Technical Mk2 Gearbox Input Shaft Seal

[richardllew]

My son has brought my Mk2 1.2 Punto back with a big oil leak from the gearbox.
It appears to be from the input shaft seal and has gone from zero leak to big leak in a short time/distance. The clutch is slipping to confirm the diagnosis.
The bearing may need to be changed, but if its OK can the seal be changed without stripping the gearbox ? I've read Mr Wild's excellent post (Thanks to him) and it looks like the gearbox needs to be stripped to change the seal. Can anybody give me confirmation either way ?

Thanks in Advance

Richard

 

[DaveMcT]

The input shaft bearing absolutely DOES need to be changed when the seal fails. See the guide by @Mr Wild. Also check out the bearings at the other end and the associated gears.

Don't forget to clean out the gearbox bottom which will have bits of bearing in there. If they get into the differential....

 

[Ziggy122]

The input shaft bearing absolutely DOES need to be changed when the seal fails. See the guide by @Mr Wild. Also check out the bearings at the other end and the associated gears.

Don't forget to clean out the gearbox bottom which will have bits of bearing in there. If they get into the differential.... it starts tapping and the one day it goes poof! - the fluid then leaks out all over the floor and the gearbox is scrap, if the diff blowing sprays into the box

Getting the box out is 1 Thing
doing the repair is 2
Getting the box back in is 3

Can you do 1 2 and 3?

Ziggy

 

[richardllew]

Thanks for the reply WhiteSei.
The gearbox is working fine, no bearing noise at all. I don't want to strip the gearbox down if I don't have to as I'm under time pressure to get the job done. My guess is that increased bearing play will have caused such a fast failure of seal, so as you say the bearing will need changing.

Back to my original question though, does the gearbox have to be stripped to replace the seal, or can it be prised out from inside the bellhousing?

I haven't taken the gearbox out yet so I can't tell.

Cheers

Richard

 

[Ziggy122]

Thanks for the reply WhiteSei.
The gearbox is working fine, no bearing noise at all. I don't want to strip the gearbox down if I don't have to as I'm under time pressure to get the job done. My guess is that increased bearing play will have caused such a fast failure of seal, so as you say the bearing will need changing.

Back to my original question though, does the gearbox have to be stripped to replace the seal, or can it be prised out from inside the bellhousing?

I haven't taken the gearbox out yet so I can't tell.

Cheers

Richard

The seal will have failed because there is play in the bearing
The bearing is supported a little bit tho due to the clutch

Input bearing and seal go hand in hand
do the seal - it'll be leaking very shortly again, as the shaft wobbles and ruin's it again

Also dont forget a New Clutch in there as well - once a clutch is contaminated, it will never be the same again

The Bellhousing and Gearlinkage ontop does have to come off - its in Mr.wild's guide

Ziggy

 

[richardllew]

Thanks Ziggy,

I can do 1 and 3 as I've already changed gearboxes on a Mk1, relatively easy compared to some other front wheel cars.
What does concern me is splitting the gearbox, I stripped a scrap Escort 5 speed box and I certainly would not have been able to put it back together without special tooling. However, from Mr Wild's post splitting the Mk2 box seems a practical proposition for me as I've been fiddling with cars for years and am a Mechanical Engineer, although designing trains doesn't help in fixing gearboxes much !

 

[Ziggy122]

Thanks Ziggy,

I can do 1 and 3 as I've already changed gearboxes on a Mk1, relatively easy compared to some other front wheel cars.
What does concern me is splitting the gearbox, I stripped a scrap Escort 5 speed box and I certainly would not have been able to put it back together without special tooling. However, from Mr Wild's post splitting the Mk2 box seems a practical proposition for me as I've been fiddling with cars for years and am a Mechanical Engineer, although designing trains doesn't help in fixing gearboxes much !

The Seal is just seated up against the Bellhousing edge
And i've lead to believe yes the bearing is on the shaft tight - but it is possible to get the Bearing off with a little hammer time

Make sure you mark where the bearing sits tho - as it needs tosit in the same place as last time

ziggy

 

[DaveMcT]

See the guide by @MrWild
The Forum search as usual didnt find it

Googlw (4th one down did it
http://www.google.co.uk/#hl=en&suge...gc.r_pw.&fp=78207bf8c2b7603b&biw=1022&bih=515
https://www.fiatforum.com/punto/158346-input-shaft-bearing-renewal.html