Strange oil leak

Post by: **tcsoar** » Mon Sep 26, 2011 6:28 pm

I know, nothing strange about an oil leaks on our cars but this one is weird.

I have removed the engine to get to the bell housing bolt that I forgot to seal :oops:

Before fitting the engine I decided to refill the gearbox to make sure the bolt no longer leaked and still had the front wheels on ramps. After filling I checked the back of the gearbox and found oil dripping from front uj on the prop. The oil seal is brand new and had not leaked when filled previously.

Thinking that, because the front was up, the oil had run to the tailhousing I took the car off the ramps and put the back up. This stopped the oil from dripping. Left it for a day and then took the car off the ramps and left it sitting level for another day, still no drips.

Today I put the front wheels back on the ramps and intially it seemed fine. But have now dicovered a small amount of oil dripping from the uj. Now the strange bit is that I had wiped the area around the seal clean and although there is now oil on the uj again and although it is no where near as bad as before, the area around the seal is still dry and clean.

The only explanation I can think of at the moment is that the oil is getting through the front of the propshaft and leaking directly into the middle of the uj, anyone else had or heard of this before?

Chris

Post by: **miked** » Mon Sep 26, 2011 7:42 pm

Chris,

Me too!

I had a major one when I to lifted the front of the car. I was taking the engine out anyway. Investigation revealed the blanking plug/cap in the centre of the yoke to be missing. I then found it in the prop shaft tunnel with a pile of oil. This space can hold a lot of gear oil. The blank is approx' 25mm ish in Dia'. PO must have smacked the yoke against the gearbox output shaft thus popping it out. He knew because he had tried to glue it back in with black silicone sealant. I had a spare yoke so fitted that. I was so paranoid that I sat the gearbox at angle on the workshop floor with oil in to make sure that the seal and this part was good. After 7 days I was happy. Bone dry.

Now done 500 miles and all is well. Also watch out for the speedo drive for oil leaks. I glued the ally adaptor to the ally body and left it o/night in the vice. Also fitted a tiny "O" ring in the drive shaft slot. Also bent the fork to ensure it pushed hard on the sholuder of the ally glued bit.

Mike

Post by: **marklowe** » Mon Sep 26, 2011 7:51 pm

There should be a Disc / Plug in the Yoke, if this is missing oil can leek through the centre of the yoke, it is shown in Brian Buckland?s book.

Mark

Post by: **marklowe** » Mon Sep 26, 2011 7:55 pm

Beaten again by a faster mind.

Mark

Post by: **bcmc33** » Mon Sep 26, 2011 8:48 pm

If the Welch plug is loose or missing - you will have oil leaking out.

Post by: **69S4** » Tue Sep 27, 2011 6:14 am

Yes, I had that when I had the propshaft rebuilt. It came back without the plug at the front and with my (then) drive on a slope I had a major mess to clean up very quickly. Their fix has obviously worked as the Elan seems to spend more of its time with the front on ramps than not at the moment and no oil leaks.

Post by: **tcsoar** » Wed Sep 28, 2011 6:37 am

Thanks for the replies guys, I think I know where to look now :wink:

This forum is great.

Chris.

Post by: **holywood3645** » Sat Nov 12, 2011 8:26 pm

DELETE

Post by: **holywood3645** » Sat Nov 12, 2011 8:27 pm

holywood3645 wrote:Great Information. Eactly the same issue on my S4. Great to find this out BEFORE fitting engine the body chassis re-assembly. Now of to check BB book
James

Post by: **tcsoar** » Sat Nov 12, 2011 9:59 pm

Seeing that Holywood bumped the thread, although I am not convinced they meant to, thought I would let you guys know that you were all correct

.

The disc in the yoke had not been fitted properly from day one as part of it was deformed, but it did not leak until I started mucking about with the gearbox and propshaft and I assume that I managed to knock it.

Luckily I had a spare yoke that I fitted and, fingers crossed, I have fimally stopped the oil leaks

Chris.

Post by: **holywood3645** » Sat Nov 12, 2011 10:37 pm

I have looked in the BB book and the Lotus workshop manual and don't see any detailed instructions or illustration on the disk/plug yoke. I had a very slight drip from the rear seal after I filled the gearbox with oil. (everthing in chassis except engine, and body not yet installed) I had though the rear seal was installed the wrong way around, but apparently not. I turned the chassis around in the garage and a larger drip has developed from the angle drive. The garage floor is a 1in in 10ft slope. The leak at the angle drive appeared when the grearbox was lower at the front.
Is oil supposed to collect in this section of the G/box?
What normall will cause a leak from the angle drive?
Does anyone have a picture of the disc in the yoke?

Thanks
James

Post by: **holywood3645** » Wed Nov 16, 2011 4:52 pm

Help?

Post by: **Mrozik** » Thu Oct 29, 2020 6:03 am

Hi
This is interesting as I have the same problem after reinstalling the engine/gearbox but where exactly is the blanking plug?
Thanks for the help

Post by: **alan.barker** » Thu Oct 29, 2020 8:59 am

The blanking plug is in the yoke of the UJ. It stops oil from Gearbox going along the Out Put splines.
It's to blank off the Splined hole in the UJ Yoke.
Alan

Post by: **gjz30075** » Thu Oct 29, 2020 9:41 am

Here's a pic of the plug in a yoke (not a Lotus)

Strange oil leak

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