I'm looking at swapping a 4th gen rear into my Formula. I know it's wider, but how far will the factory wheels stick out of the fender wells? And is everything just bolt in?

 

I just finished the same swap on my Camaro. My wheels are just inside the fenders when you look straight down on them. I am running the stock 15" Camaro wheels.

Everything is a direct bolt-in, except for the ebrake cables. Depending on how your original ebrake cables are set up will determine the cables you need to match the new rear. Even the "recommended" ones sometimes don't fit either. I have the "right" ones and they don't fit at all. Still trying to figure out what to do with them. Most people don't have problems though.

 

Thanks 92RS, what e-brake cables are needed for the swap?

 

the formula wheels will stick out a bit farther out past the quarter panel than the 15rs wheel does .
It wont look rite unless u use a 4th gen wheel.
they will be 1.5 inches farther out each side than they are now.

 

I used the 4th gen e-brake cables, with hose clamps to hold them to the stock hard mounts under the 3rd gen body. With some basic adjusting to get the tension right, it was a simple install.

 

Formula body with LS1 (98-02) axle :



I used the LS1 ebrake cables and the equalizer up underneath, so that the cables fit like factory, just had to reinforce the sides with some metal, and drill out the center to slide onto my ebrake adjuster underneath. Completely factory fit and finish.

 

It is amazing what you can find when you use the search button

https://www.thirdgen.org/forums/whee...end-stock.html

 

I appreciate the input. 3rdgenmaro, I am well aware of the search button. I did use it but I did not find the information I was looking for. Thanks for the link though.

On another note, I got the rear today and the guy I bought it from says the pinion crush sleeve collapsed and that there is too much play in the yoke. It seemed fine to me. How can someone tell if the crush sleeve is bad? It's also got an aftermarket eaton posi in it, does that take the stock carrier bearings?

 

I haven't figured out the ebrake cables yet. I decided to finish up some things on the front end of the car first. Once I'm done with those, I'll get back to the ebrake cables. I'll either have to shorten the ones I have, or modify the 4thgen cables to work.

As for the pinion yoke, you need to check 2 things. Use a dial gauge with a magnetic base to check for any in-and-out play. Then use a dial-type in-lbs torque wrench to check the amount of torque it takes to turn the pinion. The crush sleeve is there to take up any in-and-out play in the yoke, and also sets the preload on the yoke.

 

Could get some wide body rear fenders, then you can also run some real meats.

 

Gumby I would if I had the money. I borrowed an in/lb torque wrench and I measured the pinion turning torque. It was about 8 in/lbs. I know that's not within spec. Should I just buy a rebuild kit and tear it apart or just tighten the pinion nut down? I haven't had the chance to get a dial indicator to check in and out play on the yoke though.

 

What should I look out for when getting a 4th gen rear end? I heard that 98-02 has traction control and other electronics. I want to make sure before swap. Plus i currently have 3rd gen drum rear want disk. Also what gear ratios did they have and how do you know what the differential has?

 

I was reading in the link that 3rdgenMaro posted and it seems that the only real reason for changing out to a 4th gen is for the disc brakes. Am I understanding that right? If I am just planning to drag race my car, why not just beef up my stock rear? Please Bash me for not knowing!! But also enlighten me!!

 

So will the 4th gen rear disc brakes fit inside my stock firebird 15" wheels? i have drums in the rear right now.

 

For just drag racing, the drum brakes can be backed off to produce zero drag. Disc brakes will always produce some drag.

 

to put wider tires too its a cheap mod safer than spacers. would u want 500lbt with a 2inch alm spacers and stickys