So apparently the ZF steering box in the f550 chassis my 1st gen body/Cummins swap is going in, can’t be modified for extra ports for hydraulic assist.

However being that this steering gear is used in medium duty trucks, I should be able to run more flow and pressure to it with positive results.

My understanding is that our steering pumps can be modified to increase psi/gpm, what I’m not sure of if there is a limit to which the steering pump will have too much asked of it, thus reducing its life. Well I know there will be a limit, just unsure of what that is.

Ideally I would be looking for 4gpm at 1900-2000 psi which seems to be the typical range for medium duty trucks. If my stock pump can’t be modified to support this, I can always run an adapter to a medium duty pump, but it would be ideal to just use what I got.

 

I realize this may be the wrong place to ask such a question, but figured it couldn’t hurt to try.

Have been searching on pirate and getting some results, one main point being a hydro boost setup can act as a choke point for a system which can lead to excessive heat when pressure and flow are increased. There is one company that modifies hydro boost systems to allow more flow and pressure to the steering box.

 

I don't have any good help but I do know that the stock steering pumps outflow /pressure valve can be swapped out with one with a larger orifice. Also you can modify them by drilling them out larger. Don't go too far or it will get too strong easily, like steering a forklift.

 

Yea that was were I was thinking to start, to drill out the orifice for a little more flow. May as well try the free stuff first, and if that doesn’t do it then move on to the not so free stuff.

One can get an adapter to run all sorts of different capacity vane pumps for these engines, and was able to get numbers for a bigger vane pump that puts out 5gpm and 2000psi, if all I had to do was regulate it down after the pump to find the sweet spot, that would’t be so bad.