S70 Clutch Hydraulics

I've had the S70 for a while now and have not become 100% accustomed to the clutch action. I reached the conclusion that the hydraulic release is a little slow to react, so I bled it to remove any air that may have been in the system. It made no difference, but the pedal does seem a little slow to rise if I snap my foot away when it's fully depressed. My previous cars have had cable operated clutches and have returned instantly. On the Volvo, the full return stroke of the pedal takes around half a second and is accomponied by a whooshing noise. Is this a damping effect, characteristic of hydraulic releases, or do I have a hydraulic problem?

BTW, there is no sound when pushing the clutch out or when letting it in steadily, only when I release it suddenly.

Reply to
Stu
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the S60 came up instantly, without a whooshing sound. Sounds like it's faulty to me!

Reply to
Tim S Kemp

Our S70's clutch will come up as fast as you can move your foot. You have some problem with your master cylinder..

Are u wanting to do too many full bore launches?!?!

Tim..

Reply to
Tim..

"Tim.." wrote in news:djjdkk$9ve$ snipped-for-privacy@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com:

Thanks, guys. Yes, it is difficult to make a quick getaway with the sluggish clutch, which can be frustrating at junctions and roundabouts etc. I also think that it contributes to the judder I get when pulling away with 1500rpm or above, because it's difficult to control the clutch accurately - you can't 'feel' it IYSWIM. Are you absolutely sure that it's a hydraulic issue and not something within the clutch itself?. The reason I ask is that the cylinders are pretty expensive (£117 for a master!), so I don't want to buy one unless I'm sure it will cure the problem. Would it definitely be the master and not the slave? Sorry if I'm being ignorant here, I've never had a hydraulic clutch release before.

Reply to
Stu

(£117 for a

I wouldn't want to say definitely, but IMO it is 99% certain. The slave cylinder is so simple that there's virtually nothing to go wrong with it, apart from it leaking. Sounds like the valve in the m/c might be sticking or gumming up the transfer holes at the front of the piston. That would give the symptoms described. Personally I'd check on whether a m/c seal kit is available. New seals are simple enough to fit, and will be considerably cheaper than a new cylinder. Maybe 10 or 20 quid, but I haven't baught a set for years, so I'm only guessing. While I'm at it I'd probably replace the seal, boot etc, on the slave cylinder as well, just as a precaution. Mike.

Reply to
Mike G

I too wouldnt like to be 100% sure its the m/c though its the first thing to rule out, because its the easiest and cheapest first attack.

Having said that, and I believe I mentioned it in a previus post- higher mileage 70series often suffer with an unsmooth clutch action due to a combination of heat aged pressure plate springs, glazing in the clutch plate itself (which causes grabbing) and last but not least the poor idea of PTFE coating the input shaft which wears off and the plate will no longer slide beatifully along it, plus everything being coated in clutch dust.

The plate or pressure plate could actually be slightly warped too, but this doesnt explain the slow to release pedal, but would account for the juddering.

Splitting the 'box & engine, replaceing the clutch, cleaning it all up, and using some good quality graphite grease on the input shaft will help no end, but its obviously not a cheap job.

If re-sealing / replacing the m/c doesnt help then i'd suggest you live with it until the clutch does need replacing, which it will do on a T5 at around the 100-120k mile point.

Tim..

Reply to
Tim..

"Mike G" wrote in news:435d7d34$0$15054$ snipped-for-privacy@ptn-nntp-reader02.plus.net:

Right. I'll get someone to work the pedal while I listen for the source of the noise. Whichever one it is, it's a simple job to do - later models have the slave incorporated into the release bearing, hence the gearbox has to come off! Can't understand why they changed to this system - perhaps they had problems with the pivot arm?

Whatever it is, it only happens in one direction. There is no excessive resistance when pushing the clutch out. In my blissfull ignorance, I never realised that there was a valve involved - that would explain it ;-)

No seal kit available, unfortunately. It's a 'sealed unit', so to speak. Best price for a new one is £111 :-( That's a discounted price for owners club members! Normally, I wouldn't buy this type of part s/h, but at that price I may just take the gamble and hope that it lasts a while. Failure doesn't seem common, if the forums are anything to go by, at least not for the master.

BTW - just looked through the service history. The brake fluid change is at the bottom of the service checklist and is specified every 2 years at additional cost. According to my records, it's never been done! Presumably the previous owners never authorised it. Perhaps that has something to do with it.....

Thanks, Mike

Reply to
Stu

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