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save the original until you are sure that ALL the features of the new one are the same- fittings, angle of return line nipple, shape of reservoir, etc. Unless that doesn't matter. Some folks are sticklers for detail, others not so much
I just installed a hydro boost brake set up on my car and I was thinking of replacing the original one just to be safe. Can the pressure on these pumps be increased?
Pump Flow/Valve Rating: This is another aspect of the pump that varied completely by original application. The OEMs would specify what flow rating was required based on vehicle weight, steering gear piston diameter, and whether or not the pump was running a Hydro-Boost brake system. The Saginaw pump in OEM applications can be set from 2.0 on up to 4.5 GPM.
Pump Bypass Pressure: Just like the flow rating above, the OEMs would specify output pressure based on the original vehicle application and what system the pump was running. Most steering gear applications would run between 1,100-1,300 psi with heavy vehicle high demand applications on up to 1,550-1,600 psi. Rack-and-pinion steering on the other hand is generally happier at a lower operating pressure of 850-950 psi.
Excessive Response/Touchy Steering: This is generally caused by excessive pump pressure. Borgeson offers a pressure reduction kit (PN 899001) that will allow the customer to adjust the internal bypass pressure of the power steering pump (self-contained and Type II with a remote reservoir).
Every one ton Chevy pickup built in the last two or three decades has hydroboost. Just use the PS pump for one of those and don't look back. All the original Saginaw pumps have the same mounting features. Some of the trucks used integral reservoirs, some remote, so you can select the best one for your application.
I captured some various nuggets in there. PS + hydroboost, currently running the common Tuff Stuff pump with only the output restriction resized. IMO don't sweat the flow rates or pressures too much. As long as it's a Saginaw gear setup then you're fine. Some pumps are configured for rack steering which uses much lower pressure, but those are generally clearly marketed.
You can increase the pressure by reducing the washers on the control valve. But this isn't typically necessary.
A lot of the power steering pump customization knowledge out there is from the rock crawler guys who have dramatically different requirements than us. So take anything you read with a grain of salt.
The only thing you HAVE to do with hydroboost is make sure the returns don't impact each other. That is, the return from the steering gear cannot force pressure back into the hydro. Any notable pressure on the hydro return results in brake application. The cheap/easy way to do this is a T fitting, with the steering gear and pump return on the straight line and the hydro coming in on the leg. Or you can get a hydro-specific pump body with two returns. I used a Y fuel distribution block.
April 25th, 2016, 03:47 PM
