Ford Differential

[analog_me]

Hi,

I have various leaks from my ford diff (vent plug and driveshaft) and decided to replace the seal of the drive shaft (RH side)
The drive shaft seems to have a minor groove where the seal is seating.
1. How should i best polish this before installing a new seal?
2. Is a 1000 grid sand paper and wd40 the best for this job or would you suggest otherwise?
3. Is the driveshaft moving in and out the diff ( thus through the seal )as the suspension moves up and down or is the seal always in contact with the drive shaft at the same location and the transverse motion taking place in the CV?

Thanks

[DCL]

The splined part of the shaft should not move and so the seal runs in the same place. When you replace it, leave the seal a little further out than the old one and hopefully it will run on a less worn section. One problem is that the seal can be pushed all the way in and fall off the drive shaft oil seal flange. There's also an O ring on the bearing carrier that can be damaged.

[analog_me]

Thank you Dave will try not to touch too much the shaft's grove and will install the new seal a few mm further out.

[Tye Green]

I used fine grit wet and dry before to try and remove a groove on a crank nose where the end seal goes and regretted it later when I figured that the original groove would have had a smooth and rounded transition from the unworn part into the groove but that the wet and dry would have changed this to a positive step with a sharp edge. finished up having to take some off the full section so there was no groove at all.

as said above, if you can simply move the point of contact for the seal that's a better solution but in most cases imagine the original smooth groove with a new seal would be fine anyway.

[analog_me]

Ok New seal is in place, 2mm further out so not to seat on the damaged section,
Will test it soon to see if the leak has being fixed.

I noted there are two types of seals, both having the same code number, I got one from Road and Race in the UK and one from the official French caterham dealer.
They are different in terms of width of their internal diameter where it is in contact with the shaft. One is 2mm wider than the other but all other and externa dimensions are identical.
After repetitive testing i choose to use the narrower one to make sure the inner side of the seal is making good contact with the shaft and is not "landing" at the end or beyond the shaft sealing surface.

I will report the result as soon as i test it in anger.
Also i added a hose on the vent plug to extend the vent point further up. I choose to fit a plastic hose which forms a coil to allow the collection of some oil before it dips out of it.