New trailing arm pins

[440Interceptor]

Has anyone had trouble fitting replacement trailing arm pins? The rebuild was going great until today. I ordered two new pins months ago and came to install them today. First problem: the cutout that fits the thick washer with flat inner sides are different. The new pin has cutouts that are twice as deep as the old pin, see photo. That means the pin won't seat properly against the chassis bushing. Unless there are two versions of the original pin, that's a pretty poor replica. Not sure what the solution is, but I don't want to use standard washers to fill in the gap to the bushing.

Which brings me to problem #2. The new pins are actually around 0.5mm thicker than the old ones and absolutely will not go through the trailing arm crush tube. Again, if that's supposed to be an exact replica, it's pretty average, particularly as they're not cheap!

Anyone else had similar problems? I'd like to know before I contact the well known UK supplier.

Thanks guys.

Edited by 440Interceptor on Sunday 18th October 12:25

[440Interceptor]

Supplementary question: should the pin rotate in the trailing arm (guessing not?).

[mrzigazaga]

Hi mate...I only had a problem when i used the Superflex bushes/Mounts...The steel tubes were thicker but we ended up using the old tubes as the fitted straight in...However i did send a couple of "Wedge" mount tubes to them and made them aware of the differences.

I have used pins from RTR which were fine....Although "Naming & Shaming" is prohibited the people concerned will need to know and should be told ...After all its to their and our benefit...

The bolt is a "Pivot" bolt so no it shouldn't move...I recall having my trailing arms cleaned up as the holes were a bit on the rough side..Some grease was used in-between the pin and tube and extra washers were used to help clamp it all down better...TBH it was a vast improvement....I think the thought behind the grease was to stop it from seizing in the future...One of the original bolts were seized and bent and took 4 hours of blow torch and 20 ton press to remove it..

Here are a couple of posts....
https://www.google.co.uk/url?sa=i&rct=j&q=...

https://www.google.co.uk/url?sa=i&rct=j&q=...

Hope you sort it....Ziga

[adam quantrill]

As they are obviously wrong for this application (maybe they are Lotus ones?) then contact the supplier and send them back.

440Interceptor said:

Supplementary question: should the pin rotate in the trailing arm (guessing not?).

Initially when you put it in don't torque up the big nuts on either end, or if you do, back them off half a turn. Then get the rear wheels into "final" position - at this point the swivel pin may swivel. You may need the weight of the car on the rear wheels, or at least jack up that axle into position (one finger between tyre and top of wheelarch) and then you can torque up the nuts.

This is so the big rubber bushing is "relaxed" when in the level position.

[RCK974X]

Out here in the antipodes, when I found one of the pins was bent, I went to a local machine shop with a HT bolt (16mm thread I think ?)
and got them to copy the original.. they did a really good job. Cost me about 20 quid, not too bad. It's still in the car....

[TVRleigh_BBWR]

if you take the original to any machine shop they should be able to copy it, as said if it's just a modified M16 bolt or similar, would be help to bring some with you as would be easier for them to mod than to make from scratch.

[440Interceptor]

Thanks guys. I've emailed RTR as that's where they came from.

I may know a guy who can make some from scratch copying my one good pin. Sadly can't modify the ones I bought because they already have less material than they need on the "shoulders".

Adam thanks for the pointer on tightening. Is there a certain torque that needs to be applied? I might start a new thread on all the torque settings so they're in one place unless it already exists). The Bible has some but not all.

[adam quantrill]

I do them as tight as I can while under the car, and haven't had problems, I guess I can exert about 80lbf on the end of a long wrench. They are big threads so will take quite a lot before stripping.

I suppose if there's material gone you'd have to weld more on, then machine it back again.
But it wouldn't be as tough as the original.

[mrzigazaga]

Im surprised that RTR sold them...Richard knows his onions....Best let him know as he might not be aware...I had the same issue with something from ACT and once i had spoken to Tim it was swiftly rectified ...These things need nipping in the bud as it can cause a lot of unnecessary PR.

As Adams says about the torque...

[TVRleigh_BBWR]

if you measure the thread size just look up torque for that size of thread, that should give you a good idea.

[440Interceptor]

Thanks Leigh. Zig I agree but RT has been great, and he is concerned as you say.

It seems that there are at least three different washer recess sizes. 8mm and 12mm and the ones I have which are 5-6mm.

Seems logical to measure your thick washer with flats before ordering new pins to make sure they match.

I am trying to get someone to fabricate replacement pins here in oz.

Question: it might be simpler to make thicker washers to suit the bigger recess on RT's pins. Would this cause geometry problems?

[RCK974X]

For reference & parts,

My 1982 2.8 has the pins on left as your photo, with narrow 'sharp cut' slots, and large washers which match the same thickness as the slots, give or take a few thou, so all lines up nicely ready for packing washers for toe-in.

[440Interceptor]

Spoke to a guy today who is going to put the pins in his lathe and bring the recess down to 6mm to match my washers. I will still have enough thread at the thick end and clearance at the thin end.

He can also make the bolts with any required recess in case anyone wants any...