Gearbox prop oil seal change

[Wrightpayne]

Does anyone know if this can be done in situ with removal of the diff and prop shaft? 
 

Car is S3 dedion with k series engine, 6sp box and ford diff.

[Bricol]

Might be nearly as easy to pull the engine and box?

But it should be possible to lever it out - just might be awkward to be certain you have it square before driving it in?

[ChrisC]

Agreed, this I would only attempt it with a lift (which I don't have).  I just couldn't get the car high enough to make working in that confined space possible without mistakes. 

For me it would be engine out. 

[Wrightpayne]

I was thinking there might be room to swing the hammer from above with the tunnel top off.

[Bricol]

I would think access better from underneath - the handbrake mount and lever would get in the way from the top I would think?  

How bad is the drip?  Think of it as chassis rust protection . . .

Mine leaks, has done for years, but oil always runs out the filler, so . . .

 

[Wrightpayne]

Its more than an odd drip, like that coming from the diff! I may be pulling the engine out to do other stuff so pondering whether to do this winter or next!

Its quite difficult to work out where it is coming from - hopefully not porosity! 

[ScottR400D]

My 6 speed has always leaked a little from the tail seal. The oil runs forward down the tail housing and drops from the lowest point. At first glance it doesn’t seem to be the seal but it is. 

I’ve not bothered changing it because it’s a very small leak. If I wipe it clean it’ll typically be the end of the second run out before it drops and even then it’s just a drop or two (Depends on how long the runs are, of course!) 

It doesn't continue to drip when stood but there’s also a mist thrown onto the inside of the tunnel, though it takes a year or two to become noticeable.

I've never noticed any significant effect on oil level

 

 

[Bricol]

All oil seals have to leak a little tiny bit to lubricate the lip - run it totally dry and it'll fail - probably by wearing a groove in the shaft.  So think of it as prolonging seal life :)

[ScottR400D]

Ha! I like your thinking!

Am I right in thinking the seal has a thrower to send oil away from it when it’s actually turning? 

[OldAndrewE]

Throwers can only be used when the shaft being sealed comes from the "inside" of the seal. Would not be possible on the propshaft as it is inserted from the "outside" of the seal

[ScottR400D]

Of course! 

[Bricol]

Modern oil seals don't tend to need "throwers".

Lots of info on the Trelleborg website if you get really bored.

Spent the last two years working on a hypocycloidal gearbox project (1/2 tonne gear set in a 1/2 tonne case), so had to spec more than one seal . . .

[Wrightpayne]

Is that for the new SV? :-)

[7 wonders of the world]

 

have you checked the speedo drive seal... those are prone to leanking

[aerobod - near CYYC]

Many modern oil seals have a teflon lip that doesn't require lubrication to give them a long life.

[Wrightpayne]

Speedo seal changed twice along with drive spindle as thought it may be passing the metal sleeve. Still leaking.

Its SORN'd now so will jack it up Thursday, give it a good clean down and see if it dribbles.

 

Ian

[Tom_Arundel]

As a matter of interest, give the end of the prop shaft a good vertical tug- rattle at the gear box end and see how much it moves. I think that a lot of seals leak because there is too much clearance between the prop nose and the gearbox bearing sleeve causing the prop to vibrate in the seal. Not normally serious but maybe the cause of a leak

[rj]

Ian,

Depending on what tunnel top you have, access may be very limited. A race chassis (with the handbrake under the dash) will not have a long enough cutout to work on the rear of the gearbox from the top.

I would personally think that it was possible to do from under the car. The access is fair, but as it has been suggested a lift would be helpful.

 

[Bricol]

Prop slides on a spline on the gearbox output shaft - unless its worn, you have to have a certain amount of play to allow it to slide.