Ferrari 250GTE Front Suspension Bushings
The front suspension control arms have returned from nickel plating, and they look great! Even though it seems there hasn’t been much going on with the blue GTE, I’ve been doing a lot of work behind the scenes.
The issues I’ve been dealing with has been with the suspension bushings and installing new ones in the car. Ferrari used a Bakelite type material for the pivots in the suspension arms, and they often deteriorated with age and use. Brass bushings are available to replace these inferior bushings, but they bring on their own series of issues.
After removing the old bushings and pressing in the new brass bushings, the dimension of the bushing changes slightly so the pivot pin does not slide into the hole anymore. This bushing needed to be sized to the new pin, but how to do it was the question. I asked Francois how he did it. I asked a couple Ferrari mechanics how they did it, and I even asked a machinist how he would do it, and I came up with several methods.
Because Ferrari used the Bakelite material, it was soft enough to remove material to fit the pin, and because the material was soft, the accuracy was not as crucial. The brass is harder, and needed to be cut with more accuracy. My conclusion was to get reamers sized exactly to the various bores of the suspension to do it right.
Reaming the outside a-arm pivots was easy because they were off the car so I could size the bushing perfectly.
The difference in size was only about 2 thousanths of an inch, but it made all the difference in the world in the way the pivot pins moved. With the reamer, the bushings were accurately aligned and cut to size.
The next challenge was the bushings on the car. The inboard bushings were less worn, but since we’re rebuilding the suspension with better materials, we’ll install the brass bushings.
I thought about how I was going to press the new bushings into the chassis members, and came up with machining a fixture to press in the bushing nice and straight, but I tried pressing one in with a simple piece of threaded rod and some large washers, and they went in without a problem. There is a time and a place for overthinking a solution, and this was not one of them!
I’m still waiting for the special reamer I bought for the chassis bushings, and hope to get this all assembled soon!
The spring bucket pivots also got new bushings.
Speaking of spring buckets, I finally got the huge spring clip out of the bottom of the spring bucket to release. A little rim of rust kept it from moving, but the right tool, some penetrating oil, and heat got it to release!