Moser 12-Bolt Torque Arm Hardware Kit for the 1982-2002 GM F-Body

Part # 2998
Price- $21.99 per kit

UMI Performance, Inc. is pleased to announce the availability of our new Moser 12-bolt install kit. This kit adapts UMI’s torque arm bracket to the Moser 12-bolt differential housing. By using carefully selected bolt lengths and specially designed spacers, excess play is minimized and strength and reliability are maximized. This kit will also fit other aftermarket brackets which use 5/8” diameter mounting holes and 3/8” bracket thickness. The P/N 2998 kit is the finishing touch to ensure a bulletproof system. It is available separately or as an add-on to your new torque arm. UMI recommends Moser for all your rear axle needs. This product is designed and manufactured with pride in Philipsburg, PA-USA.

 

With out this kit what issues have been found in fbody applications?

 

It's common for these bolts to come loose on a 12 bolt due to the inability to use the factory style long through bolts. It's a really stupid design. Lots of guys over on Tech have had these bolts fall out. Another reason to go with the superior design of a 9" rear.

 

Like 406TPI mentioned, Moser uses a different bolt design on the 12-bolt.

Factory rear ends and all others use long 14mm bolts that run through the rear end. The Moser 12-Bolt uses four 1/2" bolts, two on the top and two on the bottom to attach the torque arm. The bottom bolts thread upward into the rear end.

The biggest issue comes in with aftermarket torque arms. Most aftermarket torque arms use a 3/8" thick mounting base, much thicker than the factory torque arm. Also most aftermarket torque arm mounts are supplied with 5/8" mounting holes to allow a little slack for a 14mm bolt. With Moser using 1/2" bolts this makes for a much larger hole than the bolt and can cause movement in the arm. The bolt also becomes too short with the thicker mounting brackets.

This kit reduces the mounting holes to 1/2" with spacers and includes longer bolts to make up for the thicker aftermarket brackets. It will help to sure the common issue found aftermarket torque arms and Moser 12-bolts.

I hope that helps,
Ryan