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Oct 19, 2018 1:54 pm
bruce carey Offline
Registered since: Sep 27, 2018
Location: -

Subject: rear main bearing 38 v-12

does anyone have knowledge on the rear main of these engines...she runs like a top but leaks oil from the rear...and i would like to understand seal availability...procedure to install...before i remove the pan...

Oct 19, 2018 6:10 pm
h14 Offline
Registered since: Nov 30, 2008
Location: Chalandray, France

Subject: Re: rear main bearing 38 v-12
I bought a rear crankshaft seal from the Club Spares many years ago,
which was fitted as part of the professional engine rebuild; so I can't offer fitting advice. The V12 spares offered by the Club today include GSKV05 "Crankshaft oil seal, V12", but doesn't state if it's front or rear.
Removing the "pan" will get you nowhere, despite the length of time taken to undo and remove the vast number of nuts and bolts! All you will see is more aluminium casting.
The V12 engine has no bellhousing, as the gearbox is separately mounted. It follows therefore that it MAY be possible to change this seal with the engine in situ. You would need to remove the cardan shaft (absolutely essential to replace all the nuts, bolts and washes in their original locations), clutch assembly and flywheel.
Welcome to the world of V12 ownership, but bear in mind rule number one. No small or apparently easy job is possible on the V12 without having to do at least one otherwise unnecessary major job first.
Before doing anything at all, you need these essential publications:
Original factory handbook; fortunately almost a workshop manual. You will need to establish if your engine is Sanction 1, or 2, as firing order and camshaft settings differ.
Motor Trader Supplement for the V12. Published in 1939, this fills in the spaces left by the handbook. as with the handbook, the Club can supply a reprint, but do note the photographs in the original are much clearer.
The Club's own Revised Owners Manual for the V12; this includes the combined knowledge of many members, with much hands-on information.
Donald Bastows book on W O Bentley is highly informative, with copy blueprints, photos etc ... but it is highly technical!

Oct 21, 2018 3:56 pm
bruce carey Offline
Registered since: Sep 27, 2018
Location: -

Subject: Re: rear main bearing 38 v-12
Thank you very much...Lawrence...I am really enjoying learning about these fine automobiles. And fortunately for me this is the only major project that needs sorting on this car.


Oct 25, 2018 5:27 pm
Julian Offline
Registered since: Dec 04, 2007
Location: Belgium

Subject: Re: rear main bearing 38 v-12
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.

Julian Messent

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