Reducing seat bolt protrusion. What solution?

[L777JDP]

Hello everyone,

I have a 2013 SV with lowered floors and the seat bolts tend to catch on speed humps. I'm interested in reducing the amount of projection below the floor so I'm thinking of having the bolt go up through the floor, rather than down, maybe using a countersunk screw into a countersunk washer. Interested to hear of anyone's experiences.

Best regards, John.

[Jonathan Kay]

It's discussed in this thread, but no clever solutions.

How much do the bolts protrude? And what's your clearance under the sump?

Jonathan

[EEK]

I did that, countersunk bolt with appropriate washer - much better, took an angle grinder to a spanner to help grip the nut, also I think I used some 8mm rivnuts in the channel, need to consider clearance on the slider but it is possible.

[SM25T]

Definitely check clearance under sump and rake of chassis lower rails .... all with the equivalent of your weight, or you and passenger if that's how you normally travel ... in the car. May need to adjust ride height.

[7 wonders of the world]

Remove the seats, weld plain M8 nuts into the lower adj runner to make them captive refit using button heads or shallow cap heads from below,

Damn sight easier to remove the seats too as theres no faffing getting to the rear bolts when the runners are jammed with grit.

You can do the same with the ally fixed box channels too using ally blocks tapped to M8

 

[Bricol]

Steel rivnuts into the seat slider frame, well internal lubed with the anti-seize compound of your choice.

I used hex heads - even when they've been punished and ground down by road contact, there's usually something left to get something around them to grip them and undo them fairly easily.  With socket cap heads, that's not always the case.

Suitable penny washer (old penny :) ) under the head to spread the load a bit - just not stainless if you like to get it regularly wet (had stainless washers cause enough galvanic corrosion with aluminium to make my Lancia petrol tank heat shields rather looser than the designer intended!) 

[NeilCSR]

Taking Bricol's advice above re. Rivnuts into sliders.  To protect against galvanic I'm going to stick some wide(ish) helicopter tape around the holes on the outside of the floor so that there isn't direct alloy/steel or stainless contact between penny washer and floor, and add Tef-Gel around there which should hopefully overcome any possible galvanic.

Did the helicopter tape layer on the exhaust bracket/body fixing point and it's holding up well after quite a few years.

[7 wonders of the world]

The rivnuts mean the runner is only resting on the protruding portion of the rivnut though, captive nuts spreads the load thro the entire area runner.

Good point re the stainless washers though 

[Bricol]

Countersink riv-nuts - inserted with a hydraulic tool.  Runner sits flat and the rivnuts are pretty unlike to come free :)

Could use hank nuts I suppose - but the riv-nuts fitted nicely in the folded runner. 

[7 wonders of the world]

Arh OK I see, will check those out...

... mine plain nuts wont move for sure...the MIG welder saw to that !

[garybee]

I also welded nuts into the channel and bolted from underneath.  Zinc plated steel washers should be fine in that area but you could always use a thicker aluminium washer to spread the load.  That way you're reducing the contact area between the steel fastener and the aluminium floor.  

[BigCol]

L777JDP said I have a 2013 SV with lowered floors and the seat bolts tend to catch on speed humps.

Me too!  Until I cut off the protruding bits of bolt.  Fine now!  

That said, some nicer and more elegant solutions above!

[wiltsathome]

I used dome head stainless steel Allen bolts from screwfix, big bag for very little money. Shorten the bolt and fit from underneath still using the penny washer, the 8mm nylocs that I again got from Screwfix in Stainless sit in the seat channel inside and can be done up with the spanner on end or more easily with a screwdriver wedge against the side of the channel. 

[sylvaman]

It's the apex of the lowered floor , that grounds out over speed bumps on my car .

Mostly the Short but high bumps on private roads ; Like Nat trust car parks, entrances etc. 

Perhaps i do need to raise it,,,,,,,or go on a diet.      

I wonder how much before you start to affect the handling ?  

Mind you ; more sump clearance on the Sigma is no bad thing ! 

[SLR No.77]

I'd only use hexhead bolts not Allen head type, it doesn't take much of a scrape to render the Allen head type immovable. The underside of my lowered floors have some serious hero marks as does the underside of the exhaust, it's inevitable.

However, after fitting good shocks and having Dave Gemzoe set it all up with 79mm below the sump, I've not bottomed out since. At 79mm it also didn't need any spacers below the steering rack to minimise bump steer, previously I had the often quoted 9mm.

Stu.

[7 wonders of the world]

The quotes for the 9mm spacer are a little misleading - far too many variables, chassis, bridge, rack mount, TRE's, steering arms etc.

Only sure way is to check each side - well worth doing though

Guessing the new coil overs came with an increase in sring rate too..?

[SLR No.77]

Oh yes, NTR1's courtesy of Simon