In this photo-heavy series, I’ll go through in detail the work going into fitting a hydraulic clutch to the Chevelle in place of the factory z-bar mechanical linkage.

To recap, I previously bought a kit which purported to be a bolt-in affair, which was nowhere near correct and presented nearly-unsealable gaps in the firewall, as well as questionable quality components (plastic master cylinder, for example). I returned that and bought a kit from American Powertrain (with Wilwood hydraulics) that doesn’t pretend to not require firewall modifications.

First up, inside the footwell the original pushrod and boot was removed, and using a straightedge I determined where-about the mounting plate for the new master cylinder must go. I also checked, and while tight I do have clearance (, Clarence) for the heim joint.

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A matching plate on the other side clamps onto the firewall to spread the loading.

This has some good and bad - the bad part is most of it is in the large hole required for the stock linkage boot (which I had to cut about 2 years ago when swapping in the 4-speed; this is a solid plate on automatics). The upside is that the whole thing lands on this plate, which will further spread the load across the firewall to prevent metal fatigue.

Since there’s a big hole there, I took the plate out and sought to make it not have a hole.

It is worth mentioning you can buy reproduction plates for automatic cars, which are solid, but that’s like $40+ vs a little sheet metal from the pile and an hour of time.

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I traced the hole with a scribe on 16ga steel (the plate is 14, which I don’t have. Close enough). I then cut it with the angle grinder and remembered that dykem doesn’t like heat.

Not bad

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Fortunately the scribe line was still visible, so out came the die grinder with some 60 grit paper to make it actually round.

Everyone should have a die grinder with a roloc spindle

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After a little more adjustment, it actually fits the hole (with a bit of clearance as required)!

I kind of like the scratched up blue, like a round starry dusk

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Everything was then cleaned up for welding (above I’ve already removed the paint from both sides and the inside edge of the hole).

Cheap and worth having: polypropylene wash bottles for things like acetone. Way easier than a can.

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You can see two pictures ago there is a black arrow on the part, I made a punch mark where this was, and used that to re-arrow it after cleaning. This is just so I know which ways is up, since the hole isn’t perfectly round.

The plug had a slight bend which probably is from clamping and grinding, but I fixed it, hence the X (that was the high spot)

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The patch is then held in place with some magnets to be welded in place. It’s then, well, welded.

A little longer beads than I’d usually risk on something this thin, but it turned out okay (didn’t turn into a taco!)

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If anyone here who actually knows how to weld has any feedback, it is welcome. I make no claim to know what I’m doing beyond being able to stick stuff together, and in this case without warping it. In any case, a grinder...

Again, die grinder and roloc sanding discs - much more control than a flap wheel on the angle grinder, good for small stuff like this

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...and paint...

This will dry semi-gloss, still very wet when photographed but I was hungry and wanted to eat more than I wanted to watch paint dry for the sake of taking a picture of it.

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...makes it look like it did a while ago.

This is all the further I have gotten so far. The next step will be to put this plate back in the car temporarily to make a final determination of where the new MC has to mount, then ironically drilling holes through my patch. There’s some other fiddly stuff I probably should do to make it as robust as possible as well. All this should be part 2. Much later, part 3 will be the transmission-end of the fun.