Early AMX / Javelin Hydraulic Clutch Setup

When I spoke to Wilwood they had no idea that the rod surface finish was an issue at all, or maybe in their opinion it isn't an issue. It's apparent that they used to hone/polish them, as I found pics online from a Cobra kit car site where a guy took his apart and you can see that the entire length of the larger OD section of the rod that contacts the o-ring had a polished finish when compared to the smaller diameter portion. 

So either their current supplier is skipping steps and Wilwood isn't catching it in their QA process, or Wilwood purposely stopped finishing the rods in an effort to cut costs.

Another issue is that the inside of the housing is anodized black just like the outside, and anodizing breaks down in break fluid, so it's constantly leaching black particles into the fluid. I thought it was the o-ring breaking down at first, but after researching I found that anodizing simply doesn't hold up against brake fluid. I'm not sure if the result is abrasive, but it's certainly worse than clean clear fluid. While the slave was apart I should have taken the time to soak the inside with brake fluid and let it site for a while then scrub it out a bit and give it a fine sanding as well, maybe with a brake hone. Bygones.

One other aspect of these that's pretty sad is the complete lack of a guide bushing for the rod where it passes through the housing. All that's there to support the rod is the o-ring, so any minor side loads will eat the o-ring up and then it leaks and strands you. Again.

But before everyone decides that the Wilwood unit is the Devil's own work let me point out that it's the only pull slave with machined pockets in both the piston and the housing to help minimize the pedal force. When you apply the clutch the slave has to compress a small trapped volume of air on the side of the piston opposite of the fluid side. The amount of force required to compress that air is dependent on the original trapped volume versus the displaced volume, and by adding the two pockets they've increased the initial volume. The end result is that is only takes about 17 lbs of additional effort instead of 25 lbs, as you would have from the Speedway, Howe, CNC, or Coleman units. It also has longer travel than all of the other units. 

It amazes me though that they put that much effort into the design and then pooch up the finish machining.

If Wilwood was to make a "Super Duty" version of this thing from stainless with a chrome plated rod, a bushing in the end to support the rod, a real u-shaped seal (or two) on the piston, etc. they would corner the market. I know lots of guys who have had internal hydraulic throwout bearings fail, and many would happily run an external pull slave instead if it was really high quality. That way if it ever did start to leak they'd have easy access to it. I even pitched this to the Wilwood guy I was dealing with, but it was pretty obvious that this was just another job for him.