Hydraulic Clutch Linkage - my cross to bear

May 10, 2005
Toronto, Canada
The picture shows the four clutch master cylinders I have replaced so far on my truck. Every two years, like clockwork, the pedal gets spongy and I have to crack open the bleeder on the slave to get a good pedal back. The good pedal only lasts for a week and I end up replacing the master cylinder. I dive in a congested city and am constantly using the clutch, so that does not help.

A bit counter intuitive but the air drawn in by the m/c travels down into the slave instead of up into the reservoir. I suppose during a quick release and reapplication of the pedal, air bubbles do not have enough time to drift upwards but instead gets pushed into the line leading out of the m/c.

The original m/c lasted six years but, since then, they only last two years. I replace the fluid in the braking system and the clutch every two years on all the vehicles I maintain. I use fresh DOT3. I have tried different m/c - GM, Delco, aftermarket. Even tried a metal bodied Perfection m/c, that one lasted the same two years.

Another issue is the clutch pedal assembly, onto which the m/c mounts. The plastic mounting flange breaks off, resulting in no pedal and a tow. Absolutely unacceptable when driving in a busy city with many streets down to one lane each way due to the introduction of dedicated bicycle lanes. I was stranded once and, to avoid this happening in the future, I fabricated a metal flange to replace the plastic one. That took care of the issue. Dorman recently came up with a metal flanged clutch pedal assembly. Here is someone posting on this exact issue

I do all my own maintenance, so it is not costing me much. This would get somewhat expensive if you had to pay someone else to do it.

On the bright side, the concentric slave has been very reliable, which is good since the tranny has to be pulled to replace it. No complaints about the actual clutch, it is nice and smooth and progressive.

Gm offers a m/c with a longer pushrod, #24242325 which is meant for Mexican built trucks. It is more expensive than the regular one and is the one I used last time. I compared the two side by side and the pushrods look exactly alike with the exact same length. Don't understand this.


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