I'm fixing to change the PS pump om my 69, and I have a faint memory of a thread here where someone said that it is very important to save the dowickie from the old pump. Said dowickie is supposed to be located right where the pressure line is attached to the pump, and I believe it's either a strainer or some kind of check valve.

My questions are: Should the dowickie be replaced while I'm at it, and what is that thing anyway?

I'd strongly suggest that you read Jim Shea's writeup on power steering hardware. (http://www.chevelles.com/techref/shea_1.html) It includes a description of the pressure relief valve, in the section on pumps about halfway down the page. Note that Jim's article is oriented toward someone who is upgrading to power steering and needs to put a new valve in their existing pump. In your case you're doing the opposite to ensure that your new pump has the same pressure relief setting as your old one.

Reid

That dewickie is the power steering pump discharge fitting. It controls the maximum amount of oil that the pump will discharge. Different fittings had different throat diameters as well as a very small cross hole that sends a pressure drop signal to the flow control valve inside the pump.

The early fittings (Chevrolet up until 1969 or so) had a male thread and a 45 degree face. The mating pressure hose had a female nut and a 45 degree inverted flare tube.

The next design (from 1970 through 1979) had a 45 degree brass seat and a female thread. The mating pressure hose had a 5/8-18 male nut with a 45 degree inverted flare.

The last change occured in 1980 when many GM parts converted to metric. In 1980 all GM power steering pumps converted to a female discharge fitting with a special throat designed to accept a pressure hose tube with a male 16x1.5mm nut and an o-ring seal.

Inside the pump, right behind the dewickie, is the flow control valve. The back side of the valve has a screen. Inside the valve is a check ball and spring. This flow control valve also controls the maximum output pressure that your pump will develop.

Those two parts control the pressure and the flow of a power steering pump.

Well, here's The Man himself! smile.gif When he said "check valve", I thought he meant the relief valve, but you're probably right - he meant keeping the fitting size the same.

Reid

Thanks a bunch guys, I took it apart late last night, and removed the discharge fitting. The reason why I couldn't find it at first was that I thought it was just a threaded fitting, brazed to the pump graemlins/clonk.gif It seems to be the "second generation", with the female fitting and a male fitting on the hose. If the fitting controls the flow, I guess it goes with the steering box, rather than the pump then?

Here's another question: I went to Auto Zone to look for a new (rebuilt) pump. My pump has the drop shaped reservoir, which I believe is correct for a -69. They showed me pictures of different pumps for -70 and -71, but they all had the straight neck on the reservoir. Do you guys know what model to look for to get a pump that will fit?

I really appreciate your help!

Ok, just got back from Auto Zone again. I brought the old pump, and after a 20 minute discussion with Mr Blank Stare, I finally got him to look again, and today he said that a pump for a -71 will match my old one. Seems like he wasn't awake yesterday, but hopefully I'll have the right pump tomorrow. Thanks again for the info!

I thought Mr. Blank Stare worked at our local A.Z. Must have cloned him.