pvr007

iTrader: (1)

I bought a 4th gen rear end for 60 bucks on craiglist and its a posi disk 10 bolt, the only bad thing is that it has no mounts, im guessing they took them off to put them on another car but they never went on with it. My question is it work having them re welded and exactly are they in the same position as my original rear end, or should i buy a custom Mounts?

Orr89RocZ

iTrader: (20)

You would have to make a jig and model it off another stock rear to remount them correctly. But id say buy a new one that has mounts. Its easier this way

AlkyIROC

Take the brake system off and put it on your diff.

Rabble

I'd just swap the breaks. Is it possible to swap the pig and axles too?

Orr89RocZ

iTrader: (20)

Original thirdgen rear is shorter so axles wont work. Not sure what rear you have, 10 bolt or 9 bolt for 88 yr? Inner guts might if you have a 10 bolt but 4th gens used 28 spline axles and early 3rd gens had 26's so youd need axles

Just doesnt seem worth it

Rabble

You can have a machinist shorten the axles. They make the splines longer than needed. From my understanding, the 3rd gen rear is 2" shorter, so have them shave 1" off each side. We did this with out 9" in our 72 camaro when we made a new rear for a 4 link and went with larger tires and narrowed the rear by 2".

fireturd350

iTrader: (8)

I'd just swap the brakes off if you wanted them and call it a day. Keep the rest around for parts if you want. The gear set might come in handy sometime.

I'm sure shortening and resplining was worth it for a 9 inch, but with an OEM 10 bolt axle setup it might be kinda iffy on the bill. Remember there is a reason why aftermarket companies sell axle kits.

Also if you do plan on swapping the axles and inner guts (to match the splines) remember the gear clearance and backlash is set to each pumpkin housing.

I believe it's 2" difference on each side.

86F.BiRD

My 86 firebird had one wheel peel and drums, i bought a 4th gen rear for $100 and put 3.73s in it and it was an easy bolt in swap.

AlkyIROC

Fourth gen is very close to 2" wider on each side. There won't be enough splines on the axle to cut them down. Generally OEM axles taper after the splines so you couldn't even get longer splines cut into them. Providing you could even find someone to do it, it would be cheaper to just buy new 28 spline axles to fit into a third gen housing. Price has probably gone up slightly but when I bought mine years ago, the axles were only $150 each so for and extra $300 plus an installation kit for the ring and pinion plus carrier (posi) swap, you could put the carrier and gears from the fourth gen into the third gens diff.

Other than that PBR brake system, there is no strength advantage to the fourth gen diff. Putting 28 spline axles in a third gen diff makes it just as strong as the fourth gen plus aftermarket axles are better than OEM ones.

If you can find a 90-92 third gen, it will have 28 spline axles that will fit your diff.

Orr89RocZ

iTrader: (20)

I feel the zexel torsen diffs found in the later 99-02 cars are a better posi. Clutchless type so it never wears out and doesnt need additives. Ls1 cars also had bigger brakes than pbr's but that makes it hard to fit 15" wheels if you wanted to drag race it. Need to cut calipers down

white_ghost

Some 91's and most 92's had 28 spline axles with 10 bolts. I just swapped out my 91 rear for a 1993 rear to get 3.23 gears. But as one mentioned before there is a width difference. The axle is easily 3 inches wider. Changes the stance a little but spacers will offset front to make look better.

pvr007

iTrader: (1)

ok guys so i bought another rear end, this time from a 99 z28 automatic, its posi and disk,,,, bad thing is it didn't come with brakes rotors or brake lines.... i took the brake lines from my old rear end from the rubber hose and on and i tried fitting the brakes from the rear end i got first, the 94 one... apparently they dont fit, but if they do how could i do this.... right now i dont want to go out and but rotors and calipers and all the other things needed... any help appreciated

Orr89RocZ

iTrader: (20)

Do the backing plates you have now bolt to the later ls1 rear? What yr car did the first rear come out of?

pvr007

iTrader: (1)

Its from a 94... To remove backing plates to i have to remove axles?

Orr89RocZ

iTrader: (20)

Yeah i believe so. C clip in so they arent to hard to change

Zach/90\irocZ

iTrader: (6)

was up didnt think you where going to work on your camaro for awhile after breaking your axle lol nice to see you getting it back up and running
im trying to get mines back up and running to im seeing more thirdgens driving around diego

yea you have to its easy to take out the axle just push axle in and remove c clips and thats it

pvr007

iTrader: (1)

so i tried removing the axles from the 94 and.... the 5-16 bolt that held the pin striped... this sucks...

Zach/90\irocZ

iTrader: (6)

your talking about the pin for the posi so you can push in axle to remove c clip
you tried smaller socket ? also are you using metric or standard sometimes i forget and have strip bolts due to my frustration to later relized i was using metric i switch to standard even tho bolt was stripped and still manage to remove bolt do you have a vice grip it souldnt be that hard to remove the pin it most be on there really good do you have nut buster spray it helps ?

pvr007

iTrader: (1)

So i was able to take the pin off... Transfered the brakes over to the 99 rear end and also tranfered the brakelined frok the 88... The lines fited where the banjo bolt goes and so i put the camaro tires.. it barely fits... All thats left is to fill the gear oil with the posi additive and put it in.. Now i have to worry about the hand brake but untill then ill just put it in gear... Ill put up the pics when i get home after work

AlkyIROC

Keep a tally of all your expenses in this swap. I'd like to know the final outcome once it's in the car. It sounds like it's adding up.

pvr007

iTrader: (1)

Well both rear ends where 60 each... After that its been all labor.. Ill spend another 30 on oil and posi additive and gasket and 35 on brake pads.. thats about it

pvr007

iTrader: (1)

Zach/90\irocZ

iTrader: (6)

swweet

DIGGLER

iTrader: (1)

wheels will stick out though. another option is to swap the gear/diff into the 3rd gen rear along with the brakes and have a set of axles made for it. would be the correct width, 28 splines, LT1 brakes, posi, and have the gear from the LT1 car.

patricklav

iTrader: (7)

$120 total and some labor to get the LS1 rear end and brakes?

Thats a great deal!

pvr007

iTrader: (1)

thanks guys! it really took a bit of me, now i have back pain and some busted fingers and some shorts i will never wear again XD i actually like the big stance that the 4th gen give, plus the 99 rear ends arent as long as the other 4th gen rear ends so ive heard.. i will install it sunday and take more pics, thanks everyone

RyanJB

When I did mine about 6 months ago it ran me about 600, rear included. Although I did replace the rotors, calipers, brake lines, e-brake cables and proportioning valve.

pvr007

iTrader: (1)

Ryan what brakelines did you use? Also i have another problem, the rotors scratch from the rear, im guessing the rotors are too deep..... The rotors are from the 94 so i might need rotors for a 99 :/ can anyone assist me ill upload pictures

pvr007

iTrader: (1)

well the rotor is not centered between the caliper , its rubbing with the inner break pad, any way to fix this?

pvr007

iTrader: (1)

Getting the project started again, the rotor is not in the middle between the caliper... Relace the rotors or add spacers somewhere, anyone else having this issue? Thanks

fireturd350

iTrader: (8)

I've heard of people having to add a small washer or shim at times, but that's normally to bring the caliper out because the outer pad wants to rub.

Are you using everything with the brakes? I've heard the 4th gen backing plates are a little thicker than the 3rd gen ones are.

Zach/90\irocZ

iTrader: (6)

How you been ..

Yea thats kinda wierd did you swap the complete brakes over .. i know rotor height and thickness varies depending on the year i dont know if that makes a difference as the offset stays the same ..there are rotor shims you can get but i would investigate the actual problem ..as you can only go so far with that

bm87ta

iTrader: (5)

had that happen on the dr side when i switched to ls1 brakes, I used washers to shim

pvr007

iTrader: (1)

Quick question people, Are rotors interchangeable between 94 and 99? So I swaped the brakes from a 99 to a 94 axle, problem is the rotors are not centered on the calipers, rubbing on the inside, the height of the rotors that rock auto gives me for a 94 is 46mm and for a 99 its 61mm
94
https://www.rockauto.com/catalog/mor...482&cc=1035874

AND 99
https://www.rockauto.com/catalog/mor...115&cc=1353136

also the diameter is different, would that interfere with the calipers from the 94? any help is appreciated! thanks