Clutch mechanism

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Mark Wilson
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Clutch mechanism

Post by Mark Wilson »

You can tell I've just retired from the number of questions I'm asking at the moment! I've joined a Midget 1275 engine together with a Midget 1275 box, from different sources, never met each other before. The flywheel is a standard six bolt Midget 1275, and I've fitted an old, apparently good, Midget diaphragm clutch with NOS friction plate. I'm using a mechanical linkage so I've fitted a 1098 release arm with a Midget bearing.

All has joined up smoothly, but Haynes tells me to check the operation of the clutch, which seems a good idea while the engine and box are out of the car. The problem is I don't have enough experience to know what I'm looking for. I've put Mole grips on the release arm, but pulling hard and looking through the top aperture I can only see the tiniest bit of movement on the pad the thrust bearing pushes. How much movement should I be seeing here?

Mark
philthehill
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Re: Clutch mechanism

Post by philthehill »

The 1275cc diaphragm clutch is very strong and would be hard to operate just using a pair of Mole Grips on the release arm.
Even when the standard Minor 1000 mechanical linkage is assembled the 1275cc clutch will still be hard to operate.
The usual modification is to lengthen one of the arms on the relay shaft to increase the mechanical advantage.
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Mark Wilson
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Re: Clutch mechanism

Post by Mark Wilson »

Thanks Phil, the modified relay is already in place, along with Declan's rose jointed links! Your information sounds very reassuring, I'll carry on and get the engine and box in and see how it goes.
IslipMinor
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Re: Clutch mechanism

Post by IslipMinor »

Mark,

We have the same Midget 1275 clutch and flywheel and use the standard Minor mechanical mechanism - apart from replacing the threaded relay rod twice in the last 19 years and 60,000 miles (badly worn near the bend), the operation is fine. In traffic at a standstill, holding the clutch out is a bit heavy, but then that shouldn't be done for long anyway, should it!

The carbon thrust has also been replaced at least once in the same time period, but more as a precaution when the engine was out, than through wear - maybe the pedal being a bit heavy helps with the discipline of using neutral more often??!!

The attached picture shows the 3 variants of the carbon thrust bearing - make sure that you have the correct one for the 1275 set-up.
Carbon Thrust Types.jpg
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Richard


Mark Wilson
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Re: Clutch mechanism

Post by Mark Wilson »

Thanks Richard for even more reassurance. I did use the 1275 release bearing, in a 1098 arm. There does seem, however, to be a lot of movement in the arm before the bearing surfaces touch, almost identical to the position of the arm in Mike Nash's photo below. Is the remaining travel going to be enough to fully disengage the clutch?
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philthehill
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Re: Clutch mechanism

Post by philthehill »

Once the release bearing engages with the clutch cover pressure/rubbing plate very little movement of the clutch fingers/diaphragm is required to disengage the drive through the clutch.
If there is any doubt as to the amount of clearance required - take a small amount of metal out of the rear of the hole in the bell housing to allow for any increase in the fore and aft movement of the clutch release arm.
Having to increase the length of the hole is a known requirement/remedy.
Even with the Ford clutch fitted to my 1275cc engine an increase in the length of the hole was required and with some applications the release arm has to be re-profiled/bent.
Unfortunately once you go away from standard build spec the matter of fettling has sometimes to be undertaken.

Here is a link which may be helpful:-

http://gerardsgarage.com/Garage/Tech/TO ... arings.htm

Mark Wilson
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Re: Clutch mechanism

Post by Mark Wilson »

Engine and box now in, with extended relay arm and Declan's rose jointed links. Pedal feels to be operating nicely, very light (before return spring is fitted). Thanks all

Mark
philthehill
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Re: Clutch mechanism

Post by philthehill »

Well done.
The return spring does not have to be strong - just strong enough to pull the arm/carbon thrust away from the clutch cover pressure pad and return the clutch pedal to its normal position.
Try clutch lever return spring 1G5999 from a 803cc/948cc Minor.

Declan_Burns
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Re: Clutch mechanism

Post by Declan_Burns »

Having had so many problems with my left leg this year with around 14 operations and a total of four months in hospital, I decided to fit the extended lever, which is really destined for the 1275 engine, to my 1098 to see if the improves the clutch operation. I had initially considered switching to an automatic gearbox or even selling up. I could hardly drive the Moggy.
Yesterday I fitted the extended lever and the result was amazing. The pedal is really light to operate even with my gammy leg which may never improve.
Regards
Declan
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Regards
Declan
firedrake1942
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Re: Clutch mechanism

Post by firedrake1942 »

Looks really good and much more robust than the original. Happy driving !
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