Clutch slave movement

[Robbie693]

Hello,

I'm having problems with my clutch bite moving around, every now and then the biting point moves to the top of the pedal travel and the free play disappears, only to go back to normal on the next press.

I recently replaced the flexible hose with a braided one and whilst bleeding the system noticed that there is movement in the slave location: I can push it back and forth against the 'c' clip. I'm wondering if this is causing my problem.

Searching the archives I notice someone else had the same problem and fitted two 'C' clips, one either side of the bellhousing.

Has anyone else had to do this? Is it normal for the slave cylinder to be able to move?

Cheers

Robbie

[rgh0]

Normal free play is less than a couple of mm. But there are 2 grooves on the slave cylinder and if the circlip is installed in the first groove much greater freeplay results.

Also the grooves are wider than for a standard circlip and take a special thicker "C" clip or you can install 2 standard circlips in the groove. using one standard circlip results in excess end float of the slave cylinder also.

regards
Rohan

[garyeanderson]

Here is another of my bore me some more post's that are not that helpful. I doubt that the clutch slave is the problem but more likely an issue with the master.

search of elan.net for c clip slave

http://www.lotuselan.net/cgi-bin/search ... oom_sort=0

this brings up many (23) posts from the past.

elan-f14/clutch-slave-ring-dimensions-t20000.html

elan-plus-f13/clutch-slave-retaining-clip-t17341.html

elan-f15/clutch-slave-clip-question-t14672.html

[69S4]

As Gary says the problem is likely to be elsewhere. My slave cylinder also moves back and forth (about 2-3mm) but the clutch release action is fine - consistent predictable release point and comparable with our modern cars.

[oldelanman]

Hi Robbie,
Is this the same problem that you posted about 18 months ago ? "Vague Clutch" In that post you said that you had replaced the master and slave cylinders about 12 months prior to that and ended by saying

The clutch was fine before I replaced the cylinders by the way.

Could it be that you got one of the dodgy "Girling" replacements that have been discussed on here recently ?

From your description of the symptoms I would suspect the slave cylinder. It could be that the slave cylinder piston is occasionally sticking in the bore. This could cause slow engagement of the clutch so that the "bite point" appears to be at the top of the pedal travel. Also, as the master cylinder and slave cylinder pistons are returning at different rates, additional fluid will be drawn in from the reservoir so the next time you push the pedal down, if the slave cylinder has still not fully returned, there will be no freeplay in the system.
You could try fitting a stronger return spring on the release lever or, if you still have the old slave cylinder why not try refitting that ?

Regards,

[Robbie693]

Thanks everyone,

The 'C' clip is the correct one I think as it fills the groove and is tight. I guess the movement to be about 2-3mm as with Stuarts car so looks like this is normal. Damn - I thought I was on to something!

Thanks for the links Gary, I had been looking through most of them before I posted - very useful photographs. Of particular interest was the shots of the proper tool for the 'C' clip. I'm going to get one on your recommendation. Finding one seems to be tricky as most UK sites call Snap Ring pliers Circlip pliers and consequently have extensive lists and poor photographs of the wrong tool. I have seen a couple of places list Horseshoe clip pliers which I think is the same thing. These for instance:

http://www.drapertools.com/b2c/b2citmdsp.pgm?pp_skmno=54219&ipadd=

Roger - Well remembered! Yes it's sort of the same problem. I managed to get a more positive 'bite' by adjusting the free play and suction bleeding (so much better than the traditional way, I found). Since then it's been mostly stable apart from the occasional problem described above. No slippage even then.

Sadly, in light of the "dodgy replacements" discussion, I chucked the old slave. How I wished I hadn't now . Looks like I may have to try another slave. I'll do that first as it's easier than the master..

Annoyingly, I can't seem to replicate the problem with the car in the garage, it only seems to do it when I'm driving around - particularly in traffic

Thanks again

Robbie

[types26/36]

Annoyingly, I can't seem to replicate the problem with the car in the garage, it only seems to do it when I'm driving around - particularly in traffic

I had exactly the same problem, eventually I found I could replicate the problem in the garage by pumping the clutch pedal 70 or 80 times in quick succession, the pedal would then "build up" having no free play.
Leave it for an hour or so and pedal went loose with free play.
The problem was that the pedal was not returning completely to rest and it got worse the hotter the car became (driving in traffic) make sure the pedal is free and has its free play even when used repeatedly.

[fatboyoz]

Robbie,
Have you checked to make sure the clutch hydraulic hose is not too near/touching the exhaust pipe?
Colin.

Thanks everyone,

Annoyingly, I can't seem to replicate the problem with the car in the garage, it only seems to do it when I'm driving around - particularly in traffic

Thanks again

Robbie

[Robbie693]

Annoyingly, I can't seem to replicate the problem with the car in the garage, it only seems to do it when I'm driving around - particularly in traffic

I had exactly the same problem, eventually I found I could replicate the problem in the garage by pumping the clutch pedal 70 or 80 times in quick succession, the pedal would then "build up" having no free play.
Leave it for an hour or so and pedal went loose with free play.
The problem was that the pedal was not returning completely to rest and it got worse the hotter the car became (driving in traffic) make sure the pedal is free and has its free play even when used repeatedly.

Thanks Brian, I had a go pumping the clutch as you described. Made my leg ache! It didn't really change much, maybe a very slight reduction in free play but not as bad as on the road.

When you say make sure the pedal is free I presume you mean that it returns to the top of it's travel? If so, then yes it does. I can hear a clinking noise if I depress just to the end of the free play which I assume is the actuating arm but I need to get a helper to check next time I'm under the car.

Colin, thanks - the flexible hydraulic hose is on the opposite side to the exhaust so that's ok, the solid tubing which connects this to the slave is no nearer the downpipes than the slave itself. It does bend around a bit though, probably a bit too long, which could explain my initial bleeding problems after fitting the braided hose. Suction bleeding worked a treat!

I have considered making a heat shield but I don't think my symptoms are indicative of too much heat, I understand this makes the pedal go mushy like air in the system(?). Also never had a problem with the last Plus 2 I had in the 10 years that I drove it around. Don't think I ever even changed the fluid on that one

Cheers

Robbie

[Jeff@Jae]

I suspect the valve in the master cylinder that opens and closes the port to the reservoir. That valve is not always opening to the reservoir when you release the pedal, leaving residual pressure in the system. Get a rebuild kit and pay close attention to the little seal on that foot valve. The rib is offset and should be biased toward the end of the cylinder away from the pushrod.

[Robbie693]

Hello again,

Thanks Jeff, the master was replaced last year along with the slave.

Haven't had chance to do any work yet as the car has been pressed into daily service.

I have, however, noticed a couple of things that may point to the culprit..

Firstly, the clutch seems to be acting up less since the pedal pumping trial suggested by Brian. Still there a bit though.

Secondly, when the problem arises, there is a slight increase in pedal pressure - maybe a feeling of the pedal pushing back.

Does this narrow it down any?

Hopefully, Robbie