Seat Belt Installation Inertia Type 1980 Model MGB GT

by David Maynard | Dec 7, 2020 | Repair, Upgrade

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Broken Seatbelt

My MGB GT LE is a 1980 model and over 40 years old.

The plastic cover over the original driver’s side seat belt latch broke recently, resulting in the release button falling out and the seat belt latch no longer able to clip together with the buckle.

Buying Tips

There were no inertia seat belt parts available from the regular MG parts suppliers looking online in Australia. I also checked the local auto parts stores, and no luck. I then found a local seat belt supplier company that could supply a suitable inertia-type replacement seat belt unit. The new unit was supplied with the seat belt unit, mounting plate, sleeve washer, bolts, and spring washers.

Following is a summary of buying tips:

• The online search offered two seat belts – a simple lap strap and latch unit or a lap/sash inertia unit. Given the year of production (1980), my MGB GT had factory-fitted inertia units.
• After looking closer, the passenger side seat belt unit was aftermarket, and the driver side unit was the original factory fitted unit.

Installing Tips

Following are some installation tips:

• The mounting plate – Installing the after-market unit was fairly simple but offered a couple of small challenges. The first being the mounting plate. The original mounting plate/metal bar was shaped to maintain a level release spool for the strap to release when pulled, which will not actually release if not relatively level. I first fitted the spool unit with the flat metal mounting plate supplied with the new unit. Given the mounting nut’s position, which is slightly to the rear and the side from the top of the wheel arch, the spool unit was not level, and the belt did not release. I then noticed the original mounting plate had a slight twist, allowing the spool unit to sit relatively level. I re-installed the spool unit with the original mounting plate, and all work properly.
• The second challenge was the wiring on the original latch component that sends a signal to the SEAT BELT warning light on the console of my 1980model MGB. I decided to cut the wires and leave them unconnected, making the SEAT BELT warning light inactive.
• The original spring washers seemed to have less spring than the new spring washers supplied with the new unit, so I replaced the old with the new.
• A couple of the new bolts were a little long, so I used the original bolts. I also used the sleeve washer to mount the new spool unit on the wheel arch, lifting it slightly higher.
• The new spool unit was supplied with a hard plastic cover that does not clip anywhere and moves around. I plan to cut that cover off.

Summary

The new seat belt installation was fairly quick and simple and would have been quicker if I used the original mounting plate the first time around (see photo). The new unit works well, and the car is now ready to obtain a Road Worth Certificate for registration.