Rear End Swap

Updating the rear Axle

The distance from the tranny to torque tube is about 23 inches, cutting it close for a two piece driveshaft. That along with a 230hp motor and lack of limited slip options in the Opel rear end led me to explore upgrading the rear end.

I decided to go with a Volvo 240 rear end. They are readily available (and cheap), and the differential is a Dana 30 which has plenty of gearing and LSD/locker options. I was able to pick up one with a 3.73 ratio at a local yard for $200.

The Opel spring hats with adjustable trailing arms and panhard bar will be used and a torque arm fabricated. The differential housing has two bosses cast into it that will be used for the torque arm mount. An Opel torque tube mounting arm will be used for both the driveshaft center mount and torque arm mount.

The R-28 driveshaft will be shortened and mated to a Volvo driveshaft end.

Volvo 240

Links

Links and Brakes Removed

The Volvo rear has disc brakes that use a small drum brake for the emergency brake. The e-brake on both sides were shot and the calipers were in need of a rebuild so I will be using VW rear calipers with BMW rotors. The rotors bore will need to be opened 6mm to match the axle.

Volvo uses a 5x108 bolt pattern. With no 5 to 4 adapter plates available, the axles will need to be redrilled for Opels 4x100 pattern. I am making a drill guide to do this.

Limited Slip/Locker Differential

I've spent a lot of time researching Lockers for the Dana 30. Options range from "Lunch box" styles where just the spider gears are replaced with a ratcheting gear set to full blown LSD's.

I ended up getting a G-80 locker from a '92 Volvo. It is a bolt in carrier that will lock when one wheel starts spinning. It disengages once you are over 20 mph and let off the throttle. That feature can be modified to allow it to lock at higher speeds.