300TDi Disco clutch slave

[Les Henson]

The difference between replacing the clutch slave on a 300TDi Disco and earlier models are only that the slave is on the drivers side of the vehicle above the front prop, and that it incorporates a damper to make clutch action smoother. Replacing it is straightforward though, and can be done without much other work. It is however made a lot easier by undoing the propshaft nuts/bolts at the transfer box end and then sliding the prop along the anti roll bar towards the passenger side of the vehicle. If the clutch slave has been leaking for a while and you have been putting off the inevitable by topping up the master cylinder - then there will be a right mess underneath where the fluid has been leaking out all over the bell housing and other bits.

Syptoms od slave cylinder seal failure is a soft pedal, which will gradually get lower - the clutch will bite as soon as you start to take your foot off the pedal, and as things get worse, the clutch will become inoperable.

There are after-market cylinders available for about £10, but I strongly suggest you use a Gen item for approx twice that amount.

Effect on the pedal:-

The leaking fluid will leak into the clutch bell housing and then drip out of the wading plug hole as shown here:-

Apply the handbrake and/or select 1st gear, then jack up and support the drivers front wheel, place a container under the slave cylinder and undo the pipe connection to the cylinder with a 13mm spanner:-

Allow the contents of the cylinder and pipe to drain out. Note that the reservoir may not empty at the same time, so there will be an intermittant drip throught the work.

Fluid leaking out of the clutch bell housing wading plug hole.

The clutch damper is held in place by the two 10mm head bolts that also holds the slave to the flywheel housing.

The two 10mm bolts can be got at with a 5" extension bar (I used 3/8" drive).

I tried to do this job without moving the front prop, but the lower bolt was tight and the socket started to slip. In order to knock a 3/8" socket on I needed more room, so then undid the prop bolts and moved it out of the way in order to use a hammer.

With the two bolts removed, the slave will come free along with the damper. Be very careful about removing the slave - if it's tight on the operating rod, then there's a chance you will pull the rod out of it's clip inside the bellhousing. In this case the dust cap was off and still on the rod inside the bell housing. If all goes well the operating rod should be left in place as shown.

The new cylinder is OEM item - most aftermarket cheaper ones are made from alloy, this one is cast iron.

Remove the dust cap, put a blob of grease inside to prevent further corrosion, then replace the cap and smear grease on the outside in order to prevent the rubber pinching as the slave is fitted to the flywheel housing.

The new cylinder can now be fitted - first screw the pipe fitting in a few turns, the thread is fine and can easily be stripped. Hold the damper bracket in place at the same time and then tighten the two bolt and then the pipe fitting.

Undo the bleed nipple one turn and attach a bleed pot to it. Top up the reservoir if necessary.

During bleeding, the clutch pedal will stay down when it's pressed - no back pressure means the pedal cranks over and will not return. Press the pedal down and then pull it back up with your hand or foot until clear, air-free fluid is coming out of the bleed pipe. Tighten the bleed nipple and test the clutch, you should be able to feel that it's now working ok.

Les.

[Orgasmic Farmer]

Oi Henson, you're too late. I did exactly that last night! 1/2 hour job but bit tight with the prop still on as you point out. Only thing I missed was grease under the rubber cap, hope that won't be an issue. Also did the master just to be safe as the price was too good to miss (Genuine AP ones). Oh and a water pump change just for good measure!

BTW Mine is a late 200tdi but has the 300 tdi setup as shown above. I also have the later cable handbrake which the local Landie place would not believe.

[SPendrey]

Thanks again Les... Just followed this through. You didn't mention the seal between the cylinder and the clutch body, but I just cleaned it up, popped some hylomar on it and stuck it back together. Only issue I had was bleeding... The pipe came off the nipple and sprayed brake fluid over the prop and diff!