Diff leak - black plate sealing?

[TomB]

I have a leak from my diff (AP LSD), which I think is coming from the rear back plate. I first noticed it last summer, but didnt do anything about it over the winter when I should have! Having been for a 3 hours run on Saturday, the back of the car is covered in oily grime, with a streak of oil behind the A frame on the bottom of the fuel tank. There is also a drip of oil on the bottom rear of the diff.

 

One option is to remove the diff, take the back plate off & reseal it with anaerobic sealer. I could also get it refreshed at the same time, seeing as its 40000 miles old. Has anyone had a refresh on a AP Suretrac diff? Roughly how much should I budget??

 

Alternatively, has anyone ever resealed the back plate leaving the diff in-situ? There doesnt seem to be space to remove the star fasteners without taking the de-dion tube off. I figure that I could remove the de-dion, crack the fastenings, drain the diff down, then remove, clean & reseal the back plate. I wouldnt have to take the drive shafts out, risk damaging seals, undo the prop shaft. This approach could be quicker, leading to less down time during the good weather.

 

Any advice appreciated

 

 

 

 

Edited by - TomB on 25 Apr 2010 21:35:34

[Englishmaninwales]

Tom

Unlikely to be the back plate. Any oil around the front drive flange? This is a common leak, requires removal and refitting with RTV sealant.

 

Malcolm

[TomB]

Fairly sure there is no oil at the front of the diff. The underside of the front of the diff is clean. Ill crawl under there and have a look tomorrow.

[F355GTS]

Tom, as said it's unusual for them to leak however it's quite normal for them to spill a bit of oil out of the short breather tube particularly if it's full and being driven enthusiastically .

 

Clean up the diff and add a longer breather tube then take it for a drive to see if the problem reappears

 

Mark

[TomB]

After having a closer look, I think its the RHS diff/drive shaft oil seal. The front of the diff is dry, the breather and top of the diff are dry. The RHS castellastion are all oily, and there was a drop on the RHS driveshaft can. The rear RHS of the back plate is much oilier than the LHS, so it looks a likely suspect. I think I must have disturbed it while removing the de dion for powder coating last winter - I remember the RHS drive shaft coming a bit loose and have to push it back in.

 

Searching the archives suggests its relatively easy job to change. Any further advice?

 

 

[The Pikey]

You could fit a new oil seal with the diff in place. Just needs the drive shaft removing. Make sure the new seal has the spring in it unlike the one I fitted a couple of years ago

 

Jason

 

 

[TomB]

Seals ordered! Common, Grey & Elephant. Im so funny....