Where to drill for 5-pt harness install? First project(s)

poorb0yw · 06:27 PM

Hi everyone,
I finally got around to installing my interior goodies today. Officially my first major p-car project

. After a pain in the butt bolt that decided to strip was finally ground off and the thread taken out of the hole (to remove the stock seat) I was able to mount my passenger side SPG.

I always see that its better to go through with the drilling when mounting the harness. However I can't seem to find any pictures or information on where to put the holes to mount the inner lap belt (coming from console side). Anyone know where a good point is to drill and attach this belt and the sub belt. Any pics or vivid descriptions would be greatly appreciated (I wanna get this done before the weekend so I can actually seat a passenger). Also, are there any good ways to make these mounting points watertight?

So far I've removed the fold down seat backs, the rear belts and buckles, and rear sound padding. As well as mounting a harness bar and lens protection. That slippery slope sure does go fast.

Thanks in advance.

89911 · 11-06-2002, 08:18 PM

The best place to mount the sub belt is directly below the opening for the belt in the seat, with the seat in its correct position. Sometimes changes must be made for obstacles, but the least amount of variance is generally the best position.

ChrisBennet · ChrisBennet's Garage

There is a way to mount the inner lap belt without drilling. I think Brey Kraus makes something for this. As for the sub belt, I've fooled around with mine for a few years and finally came to the conclusion that I was never going to get comfortable with a single substrap (5 pt harness). I now have 2 holes drilled to accomodate the separate mounting points for a 6 point style substrap. Remember, the sub strap is supposed to be tight when in use. If you have to make it loose (to avoid discomfort) you are compromising it's usefulness.
-Chris

jluetjen · jluetjen's Garage

poorb0yw;
A very common and acceptable solution to this problem is to install the bolts for the new lap belts in the same holes that the factory used. These will be properly reinforced to provide a safe mounting.

If you are going to go with custom mountings, you might want to consider the following from the SCCA's GCR which are representative of the correct way to mount seat belts:

Section 20-7:
Each seat (lap) and shoulder belt of the harness (5 or 6 points) shal have an individual mounting point (ie 2 for seat belt and 2 for shoulder belt minimum). Anti-submarine strap may share a mounting point with one or both seat (lap) belt(s). The minimum acceptable bolts used in mounting of all belts and harnesses is SAE Grade 5. Where possible, seat belts, shoulder harness and anti-submarine strap(s) should be mounted to the roll structure or frame of the car. Where this is not possible, large diameter mounting washers or equivalent should be used to spread the load. Bolting through aluminum floor panels, etc. is not acceptable. (Note large diameter washers should be read as something which is at least 2-3 inches across. You want the biggest washers that you can find, a piece of steel plate with a hole drilled in it would be perfect. You just don't want the bolt to pull through!)

Shoulder harness should be installed 90 degrees to the spine at the shoulder line to minimuse compression injuries under high G loading.

It is critical to mount the seatbelts appropriately. Keep in mind what happened to Dale Ernhart.

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by jluetjen
poorb0yw;
A very common and acceptable solution to this problem is to install the bolts for the new lap belts in the same holes that the factory used. These will be properly reinforced to provide a safe mounting.

John's advice is good for cars that have that setup. Starting around 1985 the inner lap belts were mounted to the seat rails so they moved with the seat.
-Chris

poorb0yw · 11-07-2002, 06:49 AM

Hi guys,
Thanks for the advice so far. However, with the installation of Recaro SPG seats the stock mounting point on the sliders (inside belt) is no longer there. I have used the stock point for the belt coming from the door side but a hole needs to be drilled for the other belt. Also I have heard the Brey Krause piggyback system is not acceptible in some places.