13 replies to this topic

[hungdynasty]

Hi all how are you? Need advice on oil leaking on clutch housing, please see pictures. It is right above the lower steady rod, like a hole with a metal clip in the middle, thanks in advance.

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[Quinlan minor]

Indicates a crank oilseal is leaking.

How bad is it? Leaving puddles or just a misting?

Ultimately, clutch slip may occur. Check all engine breathers are clear, in the meantime.

Plan on replacing the clutch and, probably, oil pump while you're in there.

[DeadSquare]

That oil has leaked past the "Primary Gear Oil Seal", so the seal needs replacing.

 

If you search google for "How to remove and refit a Classic Mini clutch seal", with pot-luck trial and error,you should be able to find several videos that explain where, how and what do do.

[imack]

As others have said, that could be leaking from the primary gear oil seal, but it could also be leaking from between the primary gear bush and the crankshaft if either the bush or crank are worn or mis-sized. Either way it requires flywheel removal for further investigation.

[whistler]

I have just removed the flywheel on wife's 1330 to change for a lightened and balanced version. There was oil 'misting' around the bottom of the case but the clutch plate was dry. There was no oil leak from the red oil seal, totally dry so a little oil must be tracking through the tolerance of the primary gear to crankshaft.

Fitted new flywheel etc. and boxed it up.

If there's just a hint of an oil drip on the split pin and the clutch is fine then I'd leave it and keep an eye on it.

[imack]

I have just removed the flywheel on wife's 1330 to change for a lightened and balanced version. There was oil 'misting' around the bottom of the case but the clutch plate was dry. There was no oil leak from the red oil seal, totally dry so a little oil must be tracking through the tolerance of the primary gear to crankshaft.
Fitted new flywheel etc. and boxed it up.
If there's just a hint of an oil drip on the split pin and the clutch is fine then I'd leave it and keep an eye on it.

Exactly the issue I'd been having, except the aftermarket flywheels don't have the drillings to allow oil leakage from between the primary gear and crank to exit the 'trough' on the inner face of the flywheel and escape to the outer face without getting on the clutch plate.
My floating bushed primary gear has excess clearance between the outer diameter of the bush and the inner diameter of the gear.
New primary gear solved the issue.

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Edited by imack, 19 November 2023 - 12:09 PM.

[hungdynasty]

Thank you all for your advice, the clutch is still good no slipping and everything is still fine, I didn't see any leak until I park my car somewhere on a up-slope a few days ago and start to see the oil leak out on floor, not too serious just may be ten drops a night, I wil keep watching it thank you all again!

[Ethel]

If it's  minor the advice on breathers is useful. More pressure in the crankcase than clutch housing will  force oil out more than suck air in. The oil you use can also be a factor, some is better at looking after oil seals than others, usually the ones produced for old/classic engines.

[Designer]

I had this same problem a couple of years back.

I replaced the red/Orange Primary Gear Seal/Clutch Oil Seal but to no avail still had the leak.

I thought perhaps I had damaged the new seal when passing it over the the splines even though I had wrapped a couple of layers of masking tap over them or I had not seated the seal properly.

To make sure neither of those scenarios happened again I purchased the Minispares special fitting tool CE12. Well worth it.

Fitted new seal still had the leak. Stripped engine again and on close inspection with strong light and magnifying glass I noticed that there was a bigger gap between the seal and the top of the Primary Gear

than there was at the bottom. In fact no gap at the bottom which lead me to discover that the Primary Gear bushes were worn. I believe the tolerance is .0003" - 0004" I had .0006" so the gear was sitting lower down on the crank than it should thus the gap at the top. Replaced the Primary Gear with the correct Deva bushes and problem resolved.

.

Edited by Designer, 20 November 2023 - 07:44 AM.

[hungdynasty]

I had this same problem a couple of years back.

I replaced the red/Orange Primary Gear Seal/Clutch Oil Seal but to no avail still had the leak.

I thought perhaps I had damaged the new seal when passing it over the the splines even though I had wrapped a couple of layers of masking tap over them or I had not seated the seal properly.

To make sure neither of those scenarios happened again I purchased the Minispares special fitting tool CE12. Well worth it.

Fitted new seal still had the leak. Stripped engine again and on close inspection with strong light and magnifying glass I noticed that there was a bigger gap between the seal and the top of the Primary Gear

than there was at the bottom. In fact no gap at the bottom which lead me to discover that the Primary Gear bushes were worn. I believe the tolerance is .0003" - 0004" I had .0006" so the gear was sitting lower down on the crank than it should thus the gap at the top. Replaced the Primary Gear with the correct Deva bushes and problem resolved.

.

Hi Designer where did you get the Deva bushes from?

[whistler]

 

I had this same problem a couple of years back.

I replaced the red/Orange Primary Gear Seal/Clutch Oil Seal but to no avail still had the leak.

I thought perhaps I had damaged the new seal when passing it over the the splines even though I had wrapped a couple of layers of masking tap over them or I had not seated the seal properly.

To make sure neither of those scenarios happened again I purchased the Minispares special fitting tool CE12. Well worth it.

Fitted new seal still had the leak. Stripped engine again and on close inspection with strong light and magnifying glass I noticed that there was a bigger gap between the seal and the top of the Primary Gear

than there was at the bottom. In fact no gap at the bottom which lead me to discover that the Primary Gear bushes were worn. I believe the tolerance is .0003" - 0004" I had .0006" so the gear was sitting lower down on the crank than it should thus the gap at the top. Replaced the Primary Gear with the correct Deva bushes and problem resolved.

.

Hi Designer where did you get the Deva bushes from?

 

AC Dodd is a source probably.

[Designer]

Hi Hungdynasty.

 

I didn't get new bushes I tracked down a New Old Stock (NOS) Primary Gear the part number on the box is DAM2922. I was assured had the correct Deva Bushes in as it was made before the other type of bushes were introduced. I got it from Mini Sports, Burnley, United Kingdom. I got the new gear as I did not have anyway of freezing replacement bushes in order to get them into their correct position in the Primary Gear.

They are showing as having some genuine primary gears on their website at the moment. I rang them but they could not confirm whether or not those ones have the Deva Bushes. It could be as they are at a very reduced price so they could still be New Old Stock. Send them an email and ask them if the ones they have are marked up as DAM 2922 on the box. If so you will have the correct bushes. The bushes will need to be machined right through from one end to suite the diameter of your crank plus the recommended float. You cannot machine each bush at a time turning the gear around in the lathe as they may not be in alignment done that way. The NOS that I got did need rubbing back with wet and dry on the inner face next to the thrust washer as there was a bit of rust due to it's old age. It was wrapped in the original oiled paper but a bit of the gear was exposed to the air where the paper was torn slightly. It was rubbed back on a totally flat surface in a figure of eight motion. I just needed to then get a slightly thicker thrust washer to achieve the correct end float

I finally found the photos I took of the offending Primary Gear and the new seal, so see attached. You can see the difference in the gap around the seal. The movement up and down and side to side of the Primary Gear was noticeable. 

 

Regards Paddy

 

 

 

 

Edited by Designer, 30 November 2023 - 03:17 PM.

[hungdynasty]

Hi Hungdynasty.

 

I didn't get new bushes I tracked down a New Old Stock (NOS) Primary Gear the part number on the box is DAM2922. I was assured had the correct Deva Bushes in as it was made before the other type of bushes were introduced. I got it from Mini Sports, Burnley, United Kingdom. I got the new gear as I did not have anyway of freezing replacement bushes in order to get them into their correct position in the Primary Gear.

They are showing as having some genuine primary gears on their website at the moment. I rang them but they could not confirm whether or not those ones have the Deva Bushes. It could be as they are at a very reduced price so they could still be New Old Stock. Send them an email and ask them if the ones they have are marked up as DAM 2922 on the box. If so you will have the correct bushes. The bushes will need to be machined right through from one end to suite the diameter of your crank plus the recommended float. You cannot machine each bush at a time turning the gear around in the lathe as they may not be in alignment done that way. The NOS that I got did need rubbing back with wet and dry on the inner face next to the thrust washer as there was a bit of rust due to it's old age. It was wrapped in the original oiled paper but a bit of the gear was exposed to the air where the paper was torn slightly. It was rubbed back on a totally flat surface in a figure of eight motion. I just needed to then get a slightly thicker thrust washer to achieve the correct end float

I finally found the photos I took of the offending Primary Gear and the new seal, so see attached. You can see the difference in the gap around the seal. The movement up and down and side to side of the Primary Gear was noticeable. 

 

Regards Paddy

 

 

 

 

Thanks again for all your advice, one question about the seal, there are two type of seal available at Minispares, one is red for performance like Designer using and one is black for injection models. I have a JDM spi which one should I use? Are they interchangeable?

[Designer]

I do not know others will be able to give you advice on that, also I do not know what Primary Gear is fitted into a JDM spi. The DAM2922 may not be suitable, you would need to ask Mini Sport. I cannot remember how many teeth are on DAM2922 or what you will have on your Primary Gear.

 

Paddy

Edited by Designer, 30 November 2023 - 04:15 PM.