All-Pro Rear Disk Brake Conversion NOISES

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

iortechnology

iortechnology

10 Year 15 Year
Joined
Jul 16, 2007
Threads
14
Messages
97
Location
Albuquerque, New Mexico
Here's a wierd one for you... Any input from people who have (or have had) the All-Pro rear disk brakes would be appreciated.

Two weeks ago I put a FJ-80 master cylinder, new rear bearings and the All-Pro rear disk conversion kit onto my truck. A major improvement over the drums when I'm trying to stop my 37's and a truck full of camping gear. No problems getting the system installed, no problems for 2 weeks...

...Coming down a pass up in Colorado this weekend, a nice little noise started up. After some playing around with it's source, it's coming from the rear brakes. They seem to be vibrating when the pedal is just pressed, giving out a very loud humm sound that you can feel in the brake pedal. Push a little bit harder and the sound goes away. Brakes feel fine throughout the process, so it's not a safety hazard (yet).

Checked the wheel lugs - the ones that hold on the rotors - TIGHT
Checked the brake caliper bolts - TIGHT
Checked the brake caliper mounting brackets - TIGHT

Pretty wierd. Anyhow, anybody ever run into this?
 
Well, I know you wanted input from someone with the Allpro rear disk setup but too bad :flipoff2: . I have looked at that kit a few times and it doesn't come with a proportioning valve from the looks of it. Did you happen to install one? If not it may be worth giving it a shot, the stock one is not designed for your setup and it is probably siezed up anyway. Your rear rotors may have needed to be turned from the get go because if the man in brown dropped one it could have warped it and so on, or they could have gotten too hot. I'd also check and see how the rear bearings are, since you have new calipers and they grab the rotor at one point where the drums had shoes that grabbed on opposite sides, the centrifugal (big word, geez) force could be telling you a little bit more about what may need to be fixed back there.
 
Well that's the wierd thing about this...

- Turned the rotors and they're dead nuts planar. So they didn't get warped, and they didn't get damaged in shipping...

- I did new rear bearings when these brakes went on, so I'm running a totally new rear setup.

- The proportioning valve is where I've placed it right now. Here's my theory as to what's going on...

When I press the brake pedal at speeds over 40mph, I get the noise just at the beginning of rotor contact. I think there is enough vibration from the wheel/axle interface that here the pads vibrate in the calipers. When I push harder, this vibration is stopped, as the pads are now tracking the surface of the rotor. When coming off of the brakes, you pass by that same "just touching" condition where the noise starts back up. Once you're off the pedal totally, no more noise, no more problem.

That's what I think is going on...
 
Well that's kind of baffling :confused: . But I'm thinking that if it was fine for two weeks and then you got the vibration, something has come to need maintenance? Did you go wheeling and maybe bent a wheel sending a little vibe your way when you put strain on that wheel? Also I know this may be a long shot but do the pads have those neat little metal sticky backing plates that go between them and the caliper piston?

Slightly bent axle shaft? I know that a lot of these things you would notice before such a brake upgrade but would obviously be more pronounced with the brakes applied, especially with stronger brakes you aren't used to yet.

The only other glimmer of an idea I have on this one is maybe when the pads were brand new you managed to get them really hot and glazed them over a little bit before they were broken in. I've seen that cause some problems for people before, but haven't personally had it happen to me yet.
 
Did you use calipers with a build in e-brake (83-85 Riveria)?

If you did, use you need to adjust your brakes, the pistons are pulling back in.

I had this problem with a TSM kit, since many a time the e-brake handle was never pulled. Consider it a must.

If you used front calipers, several vendors have solutions to limit the fluid return.


Several Toyotas have a proportioning valve plumbed into the system to the master cylinder.
 
Well here's my follow-up on the disk brakes out back:

They do make some noise AFTER you go out in the dirt. It seems to be dirt/dust related, because after a few times on the brakes, the noise goes away. In town the noise comes back if it's raining, but I'll take that for the added power.

I'm running the FJ80 master cylinder, and that's really brought the pedal back to a stock feel - even stopping the 37's from high speed.

No brake fade on Colorado passes or under heavy braking (NM drivers are great you know).

Rear axle looks much cleaner without the drums on (pictures to come)

Quieter brakes when 4wheeling. None of that drum brake noise that I've always had when the brake pistons retract. This is a subtle thing, but it's nice. First time I noticed it was when I pulled the truck into a garage and let off the brake...

Overall thought on rear disks for the mini truck... WELL WORTH THE MONEY!

(I think I've mentioned that I'm using the All-Pro t-case disk parking brake... the calipers are the GM metric type ones)

- Brandon :beer:
 
Total cost was something like this:

Rear axle bearing kit (from Marlin Crawler) $150
Rear disc brake conversion kit (from All-Pro) $499
FJ80 master cylinder (from Marlin Crawler) $109

If you need the transfer case mounted parking brake...

Parking brake kit (from All-Pro) $195

Shipping of course wasn't in the list. The only other stuff that might rack up a few extra bucks is getting your old bearings pressed off, doing the work at a shop (if you don't do it yourself), some new brake fluid, some welding rod (for the brake line mounts) and some time.

I did it myself without special tools in an afternoon - including getting the master cylinder installed with a custom gasket. (Custom gasket because the new one didn't come with a new gasket...)

- Brandon

I'll put up some pictures of the finished product here in the next few nights.
 
Those prices include EVERYTHING you'll need. (except beer and time)

- Brandon

:beer:
 
You must log in or register to reply here.

Share this page

Back
Top Bottom