Rack and Pinion steering pinch bolt

[Rod1883]

Whilst the front is off (see Radiator woes thread for the reason) I've been looking at what else needs doing whilst access is a bit easier.

I have the Moss rack and pinion steering conversion (fitted in 2010/11) and I'd noticed that the UJ right down at the steering box moves up and down on the spline. I've tried to tighten the pinch bolt - the nut turns, but it doesn't seem to tighten - I suspect the thread is damaged on the bolt (or nut).

 

Does anyone know the size and specification of this pinch bolt and nut - and a likely source of one?

(I've sent an enquiry to Moss, but they haven't responded yet.)

 

Thanks (again)

[RogerH]

Hi Rod,

is the UJ of the TR4/4A rubber doughnut design.

If so then there is a fault with them that stops them being fully tightened.

 

Se pic below. It is possible to remove a small amount of metal to allow the pinch to take place at a simple nip of the ratchet.

 

Roger

 

 

 

[Rod1883]

Hi Roger

No - it's just a small lump of metal as far as I can see. I'll have a better look tomorrow and post a picture if I can.

 

Rod

[RogerH]

Hi Rod,

that will be the TR6 or Ford Escort UJ. Your pinch bolt just needs replacing.

 

Roger

[Rod1883]

I have a very vague recollection that the Moss kit back then (maybe still does) involved a modern mini rack, fitted upside down. Happy to be corrected if that's nonsense.

 

So, it sounds like I just need to find a way to get the old one undone (as the nut doesn't seem to want to tighten or loosen very much) and then get and fit a new one.

Any help with the size/spec required, and where to get one, gratefully received.

 

Edit - if it's the same as the TR6 then I guess its a 5/16" UNF, Moss part number GHF104 plus suitable nyloc nut?

Edited May 15, 2018 by Rod1883

[RogerH]

Hi Rod,

if you can get straight onto the bolt head - then hold the head in a Mole wrench and drill into it to remove the head.

Start with a 1/8" drill.

 

Roger

[Ian Vincent]

Rod,

 

I had exactly the same problem with my rack & pinion conversion. The bolt is a 1/4 one if I remember correctly. It fits into a notch cut in the splined stub of the rack and that is all that is stopping the bottom of the column pulling off the rack.

 

I would suggest you remove the old bolt and replace it with a high tensile one which you do up very tight. I also sealed the connection with Loctite 270.

 

Mine has been fine since then but its something I check regularly.

 

Rgds Ian

 

PS A quick google search brings up that Demon Tweaks offer grade 12.9 cap head bolts in metric and imperial sizes. They would work.

Edited May 15, 2018 by Ian Vincent

[Rod1883]

Thanks Ian.

The spanner that fits is a 1/2" AF, so that suggests to me that the bolt is 5/16" UNF rather than 1/4" (which would be a 7/16" spanner I think).

If, as Roger says, the fitting is the same as the TR6, then the Moss website also suggests 5/16".

It seems I need to get the old bolt out to be sure.

[RogerH]

Hi Rod,

see post #6 to get the bolt out.

 

if it is a TR6/Escort type of UJ then then I have heard of no problems tightening these.

The Moss bolt (GHF104) is a general purpose bolt.

 

There should be no need for a super dupper bolt as the shear forces are through the splines and not the bolt.

That is why the bolt needs to be 'pinched' tight to keep the splines happy.

 

Roger

 

PS - just looked at the Moss Mini steering pages and the steering shaft is a direct fit onto the rack - no UJ.

Edited May 16, 2018 by RogerH

[Ian Vincent]

Roger,

 

You are right that the splines do all the work but in order to get the steering shaft to clamp onto the splines you have to 'do' the bolt up very tight. I was concerned about the same thing happening to me as has apparently happened to Rod, the threads stripping, which is why I went for a super duper bolt - which in relative terms cost peanuts anyway. Plus you have to take the shroud off and the radiator out to get at it and you don't want to be doing that again in a hurry!

 

Another thought, if the clamp has been loose on the splines for any length of time, they may be worn, another reason for needing to clamp extra tight.

 

Rgds Ian

[stuart]

This is a regular fault with them, I have come across it a few times now. Its as stated 1/4" UNF bolt which is a bit weedy compared with the 6 one. Ians approach is a good one though a steellock nut instead of a nylock would be better https://www.margnor.co.uk/nutswashers/steelnuts/hexselflockingnuts/allmetal/unf

Stuart.

[RogerH]

Roger,

 

You are right that the splines do all the work but in order to get the steering shaft to clamp onto the splines you have to 'do' the bolt up very tight. I was concerned about the same thing happening to me as has apparently happened to Rod, the threads stripping, which is why I went for a super duper bolt - which in relative terms cost peanuts anyway. Plus you have to take the shroud off and the radiator out to get at it and you don't want to be doing that again in a hurry!

 

Another thought, if the clamp has been loose on the splines for any length of time, they may be worn, another reason for needing to clamp extra tight.

 

Rgds Ian

Hi Ian,

I agree. Considering the work involved to keep an eye on it and the concerns of it coming loose then your pragmatic approach is spot on.

 

I keep comparing every bodies problems to mine on the 4A.

But TRiumph kept changing things and then the modifications come along and add to the differences

 

Roger

[Rod1883]

Thanks again for all the helpful answers and comments

 

Here are some pictures

 

 

 

Silly question - how do I check the bolt size - is it the diameter including the depth of the thread, or only to the bottom of the thread (ie the solid part of the bolt shaft)?

 

[RogerH]

Hi Rod,

try the OD of the thread and add a gnats.

 

So a 1/4 bolt would be about 0.240 (ish) - the plain shank would be 0.25"

 

Roger

[Rod1883]

What has been removed, after splitting the nut by drilling, is a pretty chewed up bolt of 5/16" diameter.

Moss advice came through today and they said it is 5/16" too, so I've ordered a couple from them - but will follow up a better make through the contact Stuart provided above.

 

Edit - any advice on cleaning up the splines before fitting the new bolt?

Also, should I put Loctite on the splines before tightening, or just the bolt threads?

Edited May 16, 2018 by Rod1883

[Ian Vincent]

Hi Rod,

 

Because I have my front shroud off at the moment (camshaft woes), I have been able to measure my bolt. You are right it is a 5/16" bolt with a 1/2" A/F head and 1.5" long from under the head.

 

Rgds Ian

[Ian Vincent]

Rod,

 

I did put Loctite 270 on the splines before tightening. It is grease tolerant so you don't have to be too fussy about cleaning out the splines. It will make it a bit of a bugger to remove in the future but it shouldn't be impossible.

 

I notice from your photos that you don't have even a nyloc nut on there - it looks as if you are relying on the spring washer to keep it tight - I would go with Stuart's recommendation and fit an all steel locking nut.

 

Rgds Ian

[Rod1883]

Yes Ian, I suspect that the original bolt that would have come with the kit got lost/damaged and replaced by the restorer with somethng similar, but clearly not really up to the job.

 

Thanks for all the tips everyone.

 

Ian - a couple of pics for the "Front apron off club"

 

 

[RogerH]

Hi Rod,

not a lot you can do to the splines other than clean with a wire brush.

 

I think Ian's Loctite is a little bit of overkill and may cause problems down the line.

having said that how often does the steering shaft need to come off.

 

Nyloks and spring washers work well. The all steel lock nut will definitely stay put.

 

Roger

[Lebro]

Can I join the club ?

(Back together now)

Bob.

 

[Ian Vincent]

Im not showing you mine its a lot more grubby. I might have to give it clean before I put it back together.

 

Rgds Ian

[Rod1883]

Welcome Bob.

Go on Ian....