What causes glazed brake linings? UPDATE

Re: What causes glazed brake linings?

A couple of guys in our club use Flathead Ted's floaters, but they put the upper return spring back on the brakes even though the instructions said not to. According to them the brakes work just fine with the spring installed.
 
Re: What causes glazed brake linings?

BRENT in 10-uh-C said:
How did we determine it has composite linings?
Click to expand...

I was wondering the same thing. :confused:

I also don't like the idea of leaving off the brake shoe top return spring. At least a section of a screen door spring would help, but I'd probably leave in the original top spring if I was to use floaters.
 
Re: What causes glazed brake linings?

I'm using woven brake linings. I can easily put the top return spring on. Another good idea. Thanks much.
 
Re: What causes glazed brake linings?

Had the same issue with my fronts also. Cast iron drums and new hardware. sanded twice but the noise reappeared after 50 miles or so. Switched fronts to the Scandinavian woven lining( riveted). Been fine for 3 years. I do miss other drivers starring at me when I stopped in traffic, however.
 
Re: What causes glazed brake linings?

Not so much, James! :) It's great to have so many of you lend a hand.

I am working the problem and hope to have an update later today.
 
Re: What causes glazed brake linings?

Here's my update. I'd describe it as "mixed news".

I found that one of the rf brake adjusting shafts was binding in the adjusting housing, preventing it from smoothly sliding in its tunnel. I noticed that the center lines of the shaft and its tunnel were not quite parallel. I found that the roller plate at the lower end of the shoes (unique to floaters) could be moved slightly to correct the misalignment. [During installation of the floater system, the position of this plate is set by finger-tightening the mounting bolt and, with the drum installed, using the adjusting screw to lock the brake. It's done without regard to other things such as the alignment of the adjusting shafts, etc.] Thereupon the binding went away. Now the adjusting shafts move smoothly and one moves in response to movement in the other.

I checked the lf brake and found a much reduced version of the same condition. I made a similar adjustment and improved the smoothness of operation.

I removed all the glaze from the front brake shoes. There was a lot more glaze on the rf shoes than on the lf shoes. Since there was a lot more binding in the rf adjusting shaft than was the case with the lf, I suspect that the difference in glazing is related to the difference in binding.

I then went through the usual brake adjustment process and encountered different results between the two front brakes:

Left Front - I found that, with no brake applied, the brake dragged noticeably when adjusted to have severe drag in the 2" position on my brake board. Loosening the brake adjuster to eliminate the "no brake drag" resulted in no braking power at the 2" position. I could either have unacceptable free wheeling drag or no braking power! I suspected that the corrective adjustment applied to improve brake adjusting shaft smoothness might be responsible for this and reversed the correction. Now I could adjust the lf brake correctly. Interestingly, the adjustments applied (to either brake) were very small - I moved the offending brake shoe upward no more than 1/32". The moral of the story is that very small changes are meaningful.

Right front - I was able to adjust the rf brake so that I had l just a bit of drag with no brake applied and severe drag at the 2" position.

I then did a road test with these results:

1. Squeal is gone.
2. Good stopping power with no pull.
3. Rears lock up on gravel; fronts do not.
4. Front brake drums are moderately hot after a 5-6 mile drive with several stops; rear drums are cooler.

One reasonable conclusion, I THINK, is that the squeal was caused by the glazing in the rf brake which in turn was caused by heat resulting from brake drag.....caused by the misaligned brake adjusting shaft.

I am still getting some drag in the fronts, though noticeably less (measured by heat) than before - especially in the rf which seemed to be the primary source of brake squeal. I've made progress, but the results should be better. I see a couple of options at this point:

A. Have the front drums re-trued and their shoes re-arced and see if this improves anything; or

B. Switch back to the stock brakes.

Of course, the drag remaining in the front brakes may well bring about more glazing and thus more squeal. But for now, all's quiet.

Comments, suggestions and questions are welcome!

Thanks again for all the suggestions heretofor.
 
Since you said the front brakes will not lock-up on gravel, when the brake pedal is fully released, can you post a picture of where the Front Brake Actuating Arms are positioned? Then, if you can depress the brake pedal and show a picture of the same thing, I'd like to see that. For the short-term, I would NOT re-machine the drums nor do anything to the linings. Also, did you re-install the missing long brake spring??
 
Hi Brent.

I did reinstall the long springs but then removed them to reduce the number of things changed.

Here are the pix you asked for. These are from the left front. Right front appears identical. First pic is the brake actuating arm at rest (no pedal depression) and the second is with the brake pedal depressed to the 2" mark on my brake board. BTW, I have adjusted all the brake rods to remove all free play.
 

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Hmmm - looking at the angle of the brake actuating arm in the "at rest" pic - does it look as though the angle is too far forward? Looks closer to 30* than 15*. Or am I imagining this?

BTW, I checked the free play in that arm this morning and found none.
 
Yet another update. Decided I would measure the angle of the front brake levers. They were much closer to 30* than 15. I pulled both sides apart and removed pills - now they are bang on 15*. I reset the anchor bolt/plate and the brake adjusters. I had time for one test drive and found that the brakes are working well though they won't lock up on my gravel lane. Happily, all four brake adjusting shafts are running cool unless I translate momentum into heat (ie, apply brakes hard). I'm going to tweak them a bit to see if I can achieve lockup. More to come.
 
good news but take it easy dont rush things..
newly surfaced drums //with new relined shoes need to seat and break in a little..
dont kill them trying to lock them up as they usually are not as responsive being fresh
if you fix your dragging problem just use it normally for a bit before you go nuts on them
 
Thanks, Mitch. Though none of the parts are particularly new - everything dates back to 2011.......several thousand miles since then. :) I'm happy to take it slowly to see what happens/changes; I can wait a while to tweak the brakes!
 
Leaving for the New England Meet Wednesday morning - will see how the brakes perform on that trip. Hopefully I can report that they continued to behave!
 
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