Trouble with air/foaming in power steering

[LA 66]

I finally got the front end aligned and the exhaust put on the '66. I've put about 100 miles on it.

Every time I drive it at highway speed for a few minutes the fluid foams up and overflows the resevoir. This does not happen at low speeds.

The system is the saginaw type from a '72 F100. All the components are new or rebuilt. There are no leaks (that I can find) and I've been through the bleeding procedure a dozen times.

Any ideas?

[jamesdfo]

Care to describe your bleeding process?

The way I was taught as an autobody apprentice was to elevate the front wheels, then with the engine running turn it lock to lock a number of times, checking the fluid level periodically.
Also, depending on the year, the system could require power steering fluid, or ATF. And lord knows there are any number of different ATF's:):)

James

[Alan Mclennan]

Isn`t the reservoir supposed to have a sealed lid?

[deadheadno1]

What ATF are you using? I strictly use Dextron (Mercron) type fluids because it has anti-foaming agents that the others don't have in them.

[LA 66]

The fluid is type F. Bleeding procedure is wheels elevated, engine running, and turn the steering lock to lock.

[DIXONBOY]

On the new cars the make an adaptor to put a mighty vac on the resevoir so you can pull a vacum to suck the air out while you turn the wheel.