Leaky diff

[Miraz]

Last Saturday I took the seven up to Bentwaters for a bit of a lark about - whilst stopped during the second session I noticed some oil sprayed up the back of the car. A quick ferret around underneath revealed that everything to the right hand side of the diff was dripping with oil, the left hand side of the rear suspension was completely clean, as was everything forward of the diff.

 

I've not had any problems with diff leaks in the last 3000 miles, the diff breather is plumbed into the neck of the fuel filler so, in theory, the only way that the oil could have come out of the diff is past one of the seals - the obvious suspect is the RHS half-shaft seal.

 

Is there anyway to confirm that this is the cause of the leak? - I can't think of anything else to check.

 

I found Alex Wong's description (below) of how to change the seal in the blatchat archives - does anyone have any other tips/suggestions to add to this?

 

I'm working on the basis that the Ford part number is 610 7894 - can anyone confirm this?

 

Cheers

 

Geoff

 

 

To change the half shaft oil seal -

 

1. Jack car up and take wheel on relavant side off

2. Undo 2 bolts holding the brake caliper off. Free the caliper from the disk and tie the caliper to the anti roll bar/rear spring/trailing arm.

3. undo 4 bolts holding the hub assembly to the de-dion ear

4. Remove hub/halfshaft assembly noting which way up the hub is (the curved surface of the bit directly bolting onto the de-dion ear faces up and the stepped surface faces down - this will be obvious when you see it.)

5. You should now be able to see the oil seal sitting in the diff.

6. Measure the amount that it is set into the diff. It should be 1.12cm (I think) - check with a Haynes Sierra manual. This should be consistant all round the oil seal. If it isn't, it is not in square and will leak. If it isn't square, it should be replaced. Incidentally, my oil seal was square and looked fine.

7. To get the oil seal out, I used a tyre iron (!) as a screw driver wasn't up to the job. Ford do have a special tool for it but I didn't have such luxuries.

8. Alternate leverage from under the car and from the boot gets the seal out but it is tedious and time consuming. Don't rush it as there's a bearing directly behind the seal and the case is easy to damage. The seal will be destroyed in the process.

9. Tap the new seal in after cleaning up all relavant surfaces and greasing the oil seal. I used an old section of exhaust pipe to help tap it in square. Be careful not to damage the new oil seal.

10. Remeasure the depth regularly and keep the seal square.

11. Replace half shaft after cleaning the splines and the oil seal surface. Be careful not to force it in. It should slide through the new oil seal.

12. Reassemble the hub/brakes etc.

13. Have a well earned beer!!

 

[EFA]

If your diff breather is plumbed into the fuel filler I would imagine its blown a seal as the fuel tank can become pressurised on an injection car.

 

I would disconnect the diff breather from the fuel tank, make sure you have the correct breather and refil the diff with oil to the correct level and test.

 

Fat Arn

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[Miraz]

Under what circumstances would the tank become pressurised?

 

Surely this would have happened earlier in the last 3000 miles?

[EFA]

The fuel return can pressurise the tank.

 

Fat Arn

Visit the K2 RUM siteid=red>

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[SJL]

I have a similar problem in that my new (300 miles) 1.6K de dion is dripping oil from the RHS diff seal albeit only a few drips after every outing - investigation suggests the driveshaft oil seal (their is oil collecting around the seating). Will this bed in and cure itself (rose tinted specs or what ?) or does it go back ?

 

PS - The breather doesn't appear to be the culprit

[mav]

Take it back. Mine was diong this within 500 miles of new - Caterham blamed a batch of faulty seals. Seems strange it is only the RHS that is affected on these diffs though.

 

No probles so far and now covered over 4.5k miles!!

 

Touching all wooden thinks within reach!!!!!

[Miraz]

I have to admit to being a little mystified as to why the seal should let go after 3000 miles without any previous problems, although I'll accept that the plumbing of the breather into the fuel filler might have contributed to the failure.

 

I'm also a little concerned that fuel might have contaminated the oil in the diff - at the very least the diff needs to be drained and refilled.

 

I'm also going to get the RH seal changed by RatRace, however if they don't get round to it tomorrow then I'll get stuck in myself as I'd like to have the car on the road this weekend.

[Bob Corb]

My diff has been leaking from the RHS too. Has done it from new. I've reported it to Simon and will get it sorted at my next service under warranty.

 

Bob

[Miraz]

This is a major leak - about a liter of oil came out in less than 10 miles.

 

Miraz

[Slarty Blat Fast]

My diff has been leaking from the RHS too.

Same here, Bob. Just been back to Midway Motors for the 2nd time under warranty. On close inspection we found minute pits on the face of the drive shaft where the seal sits. We have now seated a new seal a little further into the diff in an attempt to avoid the pitted area on the shaft - we'll see if it's successful. Otherwise it may mean a new shaft. I've reported the facts to Caterham. A bad batch of RHS drive shafts?

 

Absolutely no hitchhikersthumbsdown.gif

[mikehoile]

Yep mine as well - am on my third diff since building the car last year. Caterham have been very helpfull as they have had problems with them -it is the hassle factor to get to Darford that is a pain. Mine seems to leak on odd occassions ie a local run can be worse than after a blast. Oh yes and its the r/hand seal as well as the prop shaft one!! Hope to get it right one day..