I have an '84 Z28 with J50 rear drum brakes and recently I purchased a '92 Z28 J65 rear disc/posi/3:42. Has anybody performed this particular swap and if so what problems can I expect? I read on another post that someone had a problem with hooking up the E-brake. I have all the cables/brackets from the calipers to the E-brake splitter from the '92 as well as the brake line that runs from the proportioning valve to the rear axle(because it has a different bend in it to the valve). I also ordered a new proportioning valve for the '92 because I was having trouble locating one from the wrecking yard. I was told two different stories about whether or not I had to go with a rear disc specific prop. valve, any body have any info? Thanks alot......


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"84Z28/'91 305TPI comp cam flowmaster TB coolant bypass/shutoff valve to heater core MAT relocated Ram-Air(home-made) gutted air-box IROC ground effects/wheels GY245/50's 700R4 superior shift kit/ corvette servo(excellent shift kit BTW) Rebuilt engine and transplanted it myself. Love this engine!
LOW performance people should drive low performance vehicles!

 

Well I'm pretty sure you can keep your J50 master cylinder. That was my biggest headache on the car.. when I went from '86 drums to '84 discs, I got a bad rebuilt m/c, and spent a week on the brakes.

82-88 used different m/c's for J50 and J65 brakes.

89-92 used the J50 master cylinder for both braking systems.

You can verify this thru places like carparts.com or wrenchhead.com .. look up both cars's master cylinders.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

 

I did that swap. I have a 91 firebird that came with a drum brake open differential rear end and I swapped in a posi disc rear end out of a 91 Z28 and I didn't run into any problems what so ever. It was just a simple swap.

 

Brent, did you change the proportioning valve?

 

The p-vavle change at some point, There is a first designe and a 2nd, you may want to go back to as far as 89 (same brakes) and get the first 1, that is what I had to do.

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