Trunions, grease and oil!

[Robster]

Just read the last theme..I have been using moly grease on the trunions for the last couple of years..am I wrong? What will happen if I continue??

 

This has left me very confused!

[R2D2]

The upright used on the Seven has been around since the beginning of time and has been fitted to Triumph Heralds, Spitfires, GT6s Lotus Elans, Europas and quite a nuber of sixties F1 race cars.

 

It was designed to be used with EP90 not grease. I have never used grease in the trunnions on my car but I would imagine that it doesn't do a great deal for the steering feel/response. I can't imagine it will do any specific damage but the workshop manuals for all the cars fitted with this upright do recommend filling trunnions with EP90.

[tony pashley]

<< ...has been around since the beginning of time... >>

Pre-war at least, from a Standard saloon of some description, I believe. (So does it share some heritage with the old Standard axle?)

 

MotorSport did a piece on the Alford Alder (or vice versa...) upright, as it was known, a while back. Can't find it for now, so won't quote chapter and verse (even if you were interested), but I seem to remember it 'won' two or three world championships and an Indy 500.

 

And it was never intended to have grease in it. What the prognosis is for a grease-filled upright and trunnion - I am not best qualified to say.

[aideen]

A Google (or other) search for "trunnion ep90" should keep you occupied for a while! Here's one for starters (with good photos):

 

http://www.hockerley.freeserve.co.uk/pages/suspensn.html

 

My GT6 was about 15 years old when the upright snapped (going over a bridge). I hadn't had the car very long so don't know if grease or oil was used. Probably down to wear and tear as the above ref. suggests. I fitted new uprights (not cheap!) and trunnions to both sides after this mishap.

 

Aside: I blame all this messing about with old sports cars for germinating a desire to build a car from all new shiney bits which I ultimately did smile.gif

 

Aideen

[elie boone]

The problem with grease is airlocks.The quality of grease has much improved over the last 10/20 years but it is still posible to have some airlocks in the tread, so it will wear faster.

[Ralph Morgan]

I've always thought that the problem with using grease in the trunnions was that it gets compacted at the base of the threaded bore (as the shaft "screws in" to the threaded housing when lock is applied), and hydraulic pressure can then split the brass casting with obvious results. May be wrong,though.....

[stevefoster]

I had two trunnioned 7's.

The problem is indeed of compacting and / or grease being too think to spread over the threads resulting in premature wear. You will notice this as a clunk with the car jacked, wheel off the ground and a suitable longish plank to lever the wheel up and down before the thing fails. This or similar procedure should be part of an MOT test at any rate.

 

My first 7 )bought 2nd hand) had only had grease in it's 8000 mile life. I disassembled cleaned and could see that grease had not reached all the threads! No signs of wear.

I would not advise simply trying to squirt oil in after grease. It will not force it's way past the grease.

 

Oiling with EP90 is messy. James W does a little squirter for this but I have not used this so cannot comment. Even the highest quality grease gun with EP90 in it leaks a bit... Plenty of rags etc at the ready.