Thread: Hydraulic Clutch System Issues

I've been reading some of the AULRO treads and may be able to offer some experience with clutch hydraulics in the Isuzi Landie. I ran into reliability issues soon after the OEM fit or about 80,000km from new? First I thought it was the supply of clutch master cylinders as you can get them for $30 from Repco. I then counted the clutch cycles while driving to work and over a lot of urban driving averaged one cycle per 1-2 km. I replaced about 6 master cylinders and a couple of slave cylinders over some period of time and it was bugging me. My opinion is this: the master cylinder has a alloy bore therefore aluminium oxide can contaminate the hyd fluid e.g. turn dark or black when dirty. Fix is to sleeve the master cylinder. Another is the exhaust header exits the engine bay passed the vertical section of clutch plumbing on the fire wall which leads to the slave cylinder. Once I incorrectly adjusted the master cylinder, so the reservoir port was covered over therefore forming a closed system and the clutch started to slip from the thermal expansion of the brake fluid. So it is exposed to significant heat from the exhaust header. This was due to the degradation and loss of the aluminium foil and foam insulation that was fitted to Isuzi Landies. This insulation once protected the clutch plumbing. My remedy was to double wrap the vertical section of the clutch hyd plumbing in hi heat resistant insulation. The third fix was to use racing super DOT 4 fluid. Bleeding can be an issue but the fix is to give the clutch a sudden push to blow the air from the upper reaches of the system. I found this action has worked very well with the correct pedal height adjustment etc. 560,000km now and all is well.