v12 rear main seal

bruce carey

17 October 2018 at 17:00 #52893

is there anyone who has had to replace their rear main seal ?

Julian Messent

1 November 2018 at 12:10 #52927

Hi there,
The oil “seal” on the V12 is located behind the flywheel and is actually seperate to the sump and block.
You need to remove the flywheel which you can “sometimes” do without removing the sump.
The seal housing just un bolts, however there is actually no seal inside, it is only an oil scroll and you will need a crank out job if you want to modify to a real seal.
I have probably got pictures etc if you need them.

Regards,
Julian

bruce carey

5 November 2018 at 17:27 #52929

Thank you Julian,

a picture would really help…i purchase a rear crankcase seal from spares…that i thought would do the trick ??? any help would be greatly appreciated. Do i need to remove the transmission to get to the flywheel ??

Bruce Carey

Julian Messent

6 November 2018 at 08:21 #52930

Copy of the email I just sent to Bary if anyone else is interested.

Open the floor of the car,
Remove the cardan shaft between engine and gearbox (leave gearbox in place but can be easier if the box is loose from its mountings)
Remove the clutch and flywheel. (on occasion you must remove the sump to get the flywheel out but a die grinder and a little finesse will usually suffice.)
Remove the old seal housing,
Then you will see the situation in the first pic.
We then measure the scroll diameter carefully and then turn up a one piece ally scroll housing that has an ID about 0.006? larger, this gives 0.003? all round which works a treat. See second pic.
HOWEVER. To get this accurately, you must make the bolt holes exactly on centre of the studs and then open them out about 2mm (or 0.080?) this makes the seal housing position ?adjustable?
Fit the seal housing over the crank scroll. Put three 0.003? feeler gauges around the outside to locate the housing centrally, lock it down with 4 nuts and then drill it to dowel it.
Remove it and refit with sealer and lock nuts etc.
Re-fit all and enjoy.

Hope this helps,
Best regards,
Jules

PS.
Pics on request by email if needed, the forum takes too much time to download and am a little busy for the moment. Will try if I can find time.