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Clutch Release Mechanism and Bell Housing
Much has been written about this assembly and the failings due to poor design 
and itting and servicing. I refer once again to a proper pioneer Malcolm Robb who 
has already experienced first hand many years ago most, if not all of the possible 
problems. www.lotus-carlton.fsnet.co.uk
I had the opportunity of helping a fellow club member to change the bell housing, 
pivot pin and clutch friction disc. The symptoms were as usual a very stiff creaky 
clutch. History was that the bell housing , friction disc, pivot pin and retaining 
screw had been replaced December 2002. In Dec 2003 the pin and retaining 
screw were replaced again. Surprisingly the work was carried out by Monorep, 
who I had always held in high regard.........I suppose it's down to the individual 
fitter on the day, not helped by poor design, however this should have been fitted 
properly first time around, I'm not convinced that the pin was actually replaced 
Dec 2003 at all, and certainly not lubricated in any way. 
First jobs were to remove the gear lever assembly from the gearbox from within 
the car. This requires removal of the gear lever surround and rubber gaiter beneath 
to gain access to the 4 bolts that secure the lever assembly to the gearbox. 
Noted as is also most common was that the rubber gaiter was split and chewed 
up, my bet is that the dealers cut holes in the gaiter to get to the bolts, instead of 
drilling out the rivets which secure the gaiter retaining plate to the transmission 
tunnel.

 

This was mine. It is not a good idea to try and fit a new gaitor after the gearbox and exhaust is 
back in place especially if you are trying to use nuts and bolts to re-secure the metal frame which 
holds it all in place ;-) To do a proper job you would probably need to lift the centre console up and 
put new pop-rivets in. I wanted to be able to easily remove the gaitor for the next time the gearbox 
needs to come out.
 
With the gear lever assembly removed, the rest of work is done from underneath 
the car. Next disconnect and remove the offside down pipe with cat, a nice surprise 
was that the other down pipe can be left in position, this would have been a pain to 
remove as the connection to the turbo manifold is not easy to see, let alone get to 
the nuts. We would have had to lift the charge cooler to one side but in the event 
was saved this work.
 
Remove the nuts holding the large heat shield, slide it back towards the centre 
exhaust boxes, (it would probably be a little easier to remove the rubber hangers 
from the mid boxes first) this will then allow access to the socket head screws 
of the prop shaft to gearbox output flange.
 
Whilst supporting the gearbox, remove the cross member and mount, I also 
removed the mount bracket.Lower the gearbox down until the back of the 
cylinder head rests against the front bulk head. Also whilst lowering the gearbox 
down, keep an eye in the cooling fan as it will foul the cowling and you will 
need to turn it to avoid this.
At this point it is a good idea to jack up and support the engine from the sump, 
the reason is that when the gearbox is removed the engine will want to tip back 
to its normal position and you need to prevent this. The gearbox is bolted to the 
bell housing and the bell housing bolted to the engine block. The gear box 
comes out first, then remove the screw which secures the clutch release arm 
pivot pin, in this instance it was already loose! The bell housing can then be 
removed After removing the pin and release arm, it became immediately obvious
why the clutch felt so bad. This shows the release arm view of the socket and 
the pin, bone dry, rusty and pitted. 

 

More of the old pin. 

 

 

Old and new non vauxhall re-designed pin with hard chromed working surface.

 

This shows the damage done to the hole which the pivot pin fits into, the bell housing 
was only 2 years old. Because the pin became loose it rocked backwards and forwards, 
deforming the hole. The owner had already taken the precaution of having his spare bell
housing modified with a reinforcing plate and modified pin, we decided to fit it. The early 
pin and bell housing versions used a roll pin to prevent the pin from turning even if the 
screw comes loose. Now there is a locating flat on the pin and bell housing.
In the pic below, it looks as if this has been crushed. (1430-1600hrs), probably accounts
for the retaining screw being only finger tight, and the deformation of the hole.

 

Following pictures show the modification to a previously cracked bell housing.

 

 

 

Evidence of the original crack still visible, with the modification and stronger pin mount 
plate the stresses are more evenly distributed into the surrounding area.
The loading stress when the clutch is applied is vertically downwards in the picture, 
pulling the pin through the casting.

Now fully inspired to check out my own clutch, I have a plan to find some way of 
lubricating the pivot pin without the need for bell housing removal. Another possibility 
would be to somehow encapsulate the fork hole and pin and fill the void with grease 
so that grease cannot escape, or dust get in.
 

Overview pictures of complete (thanks Ian M)

 

 

Below is a picture of an early design bell housing mmm....somthing missing.....
Compared to above which has more ribs.

 

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