818 630 gearbox rebuild

[jolly500]

Hi.

Does anyone know why the bolts which fix the rear gearbox mounting to the box, have an o-ring seal on one end and a copper washer on the other?
Couldnt one use a copper or aluminium washer in place of the o-ring which appears to get badly mangled when the bolt is tightened?

Or is there a reason to use an o-ring?

Thanks
Steve

[tangmonster]

Hi.

Does anyone know why the bolts which fix the rear gearbox mounting to the box, have an o-ring seal on one end and a copper washer on the other?
Couldnt one use a copper or aluminium washer in place of the o-ring which appears to get badly mangled when the bolt is tightened?

Or is there a reason to use an o-ring?

Thanks
Steve

That is a very good question!!!
I was also very curious why they did it this way.
I stuck to that and replaced the o-ring and washer but it still is confusing to me.

It is exactly the same for the other (center) bolts that are not used for the gearbox mount. So this can't be linked to gearbox mount alone.

when comparing the casings there is definately a campfer on the one case with the o-ring vs flat on the copper washer side.

[Racer]

Obviously its to prevent oil leaks. I rebuilt my gearbox With exactly the same copperwasher/O-ring position as Lancia did. I thrust they had a reason for it.

Cheers

Tor

[tangmonster]

I think the question is rather why copper on the one side and o-ring on the other.

I don't however find it getting that mangled taken the chamfer into account and correcltly sized o-ring.

In short after tightening i can't see it and washer is flush

[jolly500]

That is a very good question!!!
I was also very curious why they did it this way.
I stuck to that and replaced the o-ring and washer but it still is confusing to me.

It is exactly the same for the other (center) bolts that are not used for the gearbox mount. So this can't be linked to gearbox mount alone.

when comparing the casings there is definately a campfer on the one case with the o-ring vs flat on the copper washer side.

Hi
I had a look at my casing (4 speed) and there is no obvious chamfer. Wonder if the 4 speed bolt holes are meant to be sealed the same way?

[tangmonster]

Hi
I had a look at my casing (4 speed) and there is no obvious chamfer. Wonder if the 4 speed bolt holes are meant to be sealed the same way?

Take note of the centre m8 hole and smaller on the m6 hole in your right hand picture. the small chamfer is clearly there and looks like mine.

the same hole on the left hand picture is square.

That small chamfer is the one is was referring to.

[jolly500]

Take note of the centre m8 hole and smaller on the m6 hole in your right hand picture. the small chamfer is clearly there and looks like mine.

the same hole on the left hand picture is square.

That small chamfer is the one is was referring to.

I see them now, you've got far better eye sight than me!

Would they need a very narrow o-ring then - any idea how thick?

To confirm - that means the o-rings are fitted on the right hand side of the gearbox and the brass washer on the left under the dome nut, as viewed from the cabin.

Thanks very much for your help.
Steve

[tangmonster]

I see them now, you've got far better eye sight than me!

Would they need a very narrow o-ring then - any idea how thick?

To confirm - that means the o-rings are fitted on the right hand side of the gearbox and the brass washer on the left under the dome nut, as viewed from the cabin.

Thanks very much for your help.
Steve

Yes , on the fitment. I measured the ones i got with my gasket set to be 1.5mm thick.

[jolly500]

Yes , on the fitment. I measured the ones i got with my gasket set to be 1.5mm thick.

Thank you, that's a great help.

Regards
Steve

[tangmonster]

after many months of part time wrenching and part hunting and tool making I am very happy to conclude that this rebuild was a resounding success.

not shown in pictures is the sandblasting and respraying of all the sub frame parts. I also replaced the pilot bearing and the rear main seal while I was under there. I saw no need to replace clutch.

Gearbox shifting is much much improved, in that there is NO more grinding from 1st to 2nd. no more grinding from 5th down to 4th.

With the bushes on both the long selector shaft and the bushes for short shaft inside gearbox replaced shifting has a much tighter solid feel. I had a horrible rattling when in 5th in cruising due to worn bushes witch is all gone. Gone is that sloppy gear lever.

and a clean dry gearbox with no oil leaks!!

Only did a 7km sprint around town but with this gearbox rebuild the driving experience has truly evolved in something much much nicer.

Plus I replaced broken reverse light switch so now I have reverse lights again.....

cheers from a very happy Fulvia owner.

Thanks for all the inputs and help from forum members.