[blakestone]

Hi,

I have a '98 GU 2.8TD, stock sized tires, 2" lift, 130,000 km, have also replaced the clutch/flywheel with a safari solid flywheel and HD clutch kit (much nicer than stock).

Over the last few weeks I have noticed the clutch pedal 'sticking' on the return after being depressed.

I have examined the system, found no leaks.

I have bled the system, which improved the pedal feel, but didn't fix the return 'stickyness'.

I have found that the clutch actuated smoothly when the engine is off (no vacuum to clutch booster) and when the engine is on and vacuum booster disconnected. Thus eliminating possibility of faults in the hydraulic system or the clutch itself(throwout bearing).

Thus 'sticky' pedal behavior is only present under vacuum booster assist.

This leads me to conclude the issue is with either the clutch booster or the vacuum pump.

Ideas?

Many thanks in advance.


I have two problems listed for my patrol, the other is here http://www.patrol4x4.com/forum/niss...ntermittent-juddery-power-acceleration-60066/

 

[camo75]

i would think if you had an issue with your vacuum pump you would notice a lose of pedel feel when applying the brakes.
Have you noticed the brakes feeling different to normal?

 

[blakestone]

Brakes have felt a bit soft of late. I bled the whole system replacing all fluid them a few days ago thinking the system might have had moisture in it. It did improve the pedal feel, but I'm suspecting that a vacuum leak may also be part of the problem.

A faulty vacuum pump has also crossed my mind.

I'm going to test this tommorow by hooking up the clutch booster to the vacuum of another vehicle with a short piece of vacuum hose.

This should eliminate one of the possible causes.

 

[camo75]

i think you can test the pump if you have access to a vacuum gauge. Pretty sure the specs are in the manual.

 

[GU DAN]

I had a problem like this after mine got to operating temp. My clutch would not return. Took it to a clutch guy as we were on the way to Fraser and had to get it fixed. Turns out that it is fairly common on the Patrol as they have a nylon plunger in the master cylinder that after a while swells with heat and does not let the clutch return. They are not servicable and have to be replaced. He did not have one so to get us back on the road he lathed a bit of it with emery paper and we were on our way. Never replaced it when we got back and was still fine 18months later when I sold the truck.

 

[blakestone]

I checked all vacumm lines, removed and replaced hose clamps and vacuum hose as needed. While this improved clutch pedal feel, still 'juddery' on the return stroke.

I hooked the booster up the vacuum of my very helpful little seirra with 2m of vacuum hose. Ran the sierra and left the patrol engine off, and this replicated the problem.

Too be 100% sure, I removed the booster, ran it off the sierra's vacuum, still juddery/sticky movement in the shaft indicating a buggered booster.