March PS pump & Hydroboost, Must Read

[John S]

I found out too late that the March power steering pump is not compatible with a Hydroboost. It seems that the March pump has 40% less fluid capacity and is unvented which causes pressure to build up and steadily apply the brakes on its own.
Not wanting to remove the pump and install a standard Saginaw P style pump Paul from Hydrathech gave me a few ideas on how to solve the issue.
What I ended up doing was to drill a 1/2" npt hole in the filler neck of the pump and installed a 1/2" x -10 an fitting. I then installed an ARTS aluminum resevoir on the inside panel of my fender and ran a -10 braided hose to the filler neck.
Simple fix and now everything works great.

here is an image of the fitting into the pump neck;
https://static1.pt-content.com/images/pt/2007/09/MarchPSpumpMod-1.jpg

And here is the resevoir, of course I polished it :)
https://static1.pt-content.com/images/pt/2007/09/PSRes-1.jpg

[TPI Monte SS]

Very trick, I like it! Nice work as always John!

[Hammered]

I had the same problem when trying to go to a non-factory style pump and wound up going with this: http://john.my67.net/Power%20Steering%20Pumps.JPG

and

http://john.my67.net/Suspension.htm

Paul was helpful in getting it figured out. There is a minimum amount of fluid required to keep everything happy, but there is also a minimum volume of ullage (empty space in the reservoir) that is required to take up excess fluid when the hydroboost is activated. The March reservoir does not have enough volume to accomodate both.

I need to run my fluid level toward the bottom of the safe range (which is somewhat arbitrarily defined on this aftermarket reservoir) to maintain the required balance.

John