S3 Clutch Surge

[CHRIS aka GWH]

Gday all,

Here's the latest character trait of my Series 3.
I had the clutch replaced about 18months ago (plate, pressure plate, slave & throw out bearing). I did the master cyl a few months earlier. When driving home I noticed it slipping so rang the bloke and said I was going to adjust the master - which he agreed with. Every thing went fine .... until 2 months ago.

When I pull up to a set of lights & have been gearing down, I push the clutch in coming to a stop and as I stop there is a last little surge from the engine pushing the car forward - it is obvious the engine hasn't fully disconnected as it has that shudder of a semi-stall.

When it first happened before Xmas I adjusted at the master and that seemed to solve the problem. I don't think the adjustment screws are travelling down the thread as they are tight against the pedal lever. If they were "walking" I'd expect one to be loose.

What's going on ??? To make things even foggier - it doesn't happen all the time. I'm thinking throwout-bearing isn't applying enough pressure to seperate the plates - that's obvious. Is the bearing worn from the short drive home when the clutch was slipping and if so why didn't this happen immediately?

Any ideas and input would be appreciated !

chris

[JDNSW]

This sort of problem is almost always an hydraulic problem, either the master cylinder or the slave cylinder. Intermittent problems like you are experiencing, in my experience, are usually master cylinder. It is possible that the pushrod is incorrectly adjusted, but note that this system is supposed to be self adjusting, and provided the pushrod adjustment allows the master cylinder piston to fully return, it has to be a long way out of adjustment to have any effect at all.

My guess is that the master cylinder primary seal is not working properly, due to either dirt in the fluid or a scored or corroded bore in the cylinder there is a slight possibility of it being caused by fluid contamination with hydrocarbon. Note that I have had a clutch master cylinder last less than six months on one occasion.

John

[vnx205]

Is it possible that the clutch plate is binding on the splines? I have seen a clutch that was reluctant to disengage because the centre of the plate had been distorted by careless alignment during refitting.

[UncleHo]

Gday CHRIS aka GWH

That sounds like a flexable hose collasping internally, and not allowing the fluid through, or the nylon thrust bush on the fork pivot, or the clip on the end of the fork at the pushrod to fork joint.

The pivot pin plastic insert and the spring clip are about $3/$4 each and the push rod clip about the same BUT I would replace the Push rod as well, it's under $20 I think as they will wear.

cheers

[nobbydoldrums]

Wow this is timely,

The clutch on my series 3 started slipping badly last weekend (came on very suddenly). Clutch plates were apparently replaced recently along with the slave cylinder. Master cylinder fluid was very low when I checked and filled it
It's now having trouble dis-engaging but also thowing a monumental shudder every now and then on letting it out in first / reverse.

I'll open up the bellhousing inspection hole tomorrow to see what I can find and post back here, as there are quite a few possibilities.

[DarrenR]

I'd also agree that it seems to be a hydraulic issue, I'd bleed the clutch and see how it feels, see if the bleeded out fluid has any dirt, grit etc in it.

Just on another note with regards to the work done,
Slipping on the way home? was it not atleast test driven round the block by the guy?
If it is the driven plate binding on the splines, why wasn't the shaft cleaned, inspected and lubed before installation?

which makes me think other items, has the pressure plate been torqued correctly? has the pressure plate been damaged because of a rough install? what was the condition of the flywheel, all glazed up?

Lets face it, Series III compared to later/other rovers doing the clutch is a bit of a joy.

Best regards
DarrenR

[CHRIS aka GWH]

thanks for the suggestions...

i'm hoping hydraulic from the sounds of things - couple of things I didn't mention - the flexible line from the base of the master to the back of the engine was replaced when I did the master - so i doubt that is going. The master isn;t leaking into drivers the foot well so I doubt a seal is gone there and the slave is not leaking.

I guess the easy out is too firstly bleed it out and look for some crapin the fluid. While its dry I might remove the clutch assembly and master just to let it know who is boss and check out the bore etc - I may even install an additional locking nut on the thread of the plunger.

Is it possible that the clutch plate is binding on the splines? I have seen a clutch that was reluctant to disengage because the centre of the plate had been distorted by careless alignment during refitting.

The old girl travels smoothly - would this create an imbalance that would show as a resonant vibration ?? It certainly seems descriptive of whats happening except after a brief surge they do seperate.

chris

[JDNSW]

....... The master isn;t leaking into drivers the foot well so I doubt a seal is gone there .......

The master cylinder has two seals - the main one on the piston (if this leaks you get fluid running down the pedal, although it may take a while to get into view, and the seal on the inlet - if this fails to seal properly (e.g. a bit of dirt under it) the clutch will either fail to disengage or will re-engage after it has disengaged, depending on how bad the leakage is.

John

[CHRIS aka GWH]

The master cylinder has two seals - the main one on the piston (if this leaks you get fluid running down the pedal, although it may take a while to get into view, and the seal on the inlet - if this fails to seal properly (e.g. a bit of dirt under it) the clutch will either fail to disengage or will re-engage after it has disengaged, depending on how bad the leakage is.

John

John,
is that the inlet from the fluid reservoir ??

I wish I'd taken the time to kit the old one rather than put a new one in then I might know what you are talking about.

If thats the case could passing a lot of fluid thru clear it - i have several half empty fluids that would be suited to the purpose.

chris