rear brake job for RWAL

[Daveo91Burb]

In the middle of doing rear brakes for my '91 - new shoes, hardware and wheel cylinders. Before I get too far, the PO replaced the semi-float, 9.5 14 bolt with a FF, 10.5 14-bolt. That being said, I think the rear anti-lock brakes are still functional. ls that possible? The computer on the M/C is still there and hooked up and I've gotten some action out of the back end that makes it feel like it is working. So assuming it still works, are there any special procedures for bleeding after I replace the cylinders? I've always taken my anti-lock cars to a shop to have them bled/flushed. Also, do I have to bleed the fronts? Would prefer to leave fronts alone for right now - just need to get it back on the road since I need it this coming weekend. Pads look almost new - I think the PO had replaced them recently.

What's the deal with the RWAL system from I think '90 and '91? Is it worth keeping? If not, what is required to disable/remove it?

 

[da_raabi]

Ahhh... So some squares DID have RWAL!!! While I can't really help with your first question, the second I might. I have to ask - when it rains and you get your brakes real hot, does your rear end slip and slide around when you hit the brakes? My dually does this all the time and its because the rear wheels lock up. If only I had known I would have held out for a 91 square dually - things like RWAL really would have been nice!

My point is that RWAL is really REALLY nice to have!

 

[bucket]

The RWAL is a very very basic system, it's only speed sensor is the vss in the trans. If it is operating fine, just leave it be. If all you did was replace the rear cylinders, just bleed the rears like normal.

 

[bucket]

Also, RWAL was used in the '90 model year too.

 

[da_raabi]

The RWAL is a very very basic system, it's only speed sensor is the vss in the trans. If it is operating fine, just leave it be. If all you did was replace the rear cylinders, just bleed the rears like normal.

Ugh... It needs VSS... I guess it wont be so easy to retrofit then. Glad to hear its easy to bleed though. Not like newer computerized systems!

 

[Daveo91Burb]

Well, not sure it was acting fine before I tore into the back brakes. Reason for doing so was some very uneven and choppy back braking, like the anti-lock was trying to engage or something. But it could just be a wheel cylinder or shoe problem which is what I am hoping for! Will know for sure when I get it all put back together which will hopefully be later this week. I know anti-lock has great benefits in some cases, but don't want to spend a ton of money trying to keep it functioning. If it is broke, I may be interested in disabling. But I'll re-post if I need to go that way.

 

[bucket]

ABS of any kind can't make pads or shoes wear funny, that's purely a mechanical issue.

 

[Daveo91Burb]

Yep, I know. It's an either/or kind of thing -- either I'm experiencing a traditional brake issue such as a sticking wheel cylinder or there is an ABS problem. If it's the former, the brake job I'm in the middle of now should solve it, but if it's the latter, not sure what I will do.

 

[Daveo91Burb]

Got my brakes all back together with new wheel cylinders, new spring kit, new shoes AND new master cylinder. Brakes are working well, firm pedal (as good as an old GM can be) and braking at all four corners. I did lock them up on a wet road, though, and didn't really feel any ABS action at all. Still air in the modulator thing by the M/C? Something else? Thanks for the help.