Black00SS

iTrader: (5)

Wondering if its possible to use a stock 3rd gen 91-92 axle housing, and 28 spline axles....with a 4th gen Zexel Torsen diff, gears etc.

I notice a lot of people switch over to the 4th gen rear, but I would like to keep my stock width axle, and get the added benefit of the better posi, and brakes.

Also, can I swap all of the ls1 rear brakes over to my 3rd gen housing at the same time?

Thanks in advance!

big gear head

Yes, you can use all of the 4th gen parts in a 3rd gen housing except the axles. Brakes may or may not work.


You may or may not know that when you swap the parts you will have to reset the pinion depth, backlash and bearing preload. It's not just a simple bolt in parts swap.

Ty92Z

iTrader: (11)

I’ve swapped the LS1 rear brakes to a third gen housing. Everything bolted right up.

Black00SS

iTrader: (5)

Thanks guys. The axles were my main concern. Just was not sure if the 3rd gen 28 spline axles were compatible with the 4th gen diff/etc.

Long story short, I have (2) 1991 axles. A 3.23 posi pbr disc brake rear, and a 2.73 open drum rear. Plan is to sell the disc rear, and buy a 4th gen rear to swap the diff/brakes to the drum rear I have.

Thanks again!

jmd

iTrader: (4)

The drum brake backing plate is a 3-bolt mount.
The disc brakes are 4 bolt and don't fit the drum housing.

big gear head

I think the later 3rd gen rear ends had the 4 bolt backing plates, but I may be wrong about that.

Ty92Z

iTrader: (11)

To clarify, I bolted the LS1 rear brakes to a disc rear. They do not bolt up directly to a drum rear. There is a thread on modifying a drum rear to accept them.

jakemussman

iTrader: (3)

As stated above, if you have a drum rear the axle flanges must be modified. You basically cut the top portion off (where the wheel cylinders attach). Then drill the four bolt holes out using the disc brake backing plate as a template. If you want to maintain the parking brake you can buy conversion cables (easiest). you also will need to modify the parking brake bracket that attaches to LCA brackets. The 4th gen axle tubes are something like 1.5" longer. The parking brake cable bracket in stock form is too long on the thirdgen housing and causes the cables to bind.

//<86TA>\\

iTrader: (14)

Yeah, converting 3rd Gen drums to 4th gen 98-02 disks is very simple and straight forward. Like said before, remove thendrum backing plates, cut the top off the hous8ng emd to make 8t square, drill out two holes and it boots on. The parking brake braxkets need to be cut and angled slightly diffrrent to work properly, and you will need new custom parking brake cabkes from hawks. Brake lines can be modified to woek as well, they are longer than they need to be so they can be rebent to work with the 4the gen brake hoses if they are not crusty or just bend up some new ones.

The carrier will swap right over, just be sure to measure backlash before removing you stock gears, I swapped a 4th gen torsion and brakes into my 92 housing. Stock 28 spline shafts worked fine, and so do aftermarket ones.

Black00SS

iTrader: (5)

Great info, thanks everyone for the replies! Very helpful, and I appreciate it!

dgordond

I am finishing this conversion...everything has worked well , so , i am up to last step , cables...the drivers side bracket was long enough that i bored a new cable hole closer to diff side of bracket and pie cut the passengers side and welded it up , both mods to lessen angle of cable because of diff width change...so , you used the hawks cables and all is well? hawks cables seem to indicate in text that they were intended for use with wider 4th gen axle in a 3rd gen. Thanks!

//<86TA>\\

iTrader: (14)

The problem was attaching the 4th gen cables to the 3rd gen equalizer.

The Hawks cable fit properly, but you still need to modify the brackets on the axle to correct the length/angle issues because of the shorter 3rd gen axle. They do not need modification on a 4th gen axle.

dgordond

Thanks...did you modify yours in a different manner than I described? I thought that the Flynbye adjustable cables would be the answer but he didn't even know if he had any , never called me back...I would say the way I modded my brackets changed the distance from lever to bracket face by less than 1/8".