The Triumph Dolomite Club - Discussion Forum

Does anybody have a picture or a scan of the parts list, etc., that shows what's supposed to screw the front seats to floor on a 1973 Sprint. I've got 1/2 inch / 13mm hex head set screws in there, but looking at how nearly easy it's going to be to get them out, I don't think that's right. I'm guessing they should be cap screws or maybe, I hope not, torx.

Graham

They sound correct: 1/2 inch AF with 5/16 UNF threads 7/8" long with a spigoted end. You can just get a 1/2" drive socket into the channel to remove them.

Part number HU0807D

If the screws are rusted in, be careful you don't rip the captive nut out of the floor pan, later chassis had reinforcing strips where the captive nuts are located. Done it twice.

I think these are 13mm and stainless. I can't get any of my 13mm sockets on 'em. But it's in the garage for a retest today - small hole in offide sill - so I'll have them look at it. If they come away from the body, they'll have the welding kit there anyway. I think the seat will fix - the foam's disintigrated and the pan cover has come away at the back top, where it meets the front of the back rest. I have an NVG spare and a good (last time I looked) set of 73 ones I dont wanna use yet.

I had to replace the horns yesterday, and went to pick them up from the P.O. They were in an 8x4x4 inch box and labelled “made in France”. Bloody hell, orchestra’s must be small these days, I though. Then I though, is it nearly xmas?

Graham

Like the radiator screws I suspect the spigot end is to aid fitment in the factory when the captive nuts are painted. If you're building from scratch and have time you can easily tap out the threads and fit regular ended bolts.

Not sure I would fit stainless to hold in the seats as they are not high tensile and as the seats need to be pretty tight I'd ben concerned about galling the threads.

There's nothing to stop you buying some nice high tensile Allen Bolts that you can access easily. I've always found it a struggle to get on the 5/16" bolts the factory fitted - even with expensive Snap-On thin wall sockets.

Steve

If they're 13mm then they're wrong.
The only mm thread I've found on a Dolly was an electrical connector on a starter motor, and who's to say it was original?

SprintMWU773V wrote:
Not sure I would fit stainless to hold in the seats as they are not high tensile and as the seats need to be pretty tight I'd be concerned about galling the threads.

they don't need to be high tensile, the originals were stock low grade stuff, the seat frame will tear before the bolts snap. high tensile is what you need for extremely high load situations such as big end bearings, suspension etc.

Malcolm

I've just snapped one of mine.

AlanH wrote: ↑Tue Jul 25, 2017 9:31 am I've just snapped one of mine.

It can happen, particularly if any old 5/16" threaded pin has been used that sticks some of its thread below the captive nut; road crap, rust, underseal whatever then gets pulled into the captive nut when you try to undo and the pin shears just above the nut.

Magenta Auto Sprint wrote:they don't need to be high tensile, the originals were stock low grade stuff, the seat frame will tear before the bolts snap. high tensile is what you need for extremely high load situations such as big end bearings, suspension etc.

S rated?




Ian.

Turns out all the holes are re-threaded for M8, so I've ordered some stainless cap screws. I just realized I forgot the washers, which I suppose want to be 4 * (13/2)/tan(60) = 26/1.732 = 15mm od. The TR7's have rectangular ones under caps or torxs. But there a sight thiner than M8 as I remember. I'm happy anything M8 will be strong enough unless it rusts to the nuts, etc.

Graham

sprint95m wrote: ↑Tue Jul 25, 2017 4:13 pm

Magenta Auto Sprint wrote:they don't need to be high tensile, the originals were stock low grade stuff, the seat frame will tear before the bolts snap. high tensile is what you need for extremely high load situations such as big end bearings, suspension etc.

S rated?

I would expect near enough every bolt and setscrew on the car to be S. There are a few T iirc.

There may be the odd bolt made of "something bolt shaped" holding bits of trim on but seats are something I'd want to stay put.

I want the seat runners to stay put too. But I aren't worried about using stainless instead of carbon steel. I might worry about cast iron, but not stainless bolts that thick. Spose if I was over 20 stone, I'd have a different perspective (sat lower down for a start).

Graham