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Checking clutch 'while i'm in there'


ElEsprito

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Hello all,

while the engine is out, I'm thinking of checking the clutch/ throwout bearing etc. Is this a straightforward job and are there any specifics I need to check?

Also: do I need a clutchplate centering tool to re-attach the gearbox?

Rgds

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Have a good look at the end of the gearbox clutch shaft...the end of it runs in a roller bearing (or a plain bearing if it hasn't been changed) in the end of the crankshaft. There is a nylatron (plastic) washer on the end of the shaft...this is essential....check the end of the shaft for wear at the point where the rollers run on it. Shafts can be really 'orrid and worn oval. Removing the clutch is easy...just undo the bolts holding the clutch pressure plate to the flywheel and it will come straight off. The pressure plate has defined wear limits, defined as a minimum thickness...can't remember what it is, but if you inspect the rivets where the friction material is held on to the metal work, you'll be able to see how much wear there is left before the rivets start gouging the flywheel or pressure plate. If there has been no sign of clutch slip, and all appears to be well, then there is probably no need to change it. The release bearing is a ball race and will probably just need a slight bit of lubrication. Given that yours is an S1, it might be appropriate to change the clutch as it'll be getting on a bit! Reassembly is easier with something to align the clutch friction plate with the centre, but I've always managed with bits from the socket set and some tape around them to get the diameters correct.

Good luck....(!)

Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Thanks John. Does the gearbox come of the engine easily, or do I have to fiddle with clutch fork positioning/bearing rotation or anything? (I recall splitting a Porsche 911 gearbox from engine that left us puzzled for a few hours, we had to rotate the throwout bearing before the fork would release...)

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OK, I seperated engine and box. Here are the pics (apologies if a bit unclear).

My questions:

- is this clutchshaft ok? it looks like something has been touching the last 3 millimeters as it has a wear pattern, but other than that, seems fine. Also, there doesn't seems to be a corresponding wear pattern on the flywheel side of things

- didn't see any thrust washer as was described by John. I guess I should put that on? does anyone have a parts diagram that shows where it's supposed to be?

- the needle bearing was there (in the flywheel)

- clutch plate needs the be replaced as the rivets are just 1 mm away from surfacing

- throwout bearing seems fine as well, rotates without friction points. If there are other checks I can perform, pls let me know

http://www.thelotusforums.com/forums/gallery/image/1515-img00513-20111225-1252/

http://www.thelotusforums.com/forums/gallery/image/1514-img00512-20111225-1251/

http://www.thelotusforums.com/forums/gallery/image/1513-img00511-20111225-1250/

http://www.thelotusforums.com/forums/gallery/image/1512-img00510-20111225-1250/

http://www.thelotusforums.com/forums/gallery/image/1511-img00509-20111225-1249/

Any opinions are highly appreciated!

Rgds

Hi John, on SJsportscars site I'm reading this regarding a 'spiggot bearing spacer':

'Esprit models with the Citroen gearbox have common problem that the spiggot bush gets pushed to far up the end of the crankshaft. It is very important that the spiggot bush stays in the correct position, flush with the end of the crankshaft'

I guess that this isn't what you mean by 'nylatron (plastic) washer on the end of the shaft'?

Thx

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After some more searching I've found a picture of the Nylatron washer. Do I understand correctly that it's supposed to sit on the stepped piece of the clutch shaft as shown in my picture (so it isn't a wear pattern after all)? If so, does the washer protrude forward of the shaft, otherwise I can't see how it acts as a 'buffer'?

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Piling up the questions, sorry :-)

Does anyone know the wear limit on the friction plate? To my surprise, a picture of a new one doesn't show a lot of difference in 'depth to the rivet' when compared to my use one. Maybe my current plate is ok to use, so I'ld love to hear some info on the wear limit (can't find it in the workshop manual)

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Sadly, all your photos show is a "No Entry" sign and the legend "No Permission"...so haven't been able to look at them! The nylatron washer fits on the end of the shaft, where it is stepped down to fit in the roller bearing. The shaft itself fits into the gearbox and is held in place by a circlip inside the first motion shaft, and is spring loaded towards the front. This spring loading pushes the shaft into the roller bearing and the nylatron washer prevents metal-to-metal contact between the step on the shaft and the roller bearing. The spacer referred to in S&Js lists goes inside the crankshaft, behind the roller race, and is intended to keep the race in the correct position..flush with the crankshaft. As long as it IS flush with the crankshaft, you shouldn't need it...I bought one and did some careful measuring first, and found that - had I fitted the spacer - then the race would have been positioned too far in the counterbore and been well below flush. So I left it out! As for wear limits on the clutch friction plate, I don't know, I'm afraid. You could get in touch with the clutch manufacturer's and ask them....firms are usually happy to help, in my experience. If you can get the photos to appear, I'll have a look at them!!

Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Hi John,

thanks for your response. I've changed the photo settings to 'public', so I think you'll be able to view them now.

I'm still a bit puzzled by the nylatron washer, as I have no diagram or reference. I've made a quick sketch, maybe you can tell me which option shows the correct position of a Nylatron washer (yellow)? Or which option I've missed?

http://www.thelotusforums.com/forums/gallery/image/1516-quick-sketch/

Edited by ElEsprito
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The photo of the clutch disk is a little difficult to tell the depth of the rivet but I would say the disk has about 20 to 30% of its life remaining. However almost all clutch disks are the same, if you have measured it against a new disk and found them to be similar, I would trust that more than the photo I see. Option 5 is the right location for the nylatron washer. The spigot bearing looks like it is to far in to me. From memory, the workshop manual indicates that it should be flush with the end of the crank, but the workshop manual does not show the chamfer next to the spigot bearing either.

Cheers Jim

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Jim, thx for your info. I was wondering about the 'flush position' in relation to the chamfer myself as well. Maybe the cranck was machined in the past, don't know. I don't any other option than inserting/keeping it as is, as the spigot bearing would nog be properly supported if moved forward (towards the gearbox).

Any idea about the little stepped area at the end of the clutch shaft? Is that common?

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Arrgghh I just got a new computer, right now it is not letting me load photos on the internet. Anyway the end of my shaft where the spigot bearing goes did not have a step in it, it had a chamfer instead. My spigot bearing had an o-ring seal in the end of it. That oring section protruded out where the chamfer was in the crankshaft. The area under the needle bearings was supported by the crank bore.

The clutch shaft comes out of the gearbox mainshaft. If the nylatron washer is not compressing the clutch shaft slightly, the clutch shaft will rub on the hardened snap ring that holds it in place. That makes a nice lapping paste and wears out the splines in the main shaft. I would recommend taking the clutch shaft out and inspecting the splines that go in the mainshaft. I had to replace both the clutch shaft and the mainshaft on my car.

Cheers Jim

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Jim, isn't taking the clutch shaft out an affair with removing the bell housing and exposing the diff etc.? Complex job or not? I'm asking since I'm fully aware I'm on the slippery slope of 'while I'm in there' again...

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You may be right, I did not have a choice with mine, the splines were stripped. It was about 3 years ago that I did mine.

In that case I would twist the clutch shaft back and fourth and feel for excessive slop in the splines. I would also check it while pushing in a little on the shaft (it is spring loaded towards the engine). If the splines feel good I would not worry about it. If there is excessive movement then it would be worth taking a look while you have the gearbox out. Note there should be some slop, I would expect good ones to have less than 0.005 inches of slop, for a spline that is about to fail I would expect to see more than 0.015 inches.

Cheers Jim

Crank end of the clutch shaft with nylatron washer installed.

IMG_3634.JPG

Stripped out splines on the mainshaft end of the clutch shaft

IMG_3635.JPG

Edited by s2_esprit
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