[pavel]

Tried to bleed the clutch hydraulic system on our 96 Disco 4litre V8. Even though we did not allow the fluid level to drop too low, 'somehow' the system became filled with air. Using a vacuum bleeder, we managed to get most of the air out but the pedal only engages at the lower half of its travel. If you look at the clutch master cylinder, it is on an angle (tilted up from the fire wall so that the output pipe forms an arc that is higher than the master cylinder- air trapped inside?).... if I tried to bleed the system again with the Disco jacked up at the back, which would make the clutch master sit level, would it help? One piece of advice we got from the Dealer was to pump the pedal 150-250 times!!! (sounds excessive to me). Has anyone encountered this problem? Any advice? Pavel.

 

[Kevanch]

Clutch Bleeding

Pumping the pedal 250 times is really a non starter. I would suggest that you invest in a pressure bleeding kit. Gunsons makes an excellent bit of kit that uses the spare tyre as an air source which forces fluid through the system. They cost around £30 and are, without a doubt, the best way of bleeding brakes and clutch systems unless you are happy buying professional kit for hundreds, if not thousands.

However, I am unclear as to why the system needed bleeding in the first place. If you have changed anything, ensure that master and slave cylinders are properly seated and bolted down. Unlike the Defender, the Disco clutch system cannot be adjusted. Also check for any damp patches, particlarly round flexible pipes. There might be a leak causing air to seep in.

Please post some more details.

 

[BAZZ|]

Check that the Bleed Nipple is ABOVE the pipe thats feeding it as air wont come out of the system as you suggest !BAZZ. :bgreen:

 

[lynall]

A good way to bleed these is to use an oil can and a length of pipe!.
Fill the oil can with brake fluid push the piece of pipe onto oil can spout, pump can slowly until fluid comes out of pipe, then connect pipe to bleed nipple, loosen nipple and pump away until you get bubble clear fluid out of the reservior. Wash away all spilt fluid with lots of water. This is called back bleeding and on some systems is the only to get a good pedal and its cheap.

Lynall

 

[HarleyRider]

Hi
Try jacking the front of the vehicle up as high as you can and push the operating rod of the clutch master cylinder right home.
open the bleed nipple and keep the rod up the bore while someone SLOWLY works the pedal (Remember to keep topping the fluid up)
If you work the pedal to quickly you will disturb any muck that may be in the master cylinder and you will never get a pedal.
When you have bled all the air out pump the pedal back up and i think you will find that this will solve your problem.
Another thing that may be the cause of the problem is a worn master cylinder seal - Should this be the case you can try fitting a new seal, but from experience this is only a short term option as there is always a certain amount of wear in the cylinder bore that you will not overcome so it may well be the cheapest and easiest option to change the cylinder.
Hope this helps.
Harley

 

[pavel]

Geez, sorry Kevanch, BAZZ, Lynall and HarleyRider - just realized I never replied to your comments all that time ago!!! The problem with low clutch pedal was cured the 'easy way'. We drove out to a steep hill, pointed the nose downwards and pumped the pedal about 50 times - voila, the air escaped into the reservoir, pedal came up and all was well. The reason I changed the clutch fluid was simple maintenance. I change all our vehicle brake/clutch fluids every 2-3 years unless it is the Dot 5 silicone type (I understand silicone fluid can be left in indefinitely because it is not hydroscopic). Once again, sorry I missed replying and hope I haven't done the same omission elsewhere!