hey guys... i still have my totalled IROC that i use for parts.. i just bought a 92 RS V8 TBI 5 speed.

My question is this.. i have my 86 IROC.. and i wanted to completely swap out the entire rear section (basically the entire complete axle, disk brakes, ect.) and i was wondering since my 92RS has drum brakes.. and my IROC has disks.. what do i need to do to the brake lines? anything? will this work ??? anyone done it?

please dont say "use the search button" cause i did and i cant find jack crap on the subject.. the rear end from the IROC is in great shape, in fact it had a brand new brake job right before it was crashed. so will it work? or will i have to mod. the brake lines?

thanks guys

David Fisher
Orange CA

 

KiLLJOY, you have both cars at your disposal, the only thing I can say is get under both cars and see what is the same and whats not. The brake lines swap out with the rearend and everything is interchangeable so you have all the parts to do the change over. All should go easily with no major problems. Don't forget to change the distribution block under the master cyclinder over to the RS as well. Hope this helps.

Steve

 

awesome, thanks Steve.. i didnt think about that block.. i'll make sure i pull that too.

as i recall, this rear end was a 3:23.. and is a posi... new disks, new brakes.. man im glad i kept this thing.

thanks again



David Fisher
Orange CA
92 RS TBI 5 speed

 

The main thing you'll need to swap from the donor car, for that brakes, is the combination valve. This is the device which is connected on the driver's side frame rail under the master cylinder. The combo valve for drum brakes are different then the combo valve for rear disc brakes. The combo valve for drum brakes has a residual pressure valve as part of the device which applies a constant 4 psi of pressure to the drum brakes. Disc brakes do not require this (that's on of the main differences of the to). Plus, the proportioning part of the combo valve might be different, too.

I'm not too sure if the master cylinder is different or not. (Personally, I don't think so... but don't take my word for it).

Later,
-Mike

 

Ive never got a straight answer on the brake lines. I guess I'll find out over spring break.

 

The brake lines should all be the same.

 

Last time I looked into this I rember needtin to swap the master cylinder as well due to the volume they put out. The early disc rears (pre '89 I think) needed more volume than the drum breaks. I belive the '89 and later disc rears use the same master cylinder as drum cars. you could look up the master cylinders part numbers for the differend rear break setups (i think you could find this at www.autozone.com ).

I could be completely out to lunch

hope I could be of assistance
Ryan

 

teh lines are teh only thing you need to change over to convert from disc to drum. gm did supply the 4wheels disc brake cars with a different proportioning valve, but i have been in cars that were converted and kept the rear drum prop block and i never nioticed any difference in performance or wear.

later
tim

 

An easy fix for the proprtioning valve is to plumb an adjustable prop valve in the line. You can tune the brakes pretty damn well and even adjust for diffrent size tires/tread in the back. A disk brake swap/master cylinder/prop valve cut the stopping distence on my blazer by about 60% from 60-0.


Charlo