Cascade Crew

fiveoformula · Posted: Thu Aug 13, 2009 1:26 am Post subject: More rearend/brake stuff

Just aquired Chris' old posi-disc rearend, Ill be swapping it out next week and I had a couple questions...

Will the center brake hose on this rearend fit the factory fitting on my car?
Or any lines I have to worry about?

Aside from the limited slip additive, What fluid would be good for a used diff? Cheap? Synthetic? 75w-90? 75w-140?

I have 2.73's now with a 700R4, how much is my speedometer gonna be off once I have these 3.73's in?

Al Hasse · Posted: Thu Aug 13, 2009 4:18 am Post subject:

Brake lines from 82-83 are most likely SAE, and 84 on have metric lines. My rear came from an 82 TA and I adapted the fitting on the car to the rear. If the rear you got from Chris is post 83, then the lines should match up.

The posi I just bought (new in the box), has a note that says not to use synthetic fluid. Recommended 80W-90 oil as well as the GM posi additive..

My speedo is off 5% now with the 3.23 over the 3.08 I used to have - it reads high. It will be off another 20% when I put in the 3.73 in that I have, but I have the correct drive/driven gears on the way.

83Z28BlackBetty · Posted: Thu Aug 13, 2009 7:14 am Post subject:

do you have discs already? if not you are supposed to get a new proportioning valve to reduce rear brake line pressure.

~JAKE <- wishes he had taller gears

DBL_TKE · Posted: Thu Aug 13, 2009 12:06 pm Post subject:

Taller gears? what do you have now?

83Z28BlackBetty · Posted: Thu Aug 13, 2009 12:16 pm Post subject:

oops... er.... mmmm Embarassed

I have 3.27's 9 bolt now. I'd love a 3.45 or 3.70 gears. so shorter?

DBL_TKE · Posted: Thu Aug 13, 2009 12:27 pm Post subject:

Lol, I used to get that backwards too. But after years of seeing Evo' and civics with the sticker "short geared" and then seeing them cross the finish line at the top of 5th gear I now have the definition stuck in my head.

Derek, I think you'll need longer flexible lines if I'm not mistaken.

fiveoformula · Posted: Thu Aug 13, 2009 9:43 pm Post subject:

Skyler, I think the rearend came with the correct hose attached.

Al, Chris says this rear is from an '83, which lines will need to be changed? and with what fittings?

Jake, im on the lookout for a prop valve Smile

Al Hasse · Posted: Thu Aug 13, 2009 9:54 pm Post subject:

83 is a crossover year IIRC, which means it may or may not have a metric (10mm X 1 I believe) fitting on the line.

When I picked up the rear end for my car, it still had part of the chassis line attached - the line was cut off the car, so I flared that fitting onto my chassis line. I think it's a 7/16 X 24, but I might be wrong. SAE fittings are easier to find, so if you can remove the T-block from the axle, do that and take it to a parts store and find a flare nut that fits. NAPA in my neighborhood has flare fittings.

fiveoformula · Posted: Thu Aug 13, 2009 10:15 pm Post subject:

Oh I should probably go out and look to see if its metric, maybe Chris could chime in?? He had this rear on his '86 I believe.

*Edit just went and looked, looks like the fittings take a 12mm wrench.

Quasi-Traction · Posted: Fri Aug 14, 2009 8:39 am Post subject:

sorry to be late on this........

everything should be there to attach it to the hardline on the chassis. never had to buy any adapters or hoses (my car started out with drums), so yes, its safe to say they are metric.

also, there should be 80W-90 gear oil in it now, plus I put a bottle of the LSD addative when I got the axle orginally.

fiveoformula · Posted: Fri Aug 14, 2009 8:45 pm Post subject:

Cool thanks Chis, I was happy to see metric. I just picked up some plain valvoline gear oil and a cover gasket, it's going in tuesday!

fiveoformula · Posted: Tue Aug 18, 2009 9:27 pm Post subject:

It's in! with minimal problems! I have a slight brake fluid leak near one of the calipers that ill fix tomarrow, and we broke one of the sway bar end links... but all in all, things went pretty good.
Heres some pics...

fiveoformula · Posted: Tue Aug 18, 2009 9:29 pm Post subject:

one more

83Z28BlackBetty · Posted: Tue Aug 18, 2009 9:38 pm Post subject:

Way to go!

Now go take it for a spin!!! Burnout

~JAKE

DBL_TKE · Posted: Tue Aug 18, 2009 9:40 pm Post subject:

Hey, you do have my jack stands!

aaron_sK · Posted: Tue Aug 18, 2009 9:42 pm Post subject:

Al Hasse · Posted: Tue Aug 18, 2009 9:45 pm Post subject:

Nice job, I did the same swap a little more than a year ago, along with the C5 front brakes.

What gear is in the axle you took out?

fiveoformula · Posted: Tue Aug 18, 2009 9:54 pm Post subject:

Sorry Skyler... lol
The original gears were the 2.73's, these 3.73's are a pretty dramatic difference! the speedo is anywhere from 10-20mph off.

Al Hasse · Posted: Tue Aug 18, 2009 10:03 pm Post subject:

Mine would be about the same when I get my new 3.73 ring & pinion installed, but I have the speedometer drive and driven gears for it Very Happy

My speedometer is about 5% high with the 3.23 using the drive/driven gear for the 3.08 rear end. I figured I would be about 20% high after putting the 3.73 in without changing the speedometer gears, which means about 85mph indicates for about 70mph actual.

fiveoformula · Posted: Tue Aug 18, 2009 10:51 pm Post subject: