Oil leak - suspect from speedo drive

[1969Mk3Spitfire]

I have a gearbox oil leak on my Mk3 Spitfire which I suspect is coming from the region of the speedo cable attachment.  I've been underneath the car today and this looks to be the wettest area, albeit I'm not 100% certain.

After a drive, over the next couple of days it will deposit a large spoonful of oil into the drip tray.

Is this a common leak path?  Any suggestions for a fix? Using water pump pliers, I managed to tighten the cable nut a few degrees but I didn't want to over-tighten it.

The car has another leak but very minor by comparison.  This one seems to be coming from the differential nearside half shaft seal.  I doubt that I'll do anything with this, maybe simply check bolt torques.

Any advice much appreciated. Thanks.

 

 

 

 

 

[Colin Lindsay]

The diff might be leaking from the breather on the top, check that it's not running down from higher up before blaming the poor halfshaft! 

It's on the driver's side top, if you can reach it and jiggle it about it may clear and so stop pressure blowing the oil out. You can see the state they get into...

The speedo drive may need a new O-ring; easy to get and fit provided you have access whilst it's fitted to the car, as the drive unit has to come out - it's just one screw. If it's just the sealing of the cable I wonder would a fibre washer help on the end of the speedo cable? 

[1969Mk3Spitfire]

Thanks, Colin,

I'll check the diff breather, thanks for the tip.

Do you know if there's access to the speedo drive unit retaining screw from underneath the car? I've only recently done the bushes on the gear change so I really don't fancy removing the tunnel again in a hurry.

 

[Colin Lindsay]

I suspect it's like the Herald and the screw is on the top... there's also a speedo drive oil seal, seems to be about £5, which fits into the drive so it could be that, or the O-ring, which is allowing oil to leak out. You may need to remove the tunnel (again!), undo the two rear mountings and jack the rear of the box up so that it clears the chassis rails, but I'm hoping that will be clarified by a fellow Spitfire owner?

[Pete Lewis]

the drive shaft leak ...yes check the breather ...i thought it was N/S ..??

the output shafts do not have a gasket , needs a careful look is it the shaft seal or the bearing case face ???  changing the seal is not easy the shaft comes out by using a hex key thro the coupling holes and just pulls out , getting the bearing off is difficult without a slim nosed puller .

speedo seals are common leak  there is a seal and 0 ring ...and its tunnel off

see 33 34  35 on canley's 

https://www.canleyclassics.com/?catalogue=triumph-spitfire-mkiii&diagram=triumph-spitfire-mkiii-gearbox

Pete

 

[Nigel Clark]

There's a bolt, think it's a peg bolt, that holds the speedo drive output into the overdrive case. The bolt has a copper washer under its head.

If this leaks, it can loose a surprising amount of oil. It's a fiddle but possible to access from under the car.

I've fitted a new copper washer and tightened it up on my Spit a few months ago and since then it's been completely oil tight.

Nigel

[Pete Lewis]

old trick with oil leaksto tace where from.     , dry off with a squirt of brake cleaner or similar, then puff some talc powder around the leak area  the  leak will leave a trace thro the dust

and makes it smell nice .

Pete