740TD clutch hydraulics fail repeatedly

May 30th, 2005, 13:55

The slave cylinder on my diesel 740 estate split its seals and failed recently. It was replaced, though only after the garage's trouble bleeding the new one led them to replace the master cylinder too. As both were probably pretty ancient it wasn't unreasonable.

Alas, the replacement slave started to leak after about 40 miles (fluid coming back under the boot and along the pushrod). They say they've fitted the right type - not the Lockheed, which they had first and sent back, but the other one.

So that was replaced under warranty. And now it's happening again - clutch getting spongey and the fluid level dropping.

It could be a freakishly bad batch of cylinders, but is it more likely that a bent release arm and/or worn clutch (it's not in first bloom) is forcing the slave piston past its limits?

Steve

Peter Milnes · Jun 2nd, 2005, 00:17

You would seem to be unlucky and either the bleed screw was not tightened properly after the job was done or the seals in the slave are useless. It would seem to be the slave seal that is causing your problem. Back to the garage and tell them to do the job properly this time please. I would assume that the master and slave cylinders may be available from Sachs-Boge who make the clutch assembly. They should ensure that the slave cylinder is of exactly the same pattern as fitted originally.

All the best, Peter.

Jun 13th, 2005, 00:24

Many thanks, Peter

(Sorry about delayed reply - I was waiting for an email alert for a reply; I'm subscribed to the topic according to the screens here, so I assume the 'subscribe to this topic' feature is not working properly since the site crash on 15 May.)

Well, the clutch is back and working now, though I did ask them to fit a clutch kit and they added a release lever and pivot too. More expense, and a risk of the 'add new parts till it works' school of repair.

However, the new slave cylinder (the third replacement on warranty) looks to be holding up better this time. For one thing, there's less pedal travel than when the clutch was biting near the floor. The cylinder looks more substantial this time too, so perhaps it's an 'OE' replacement rather than a cheapie, as you suggest.

I'll get back if the beast fails again.

Steve

May 30th, 2005, 13:55	#1
Anlotti Guest Location:	740TD clutch hydraulics fail repeatedly The slave cylinder on my diesel 740 estate split its seals and failed recently. It was replaced, though only after the garage's trouble bleeding the new one led them to replace the master cylinder too. As both were probably pretty ancient it wasn't unreasonable. Alas, the replacement slave started to leak after about 40 miles (fluid coming back under the boot and along the pushrod). They say they've fitted the right type - not the Lockheed, which they had first and sent back, but the other one. So that was replaced under warranty. And now it's happening again - clutch getting spongey and the fluid level dropping. It could be a freakishly bad batch of cylinders, but is it more likely that a bent release arm and/or worn clutch (it's not in first bloom) is forcing the slave piston past its limits? Steve

Jun 2nd, 2005, 00:17	#2
Peter Milnes Premier Member Last Online: Apr 10th, 2014 00:01 Join Date: Feb 2002 Location: Tonyrefail	RE: 740TD clutch hydraulics fail repeatedly You would seem to be unlucky and either the bleed screw was not tightened properly after the job was done or the seals in the slave are useless. It would seem to be the slave seal that is causing your problem. Back to the garage and tell them to do the job properly this time please. I would assume that the master and slave cylinders may be available from Sachs-Boge who make the clutch assembly. They should ensure that the slave cylinder is of exactly the same pattern as fitted originally. All the best, Peter.

Jun 13th, 2005, 00:24	#3
Anlotti Guest Location:	RE: 740TD clutch hydraulics fail repeatedly Many thanks, Peter (Sorry about delayed reply - I was waiting for an email alert for a reply; I'm subscribed to the topic according to the screens here, so I assume the 'subscribe to this topic' feature is not working properly since the site crash on 15 May.) Well, the clutch is back and working now, though I did ask them to fit a clutch kit and they added a release lever and pivot too. More expense, and a risk of the 'add new parts till it works' school of repair. However, the new slave cylinder (the third replacement on warranty) looks to be holding up better this time. For one thing, there's less pedal travel than when the clutch was biting near the floor. The cylinder looks more substantial this time too, so perhaps it's an 'OE' replacement rather than a cheapie, as you suggest. I'll get back if the beast fails again. Steve

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