Loss of clutch (Duratec R400) -- Part 2

[John Vine]

Regular readers will recall my previous tribulations and subsequent fix.  Although all seemed OK, the one remaining puzzle was that I had to extend the length of the m/c piston rod about 1cm by adjustment at the pedal clevis.  This seemed odd at the time given that the new m/c appeared to have the same dimensions as the original.  

Yesterday, I suffered another clutch problem (possibly related?), more serious in that it required recovery by breakdown service.

Symptoms:

• Almost 100% loss of drive, but with some slight engagement right at the very top of the pedal stroke.  Very similar to a terminally slipping clutch.
• Pedal action, feel, and pressure all normal, except that suddenly the pedal had become very firm, with the usual initial free play at the beginning of the stroke completely absent.  The slightest pressure on the pedal would disengage the clutch completely.
• Master cylinder action OK, and reservoir full.
• No loss of hydraulic fluid.
• No aroma of burning clutch.
• Drive from clutch to diff OK (that is, no gearbox problems).

Thoughts and suspects:

1. Slave cylinder.  The clutch pedal feel suggests that this is still doing something useful when I press the pedal.  However, it's almost as though the slave was partially operating even at rest.  Could the bellows somehow have "popped" out or been extended such that the CRB was pressed further/closer against the diaphragm springs at rest?
2. Clutch friction plate.  A burn-out here would match the high degree of clutch slip, but I would have expected to detect the usual unpleasant aroma.
3. Clutch pressure plate. Could something have broken here (such as a diaphragm spring) such that the plate no  longer clamps the friction plate firmly against the flywheel?  (A broken spring was put forward as a possible cause in my earlier thread.)

The car is currently on its way to Marcassus Sport near Toulouse, the nearest Caterham dealer.  I'll be calling in on them tomorrow to discuss diagnosis and repair options, but in the meantime any pointers you can offer would be much appreciated.

JV

[elie boone]

Long shot but maybe the fixing nut on the master cilinder rod  has come undone and the rod winding itself out and this leaves your clutch sort of on

[John Vine]

Hi elie,

Definitely a long shot, I'm afraid.  I checked the piston rod adjuster at the time, but it was tight.  In fact, I even tried slackening it off to see if that would help, but to no avail.  Certainly the symptoms match a clutch half-way engaged even at rest.

JV

 

[John Vine]

Well, I'm told Marcassus have taken the engine out, but I've yet to receive their assessment and repair quote.  Should arrive Monday, I hope.   Watch this space....

JV

[John Vine]

Received an estimate from Marcassus -- eyewatering or what?!  Luckily, I was sitting down at the time.

It confused me a bit as it included all the clutch parts -- slave, cover and disk -- and at very inflated prices compared with  CC's online store.  Plus 10 hours labour -- even I could do the job in my own garage in less time than that.

So, I went in to see them.  Expecting to see the engine out and clutch bits lined up along the shelf, I was surprised to see the car still virgo intacta as it were.  The upshot was that, as they hadn't taken the engine out, they hadn't made a definitive diagnosis.  As a result, they'd recommended replacing all clutch parts to be on the safe side.  That was all very well, but it was (still is) unclear whether they would take into stock any unused parts.

Anyway, parts are on order -- estimated arrival time une dizaine de jours so I'm going to be here for a while yet.  Tony in CC Parts has been amazingly supportive and helpful -- what a star!

Watch this space....

JV

[ECR]

If they do replace ALL the clutch parts, I'd insist on having the old parts back as 90 percent of them will be quite useable.Now if you could have trailered the car to Lamongerie, we could have spent a pleasant 2 days doing it ourselves ....

[John Vine]

You're right, Roger.  They did say they'd give me back any replaced parts.  As for doing the job in your spacious garage, that would have been an irresistible temptation! Very kind of you to suggest it.  And I could have brought a selection of gersois wines, and maybe a nice armagnac, to help us along!

JV

[John Vine]

An update....

Marcassus have just called to say they've lifted the engine and have found the basic problem: clutch friction disk completely worn down to the rivets.  They didn't comment about the slave except to say it wasn't in very good condition.  So, I still don't know what the root cause of all this is.  I'm surprised that the friction disk is clapped out as I always thought I was relatively gentle on the clutch.

They also say the flywheel has been scored, and they are recommending a new one.  This is very expensive in the UK, and horrifyingly so here in France (exchange rate, shipping, social charges, etc etc).

My question is....

In principle, can R400 flywheels be skimmed (I don't yet know the extent of the scoring but will find out later today, I hope).  Or is this a complete no-no?

JV

 

 

[Rattie]

I'll just leave this here...

http://www.burtonpower.com/catalogsearch/result/?q=flywheel

HTH

[Shaun_E]

I had my flywheel skimmed recently. Is it OK? - Yes. Would I recommend it? - depends on the clutch plate. Probably OK with an organic clutch as the plate will bed in. With the ceremetallic paddle clutch I have, it's even more "grabby" than before and unlikely to wear enough to bed in.

[John Vine]

That's interesting.  I've opted for the new flywheel in the interests of getting mobile asap, but I intend to bring all the old parts back to the UK.  I'll ask CC/Titan/Cosworth whether the old f/w can be skimmed.  If it can, I'll get it done and either keep it on the spares shelf or sell it second-hand.

There's still a nagging thought at the back of my mind that I brought all this horror down on myself by not setting up the new m/c correctly in some way.  Examining the old slave should provide a clue. 

JV