Lotus Elan

Odd clutch

PostPost by: Robbie693 » Thu Sep 03, 2015 2:15 pm

Hello,

I've been using the Plus 2 a fair bit recently including a lot of motorway/fast A-road jaunts and it's been fine up until the last trip. Everything was ok for about 120 miles or so until I tried to change down to leave the motorway - the clutch wasn't behaving as it should. The biting point had become very drawn out, the initial bite was where it should be but with the clutch only fully engaging at the top of the travel. There also seems to be a feeling of friction/rubbing as the pedal is depressed (a bit like creaking spring if that makes any sense) but only when the engine is running...

My first thought was I had lost fluid, but no - all fluid present and no leaks. Then I thought maybe I had cooked the fluid as it was pretty warm and my cruising speed was fairly high. Let it cool down at the services for an hour but no joy - still the same.

The odd part about it is that the clutch feels fine with the engine off - normal amount if free play, normal and consistent pressure throughout it's travel and definitely doesn't feel like it has air in it.

As whatever happened happened while I was cruising along not using the clutch, I thought something had fallen off but I've been underneath and checked the return spring and freeplay adjustment but this is fine too.

I'm going to try bleeding it, though I doubt this will have any effect, and was wondering if anyone could give me suggestions as to where else to look and what to check please?

Robbie
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PostPost by: Robbie693 » Tue Sep 08, 2015 9:39 am

Wow, 111 views and no replies :?

So I bled the clutch and as expected there was no change.

I am now convinced the hydraulics are fine, no leaks and air-free so it must be a mechanical problem.

Now time to call in the cavalry as I don't have the facilities or the time to remove the engine myself.

My latest theory is that the clutch plate has become oil-soaked during it's motorway thrash, probably from the crank oil seal, which I think I am correct in thinking that it (the clutch) is now ruined?

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PostPost by: mbell » Tue Sep 08, 2015 12:20 pm

I wouldn't expect it to be oil, as that would normally cause engagement judder and clutch slip. The oil would also have to get from one side of the flywheel to the other in enough volume to cause problems. I'd guess it's more likely a sticking mechanism, could be oil thou. If it isn't hydraulics you're going to have to pull the engine and assess. Worth spending a decent amount of time making sure it isn't hydraulics...

One check would be to get some one to operate the pedal with you under the car and check the amount of movement and smoothness of that movement (hydraulics and clutch leaver).

What is the condition of the clutch line? Could it be expanding under pressure?

Have you tried new fluid?

How long since the master was rebuild? Could the piston be sticking on the bore?
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PostPost by: gjz30075 » Tue Sep 08, 2015 2:21 pm

mbell wrote:One check would be to get some one to operate the pedal with you under the car and check the amount of movement and smoothness of that movement (hydraulics and clutch leaver).



Your best bet here. Pull the dust boot off the bell and slide it down the fork as far as possible to be
able to peer in the hole and watch the movement.
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PostPost by: EPA » Tue Sep 08, 2015 2:57 pm

Years ago I had a ford rs2000 that started to do something pretty similar after motorway journeys, fixed by replacing the rear crank seal.
It did display fairly obvious symptoms of clutch slip however when accelerating hard or going up hill and a smell of burning oil.
I used to slip the clutch whilst stationary for a while (which may not be the most recommended course of action) which stopped it until the next motorway journey.

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PostPost by: wotsisname » Tue Sep 08, 2015 3:37 pm

mbell asked....

What is the condition of the clutch line? Could it be expanding under pressure?

Have you tried new fluid?
============
what does the connection between master & slave cylinder look like ? braided or red plastic ? IIRC braided lines were an upgrade to prevent issues with the plastic line getting hot.

Assuming it's not a silicon based fluid, this will absorb moisture as brake fluid does.
===========

any idea on the age of the clutch plate ?
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PostPost by: Robbie693 » Wed Sep 09, 2015 9:51 am

Thanks all,

I haven't been able to look at the clutch actuating yet for lack of a helper, but will try as suggested. The action feels fine from the driving seat with the engine off though.

The clutch line I replaced with a braided one a couple of years ago and the cylinders are about 4-5 years old if I remember correctly. I bled the system enough the other day to ensure all the fluid was new.

As for the plate itself, I assume it is the one that was fitted during the car's restoration in the early 1990's, some 10,000 miles ago.

I take your point about the oil soaked plate theory - slipping the clutch makes no improvement so maybe I'm barking up the wrong tree there

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PostPost by: nmauduit » Wed Sep 09, 2015 12:34 pm

Assuming it's not a silicon based fluid, this will absorb moisture as brake fluid does.


I believe silicone brake fluid has some specific drawbacks to some extent (e.g. cost, compresssibility, boiling temperature, lower lubricant power ...) but not absorbing moisture
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PostPost by: wotsisname » Wed Sep 09, 2015 1:12 pm

Fair point - Not sure I worded it well before..
so agreeing with your post & what I was actually trying to say....

Silcon fluid doesn't absorb water whereas the usual (glycol based) brake/ clutch fluid does.
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PostPost by: worzel » Wed Sep 09, 2015 1:27 pm

Hi Robbie

Try this before resorting to major work- using something like a G clamp get a helper under the car and position the clamp so that the pushrod on the slave cylinder cannot move- then push the pedal- should be rock hard with no discernible movement.

If it moves you've a hydraulic problem.

Regards

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PostPost by: billwill » Wed Sep 09, 2015 3:30 pm

If you have no-one available to help on these things, perhaps you should consider buying a cheap endoscope with USB connector to use with a laptop.

http://www.amazon.co.uk/Endoscope-Water ... B00A6K4DCK

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PostPost by: Robbie693 » Sun Sep 13, 2015 3:59 pm

Thanks for the further tips, particularly John's G-Clamp test - great idea. I did something similar by wedging a piece of wood in there and the pedal was firm with it in place.

I've had a look into the bell housing but I can't see a lot, just the side of the thrust bearing and a couple of clutch plate fingers. I was chatting to Roy at Paul Matty about it and he suggested lubricating the part of the shaft where the bearing runs to see if this affects the slight juddery feeling that comes through the pedal when the engine is running. I did but there was no change.

Roy also offered to take it for a spin so I will try and drop it round there sometime this week for a second opinion.

Thanks again everyone

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PostPost by: pereirac » Mon Sep 14, 2015 2:21 pm

I had something similar happen to me, when I (finally) took the engine out to have a look it, the two springs holding the clutch thrust bearing and carrrier to the clutch arm had vanished .. which probably explained the metallic scraping noise the clutch made :oops:

Hopefully you should be able to check this via the release bracket hole without removing the engine ...

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PostPost by: Robbie693 » Tue Sep 15, 2015 3:50 pm

Thanks Carl,

I don't have any rattling or craping noises which is odd too. I ran this idea past Roy but he reckons it would be making a racket that we would notice. He also is convinced the problem lies with the clutch itself so it's now booked in to have the engine pulled :(

Just when I was able to get some use out of it....

I'll report back with their findings

thanks all


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PostPost by: steve.thomas » Thu Sep 17, 2015 9:18 am

Robbie
I had clutch failure on my Plus2 a couple of years ago and it turned out to be the crankshaft spigot bearing having completely destroyed itself. I'm sure Matty's would replace it anyway while the engine is out, but it might be worth asking them specifically.
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