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Posted: Fri Feb 04, 2005 7:26 pm
by skypilot30
GroovyCarrot wrote: All I know is that it makes a noise like a belt slipping with the clutch floored.
I would say that this sounds very much like the thrust bearing. I had an old battle wagon of a MkIII with those exact symptoms. It was going to cost £ 180 for a new clutch job, so I ran it for a year like that and then consigned it to the breakers yard.

Posted: Sat Feb 05, 2005 12:22 am
by GroovyCarrot
Righto, thrust bearing it is. Any pointers as to what the thrust bearing actually is/does? ;) I assume it's a part that gets changed along with the rest of the clutch gubbins? Never really noticed what was going on in that area when I had everything apart last year.

Posted: Sat Feb 05, 2005 12:43 am
by bstardchild
GroovyCarrot wrote:Righto, thrust bearing it is. Any pointers as to what the thrust bearing actually is/does? ;) I assume it's a part that gets changed along with the rest of the clutch gubbins? Never really noticed what was going on in that area when I had everything apart last year.
hmmmm - where do I start.....

Well the engine rotates - well the crankshaft does and it's bolted to the flywheel and the clutch assembly

The gearbox rotates along with the friction plate

The friction plate is sandwiched between the flywheel and pressure plate located on the input shaft of the gearbox by way of some splines through it's centre

In order to dissengage the clutch you need to have something to press against the pressure plate (relieving it's pressure on the friction plate) that can withstand being stationary and then pressed against something that is rotating

the something is the thrust bearing -able to transfer the "thrust" from the clutch pedal via the cable and the release arm to the fingers of the pressure plate thereby allowing the clutch friction plate to no longer forced in contact with the flywheel

Everyone follow that?

Posted: Sat Feb 05, 2005 12:53 am
by GroovyCarrot
Gotcha :) Ta for that.
Would this be why after a longish drive my clutch pedal feels 'crunchy'? Used to assume it was a worn cable until I replaced it, been looking for a cause for that since..

Posted: Sat Feb 12, 2005 8:17 pm
by Tahrey1043
crunchy o_O

Posted: Sat Feb 12, 2005 8:51 pm
by GroovyCarrot
Well.. yeah. Imagine kinking your clutch cable and then pressing the pedal, it would feel kinda crunchy, rough, whatever.. that's what mine feels like after a while.
And squeaky as well, but I think that's just a case for a bit of WD40 :D

Posted: Sun Feb 13, 2005 2:31 pm
by Gareth_GT_Hatch
If i were you GC Id have changed the clutch with the engine on the bench. (hindsight eh? :( ) its like £50-£60 for a new one and theres only 6 bolts holding the thing on. Is the thrust bearing the same as a release bearing? I thought there was a bearing inside the engine as well that sort of pushes the other way, i always thought that was the thrust bearing. and the one that operates the clutch was the release bearing.

It doesnt sound like your clutch is worn out anyway, as I would have thought a knackered clutch would just slip as the friction plate will have worn down over time untill the pressure plate is at its limit.

My mk2 has a tendancy to cruch gears as well, (particularly 2nd) and the gearchange and clutch operation is very heavy when compared to my mk3 (which has a bigger clutch and the same gearbox) Im gonna try new box oil to see if that stops the crunching but other than that there isnt alot I can do.

Posted: Sun Feb 13, 2005 4:39 pm
by GroovyCarrot
Yeah, would have done but I'd run out of money by that point :(
The box was never exactly smooth.. but it's certainly become very bad very quickly, it's gone from normal to extremely crunchy and sticky over the course of a month or two, so there's definately something wrong there and I don't really want to leave it.. Clutch operation is no heavier really than it was with my old engine/box - heavy, but not anything out of the ordinary, it's just the crunchy business that I find a bit strange.

Posted: Sun Feb 13, 2005 8:12 pm
by Tahrey1043
Worn synchros?

Have you tried adjusting the cable so that you get a very slight slip (in top, at torque rpms, with it floored) without pushing the pedal, seeing if it becomes easier than previous when you DO push it?

if so then i'd vote for worn clutch........

Posted: Sun Feb 13, 2005 9:02 pm
by GroovyCarrot
Hrm.. now there's an idea. Project for tomorrow afternoon methinks.. along with WD40'ing that clutch pedal, which is beginning to drive me round the bend..

Posted: Wed Feb 23, 2005 11:23 pm
by GroovyCarrot
Just got back from a -long- drive to bath, got stuck in a tailback on the A404 for 2 1/2 hours.. during which time I discovered that the crunchy business is enough to drive me round the bend, my clutch pedal squeaks like a demented hamster and my clutch plate is very much on it's way out.. juddering like crazy trying to do low speed creeping in the traffic and making nasty squealy noises if I tried to pull away quickly (when the traffic started moving and I was still reading my book for example - that kind of tailback.)
However, I have solved the squeak and the crunchiness (sort of) with a great deal of WD40 - the squeak was on the clutch pedal pivot, predictably, and the crunchy feeling was on the lever on the gearbox. Why it should get stiff when it's warmed up a lot I don't know, but anyway that helped. Just got to get the clutch change arranged now..

Posted: Mon Apr 18, 2005 10:00 pm
by GroovyCarrot
Wahay, got this lot all sorted. The damage: a £19.99 clutch kit from ebay and a damn good workout :lol:

The clutch is as light as a feather now, it's incredible, I really thought that having a ten tonne clutch pedal was all part of driving an old polo, now I realise it's just part of driving a badly maintained one :lol: . I've yet to take it on a long drive, but I'm pretty confident that the whole crunchy squeaky business is all sorted - the pressure plate spring fingers had almost worn right through, save a little jaggy bit sticking up at the end of some of the fingers that was slowly but surely eating away at the innards of the release bearing, both components were absolutely knackered. Friction plate was pretty much on the limit as well, although in less shocking condition than the other bits.

Clutch change isn't actually that bad a job, although you really do need two people for some bits of it and my arms are practically siezed up from all the awkward positions I had to lift the box into :roll: Still, all worth it :D

Posted: Mon Apr 18, 2005 10:07 pm
by ste mk1lx
well done for biteing the bullet and doing the job yourself. :o

Posted: Tue Apr 19, 2005 12:26 am
by bstardchild
^ what he said

Good on ya Groovey - not much left to tackle now is there :lol:

Posted: Tue Apr 19, 2005 12:52 am
by GroovyCarrot
There's always more to tackle :D
Head rebuild, piston rings, big end bearings, carb rejetting, gti brakes and remote servo are currently on my mechanical 'to do' list, and I'm sure there'll be more by the time I get all that lot done :lol: