325 sport LSd

Post Tue Oct 31, 2006 9:28 am

Came Back from the classic car show at the NEC and decided to get stuck into preserving the sport. Removed all the spash guards front and rear and gave behind them a good clean and a coat of wax oil.

after my hard work i decided to take her out for a run and thats when i discoverd that the LSD is'nt working as it should. It seems to only spin the inside wheel.

Will a change of the diff oil make much difference? I printed out some information form "autodata" and it recomends 90SAE.Is this the correct oil or is there anything better i could use?

If worse comes to worse am i better getting the Diff reconditioned or looking for a second hand one?

Post Tue Oct 31, 2006 10:24 am

this may sound like a daft question but make sure some tool that has owned the car in the past hasn't changed it for an open diff without realising

its easy to do, just jack up the rear of the car so both wheels are clear of the ground, take it out of gear with the handbrake off and spin one wheel by hand, if they both turn in the same direction then its an LSD, if they go in the opposite direction then its an open diff

P.S. if you already know this and it sounds like i'm teaching you how to suck eggs then just ignore me and tell me to piss off

Post Tue Oct 31, 2006 10:39 am

yeah - i'll give that a go when i get outta work.

I have a pile of reciepts that came with the car and none of them mention a replacement diff, but i'll cheack the diff tags too.

So, even if a LSD is'nt working, it should still spin both wheels in the same direction when you jack her up?

Post Tue Oct 31, 2006 4:41 pm

i think so, becasue there should be enough (grip) in the plates to lock up when under next to no torque as your turning by hand, but as soon as you try and put alot of torque through it, i.e. with the engine, then it just slips and acts like an open diff

Post Sun Nov 05, 2006 5:09 pm

Ok, jacked the car up and it spins both wheels in the same direction.

Had a look at the diff tag too, its fairly corroded but there is definately an "S" which I believe indicates a LSD?

Changed the Diff oil for Castrol 80W 90 and took the car out for a run - seems to have made a difference.Can a change of oil really effect the performance of the diff that much?

Also, while i was waxoiling the rear drivers side arch, i removed the splash guard to reveal a plastic bottle. What is this for? Looks like it's linked to the fuel line, but another sport owner told me its a vacuum bottle for the central locking??

thanks

Post Sun Nov 05, 2006 5:15 pm

I think that the bottle you are refering is the one that lives under the battery tray in the boot? Its meant to drain the area under the battery should a water feature start to develop there, which it so often does!

Post Sun Nov 05, 2006 7:22 pm

The bottle in the wheel arch is where all the various vent lines from the fuel tank/filler collect together and connect to a single vent line to the front left of the car.
Vacuum bottle for central locking??? This is BMW, not old fashioned Merc crap.
LSDs require a special oil for the purpose. Drain out what you've put in there, and get the right stuff. (Generally only available from your friendly dealer.)

Post Sun Nov 05, 2006 8:03 pm

the oil i put in was propper diff oil.

did try the local dealer but he was as much use as a chocolate ashtray!