The seat must be firmly anchored to the vehicle. This may entail welding in additional mounting plates to strengthen the floor pan.
The original seat mountings are usually quite flimsy comprising a captivated nut on a thin plate spot welded to the underside of the vehicle. This needs to be reinforced with a good sized plate welded all the way around.
A number of seats have the ability to be adjusted backwards and forwards on runners. These are frequently loose and allow the seat to move from side to side. A solution to this is to adjust the seat to your personal position and then place a jubilee clip around the runner and tighten it up. If you need to adjust the seat afterwards just loosen the clip.
Welded in Mountings
A common way is for the seats to be mounted onto cross bars that run from the inner sill to the centre tunnel. Please remember that these must be firmly fixed and if welded the weld must be around the whole 360 degrees. It is all to often the case that a piece of box section is only welded on three sides and not the underside.
It is possible to purchase a kit for seat mountings, this comprises cross tubes and the mounting bracket for the seat to fit to.
It is not always possible to weld the underside with a Mig type welder because of the size of the hand lance. The old type stick arc welder is favourite in this situation as the welding rod can be bent to access difficult area´s.
Current seat mounting requirements for Stage Rally Cars
There are new requirements for seat rails and their fixings. These can be found in the current MSUK Blue Book.
It is important when installing a seat that it is mounted in a unstressed condition. By this I mean the side mounting seat brackets. They must be positioned so that the seat fits snugly between the side mounting plates. It is not good practice to pull the seat into the mounting brackets by its securing bolts. Please remember to use adequate sized washers between the securing bolt and bracket.
The seat must not tilt, in other words when checked at scrutineering the scrutineer will attempt to lift the seat. A number of vehicles had a release lever to allow the seat to hinge.
A quick method is to obtain an exhaust clamp which is a 180 degree radius with threads each end. Cut the clamp in half and fit to floor pan close to rear seat mount. This is achieved by a nut and washer in the car and one on the underside. When you need to lock the seat move the clamp over, this will be enough to stop the seat lifting. When needed for everyday use move the clamp back. This requires a 90 degree movement to achieve a locked and unlocked situation.
The actual seat tilt/recliner mechanism if fitted must be a geared type, not a quick release lever. (Lovers Handle)
This type of tilt mechanism comprised two surfaces that moved against one another, like a clutch. When the lever was pulled the pressure was taken off the surfaces and seat reclined.
If your seat has this type of fitment a quick method is to drill a hole through the two moving sufaces and place a nut and bolt between them.