44 replies to this topic

[tiger99]

The old trick, before the ali bush was available, was to fit two seals, pushing the old one in by fitting the new over it. Don't do that, as without the ali bush it will be leaking again very soon. The seals don't tolerate much shaft wobble, which was the cause of the problem. There isn't sufficient room for two seals and the bush.

[Andrew22-10]

i saw that where the seals go there is a seam, is there a way of removing that section without dropping the engine. (previous owner has used a chisel or something like it to remove the seals and damaged the casing)

[Spider]

I recently put the new seal kit in my mini and it hasnt helped. I did notice that the insideof the casng were the alloy seal goes was abit damaged, is there any wayof removing the casing were the seals go, i am trying to avoid removing the engine if atall possible.

 

That will make it leak for sure. I've fixed a few like this over the past few months in fact (must be a run on them!). The damage appears to have been from POs getting the old seals out at a guess.

 

You could try something like an RTV Sealant smeared around the inside of the bore for the seal, then fit the Seal. Might work.

 

The ones I fixed I did by removing the diff cap (which does necessitate removing the engine), machining this bore out bigger, turning up a short aluminium bar to the same size + 0.003", using loctite, press them together then re-machine the bore for the seal.

[Andrew22-10]

thanks for the advise. i did put some sealant on the seal before putting it in. is there any way of sorting the damage with the engine in (would a round file help, or just cause more damage?)

[tiger99]

Without high quality photos I can only guess the nature of the damage. If it is in the bore where the seal sits, a round file will do you no good at all as the gear change shaft is in the way.

The ultimate answer is to strip the box completely to a bare casing, build up some new metal by MIG or TIG welding and reaching it. Or if there is sufficient metal, bore it out a bit larger and press in a sleeve.

But with care and luck a repair with sealant may last a long time. Or not...

[tiger99]

Oh, and removing the diff casing does not necessitate removing the engine, but it is tricky and messy. You have to redo the diff shimming. In the early days it was common because rally teams needed to change diff by the roadside. I have done it once, to change a final drive ratio.

Although it was quicker (just) than lifting the engine I would be reluctant to do it that way again.

[Spider]

thanks for the advise. i did put some sealant on the seal before putting it in. is there any way of sorting the damage with the engine in (would a round file help, or just cause more damage?)

 

None that I can think of. Filing it (if you could) would likely make matters worse. The bore does need to be perfectly round and a very good finish for the seals to seal on the outside.

[Ethel]

See if you can figure out where it's leaking. Either the casting has been chewed up enough to let oil escape between it and the seal, or the hole has been distorted so the seal is no longer concentric with the selector and oil is getting between the seal's lip and the rod. In the first instance, your chances of sealing it with RTV silicone are better. If it's a wonky seated seal some very judicious scraping might  remove a dink that's causing the seal to skew  - you may swap one leak for another though.

 

The selector rod isn't burred and damaging the seal when it's fitted?

[Dusky]

The problem with these casings is that there is (an urban Legend) Out there to get the aluminium Bush Out.
Something with a screwdriver and quickly putting it in First. I damaged my case like this when I Just had the car

[Magneto]

What is the point of removing the aluminum ring? Seems to me all you really need to do is replace the seal itself.....

[Dusky]

Because the myth also says these can wear out very badly

[A-Cell]

What is the point of removing the aluminum ring? Seems to me all you really need to do is replace the seal itself.....

The aluminium ring has a groove around the outside which locates an o ring seal. So if you want to fit a new o ring then you need to remove the alu ring.

[tiger99]

You usually don't need to change the O ring. It is not providing a sealing function, only friction to keep the bush in place. It is inboard of the actual seal. But as said above, the bush wears. It would help to get one made from the correct grade of a bearing material such as Oilite instead of ali.

[Guess-Works.com]

It does provide a sealing function as the aluminium support is not an interference fit, therefore there's a clearance, which we all know, oil will find the minutest hole, gap or perished seal to flow past...

The very first plastic support bushes did not have the seal, but it was added to the plastic bush and has always be present on the factory fit Aluminium support.

[Mini Manannán]

We're considering getting hold of a Viton seal which should last longer.   Might work, but whether Viton is soft enough to seal well is another thing. Also, machining an O-ring groove on the inside of the aluminium support.