Trunnions and Ball Joints

[collins_dan]

To replace ball joints, and rebuild trunnions and seals, do I need to remove the vertical link and hub? In reading the manual, it reads like you can remove the ball joints without having to remove anything other than the wheel. The manual does say to remove the hub and vertical link to get the trunnion out, but I'm questioning why? Thanks. Dan S4 (Federal)

[paddy]

As I remember it, the trunnion can't be unscrewed with the disc in place so you have to remove the hub and disc, which in turn means removing the caliper. If you have the disc shield fitted you probably also have to remove that. To do that, you have to take out the bolts that retain the steering arm. Then there's nothing left except the upright hanging by the ball joint. If you've also taken the ball joint off, then your upright will have been completely removed and dismantled.

Paddy

[rjaxe]

Dan, busy formulating my response and Paddy beat me to it, never mind. However I think it is possible to replace the trunnion sleeve, bushes, seals and shields leaving the trunnion on the upright if that is all you want to do.

[collins_dan]

It's the seal at the top of the trunnion on the vertical link that is the issue. It appears to have completely disintegrated and all that's keeping grease inside is an old crusty layer of grease. Dan

[paddy]

If that's the case then you also have no real idea of the condition of the trunnion or the threads on the upright, so it all has to come apart anyway

Paddy

[collins_dan]

Shoot... good point. I'm really new at this taking everything apart game. I enjoy it, but also enter with caution and try to disturb as little as possible. Is there anything that I need to be extra careful of as I remove the hub, brake caliper, link... Thanks. Dan

[paddy]

You need to watch out for the temptation to get new grooved discs, aluminium competition hubs, bigger calipers ...

Paddy

[ppnelan]

I can't remember whether the caliper has to come off, or whether you can just remove the pads & hub nut to get enough disc movement to remove the trunnion
I made 2 saw cuts in the bottom of the disc shields so I could bend the part next to the trunnion out of the way when they needed replacing (I was in a hurry! ). It saved unsticking the rusty disc shield fixings...

Matthew

[Allison]

Dan,

taking off the caliper is no big deal - just tie it up with some string so there's no weight on the hose. I reckon that if you do take these things apart then it stops the bolts from seizing up - after all how often do you do the trunnions? Though to shoot my own argument down, one of our Elans failed the last MOT on the n/s trunnion and the other had a warning for next time around!

Peter

[Jas]

Paddy - good point, wife tells me to follow your advice? but she takes it nicely... I only show her the new stuff a little at a time.

[freddy22112211]

Need to replace the rubbers on the ball joints (top of vertical links) - but I can't get 'em off - any tips?
Gordon

[ill_will]

Gordon,

I had to take off a couple of very seized-in-place upper ball joints recently. I used liberal application of heat from a butane/propane blow torch and then a heavy hammer to hit the top of the upright (sideways) to free it up. Next step was to put a nut on the threaded stub of the ball joint (that passes through the upright) and hit that (to push it out of the tapered hole it sits in) using the same heavy hammer and a bit of approx 400x25x25mm wood as a 'punch'. It's a little awkward as you're swinging upwards.

w

[Barney]

and all that's keeping grease inside is an old crusty layer of grease.

I thought that grease was not used in trunnions. Instead a heavy oil was the preferred method.

Can somebody put me right on this?

Cheers
Barney

[paddy]

I thought that grease was not used in trunnions. Instead a heavy oil was the referred method.

Can somebody put me right on this?

You'll find both advocated vigorously if you look back through the archives.

Robinshaw and Ross states a strong preference for EP90 and that's good enough for me.

<heresy>
Given the miles you're likely to do, and your likely tendency to re-grease/oil very regularly, I'm sure it doesn't matter that much.
</heresy>

Paddy

[bcmc33]

If you use oil you will need to solder the peened blanking plate at the bottom of each unit to prevent oil leaks ? this is a Spitfire/GT6 forum recommendation.

Grease is a ?bad? lubricator for this type of application.

The best lubrication for this application (and steering gears for that matter) is a fluid grease. You can buy such a thing from any good source, but I make mine by mixing an EP90 oil with a good quality lithium grease in a 70/30 ratio.

I discovered fluid grease in the mid 60?s as a rooky plant engineer when asking for help from Shell Oil.

There was a thread on this subject some time ago, when an Austrailian engineer reminded me of my ancient experience:
http://www.lotuselan.net/forums/viewtopic.php?t=14069