Leaking LSD Half Shafts

Tue Mar 17, 2015 9:03 pm

Me again hoping for some more technical help! This time about my LSD.

I gave it an oil change with Castrol B373 (recommended on the wiki) and I have noticed now that the oil is leaking quite a lot from both half shafts where it joins the main body of the case.

I don't know how much oil it's lost in real terms, I know a little can look like a hell of a lot. But I'm guessing its a bad idea to be driving the car like this, wouldn't want to destroy an LSD.

Any any ideas on how to sort this out? Its a bloody awkward job getting the diff on/off so I'd love to have a plan of action before I do that!

Wed Mar 18, 2015 12:43 pm

I thought the recommended oil was Castrol SAF-XJ?

Ben

Wed Mar 18, 2015 1:04 pm

Thanks. Hopefully it'll just be the seals, but I am looking at doing a back end overhaul to tighten the car up so will end up having the diff out, should make the job easier as I haven't got a pit or anything.

Just double checked the wiki:
"For Limited-Slip differentials, use a 75W-140 specifically designed for plate-type LSDs. A normal gear oil will destroy the plates and make it work like an open diff. The recommended options are Castrol racing b373 or Syntrax limited slip (which replaces the old SAF-XJ oil)"

Wed Mar 18, 2015 1:15 pm

I was looking at this page: http://www.e30zone.net/e30zonewiki/inde ... fferential

I can't find your one.

Ben

Wed Mar 18, 2015 1:20 pm

WillNZ wrote:Also check the flanges do not have rotational play, if they do, the shaft bearings will need replacing, this is a diff out job unfortunately.

Are you referring to the bearings in the diff?

Do you mean rotational play between the cups or movement of the cup up/down relative to the housing?

Wed Mar 18, 2015 1:39 pm

BenHar wrote:I thought the recommended oil was Castrol SAF-XJ?

Ben

I find putting newer synthetic oils in old diffs running old seals is a sure way to make them leak. Nothing wrong with B373

Wed Mar 18, 2015 2:10 pm

DanThe wrote:
BenHar wrote:I thought the recommended oil was Castrol SAF-XJ?

Ben
I find putting newer synthetic oils in old diffs running old seals is a sure way to make them leak. Nothing wrong with B373

I was just going by what I found in the wiki.

I've now found the other link: http://www.e30zone.net/e30zonewiki/inde ... fferential which recommends either.

In this case it seems that the mineral version has also made it leak.

Ben

Thu Mar 19, 2015 1:07 pm

DanThe wrote:
BenHar wrote:I thought the recommended oil was Castrol SAF-XJ?

Ben
I find putting newer synthetic oils in old diffs running old seals is a sure way to make them leak. Nothing wrong with B373

I find that with a lot of things. Most modern oils are thinner but have better film strength.
The idea is to reduce viscous friction but it does leave old seals pissing oil out.

Sat Mar 21, 2015 1:29 am

Check the breather on the backplate isn't blocked. It's the small hole on the side of the tube, poking up from the top of the backplate.

If these get blocked, oil will vomit out everywhere regardless of whether new or old seals are fitted....

Mon Mar 23, 2015 1:02 pm

Thanks. It looks clear but i'll have a closer look when I get chance and make sure its not blocking the pressure in. It seems to still be leaking despite not having been moved for days though.