Gunslinger

Engine running the system should be charging at 13.8 volts.

The hydraulic brake switches suffer from a dual problem beyond aversion to silicone fluid…current ones are made offshore now and simply don’t last…and original, well made switches are old enough now that they’re suspect in how well they work for any length of time.

You have "DOT 5" on your master cylinder cap so I assume that's what's in it. Silicone brake fluid is notoriously difficult to bleed all the air out of...the little air bubbles like to hide wherever they can and defy being bled out. If the car had standard DOT 3/4 fluid in it and wasn't completely flushed out and all the hoses replaced you will have spongy brakes or even fail in rare cases. The best performance cars don't use DOT 5 as strong cornering can cause bubbles in the system. DOT 5 also can kill the hydraulic brake switches...why I don't remember but it was explained to me once. The use of DOT 5 might be the cause of your problems.

It was sometime during the '71 model year Avanti Motors switched from the Borg Warner to a GM Hydramatic...not sure whether it was the TH-350 or TH-400.

If you can find Ford Type F…use that. GM Dexron will work but the Type F will give firmer shifts with less slippage. Whatever type you choose flush the transmission first…including the torque converter.

There is a vendor…don’t remember who…that fabricates and sells an Sanden adapter for the Avanti II. You might check with Myer’s Studebaker…Mike Myer may have what you need or know where to get it.

The Borg Warner used in the Avanti II had a different torque converter but otherwise fit the same.

To be straight...few Avanti II automobiles carry great value. It shouldn't be that way but it's the truth. Having said that...an early Avanti II such as a '66 is a great car for restoration...few emissions devices to deal with...lots of performance from the Corvette 327 engine...pretty simple compared to later cars. Outside of the engine and a few other pieces it's all Studebaker and most parts are pretty easily sourced...outside of some Avanti specific trim. Depending on the condition of the frame and hog troughs it would be a fine candidate to rebuild. I've advocated that any Avanti that can be rebuilt should be rebuilt...but I'm realistic enough to know that's that not always economically possible and we do need parts cars to keep other Avantis on the road.

Anything Avanti specific and not general Studebaker parts…such as trim pieces. Some have been and are being reproduced. Some are considered to be unobtantium.

The master cylinder might be the source of the problem. If it’s a non-original master cylinder…it could be from a car that has an identical looking master cylinder but a different bore which can create such an issue.

The ‘70 Avanti I had was equipped with what must have been an aftermarket 4-way flasher unit. Believe me…it was an abomination of wires and connections under the dash. If you’re compelled to have one…I would think Dan Booth at Nostalgic Motors is the guy to talk to.

Here’s a way to find an electrical short! 🤣

I used to own a ‘69 Corvette 427 435hp tri-carb…the intake manifold…instead of being raised was sunken for hood clearance…plus the hood itself was slightly raised compared to the small block hood.

While I could be wrong on both counts...during the mid-'70s a lot was going on with Avanti Motors...the change in door locks could have been related to complying with federal safety standards or running out of original Studebaker parts and the need to substitute something different at the least cost. The death of Nate Altman in 1976 probably had an effect in decision making as well.

Didn’t Studebaker state there was no warranty on an R3 engine…and it had 9.75:1 CR? And the R3 was Granatelli developed. They must have expected a combination of a supercharger and R1 heads to grenade on a regular basis and send parts into lower earth orbit. That would have made for some really bad publicity and lawsuits.