Lotus Elan

Leaking Rear Bearing on +2!

PostPost by: david.g.chapman » Sun Aug 27, 2006 7:12 pm

Yes, that's right. My offside (for the UK) rear bearing is leaking oil!

There are one or two drops appearing after a drive, at the bottom of the outer rear bearing. The oil then runs down the hub housing and drips onto the rear wheel. The shock absorber was replaced recently with an insert (Monroe type). my first thought was that the insert was leaking internally and oil was finding its way onto the stub axle. There is no external leaking anywhere else and the shock absorber action is fine.

There happened to be a plugged hole in the outer shock absorber tube below the level of the bearings (drilled some time ago). I unplugged the hole expecting oil to pour out - nothing! And yet the oil is still slowly leaking.

So how can shock absorber insert oil get through two layers of steel and find its way onto the bearings? :shock:

I remember applying some grease on the inside when I changed the bearings a couple of years ago. This grease was quite old, and oil may be leaking out of this. Can the bearing housing pressurise and force this oil out when the bearings are turning? The oil is tan brown in colour. Is shock absorber oil clear or brown? Any other ideas? - this has me foxed.

Dave Chapman.
david.g.chapman
Fourth Gear
Fourth Gear
 
Posts: 685
Joined: 26 Nov 2003
Location: Writtle, Essex

PostPost by: Jason1 » Sun Aug 27, 2006 7:59 pm

Dave

Any leaks at the hub I would suspect the brake caliper first. Old brake fuild goes brown and tastes very bitter if you put a drop on your tongue :)

It's unlikely that oil would leak from the diff and along the shaft :?

As it is the offside you can rule out fuel spilling from the cap.

I would suggest you make sure it is oil first (rub it between your fingers and smell it) then clean the whole area off and go for another drive.

Another thought; make sure there is nothing leaking in the boot???

Good luck

Jason
User avatar
Jason1
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1588
Joined: 03 Nov 2005
Location: Colchester, Essex. UK

PostPost by: gjz30075 » Mon Aug 28, 2006 11:55 am

David,
When the Monroe inserts were installed, was a light oil put in the shock tube? There should be some in there to aid cooling of the shock and the shock tube is just a press fit into the hub and possibly not a perfect seal, or your hub is a bit porous and the 'cooling' oil is finding its way out.

If you found nothing when you pulled the plug, then most likely the oil is finding its way out. I'm sure its not the shock oil but rather the cooling oil.

The wheel bearings are sealed units, filled with grease so I doubt if that's your problem. Even if they were to leak grease, I doubt if it would come out in a liquid form.

Also, as Jason suggested, it could be brake fluid.

Greg Z.
User avatar
gjz30075
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2816
Joined: 12 Sep 2003
Location: Roswell, Georgia, USA

PostPost by: gjz30075 » Mon Aug 28, 2006 11:59 am

Let me re-phrase the part about pulling the plug. If you filled the tube with oil and inserted the shock which could displace the fluid enough to be higher than the plug, and you know this, then pulling the plug and finding nothing could be legitimate. Otherwise, it much like pulling the plug on the trans or diff. You don't expect to see fluid there unless you poke your finger in there.
User avatar
gjz30075
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2816
Joined: 12 Sep 2003
Location: Roswell, Georgia, USA

PostPost by: david.g.chapman » Mon Aug 28, 2006 6:31 pm

Thanks for your replies so far. I have done some further investigation and drilled a small hole (about 2mm dia) in the bearing housing quite low down, just above the outer wishbone joints. Not something I wanted to do, but I had to know what was going on in that housing. And.....

Brown oil came out of the hole - smelling stongly of grease! The total volume of oil (including the amount that has already leaked) seems about the same as the grease I had but in when I did the bearings. This is enough to fill 25% of the housing.

As I suspected, I think this grease had liquified, as has been sloshing around the housing much like in a gearbox. I must add that a modern LM grease will not do this! Serves me right for using this ancient stuff in the first place. :oops:

As a bonus, I also solved a recent problem with transmission "backlash". The oil had penetrated the morse taper on the hub, so the rear wheel was moving against the hub key on the taper between drive and coast.

So I have cleaned everthing up, plugged the hole, and I dont have to nurse the clutch any more. Result! :D
david.g.chapman
Fourth Gear
Fourth Gear
 
Posts: 685
Joined: 26 Nov 2003
Location: Writtle, Essex

PostPost by: gjz30075 » Mon Aug 28, 2006 7:50 pm

Nice find, but I guess I'm still confused. Are you saying that your wheel bearings are/were not sealed and lubricated by packing them, or something, hence liquified grease in the housing?

The only rear wheel bearings I know of for an Elan are the sealed type and doesn't required a housing full of grease.

Greg Z.
User avatar
gjz30075
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2816
Joined: 12 Sep 2003
Location: Roswell, Georgia, USA

PostPost by: david.g.chapman » Tue Aug 29, 2006 11:21 am

Greg,

You are quite right. There is no need to pack the bearings with grease, as they have internal shields fitted. I was not sure about this at the time, so tried to play safe.

The Brooklands Books workshop manual on the +2 (which I followed) mentions adding grease, so maybe at the time of writing internal shields were not always fitted.

Dave Chapman.
david.g.chapman
Fourth Gear
Fourth Gear
 
Posts: 685
Joined: 26 Nov 2003
Location: Writtle, Essex

Total Online:

Users browsing this forum: No registered users and 7 guests