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Gearbox input shaft seal replacement

Posted: 15 Mar 2014, 18:00
by toolsntat
Just mangled it up trying to get it out and failed :twisted:
So do I have to split the box (no oil and not in van)?
Will there be bits dropping out :roll:
Guess new gasket required? And where on a Sunday :?:

Was not leaking (32000 miles) but just being precautionary as the box was out...

Andy

Re: Gearbox input shaft seal replacement

Posted: 15 Mar 2014, 22:35
by Theclash
Just done my output shaft seals on my golf mk2 gearbox still in car and I can honestly say its a pig of a job.
Would imagine t25 be very similar. I needed to make a puller to get the driveshaft flange off the gearbox and same tool to put it back again once seal was replaced,without the tool the job would have been impossible to do.
Had the gearbox out last year to fit new clutch I sooo wish I had changed them then ,
Good luck and take your time coat the new seals in gear oil to aid installation

Image

Re: Gearbox input shaft seal replacement

Posted: 16 Mar 2014, 00:53
by CovKid
In? out? Above pic is an output shaft and on a T25 entails removing one circlip and the use of two claw hammers. Input shaft seal just needs an oil seal remover (about a tenner from Machine Mart). Pops out easy with that Andy.

Re: Gearbox input shaft seal replacement

Posted: 16 Mar 2014, 06:49
by toolsntat
Yes the outputs were easy 8)
Its the input seal with the shaft still in that's the mare.
I had a look at that seal tool Ralph but fail to see how it would help, as it has had 3 pulls with self tappers screwed into it and not budged :evil:
I even cut away the outer rubber and made a puller, acting against the inside bore of the seal which might have gone, but it just bent the ends of my puller:twisted:
Maybe it was gunked in?

I'm loathed to split the box because the case is bone dry, almost wishing I had left this seal alone now but sod's law would have had it leaking sooner or later :roll:

BIG question is, can the shaft take much pressure acting against its end and pushing into the box if I grind up some pullers using silver steel rod, instead if the re-bar I used before?

Andy

Re: Gearbox input shaft seal replacement

Posted: 16 Mar 2014, 07:13
by CovKid
I know what you're saying but getting the seal out is a complete pig without that tool. I was amazed me at just how quickly input seals pop out with one of those things. I too have used self-tappers, even screwdrivers in the past and they never seem to budge. Its an awkward angle, not helped by the input shaft itself. For the price they are, it has to be worth trying before attempting to remove bellhousing. The oil seal remover seems to hook in where screwdrivers can't even reach. Either way, its an important part of a toolkit in my vierw and worth its weight in gold. Aidan may have a solution if he's about.

Re: Gearbox input shaft seal replacement

Posted: 16 Mar 2014, 07:23
by toolsntat
Ok cheers Ralph, will have a go, bet my brothers got one somewhere :ok

Andy

Re: Gearbox input shaft seal replacement

Posted: 16 Mar 2014, 07:51
by Aidan
just take the bellhousing off, 50/50 whether the gasket tears or not, can seal with flange sealant if gasket trashed, means you get to inspect the crown and pinion and the oil thrower, yes the input shaft wobbles about it does that, clean up the mark made by the puller, seal can be "bar-steward" tight in there and is deep; smooth and lube the bore to aid fitting the seal, fill lips of seal with grease, note orientation of the guide tube when refitting, small holes top and bottom, 18ftlb for the bolts holding the bellhousing to the case

Re: Gearbox input shaft seal replacement

Posted: 16 Mar 2014, 08:32
by toolsntat
Cheers Aidan.
Yes am aware of the wobble thanks and this is the plug tree, ok for 32000 miles?

Image

Will look out for guide holes, inside box?

Thank you
Andy

Re: Gearbox input shaft seal replacement

Posted: 16 Mar 2014, 12:12
by Aidan
plug's a bit heavy but stem not too sludgy so not massive pinion bearing wear
holes are in the tube part of the guide tube

Re: Gearbox input shaft seal replacement

Posted: 23 Mar 2014, 20:42
by toolsntat
Well, got it split with the gasket intact :D
But what a game to get that seal out :evil: even with whacking it from behind it did not budge :shock:
In the end had to get the Vise Grips on the remaining flange and lever it out.....

Just a thought, how do you know when a crown wheel etc is worn without having new to compare with?
Are there any measurements to go by?

Thanks
Andy

Re: Gearbox input shaft seal replacement

Posted: 23 Mar 2014, 22:23
by Aidan
Just a thought, how do you know when a crown wheel etc is worn without having new to compare with?
Are there any measurements to go by?

visual inspection
measure the backlash

yes the seal can be a "bar-steward" to get out after 25 years,especially in diesels with no timing mark cover and plug fitted

Re: Gearbox input shaft seal replacement

Posted: 23 Mar 2014, 23:31
by toolsntat
Cheers Aidan 8)