24 replies to this topic

[dsgoody]

Morning all,

 

I need to fit a new pot joint to my Mini; does the whole driveshaft have to come out for this or can it be done in situ with the ball joints split?

 

Cheers,

 

Dave

[nicklouse]

easier to remove the whole unit, as you need to drain the oil anyway.

[MIGLIACARS]

What happened to the pot joint, In all my mini/metro time ive never seen one fail!!!!

[Spider]

You can also remove the Pot Joint by just splitting the Top Ball Joint - it's all I've ever done.

 

And I jack up that side of the car about 400 - 500 mm so I don't have to drain the oil.

 

The Lazy Spider.

[dsgoody]

What happened to the pot joint, In all my mini/metro time ive never seen one fail!!!!

Nothing as such; but between two gearboxes and a Guessworks rebuild the diff outputs are still leaking really bad. Like oil being flung about, running along the floor pan and burning up on the exhaust bad. Before having it all out again (possibly for some re-bushed side plates) I would like to just try them as the output seals seal against them.

 

You can also remove the Pot Joint by just splitting the Top Ball Joint - it's all I've ever done.

 

And I jack up that side of the car about 400 - 500 mm so I don't have to drain the oil.

 

The Lazy Spider.

Sounds like a winner; need to do an oil change anyway but anything so I don't have to undo the hub nut! Do they just pull straight off the driveshaft?

[Spider]

 

Sounds like a winner; need to do an oil change anyway but anything so I don't have to undo the hub nut! Do they just pull straight off the driveshaft?

 

 

 

After popping the top ball joint, you'll need to knock the drive shaft out of the pot joint. i have an old tang through screw driver I do that with, just put it against the inner part of the pot joint at as much angle as the subframe will allow and give it a sharp tap, 99 / 100 they come apart easy like this. Then you should be able to lift the drive shaft clear, or maybe go full lock with the steering on that side can help.

 

Then in a similar way, knock the pot joint off the diff. I used to do these from underneath but a few years back, it occurred to me with a long (like 4') bar of 3/4" steel (or there abouts) the LH Joint can be done from the top and in some cases, the RH one too, though, it may depend on what exhaust manifold you have if you can land the bar on the joint.

[MIGLIACARS]

 

What happened to the pot joint, In all my mini/metro time ive never seen one fail!!!!

Nothing as such; but between two gearboxes and a Guessworks rebuild the diff outputs are still leaking really bad. Like oil being flung about, running along the floor pan and burning up on the exhaust bad. Before having it all out again (possibly for some re-bushed side plates) I would like to just try them as the output seals seal against them.

 

You can also remove the Pot Joint by just splitting the Top Ball Joint - it's all I've ever done.

 

And I jack up that side of the car about 400 - 500 mm so I don't have to drain the oil.

 

The Lazy Spider.

Sounds like a winner; need to do an oil change anyway but anything so I don't have to undo the hub nut! Do they just pull straight off the driveshaft?

 

while your under the car look at the diff covers, they may be damaged or oval where the seal sits in.

also the seal my be damaged or not sat in correctly,

when the pot joint is out, measure it and compare to another, also change the seal, these are a few quid only.

 

what oil are you using its not to thin is it!!!!!

[Spider]

If you haven't already, find the seals that have two lips and 80% fill the space between the lips with grease.

[dsgoody]

I have a new seal; but just one of the normal ones from Mini Spares. Where can you buy the twin lip seals?

 

As for the diff covers being oval or the seals not sat properly; the gearbox was just rebuilt so I would hope this wasn't an issue. This has happened with Mini Spares 20w50; Millers Classic Mini Oil (expensive stuff to throw all over the road) and Silkolene 20w50.

[panky]

Are you sure it's the pot joint? I had a horrendous oil leak that I suspected was the pot joint seal. turned out to be the half moon between block and gearbox spraying everywhere

[dsgoody]

Are you sure it's the pot joint? I had a horrendous oil leak that I suspected was the pot joint seal. turned out to be the half moon between block and gearbox spraying everywhere

To answer the question; no I'm not sure - this is purely a shot in the dark. I used a decent amount of RTV on the seal and it was installed with the timing gear fitted so couldn't become dislodged.

 

The leak seems to be worse after 400 miles of running every time the gearbox/engine comes out; and I couldn't see the half moon 'worsening' after running so I'm looking at the diff output/pot joint areas.

[MIGLIACARS]

wipe it all down with brake cleaner so its clean.

 

start the car run until hot and switch off the engine, lay some cardboard underneath the pot joints and leave for 24 hours if its the potjoint you will see it dripping out visually.  

[Spider]

Is there any 'play' in the joints in the bush?

 

Apart from external leaks, there is a plug, similar to a freeze plug, fitted inside the Pot Joints to seal the Oil from the inner part of the joint itself. I've found a number of these over the years that have leaked. You can usually pick this up from oil leaking out from under the pot joint boot.

 

Easy to fix, pop the joint, take it apart, carefully knock out the plug using a big dolly down the hole for the shaft, clean everything up - really super clean - then refit the plug with loctite (to seal it).

[tiger99]

When I first saw this thread at lunchtime, I wondered about the pot joint plugs, but was not completely sure about them, as I have never had one fail, and my memory of them was a bit vague. (Not had a pot joint fail either, as someone has noted above. Life maybe over 150k miles in a standard 998? They were such an unbelievable improvement over the old rubber couplings.)

 

In theory they could be the problem, but you should be able to tell, because the oil would be leaking into the pot joint. If you pull back the gaiter and find (not so) nice, black engine oil trickling out, that would be confirmation, but if you only find the proper grease the leak is elsewhere.

 

You will likely want to have the pots out for inspection anyway, and check for scoring or grooving on the surfaces where the seals run. I would be most concerned about the diff side cover bushes, as I have had these wear out, and cause leaks, loooooong before the pots were showing distress.

 

Seals:  http://bullmotifmini...ahu1448_adu5738

 

Side covers with reamed bush: http://bullmotifmini...r_chm85_dam0133

 

 

Other suppliers have them too or you can get the bushes, about a tenner each, and get them machined by someone competent on a lathe.

 

Edit: As for the half moon seal, we are seeing quite a lot of these. It used to be a very rare problem, even when assembled with minimal RTV at the ends only to make a good seal where they meed the engine to transmission case "sump" gaskets. Manufacturing quality is prime suspect, some being made too long, or of dubious material. But I get the strong impression that people sometimes fit them backwards. The lip should trap them in place, and I suspect that they are slipping out, or rather, in.

Edited by tiger99, 01 June 2017 - 10:16 PM.

[black olive]

Ive had a leaky pot joint plug, confounded me for ages