Bits and Pieces

The following has just been received from Doug Pelton:


The well-known Tompkins Steering Kit was designed to accurately adjust the MG TABC steering box and thus improve the driving experience. However, it has been discovered that this kit (as provided by suppliers) is actually the primary cause of poor steering control on our early T-Series cars. The problem lies with the size of the needle bearing and thrust washers.

Principle: The Tompkins kit provides adjustment of the end float on the top of the sector shaft. This keeps the steering peg engaged properly in the steering cam (eliminates play). The friction of the adjust screw on the sector shaft is effectively eliminated by adding a needle bearing sandwiched by 2 thrust washers.

Problem: The thrust washers fit nicely into the Tompkins cover. But, due to variations in the casting of the steering box itself, the thrust washer has been found to sit on top of the box and not within the box itself and on top of the sector shaft. This means that when you tighten the adjust screw you cannot get full adjustment because the thrust washer is hung up on the top of the steering box body. In the photos you can see the distinct difference in the wall thickness of the Tompkins cover and the steering box itself. You will also note that the thrust washer has ample clearance from the cover wall but when centered on the sector shaft there is no clearance to the box wall.

Solution: The singular solution is to install a set of thrust washers with needle bearing that is a smaller diameter to clear the steering box wall. FTFU has developed a retrofit kit that is now available and corrects the problem. FTFU item #ST229, replaces the adjust screw, thrust washers, and needle bearing.

Testing: The primary question is how do you know if this is the true problem with your steering. If you have a Tompkins kit installed on your car and you have excessive play in your steering wheel while parked, then do the following.

  • Jack up the front end of the car and turn the Tompkins adjust screw down to full tight. Then try to turn the steering wheel.

  • If the wheel will not turn then your Tompkins kit is ok. Simply back off adjust screw slightly and tighten locknut. If you still have steering play, troubleshoot other components such as tie rod ends, kingpins, loose bolts, suspension, etc.

  • If the steering wheel turns with the adjust screw full tight, then you probably have the thrust washer hanging up on the top of the box. Remove and replace the Tompkins internals with FTFU ST229. If needed, email: [email protected]

If you would like more information on how the Tompkins kit works or how to install and adjust, please see our YOU TUBE video: MG TABC Tompkins Kit.

Easy access: /Videos

FTFU continues to work hard to help you keep your cars on the road. Doug Pelton

Ed’s note: Just another reminder of the advice from Eric Worpe given at the end of the ‘MG TC1187 Bishop Cam steering gear renovation’ article earlier in this issue about fitting a new modern steel alloy sector shaft.