1098 diff in a 948 housing

[XDB]

I am putting a 1098 diff in my 948cc moggie. The refill/level plug goes with the old diff. Which is the easiest way of doing another. Either drill and tap the rear of the casing or drill and tap the diff in a similar position to the 948 one. any advice welcome[/img][/img]

[bmcecosse]

I think it would be easier to drill/tap the new diff before you fit it - working at the bench must be easier than working under the car!

[forbesg]

I am putting a 1098 diff in my 948cc moggie. The refill/level plug goes with the old diff. Which is the easiest way of doing another. Either drill and tap the rear of the casing or drill and tap the diff in a similar position to the 948 one. any advice welcome

Why not transfer the crown wheel & pinion into the old housing?

[Nadir]

I think the point is that there's no filler/level thingy on the old housing - never had a 948, me, but I've read it's possible to put a unit together without one.

Yes, the EP is the correct oil and yes, there is a drain plug at the bottom of the axle casing. Don't know which model you have but there can be problems if an earlier axle has been fitted with the later diff unit i.e.
there is no filler hole!!

As I say, I don't understand it, but it can happen.

[Willie]

I would suspect that it would be easier to tap the axle casing. The only alternatives to making a new filler/level orifice as far as I know would be to measure out the official amount of EP and then inject it through the breather hole or remove a half shaft and inject through there. Somewhat involved but not something you would do too often[if there is no leakage.

[bmcecosse]

Is the axle casing thick enough to take a good thread ?

[paulhumphries]

Is the axle casing thick enough to take a good thread ?

I suppose it doesn't have to be a perfect visual match to the original so maybe a visit to an engineering pipe fitting specialist might help.
I suspect they will have bolt in bosses that a standard BSP plug will then fit.
Drill hole in thin diff cover on casing, bolt on boss and job done ?

Paul Humphries

[IslipMinor]

The axle casing is not thick enough to tap for a filler plug. I had to weld on a 1/2" BSP tapped boss to take the filler plug on the 948 casing, to convert it so that I could fit a 3.9 diff, with no filler plug in the diff itself.

[Willie]

There you are then,I was right, it wouldbe easier to drill and tap the axle casing because it is too thin!

[bmcecosse]

Well - that's one way of being 'right'!

[Willie]

It's called irony!

[XDB]

I have drilled and tapped the side of the casing. It isn't very thick. I have managed to get a 12mm bot with a fibre washer to seal ok. I was thinking of using the old case, but I am worried about damaging the pinion bearing when I swap them over.

[bmcecosse]

You've got welding gear there - maybe weld a 12mm nut to the casing? Screw it on the bolt - run it up against the casing - and weld around.

[XDB]

what sort of metal is the housing, will it weld normally?

[IslipMinor]

The axle casing is mild steel and welds easily, once you have removed ALL the oily deposits! Don't forget to disconnect the battery and alternator (if fitted).

[XDB]

my apologies, I think somewhere in the thread I have confused between the diff carrier and the axle casing. The diff carrier is some sort of alloy.

[img][img]http://i218.photobucket.com/albums/cc17 ... C00823.jpg[/img][/img]

[IslipMinor]

Aluminium casting for the diff housing - not nice to weld!! How many threads in the tapped hole do you get?

[XDB]

not many. I have seen some modern cars with a plug either plastic or something similar. I'll put some thread lock on, if it doesn't leak I hope not to have to disturb it again.

[alex_holden]

You could always just bung a cork in it!

[XDB]

Hey Alex ow come I need a password to see your workshop, is it a lancky
thing