Please help save my life....brakes are important you know. I have an 87 gta which was originally rear drum and a 10 bolt. I swapped in a austrailian 9-bolt with disc which I THINK was from an '89 or maybe '91. Basically the rear brakes don't really work at all. I bought a disc master/prop combo from a guy that said it was off of a '89. As you know, there are no part numbers on the master/props to verify. I ordred a set of calipers for a 89 disc car. I assume when i put it all back together it should work, but when i did research a while back, i see that they used about 20 different prop valves over about a 5 year period. Can i assume that if the master/prop that i bought is from an 89 disc, it should work well with the new '89 calipers that i bought. I'm hoping it'll be better than the '87 drum master/prop combo that is controlling the '89 disc calipers on the car now. thoughts? the rear end p/n is 10085391 and the s/n is 1491, if that helps...don't know if that can help narrow what i should have.

 

I'd try adjusting them first.

 

how do u adjust a master/prop and disc calipers?

 

If the discs are from an 89 they should be the old cast iron saginaw disc brakes (as opposed to the better aluminum PBR rears). There is a recall kit that will fix some issues with the self adjustment of these brakes. Use of the emergency brake-religiously-is required to keep these brakes adjusted AFTER installing the recall kit.

The disc/disc prop valve from any vehicle prior to 89 will work, there may be some issues with earlier (82-84) metric to SAE connections at the prop valve but I've no direct experience with that.

Even re-built and properly adjusted they are only marginally better than the rear aluminum drums.

Look here for the part number for the recall kit. Maybe it's still available.

https://www.thirdgen.org/forums/brak...tml?highlight=

 

at the part store, they said the part number was the same for 89/90 and i think 91 92, so i think i may be getting the pbr's. my other big question is if the master/prop that i am putting in will work better than the original 87 disc/drum one that is in there now. i have pbr calipers that i took off the rear, but one is frozen, so i was gonna replace both.

 

The change over year was 89.

If it came with the aluminum PBRs then you may not need to change the prop valve. The later brakes didn't have the fluid requirement to older iron ones did.

 

okay, so i assume the calipers that I have on order are gonna be okay, since they were the same part number as the 90's ones. As far as the prop goes, I might as well change it to the disc/disc '89 prop/master combo that i have, and remove my factory'87 disc/drum one, since i already have the lines disconnected. good idea or no? i assume it could be better, since ther rears were just not working