rod is re-connected. That is my problem in a nutshell.

Re: Rear brake adjustment
 

Thanks Bob,
You might have a point. The shoes were not arced to the drum and also I did not taper off the ends of the new linings as recommended by some. But I find it hard to believe that my problem (as described in the above posts) can be attributed solely to those two omissions (especially if you read post#39 above).