Vintage Mustang Forums banner

How do you tell if brake shoes have crystallized?

5886 Views 4 Replies 5 Participants Last post by  Sportsroof1970
I've been working to improve my brakes, with very little success. A while back I put in a 9" rear with big drum brakes. New spring kit, new shoes, new wheel cylinders. My brakes might have been a *little* better. Over the course of a couple of months my brakes got progressively worse. I put new shoes and springs on the pass side (it was raining, didn't feel like fighting the weather to do boths sides and the shoes looked good anyway). Well, I finally got around to doing the driver's side. I pulled the drum, and the shoes were in good shape. I put in new springs and shoes, and a new wheel cylinder. I also replaced the wheel cylinder on the pass side at this time (I was told to replace them in pairs). The brakes weren't any better. My father-in-law tells me to adjust the brakes out. I did, until just barely causing resistance when raised off the floor and rotating the wheel. I go for a ride, and the car tries to pull to the left (driver's side) when braking. I figure it's because of the newer shoes on that side. So I brake often, and drive a little with my brakes applied. Smoke starts coming from the rear drums!. I pulled the drums (after letting everything cool) and saw no damage. Must be the master cylinder, so I install a new dual res master cylinder. No improvement. Now I'm wondering if I made the shoes crystallize when I did my driving with the brake on. If it was enough to make smoke, I figure it got pretty hot. This weekend I plan to pull the drums again. What should I look for to tell me if the shoes have crystallized? It takes way too long to get the car to stop, and that's about all I can think of that would be causing this. Thanks /forums/images/icons/smile.gif


PS - Yes, the master cylinder was bench bled and all the lines were bled afterward.
See less See more
1 - 5 of 5 Posts
If you find the lining has multiple cracks, replace them. After you have adjusted your shoes to the drums (very light dragging), also do this; back the car up and apply the brakes rapidly several times. This action will cause the self adjusters at each wheel to do a final adjustment. That should help eliminate the tendency for the brakes to pull the car to one side.
so what kind of increased performance are you looking for? I'm sure those huge drums will last longer in an autocross before you get fade...
Does the pedal travel feel o.k.? It's a good possibility that you did do some crystallizing of the shoes, but my drums that I used to have on the front of my car would always crystallize/crack, but I still seemed to have pretty good braking power, surprisingly.

I didn't see in your post that you've installed new drums. Have you had them checked to see if they're past their wear limits? They could be too thin and getting too hot for proper braking performance, or maybe they're grooved, warped, or who knows what else. A good clean machined surface might help them out.

What setup do you have on the front of your car? Have you checked these lately? I'm assuming they're discs since your car seems pretty built in the first place. Maybe they need some attention, too?

Could very well be the shoes are too cooked to get the job done now, depending how hard you were on them, and how good of a brand they are (Autozone's suck IMO, get NAPA shoes).
Let us know what you find... good luck
See less See more
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.