Trailing arms

[DaveN]

I've picked up a pair of trailing arms with the intention of overhauling them. I've got the bushes out and the studs removed.

Couple of questions:

The stud threads in the castings are perfect so was thinking of just new studs... Is it worth reworking them anyway?

If I reworked them I will go for Helicoils.

They have been painted in the past. (Hammerite I think.) What's the teams view on stripping, media blasting and

Powdercoating?

Finally, Poly bushes: blue or red?

[RogerH]

Hi Dave,

'if' the threads in the arms are OK then I would stay as is - this way you keep as much metal around the stud as possible. Easy enough to Helicoil in the future.

Hammerite is 'orrid. Get them grit blasted and paint with ordinary 'wheel silver ' paint. Powder coating is good but when it starts to peel life becomes less funny.

 

There is a rubber bung that will allow a look inside - have a peek and see what condition they are. May require cleaning out and waxoyl'ing - they do corrode.

 

Blue bushes.

 

Roger

[Geko]

Plenty of advices including coating and bushing here

[DaveN]

Cheers Roger

My first thought is to leave the stud fittings as is! Interestingly, I asked a couple of structural guys what would be best, helicoils or upto UNC. They were of the opinion helicoils would give the best mechanical joint!.

I'm going to peer inside with a flexi borescope next week, just for my own interest, then flush them out and treat with deoxidise and alocrom. Followed by the waxoyl.

Wheel paint sounds like a good idea.

The existing TA's on my car are covered in that damn shutz stuff and look unsightly.

Will pick up some blue poly bushes, studs and bungs next week.

[RogerH]

Hi Dave,

I also think that Helicoils in Ali alloy would be stronger than any size of thread in the Ali on its own.

If you tighten a bolt in Ali alloy then you simply shear the threads (given enough force)

With a helicoil as the bolt is being tightened it is forcing the helicoil out and causing it to grip into the Ali more and more. The Ali thread would have less tendency to shear.

 

However if the is plenty of good metal left then they will last another 40+ years.

 

Roger

[AlanT]

Why do we have coarse and fine thread standards?

Because fine threads don't work well in alloy.

 

You could use 5/16in UNC Helicoils I suppose.

If you did this you would drill away more metal than a 3/8in UNC.

 

There is not a lot of metal in these to drill away in some cases.

Being castings they vary a bit.

 

This is why you should leave as is if possible.

[ctc77965o]

I would inspect carefully for cracking of the web that runs parallel with the brake backplate from the hub towards the chassis attachment point. My original set had both cracked..