And then attach the new supply plastic tubing to the metal tubing ends.

I first tried warning the end of the plastic tubing to push onto the barbed fitting.

But, the tubing got too warm and buckled when I tried to push it onto the cold barbed fitting.

So for the second try, I warmed the metal barbs and then pushed the plastic tubing on. Much easier.

I lubed the grommets with brake fluid.

And then eased (and pushed) the flanged ends into the grommets.

My logic here is to install the MC by feeding the supply lines up through the floor. I still plan to "bench bleed" the MC in place, with some long return tubing on temporary output fittings. We will see how that works.

MC mounted, with the supply lines up through the floor.

I think I need new angled grommets for the supply lines.

Also, a new boot for the warning switch. I decided to use the old switch with two contacts, so I would not have to fuss with making sure the MC body is effectively grounded.

Before mounting the banjo fitting for the front lines, I need new crush washers.

Meanwhile, I put my visiting son to work again, first on the engine relay board. I had removed the cracked and failing tar-like material on the underside, and wanted to replace this with more modern potting material. This is a two-part flexible potty compound.

The obvious thing is to pour this into the inverted relay board. But a few holes, for the cable retaining clips and the 3-prong socket, would let the compound leak through.

So I decided to try wax to create temporary filling for these holes. This furniture wax seems like the purest material that can be dissolved later with solvent. Yes, we did test this.

Here's the wax, forced into the holes from the top side.

And from below (sorry for the fuzzy photo).

Finally, we leveled the relay board.

Then mixed the potting compound and poured in about 75 ml.

For about 15 minutes, we popped some air bubbles. The compound was fairly thin for at least 1 hour.

Now just wait 24 to 48 hours for full cure.

On my Notchback I am using the 19mm MC. Grommets started leaking before it ever was driven so I ordered some ATE grommets. They were much beafier, larger diameter and the leading edge is rounded to ease with smooth installation.
Dry as can be now.
Fill your system as soon as possible and look for weeping. Easier to fix early on.

This is good to know. I had the same experience with the grommets weeping and have had replacing them on my to-do list. New grommets are on the way from Porsche now so hoping they work better.

Finishing up the relay board. The potting compound looks pretty solid after 36 hours.

And some leaks, from over-filling.

Compound leaked through the side notches, and onto one of the 12-pin sockets.

And the compound found more leak points, including the pins of the other 12-pin socket.

And the 3-pin socket, and one tab for the fuses.

And the 4-tab socket. Damned stuff was very sneaky.

At least the wax in the big holes worked.

And was easy to clean out with a tooth pick, Q-tip, and 3M solvent. I also scraped the compound off the other pins and tabs where it leaked through.

Ready to go!

A few lessons:

To fill the underside takes 70-75 ml. Any more will overflow.

The wax worked to fill the big holes, but a thin compound will find a way through other small holes.

One more task done today: a new shift rod bushing in the firewall.

This was a bit difficult to install. I tried pressing with a 2x4 levered against the car dolly frame without success. With a step-down spacer and big hammer, I was able to get it most of the way in, and finished with a pry tool against the inner lip.

Next, mounting new air deflectors.

@bkrantz there was something that left here today for your project.

Three holes on the right side, that match the center and end holes on the deflector.

And 3 holes on the left. Note the parking brake tube blocks the left end hole on the deflector. Instead, the deflector has a 4th hole offset from the left end.

The bolts screw into under-sized holes in the plastic deflectors. It helps to "thread" these holes before mounting.

Left side in place.

And right side.

Note the factory manual has a page about mounting the deflectors.

A couple of weeks ago, before installing the wiring harness, I added a switch (from CarMagic) for a new washer pump to the steering column sub-harness.

I had also ordered a plug connector so the switch can detach from the harness if I ever need to pull the column control stalk module. Here is the connector installed.

Half the connector stays with the harness.

The other half stays with the switch, which needs to be installed.

Here's the column control module, with the original washer valve, operated by the right lever. IMO not the best idea to route washer fluid into the passenger compartment, through the steering column, and around electrical components.

The CarMagic switch replaces the fluid valve, but the end of the switch plunger is narrow, unlike the head on the valve plunger.

I decided to cut off the narrow end of the switch plunger, so the equally narrow actuator has a bigger contact target.

To make this work, I need to get the switch to sit further into the module, and so drilled a hole large enough for the flange to mount flush onto the module surface.

With the switch mounted, I checked the function. The circuit is open, until pulling the lever pushes the plunger, and closes the circuit.

You’ve left no bolt un-turned!!!

Last detail: the mounting flange for the switch protrudes beyond the module edge. I trimmed this with a utility knife.

Just a small air gap in "resting" state.

And when the wiper/washer lever is pulled, it pushes the switch plunger all the way in.