Leaking Clutch Oil Seal

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JonnyP
Posts: 64
Joined: 24 Feb 2021 17:03
Location: Cheshire, UK

Leaking Clutch Oil Seal

Post by JonnyP »

Hi, I hope some of you can please help here.
I recently fitted a new clutch casing, using Paul Compton's excellent YouTube videos as a guide. I don't have a 'sleeve' to help fit the main clutch oil seal, so I just used plenty of silicone grease instead. Result, oil leakage from behind the clutch (I did use hylomar on the hub bush).
So, to try to fix it, I removed the 'new but leaking' seal externally and replaced it. The clutch basket dowels presented no problem when reassembling. However, it still leaks but not so much. Very frustrating!
I'd appreciate any comments as follows:
1. Is it realistic to expect to fit a new clutch seal without removing the clutch casing, and being oil tight as a result?
2. Do you really need to use a sleeve when you refit the clutch basket into the seal?
My dream is an oil tight clutch... thanks for any feedback!
Last edited by JonnyP on 14 Jul 2023 18:22, edited 1 time in total.
MickeyMoto
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Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Leaking Clutch Oil Seal

Post by MickeyMoto »

Do you mean the small seal or the large seal?

You can use an old yogurt pot cut up as a sleeve.

I would remove the whole casing and start again. I had a problem with the crankshaft seal, using the ones in the kit from NLM. I bought a good quality one and resolved the leak.

Don't forget the little tube to the oil pump! :)
JonnyP
Posts: 64
Joined: 24 Feb 2021 17:03
Location: Cheshire, UK

Re: Leaking Clutch Oil Seal

Post by JonnyP »

Thanks Mickey, yes I do mean the large clutch seal. I was hoping to change it without removing the entire clutch casing, not sure now whether this is possible?
'It must be a .....'
Posts: 365
Joined: 12 Sep 2010 12:25

Re: Leaking Clutch Oil Seal

Post by 'It must be a .....' »

I've always removed the whole primary casing
On a BMW bevel drive box I once replaced a large seal by punching two holes in the seal with a hardened/sharp nail, then screwed in self tapping screws and easily removed the seal with two pairs of pliers. It's important to punch rather drill the holes.
Might be worth trying?
Let us know how you get on
JonnyP
Posts: 64
Joined: 24 Feb 2021 17:03
Location: Cheshire, UK

Re: Leaking Clutch Oil Seal

Post by JonnyP »

Thanks for the feedback. In fact, I have already removed the old seal externally without removing the clutch casing, but having replaced it, it still leaks.
The question is, is it technically possible to replace this seal without removing the clutch casing? I'm interested to know if anyone has successfully done this?
MickeyMoto
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Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Leaking Clutch Oil Seal

Post by MickeyMoto »

Surely the clutch basket goes through the seal and screws to the clutch end of the primary drive? How would you remove the seal, unless you unscrew the basket from the drive gear?

Easier to remove the whole casing, in my opinion.
JonnyP
Posts: 64
Joined: 24 Feb 2021 17:03
Location: Cheshire, UK

Re: Leaking Clutch Oil Seal

Post by JonnyP »

You can easily unscrew the clutch basket to separate it from the primary drive gear, thus exposing the oil seal for easy access.
terrys31/2
Posts: 4
Joined: 29 Mar 2023 10:55
Location: Swadlincote

Re: Leaking Clutch Oil Seal

Post by terrys31/2 »

Hi Jonny P,
Did you manage to cure the oil leak/clutch slip, as i have the same problem on my 31/2
JonnyP
Posts: 64
Joined: 24 Feb 2021 17:03
Location: Cheshire, UK

Re: Leaking Clutch Oil Seal

Post by JonnyP »

Hi Terry, sorry for the late reply. No, I haven't yet solved the leak, but I'm planning to remove the clutch casing again soon. I'll be using double lipped seals from Simply Bearings, which are excellent quality. Hopefully this will be the last time!
JonnyP
Posts: 64
Joined: 24 Feb 2021 17:03
Location: Cheshire, UK

Re: Leaking Clutch Oil Seal

Post by JonnyP »

Sorry about the late reply and update to this. I decided to remove the clutch casing and primary drive, and replaced all seals including the main seal. I took great care to fit the new main clutch seal (a quality, double lipped Viton type) before refitting the casing assembly with primary drive already bolted to the clutch basket.
The latest is that now, a few weeks later, there is still the smallest evidence of a leak from this seal after a run, despite all the care I have taken 😕 To be fair, there's only about as much oil dripped out as would cover a 1p coin on the garage floor, and it stops fully after a couple of hours. Maybe it's impossible to have a clutch seal that never leaks!
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72degrees
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Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: Leaking Clutch Oil Seal

Post by 72degrees »

JonnyP wrote: 09 Sep 2023 19:43 Sorry about the late reply and update to this. I decided to remove the clutch casing and primary drive, and replaced all seals including the main seal. I took great care to fit the new main clutch seal (a quality, double lipped Viton type) before refitting the casing assembly with primary drive already bolted to the clutch basket.
The latest is that now, a few weeks later, there is still the smallest evidence of a leak from this seal after a run, despite all the care I have taken 😕 To be fair, there's only about as much oil dripped out as would cover a 1p coin on the garage floor, and it stops fully after a couple of hours. Maybe it's impossible to have a clutch seal that never leaks!
Wear on the shaft where it runs in the seal?

A little light 'misting' aids a smooth clutch take up in my experience - though that's with WeeVee's clutch spring assisters (washers under the spring cups) to be fair.
mbmm350s
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Location: Berkshire UK

Re: Leaking Clutch Oil Seal

Post by mbmm350s »

72degrees wrote: 10 Sep 2023 17:08
JonnyP wrote: 09 Sep 2023 19:43 Sorry about the late reply and update to this. I decided to remove the clutch casing and primary drive, and replaced all seals including the main seal. I took great care to fit the new main clutch seal (a quality, double lipped Viton type) before refitting the casing assembly with primary drive already bolted to the clutch basket.
The latest is that now, a few weeks later, there is still the smallest evidence of a leak from this seal after a run, despite all the care I have taken 😕 To be fair, there's only about as much oil dripped out as would cover a 1p coin on the garage floor, and it stops fully after a couple of hours. Maybe it's impossible to have a clutch seal that never leaks!
Wear on the shaft where it runs in the seal?

A little light 'misting' aids a smooth clutch take up in my experience - though that's with WeeVee's clutch spring assisters (washers under the spring cups) to be fair.
I would as 72degrees says take a look at the bearing face of the clutch outer basket that runs in the seal may be it has some wear or grooves. Another possibility is that the bush in the primary drive which allows the primary drive gear to rotate on the sleeve when the the clutch is disengaged, i.e lever pulled in, is worn thus allowing the whole basket to wobble.

A little oil seems to actually not be a bad thing anyway.
There is even a little drain notch in the outer case.
JonnyP
Posts: 64
Joined: 24 Feb 2021 17:03
Location: Cheshire, UK

Re: Leaking Clutch Oil Seal

Post by JonnyP »

Thanks guys for your valuable insight. It perhaps doesn't help that I have a PVC tiled garage floor in pale grey, that I keep very clean...every last speck of oil shows up - ah well!
Last edited by JonnyP on 11 Sep 2023 14:04, edited 2 times in total.
MickeyMoto
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Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Leaking Clutch Oil Seal

Post by MickeyMoto »

Newspaper? Drip Tray? If you owned an old British heap it wouldn't stay clean for long. :)

Just done my garage floor with Leyland floor paint. Covered it with a rug and some foam.
terrys31/2
Posts: 4
Joined: 29 Mar 2023 10:55
Location: Swadlincote

Re: Leaking Clutch Oil Seal

Post by terrys31/2 »

Hi Jonny, I am on the same journey as you were, trying to tackle the clutch oil leak.
Did the double lip oil seal behind the basket help? and have you any advice ?
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