Jump to content

300TDi Defender clutch master cylinder replacement

Recommended Posts

The vehicle used in this thread is a very nice 1996 300TDi CSW, belonging to a local window cleaner (must change my job!)

Replacing the clutch master cylinder is fairly straight forward, but very fiddly due to it's location in the left hand corner of the engine bay. To replace it you either need to raise the bonnet up to the windscreen or remove the bonnet completely. Usually the signs of the clutch master cylinder leaking is a steady dribble of fluid that comes out of the cylider into the dust cover, then out of that and onto the clutch pedal shaft, where it runs down to form a puddle in the drivers footwell.


Method is as follows:-

First you need to raise the bonnet. The stay is held in it's place on a pin by a spring washer, flat washer, and split pin - remove these.



The top oil cooler pipe is in the way of removing the stay from it's pin.


Either undo the 24mm pipe union that secures the pipe to the cooler,


Or VERY carefully lever the pipe away from the bonnet stay bracket just enouhg to get it off the pin.

Then raise the bonnet and tie it back. Don't just rely on it staying there, it takes just a very small gust of wind to make it fall back down on you. If the bonnet catch pin hits you on the head it will most likely fracture your skull.

With the bonnet out of the way, you can now gain better access to the master cylinder.


Air filter next - release the clips on the two bands that hold it to the mounting frame.


Then slacken the jubilee clip that holds the rear hose (6mm socket or blade screwdriver).


One more jubille clip on the bottom hose, same tools.


The air filter assembly will now lift out of the way.

Tie any cables/pipes out of the way, you need to remove the whole pedal box assembly and turn it to the right 90 deg to remove it, so bear in mind the amount of room you will need.

Speedo cable is held to a small bracket on the top of the clutch pedal box, this type is reusable. Release the cable tie and tie it out of the way.


Undo the 6 phillips screws and remove the pedal box cover and small bracket.


Clutch pipe next. The union is 13mm and the adaptor it screws into is 15mm. Place a spanner on the adaptor to prevent it turning while you undo the pipe union.


Once the pipe is loose, carefully move it towards the front of the vehicle and tie it out of the way, then undo the union and put it to one side - you need to put it on the new master cylinder.

The inside of the pedal box.


The two thin nuts are locked against each other and used for adjustment purposes. The nyloc nut and washer at the front (end) of the rod has to be removed. Usually you put one 13mm spanner on one locknut and then undo the end nut with another 13mm spanner. Sometimes the whole lot still turns, if this happens, then you will need to grip the shaft with a pair of long-nosed mole grips.

To make access to the shaft and the nuts easier, place a cloth over the hole that the pipe was removed from and then press the clutch pedal. As there's no resistance, the pedal will go too far, and the springs on the shaft will 'go over' and hold the pedal to the floor.


Better access, but still very fiddly, due to working in such a narrow space inside the pedal box.


There are six bolts that hold the pedal box in place - all from inside the vehicle. Three on the engine side and three close to the steering column.



You now need to work inside the vehicle in the drivers footwell.

The pedal lining is held in place at the top by it being tucked over the lip of a long bracket that also has to be removed. Pull the lining out, then get it as far down as possible without damaging it. Press the brake pedal and ease the lining over it.


The thin strip at the top has to be removed - it conceals two of the pedal box bolts. There are 4 x self-tapping screws, one of which is hidden behind the lower vent, which has to also be removed - there are two self-tapping screws holding it in place.




All the pedal box retaining bolts can now be removed with a 13mm socket.


Back under the bonnet now.

Raise the pedal box - moving the odd wire or cable out of the way as you turn the assembly clockwise 90 deg and it will lift away from the bulkhead.

The pedal box assembly with the master cylinder still attached.


The master cylinder is now only held to the box by two 8mm nuts/bolts. One at the top, and one inside, underneath.



Undo the two bolts, remove the old cylinder and transfer the two lock nuts and washer over to the shaft of the new cylinder. Wipe old fluid off the box and fit the new cylinder in place - making sure that the operating rod goes through the pivot point at the top of the pedal shaft. Then refit the washer and nyloc nut to the end of the shaft and tighten - not too much as it will clamp the pivot point and prevent it from working properly.


It's easy for the spring end to come out, check this before refitting.


Putting the pedal box assembly back in is the exact reverse of taking it out.


The pedal will still be in the down position and will now prevent the box from sitting squarely over it's fixing holes. Pull the pedal up, it will come back over the springs and stay up. Put all 6 bolts in by hand and then tighten (you will need to push the pedal back down in order to get at some of the bolts.

Refit the retaining strip and lower air vent, then the sound proofing.

Back under the bonnet.

All secured in place.


Refit the adaptor to the pipe outlet - there should be a copper sealing washer. Then reattach the clutch pipe (do not tighten yet), and fill the reservoir. place a rag around the bottom of the pipe union, get someone to sit in the truck, udo the pipe union a few turns and get them to press the clutch pedal down. While it's down, re-tighten the pipe union and get them to pull the pedal back up, repeat this a few times until clear fluid comes out and soaks into the rag. Once there is no more air in the system, it will be noticeable by the feel of the clutch. If this method doesn't work, then you may need to bleed the system down on the slave cylinder bleed nipple. Put the air filter back - making sure that the small spike on the bottom of the air filter housing is in the hole in the front clamp. Check and top up the reservoir, and refit the cap - not too tight.

Les :)

Link to comment
Share on other sites

  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy