12 replies to this topic

[Woreign]

The pot joint gaiters on my Mini are shot. Rather than take a chance that the CV joint is bad (I can see trash in them already), I'm going to replace the entire pot joint. This will also make the job a lot less messy since I won't have to clean and re-pack the old joint...

Is it necessary to remove the drive shaft from the pot joint first, then remove the point joint from the differential? Or can I remove the pot joint and drive shaft at the same time and separate them after they are out of the car? I will also replace the drive shaft seals at this time as well. Is it necessary to drain the oil? Or can the seals be changed with minimal oil loss?

Thanks!

[tiger99]

You will need to drain the oil. The pots will not pass through the openings in the subframe, so they need to be taken apart somehow. The official method is with tool 18G 1243, which pulls the shaft out of the inner part of the pot joint, but as you are unlikely to come across one of these you will need to do it the messy way, by seperating the pot joints. You should ideally pull back the gaiters first and mark the orientation on the inner and outer elements, so everything goes back together as it was, balls in same slots etc.

The pot joints should be regreased and reassembled with new gaiters if needed, off the car, and fitted back into the diff first, giving them a good hard thump to ensure that the locking clip engages. The drive shafts can then be refitted easily, with the overhauled outer CV in place on the shaft.

[xrocketengineer]

I am too slow typing! tiger beat me to it!
You need to drain the oil first if you are going to replace the seals and the pot joint. The pot joint is too big to fit through the hole in the subframe. Its going to be messy anyway. If you are lucky, you might be able to get the pot joint off the drive shaft by giving it some sharp blows against a lip of the inner part of the joint to make it slide along the drive shaft. If you are unlucky (like me) you might be better off cutting the gaiter off and pulling the inner part of the joint out together with the drive shaft and all will fit throught the subframe hole. It will be very messy at this point. To remove the joint from the drive shaft you can do what I did:
http://www.theminifo...-stuck-to-axle/
To get the pot joint off, do not pry between the joint and the gearbox. Use a couple of large flat screwdrivers or chisels and drive them in between the gearbox an the joint. The factory tool is basically a "horseshoe shaped" wedge that you drive it with a hammer between the gearbox and the joint.
As far as the seals go I can not help you, I have not been fortunate enough to have to replace them. I had to replace the whole gearbox!

Edited by xrocketengineer, 23 November 2012 - 11:50 PM.

[tiger99]

The horseshoe shaped tool, 18G 1240 (Mini suppliers can sell you an equivalent) DOES NOT wedge between the casing and the pot joint. It has a bump on the back, which buts against the bottom bolt head on the diff side cover, so when you whack it with a hammer it pivots about that point and forces the pot outwards.

You MUST NOT use any kind of wedge, or you will ruin the diff side cover, and possibly the diff casing, which is matched to the main transmission case, so you could end up needing a new tansmission case and a full strip and rebuild, just because you used a wedge.

If you do not have 18G 1240 or similar, you can use a heavy tyre lever. You fit a 1/2" AF socket to the bottom bolt as a spacer. put the flat end of the tyre lever between pot joint and casing (NOT wedged), pivot it agianst the socket, and whack the end hard. It is not so good as the proper tool, as it applies force only at one point, rather than two opposite points like the official tool, but it usually works and never does any damage.

The lower casing bolt is the ONLY place where force can safely be applied.

[xrocketengineer]

I stand corrected then. Here is an illustration on how to use the tool:
http://www.reizendem...fronsusp/13.htm

Edited by xrocketengineer, 24 November 2012 - 12:45 AM.

[Woreign]

Thanks for all the info and alternate site references! They are very helpful!

I was going to order the 18G 1243 tool anyway, along with the new pot joints.

Regarding the oil seals, I noticed that the bolts holding the differential side covers were loose when I removed the gear shift linkage. I'm wondering it that is the source of the oil leak and not the seals? Especially because after I removed those bolts, the oil drip is more steady!

[Guess-Works.com]

There should be an exhaust bracket attached to 2 ( sometimes 3 ) of the diff cover bolts on the selector side of the gearbox. These can be pulled out bu excessive movement of the engine and or exhaust...

Once pulled the only remedy is a helicoil.

[Woreign]

The exhaust bracket was broken, which I removed to find the bolts were loose. I needed a wrench to remove the bolts completely, so I don't think they are stripped. I'll put them back in for now and see if my leak stops.

[tiger99]

xrocketengineer, that link is very useful, as it shows both special tools in use. There should be sufficient information in the pictures for anyone with the capability to make them, or something very similar, for themselves. I do wish that Mini spares suppliers would collectively get someone to make a batch of 12G 1243 tools, to save a lot of hassle. I would have thought that there would be a demand for a few hundred if the price was right.

[Woreign]

I was able to pull the axle out, along with half of the inner CV joint. The races in the joint show some wear, so the decision to replace them sounds like a good one...

I might go ahead and try to pop the inner pot joint free of the differential, taking care not to press against the diff covers, as discussed above. If it works, it will save me money on the tool that I will only use twice (once on each side).

Also, how do you know if the ball joints are good or bad? Now would be a good time to change them if I need to...

Edited by Woreign, 24 November 2012 - 12:56 PM.

[Ethel]

I use a big cold chisel as a wedge, just take care not to hit it into the shiny shaft of the joint that the oil seal runs on. They often pop out with little force, of course you wouldn't want to hammer hard with it pressing on an unsupported part of the diff cover.

[Woreign]

I cleaned up one of the CV joints and and it shows some wear: small, smooth, shiny grooves from the ball bearings. Nothing rough or irregular. Should these be replaced?

[xrocketengineer]

If the balls fit snugly in the pot joint with no play, it should be ok. One of mine was replaced because there was corrosion and pitting on both the balls and the races. The other one was good and the fit was snug with no play between the balls and the races. The inner piece of the pot joint was stuck to the drive shaft, therefore it was better (and easier) to remove the driveshaft from the outer CV joint and replace both gaiters by installing them from the outboard end of the driveshaft.