Date: Mon, 9 Mar 1998 07:34:36 -0500 (EST)
To: imps@coollist.com
From: Bert Clewits
Subject: release bearing
Hi Impers,
Does anyone have an Improved clutch release bearing system in his Imp if so what construction did you use ?
Again one of my imps suffered from a broken release bearing and I'm rather fed up with it !
Either the carbon ring breaks out or the whole casing breaks in two or one of the spings comes lose !
Thanks for any help.
Bert
Date: Mon, 9 Mar 1998 17:18:53 -0500 (EST)
From: Gary Henderson
Subject: Re: release bearing
Hi again
If you get a diaphragm-spring cover with excess runout on the thrust pad, it will rattle the bearing to death. Those are hard to get down here now - the only common 6.25" cover assembly is the lever-type for Morris 1000; also fits Triumph Spitfire etc as well as Imp. You can adjust the runout on these to practical zero. CT475 still has original 1964 release bearing.
Good luck
GaryH
Date: Tue, 10 Mar 1998 08:23:32 +0100 (MET)
From: Bert Clewits
Subject: Re: release bearing
Gary Henderson wrote:
> If you get a diaphragm-spring cover with excess runout on the thrust pad, it
> will rattle the bearing to death.
Thats a good one !
Yes that is an obvious explanation, I didn't think about that one !
Thanks,
--
Bert Clewits
Date: Mon, 9 Mar 1998 22:16:59 +0100 (MET)
From: Nickcleak
Subject: Re: release bearing
I have only ever broken the carbon in one in 26 years and 300000 miles , that was a non genuine one , .....i have worn a few out , but they are not a problem with the mileage i do ..( 300 miles a week EVERY week )
Nick ...
Date: Tue, 10 Mar 1998 08:53:24 +0100 (MET)
From: Bert Clewits
Subject: Re: release bearing
I used to do the same (300 miles a week) no problem at all, they allways brake less then a week after building in, sometimes you see micro cracks in the housing/carbon that might be due to bad storage or they might be dropped sometime before.
Can you tell me which ones/make you have to check ?
The other questions are must the carbon be oiled with engine oil during storage ?
and do you soak them in oil before building in ?
thanks
Bert
Date: Wed, 11 Mar 1998 07:19:19 +0100 (MET)
From: Gary Harding
Subject: RE: release bearing
Bert,
I like the slogan, have I seen something like somewhere, I wonder???? There is a VW beetle release bearing that just about fits the existing fork. The retaining springs are reused and the inner section of the fork needs to be relieved a bit. There are several people running this mod and all appear to be happy. I do not know the part number of the required VW bearing - does anyone else know?? I'm sur your local spares shop could help.
Gary
Date: Wed, 11 Mar 1998 09:17:08 +0100 (MET)
From: Bert Clewits
Subject: Re: release bearing
Thanks.
What I'll do is take a Imp clutch fork, springs and Imp release bearing with me to the VAG dealer so we can sort things out. I'll let you know about the results, parts numbers, prices, mods OK
Bert Clewits
Date: Wed, 11 Mar 1998 16:08:47 -0500 (EST)
From: Nickcleak
Subject: Re: release bearing
I always use the 'Borg & Beck' or 'Laycock' ones , there are a lot of cheap makes maybe those are the ones which break ? No , the carbon is self-lubricating , oil is not required ...
Good Luck !
nick ..
Date: Thu, 12 Mar 1998 04:34:36 +0100 (MET)
From: Paul Greville
Subject: Re: release bearing
Hi Nick,
Do you know of any good Rover dismantler in the U/K?
I am after Rover SD1 bellhousings from manual vehicles. They are to be fitted to TR7 five speed manual gearboxes (TR7/8 conversions).
Thanks.
Paul Greville.
Date: Tue, 17 Mar 1998 14:00:43 +0100 (MET)
From: Bert Clewits
Subject: clutch
Hi Guys,
I've been talking to a parts specialist here and he said that the imps carbon ring release bearings indeed have to be soaked in engine oil before installing. This to reduce friction and improve live. He allways even stored them in engine oil (the old beetle ones similar)
The other thing he said was that there should be a teflon layer on the friction side of the clutch unit to improve the live of the release bearing I have never seen this.
Does this ring a bell ?
The new conversion with the later VW beetle proper release bearing: this bearing runs on the tips of the springs so for the Imp the central boss may have to be removed, but maybe it also works with the boss but then the hight of the clutch must be reset for the free movement by making a adjustable pin instead of the fixed one.
The release bearing cost about 70 guilders/35 US dollars
Any comments ?
Bert
Date: Wed, 18 Mar 1998 10:15:47 -0500 (EST)
From: Gary Henderson
Subject: Re: clutch
Hi again Bert
I am certtain that new release bearings were fitted dry at the factory (also for Hunters etc etc). Also, I have never seen any instruction re soaking in engine oil packed with a replacement.
Is this issue getting confused with the spigot bush in the flywheel, which MUST MUST MUST be soaked overnight in oil?
For factory supply there were also different grades of release bearings; the 'deluxe' grade was normally supplied for service replacements. Hunters were prone to clutch-squeal when new; change to the deluxe grade bearing usually fixed it.
Cheers
GaryH
Date: Wed, 18 Mar 1998 20:01:57 -0500 (EST)
From: Nickcleak
Subject: Re: clutch
> I've been talking to a parts specialist here and he
> said that the imps carbon ring release bearings indeed have to
> be soaked in engine oil before installing.
> This to reduce friction and improve live.
> He allways even stored them in engine oil (the old beetle ones
> similar)
That's new to me !
Carbon or graphite is self-lubricating ....
> The other thing he said was that there should be a teflon layer
> on the friction side of the clutch unit to improve the live of
> the release bearing I have never seen this.
> Does this ring a bell ?
Not at all ????
> The new conversion with the later VW beetle proper release bearing:
> this bearing runs on the tips of the springs so for the Imp
> the central boss may have to be removed, but maybe it also
> works with the boss but then the hight of the clutch must be reset
> for the free movement by making a adjustable pin instead of the
> fixed one.
> Any comments ?
YES , firstly , i tried a similar mod on a Californian back in 1977 using a volvo 343 CVT release bearing which is very similar to the Imps in size but with a ball race thrust pad ..
it worked well for a number of years , but it must be remembered that the bearing runs off centre to the pressure plate thrust pad when the clutch is depressed , this results in the bearing surface and thrust pad rubbing against each other in a sliding motion , fine metal particles wear off the faces .....
the bearing should be supported on a central tube to guide it and keep it on-centre .. the fork then takes up the sliding action . There is just no room for one on the Imp's clutch housing ...
Why bother , just use a genuine good quality Imp release bearing !
nick ...
Date: Thu, 19 Mar 1998 09:04:34 +0100 (MET)
From: Darcy Maddock
Subject: Re: release bearing
Hi Bert, someone is having you on. DO NOT soak the release bearing in oil. It is made of graphite and is self lubricating. Having said that when you buy one examine it and its box carefully for any sign of damage. If it has been dropped it has a good chance of expiring earlier than later. Darcy
Date: Thu, 19 Mar 1998 09:30:04 +0100 (MET)
From: Allan Duncan
Subject: Re: clutch
> I've been talking to a parts specialist here and he
> said that the imps carbon ring release bearings indeed have to
> be soaked in engine oil before installing.
> This to reduce friction and improve live.
> He allways even stored them in engine oil (the old beetle ones
> similar)
I've been using _dry_ carbon blocks for 20 years without trouble.
Maybe the rest of you leave your foot on the clutch pedal - just a little extra contact pressure will greatly increase the temperature and hence the wear.
> The other thing he said was that there should be a teflon layer
> on the friction side of the clutch unit to improve the live of
> the release bearing I have never seen this.
> Does this ring a bell ?
No, but some of the friction material I have seen of recent time is a softer composition.
> The new conversion with the later VW beetle proper release bearing:
> this bearing runs on the tips of the springs so for the Imp
> the central boss may have to be removed, but maybe it also
> works with the boss but then the hight of the clutch must be reset
> for the free movement by making a adjustable pin instead of the
> fixed one.
> The release bearing cost about 70 guilders/35 US dollars
I have, in the past, used a conventional clutch thrust race direct on the Belville spring fingers. To use it I machined up an appropriate mount. A pair of light coil springs on the pivots are needed to counter the imbalance from the bearing to fork offset.
It worked well - in fact I was onto the second thrust race and driven plate when I replaced the whole pressure plate assembly, and put the carbon block back in for a lighter clutch for a learner driver in the household. The last time I had the gearbox off the carbon block was almost worn down, so I added a few more miles to its life by machining a little of the cast iron mount. Next time I'll put the thrust race back in, carbon blocks cost twice the price of the real bearing!
When you modify the diaphragm, break the tube that holds the thrust block inwards, away from the fingers, as any excess bending of the fingers may case cracking and failure of the diaphragm.
This is all on an Imp Sport size clutch.
--
Allan Duncan a.duncan@trl.telstra.com.au
Date: Thu, 19 Mar 1998 11:36:13 +0100 (MET)
From: Gary Harding
Subject: RE: clutch
Bert,
All the converted release bearings I have seen simply replace the carbon ring and housing with the new VW bearing. There is certainly no changes made to the clutch cover plate itself. Only the fork needs to be widened to give the necessary clearances to the new bearing.
Gary
Date: Thu, 19 Mar 1998 13:00:25 +0100 (MET)
From: Kristian Jonsson
Subject: RE: clutch
Yes Bert, there are comments!!
Can this really be right !!
Soaking a carbon ring in oil??
And teflon layer on the clutch unit ??
Is someone trying to "pull my leg"
How come that an 'unsoaked carbon' ring on my other Rootes cars last for at least 60000-80000 km
Is it just that i am never waiting at the red light in gear with clutch depressed. (you never do that when you think about that fragile looking cabon ring)
Kristian Jonsson
Date: Fri, 20 Mar 1998 08:35:22 +0100 (MET)
From: Gary Harding
Subject: RE: clutch
Kristian,
I have to agree. If you want the clutch release bearing to last then stop using it! That's what I do and it pays off.
Gary
Date: Sat, 21 Mar 1998 12:41:09 +0100 (MET)
From: Bert Clewits
Subject: Clutch
Hi Impers,
Thanks for all your comments !
Yes you've convinced me no oil soaking for the release bearing I suppose I must have had a bad lot of release bearings with cracks in the graphite or housing and or rattling center bosses. Anyway the Stiletto is running again and the proper release bearing is holding !
Thanks
Bert