David Heacock's 1985 Avanti EV Conversion (In Process)

Steering, Brakes and Suspension Update
Updated 9/13/09.

The body was now back on the frame and it was time to start returning some components removed during the total tear down. I had decided early on I would try to eliminate the power steering and replace it with a much simpler and lighter manual set-up incorporated in the early Avantis built in the 60's. The picture below is of the Avanti just before it was rolled out of the garage and into the shop where I could start putting components back together. My wife was very happy, as I had told her it would probably take only a few months before she could have her parking spot in the garage back. I underestimated by a couple of years.

Once I got the Avanti into the shop I was ready to replace the steering box and determine what I would need to do about installing a manual steering system. As it turned out, I talked to Dan Booth at Nostalgic Motor Cars and he indicated that if I sent him my old pitman arm and reach rod set-up he would provide me with a different pitman arm and reach rod made for the earlier manual steering models. I should point out that when I first weighed the Avanti it was approximately 400 pounds heavier in the front than at the rear. My reasoning for replacing the power steering with the manual set-up, aside from the weight and complexity reduction, was that I could move components around, such as the batteries, to provide a better weight distribution and thus eliminate the need for power steering. My target weight distribution is 50/50 when loaded in the new configuration. The picture below shows the manual steering reach rod and the manual pitman arm with a tapered insert on one end matching the taper on the reach rod.

The pictures below show the old power steering set-up and the cleaned up steering box with the manual set-up. All the bolts mounting the steering box were replaced with Grade 8 bolts.

Next on the agenda was the replacement of all the brake lines and fluid. Notice in the picture above you can also see the new brake lines from the master cylinder. Since the Corvette rear end and disc brakes were new to the Avanti I had to figure out how to run the lines and make the connections. The master cylinder was retained and from a discussion with a speed shop I determined I could replace the old proportioning valve with a simple adjustable valve connected in the brake line running to the rear brakes. Since I no longer had drum brakes in the rear, it was felt the valve could be adjusted to get the correct balance for the front and rear brakes. The pictures below are of the original proportioning valve and the new adjustable valve. I plan to place a clear plastic cover over the new valve to keep it free from road dirt and bad things.

Before I installed the lines to the master cylinder I flushed out the old fluid from the cylinder and then connected the lines to it. I decided to use DOT 4 fluid, as it would be compatible with the DOT 3 fluid that was in the master cylinder originally and would give me some higher temperature protection. Based on stories I had heard about electric vehicles and heated brakes I decided on the DOT 4 fluid. A DC electric motor without regen does not tend to slow the vehicle in the same way as the compression would in a gas car. Since the Avanti might weigh 4000 pounds the added temperature range of the DOT 4 fluid might be of some help. An adjustable proportioning valve and different fluid were more things to add to my "I'm not sure how this is going to work" list.

Next on my list was to start replacing some temporary bolts on the rear suspension with Grade 8 bolts. The picture below shows the rear of the Avanti after it had been placed in the shop. With the body back on the frame the new measurements showed the rear end to be approximately one inch lower than the original position, which I figured was pretty good considering all the modifications that had been made. The front of the car was several inches higher because as yet there was no weight in the front of the car.

The following picture shows the left side of the rear suspension before the coil-over springs were installed. A bar had been temporarily used in place of the coil-over arrangement and can be seen just behind the half shaft in the center of the picture.

The next step was to install the coilovers in the rear suspension. The following picture shows the coilovers as received from Aldan Shock Absorber. The coilovers were custom made after determining the expected final weight at the rear of the Avanti and by measuring the minimum and maximum amount of travel of the rear suspension.

Placing the coilovers in the Avanti was fairly simple because during the initial planning for installing the Corvette independent suspension the mounting points had been determined. These coilovers have a number of adjustments and it was therefore possible to raise the rear of the Avanti back up to within one inch of the original ride height with additional adjustment still available.

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