TooSlow

Hi all,

I have an '89 RS coupe with rear drum brakes. I just purchased a posi rear from a '98 SS that came without brakes. My project is being done on a shoestring budget. Can anyone tell me if I can bolt the existing drums up to this '98 rear?

Thanks in advance for your help!

91phoenix

iTrader: (5)

Probably not very easy as the drum brake backing plate oy yours is much bigger and has the mount for the wheel cylinder made onto that backing plate and it does not unbolt from the axle. Look for a set of LT1 discs fom 93-97 cars or see if the later cars drums had a different type of backing plate as compared to yours. I know that some 2nd gen drums are the same so you might be able to make those backing plates work. They are definitely not necessarily the proper bolt pattern though.
Of course this is still a drum brake rear then and not an upgrade of the brakes at all.
Good Luck

TooSlow

Thanks for the info, 91Phoenix. I bought the '98 rear for the 3.42 posi in it; my car is a 2.73 pegleg. I'll have to decide whether I am better off swapping the gears and carrier into my rearend or trying to get some cheap brakes to bolt on and fit the '98 rear.

91phoenix

iTrader: (5)

If you decide to swap the gears and posi carrier over you may need to reshim it for proper gear pattern. You also may need different axles. It seems that some 89's had 26 spline and some had 28 spline axles. The 98 carrier you have is designed for the later 28 spline axles. In general that means 90 - 92 axles.
If time isn't critical I would look for a T/A or a Z28 (93-97) in the yards to find a complete disc brake setup. Calipers, rotors, muonting brackets, cables, 4th gen inner e brake cable routing loop brackets, everything from the axle flange out with all cables and brackets. Or look for a 98 up for the LS rear brakes and do the same.
Then I would do more research on here for that type of brake and put that rear end under the car when you feel you are ready.

sofakingdom

iTrader: (1)

Can't think of very many WORSE ideas for this situation...

Best plan would be to go to the junkyard and get all that crap off of some crappy 6-cyl car or something. Anything 98-up will do. AFAIK it's identical in every way.

Just don't talk about "LS1" this and "upgrade" that and and "swap" something else, and they'll prolly figure you're just helping your little sister in HS out or something and cut you some slack.

TooSlow

Good advice and info, thanks! Time is not of the essence, so I've got some time to look around. 3rd gen cars are pretty thin in the salvage yards here, but 4th gens are fairly common, so it is more likely that I'll make the brake swap.

One more question--will I likely need the brake proportioning valve from the donor car as well?

sofakingdom

iTrader: (1)

For best results, yes, if you can get it.

91phoenix

iTrader: (5)

Sounds as if you now have a much better plan on what you are going to do and be much better off in the end.
Sofakingdom is right that drums on that rear is a poor choice. I am not sure if the proportioning valve from a 4th gen will work on our cars though. I know that they changed the threads for 90 or 91 and do not know how the 4th gen proportioning valves may have changed, especially considering the anti lock brake systems.

TooSlow

Thanks again for the advice. I'm going to tear into the rear this weekend to confirm what I think I have an move forward from there.