Lap Belt

[Dwleo]

I will use my age as my excuse. I cannot remember what I did when building my mk 3 when it came to the lap-belt part of the Simpson belts. The manual states ....."Drill through the inner lap belt mount into the tunnel with a ½ in. bit. Bolt the lap harness in position with the inner most nut inside the transmission tunnel. ".
First of all the bolts are not long enough to travel through the tunnel to allow for the nut. Also the nut cannot tighten even if it could reach as the nut is larger than the 1/2" hole. Then there is the space between the mount and the tunnel. I know I am missing something really obvious here but cannot put my finger on it.

Ideas?

[BadAsp427]

So on mine, I had to put a couple washers between the seat belt tie down bracket and the trans tunnel. This is inside the cockpit... then I placed the bolt through the seat belt bracket, into the tie down bracket, through the washers and the side of the tunnel. Washer and Nut on the inside of the tunnel and then wrenched them down. Sandwiching the side of the tunnel... But remember, you will have some carpet in there later (if not now) so you may only need one washer not two or three... Clear as mud I hope...

[Dwleo]

So on mine, I had to put a couple washers between the seat belt tie down bracket and the trans tunnel. This is inside the cockpit... then I placed the bolt through the seat belt bracket, into the tie down bracket, through the washers and the side of the tunnel. Washer and Nut on the inside of the tunnel and then wrenched them down. Sandwiching the side of the tunnel... But remember, you will have some carpet in there later (if not now) so you may only need one washer not two or three... Clear as mud I hope...

Wouldn't it be better to enlarge the trans tunnel hole to accept the nut then one could use a deep socket to attach the nut to the bolt at the belt bracket. This is what seems obvious to me but since that isn't mentioned in the manual nor do they mention the washer method it makes me wonder.

[Scott Zackowski]

I changed all my harness bolts out to Grade 8 as recommended by Simpson. FFR supplied in my kit Grade 5.

If installed as per the manual, you will need a longer bolt.

I am not sure it is important to cinch or tighten it. The bolt, I think, only needs to function as a pin. And with a nylon lock nut inside the tunnel just to prevent the bolt from sliding out.

Drilling and going with a smaller hole into the tunnel AL make it easy to seal the hole around the bolt with silicone.

[Boydster]

I drilled my aluminum larger to allow the nut to go all the way down. Not tight, but tight and backed off about 1/8 - 1/4 turn. Patched the underneath with some aircraft aluminum tape, then the carpet tucked in and covered from the inside. Yes, all gr8 bolts and hardware.

[Dwleo]

Used extra washers and after some swearing, got them in. Now on to the next question.