Hard Brake Pedal - Update on Post #9

[Pilotdave]

jb-ob, thanks for your input! A couple of things:

1. After installing the new shoe I kept checking the drum as I tightened the adjusting wedge and could feel it progress through stages from free wheeling to locked. I checked each time I tightened it to be sure that the adjusting wedge wasn't hung up on one of its ridges.

2. The old linings have a glazed appearance and feel slick in comparison to the new lining.

3. The internal parts of the brake unit appear to be in proper condition. The tracks are in good shape, the operating pin, wedge, rollers and roller pins are new and in good shape, and the brake unit operates freely and smoothly when I operate the brake lever which is set at slightly more than 15 degrees with free play removed.

4. My plan is to replace all 4 - not just 1 - of the front brake linings. I'll then check the rear brakes, then reset all the brakes.

I agree with you that these brakes are a simple system! I'll report back....

Dave

[1931 flamingo]

Is it possible that the whole problem has been glazed linings??


Glad to see you're still "playing" with the A's. Is the problem on the 400??
Paul in CT

[Pilotdave]

Hi Paul. Nice to hear from you!

I THINK it's possible that one of the problems is caused by the glazed linings. I don't see how the original hard brake pedal would be related to that, but then I don't follow why changing the adjusting wedges would have caused that to go away! I suspect that poor braking power is related to the glazed linings, but time will tell.

Yes, this issue is happening with the A400......though once I get it fixed I need to turn my attention to our Roadster!

[jerrytocci]

I had two stuck front wedges .

[ericr]

exactly what causes glazed linings?

[jb-ob]

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Really Dave, this isn't personal that I keep re-directing your thoughts .....

Glazed brake pads & linings are the end result of brakes working correctly. While it might be possible to heat linings so much they might be fried, ain't happening on your common Model A Ford.
The glazing on the old brake shoes could be sanded off with 100 grit paper.... good only until you hit the brakes again.

You are going to have those 'new' shoes arched to the drums ??

The reason for arching is to have as much brake shoe contact with the drum. Yes, you could toss in new shoes but until they take a seat to the drum you'll have less than perfect stopping. Examine the original shoes to see the amount of contact (glazed surface) around the surface of the shoe.

[Pilotdave]

jb-ob, thanks for your input.

So you are saying that I could restore the surface of the existing linings by doing a little sanding.....I will try it and see if I can now lock the drum with the adjusting wedge. Who knows??? I know that the new lining appears to be thicker than the old one...perhaps the issue is not the glazed appearance so much as the thickness of the lining.

I have checked both rear brakes and can lock the drums with the adjusting wedges. So now it appears that the front brakes are the culprits.

ericr, I'm unsure what might cause the glazing on the linings. I suspect that heat might do it, but if so, I don't know how much heat would be needed nor what would generate that amount of heat.

[RonC]

Originally Posted by Bob C

The drums Bratton's sells are nodular iron.
Definition of nodular iron
: cast iron in which the graphite is present as tiny nodules of characteristic structure.

Yes they are ductile iron

[CWPASADENA]

[QUOTE=Pilotdave;

ericr, I'm unsure what might cause the glazing on the linings. I suspect that heat might do it, but if so, I don't know how much heat would be needed nor what would generate that amount of heat.[/QUOTE]

There is a lot of lining out there that is a lot harder than the original, especially most of the lining material that comes from China. It will glaze especially if it was not arced correctly to the drums when it was first installed. Hard lining requires a lot more pedal effort to get the car to stop than the original soft woven lining that Henry used. I have woven lining on all my Model A's and all of them really stop good.

My opinion,

Chris W.