Oil leak at rear diff

Just noticed a fair oil leak has developed on my Disco 300tdi, leaking from where the rear prop enters the diff. Only started after off-roading yesterday.

Is it an easy fix please?

Reply to
Andy
Loading thread data ...

I know it was an easy job on my Defender 110, but I'm not sure if they've got the same rear axle as you have. If so it's a case of taking off the rear prop yoke, undoing a nut that's hidden behind it, pulling out the shaft, then a metal guard, then the seal, putting a new seal in then fitting it all back. Should take about an hour or so but as it's a landy, it'll take about 6 hours and will require frequent visits to the dealer to get replacement bolts and all sorts of stuff that should just come off :-(

All the above from memory, although I know it's not a hard job.

Reply to
Ian Rawlings

Thanks Ian, sorry if it's a silly question but do I need to drain the rear diff of remaining oil first?

Reply to
Andy

No, not at all, it'll just spill out the hole all over your face when you pull the shaft out.

Please, no fnaar fnaars.

Reply to
Ian Rawlings

Now I think of it, there was a complication, in that once you remove the prop shaft yoke to expose the nut that holds the shaft on, you then have to rotate the nut while keeping the rear diff input shaft from rotating. However the handbrake and gearbox are now behind you, and are not connected to the shaft so you can't use those. Plus you suddenly notice that you twisting away at the shaft has started the truck rolling while you're underneath it! Whoops.

IIRC I bolted sommat to the bolt holes vacated by the prop shaft yoke, and made that hit the chassis to stop the shaft moving.

Reply to
Ian Rawlings

Before you do anything check that the axle breather is not blocked. You may cure the problem by just correcting that and thereby eliminating pressure build up in the axle casing which is forcing oil out past the seal.

You won't lose much anyway as the oil level is about half way up the pinion shaft (from memory). Depending on how much remains you can reduce the loss by arranging for the front of the vehicle to be higher than the rear before you start dismantling. Some loss, however, is inevitable whatever you do.

To see how long your repair is likely to last, inspect the surface of the yoke where the seal was running. If you have a groove you'll not cure the problem. It may be possible to fit the seal more/less deeply so that it runs on a fresh bit of the yoke.

Reply to
Dougal

I do hope that you aren't working on a vehicle without ensuring that the wheels are chocked first......

And don't rely on something blocking the flange against the bodywork either. There is enough weight in a Disco/Rangie that if it wants to roll it will bend whatever is in it's way in that manner. I once had a RR roll backwards off a set of wheel ramps whilst there was a spanner on the propshaft/brake drum nut. The spanner did not stop the vehicle moving, however the vehicle did twist the spanner into a 'U' shape.

Alex

Reply to
Alex

I'll second that but beware oil is lighter than water so if you have sucked water in you'll want to drain it.

AJH

Reply to
andrew

Chocking the wheels wasn't enough, when you're twisting the input shaft on the rear axle, the rear wheels will be turned, and the truck started climbing the chocks (very slowly), so you need to stop the shaft turning as well. In addition to that, if the nut needs a hammer blow or two on the spanner to free it off, without stopping the flange from turning the blow will just get absorbed in the drivetrain and tyre flex.

Reply to
Ian Rawlings

Now I think about it, what I think I did was to put one of the bolts back into the input flange mount and wedge a metal bar vertically underneath it with the other end on the ground, so in order to turn, the flange would have to lift the truck. While that might happen to a degree if I was on the end of a long spanner (or at least it might cause enough force to shoot the bar out), it wasn't an issue when I was thwacking away at the spanner with a hammer due to the short, sharp shock. Once it was going it was fairly easy to remove. You just need to stop the drivetrain absorbing the hammer blows and the twisting from the spanner, and avoid it passing it on to the wheels, even with chocks in place.

Also I think it was a nyloc nut, so rather than chance it I think I replaced it with a new one.

Reply to
Ian Rawlings

Removing a rear half shaft (or both if you have anything other than a standard diff.) will stop the rotation of the pinion turning the rear wheels. You'll still need to hold the flange, though, to undo the pinion nut.

In addition to that, if the nut needs a hammer

Reply to
Dougal

Stopping the flange rotating is required, and that'll stop the rear wheels rotating in itself so no need for messing about with half shafts.

Reply to
Ian Rawlings

Think you have hit the nail on the head. Water and oil is seeping from the breather pipe so I think it sucked some in when I crossed the deep water :-(

I'll drain and re-fill it next week after Sunday's off road play day.

Reply to
Andy

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.