Author Topic: gear pump power steering  (Read 125 times)

mr.mindless

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gear pump power steering
« on: October 07, 2019, 02:08:01 PM »
Jeff and I have been talking about this. Vane pumps have been an annoyance to every one of us at some point or another. They're occasionally fragile, the hot rod pumps are unreasonably expensive, DIY mods seem to be OK but black magic. I know all of you will say it's fine and whatever, but I know that every single time I put a fresh pump on, my car drives like new. That means it's been cavitating and eating itself and dropping pressure/volume its whole life. I'd love to have a pump that stays happy for longer, and gives better volume for needs.

This is a thing that some rock bouncers have been doing for a year or two, and Scott's Custom Offroad is selling kits for $600+ to put this together.
https://www.facebook.com/scottscustomoffroad/photos/a.675407549257832/1182728208525761/

I've got most parts lined up to DIY:

The pump is $100-120.
I've found a couple source for overhung load adaptors, $210-$226 plus Tax/Ship
bolt-on serp pully is around $30 at Summit
Need keyed adaptor for pulley to OHLA, ~$15 for a 1" keyed "go kart drum mounting hub", I expect there are other options to research

The one remaining part to identify is a proper crossover relief, since there's no internal bypass in the pump. Scott is using something by Prince. Northern Hydraulics lists some Cross parts that are about $60. I'm not sure on plumbing if there also needs to be a check valve if that pressure return goes into the pump feed line - which I think it would? or should it be another return to the resi?

Fab OHLA to accessory bracket mount on engine. Just a dumb plate for most. I may do that, or might want to remake the front plate of my Goatbuilt brackets.


Need to verify clearances for pulley size/pump location and plumbing in/out.
Need proper plumbing changes and a proper reservoir, and make sure my line sizes are up to snuff.
Quote from: etk300ex
oh lord!

mr.mindless

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Re: gear pump power steering
« Reply #1 on: October 07, 2019, 02:08:16 PM »
reserved for actual parts list
Quote from: etk300ex
oh lord!


M4wdFab

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Re: gear pump power steering
« Reply #3 on: October 07, 2019, 02:15:37 PM »
steering and brakes are the only thing that holds up our cars....


hope you learn something cool! 

mr.mindless

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Re: gear pump power steering
« Reply #4 on: October 07, 2019, 02:18:44 PM »
Brakes is another thing - I bet it would be a new world to trim a bunch of rotating weight and improve braking at the same time. Karl has some ideas on that, he's got some fancy 6 pot stoppers on the IFS knuckles that are a Porche-Audi part for _way_ less money than comparable Wilwood stuff. Could be interesting to explore.
Quote from: etk300ex
oh lord!

TrailTamer

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mr.mindless

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Re: gear pump power steering
« Reply #6 on: October 07, 2019, 05:18:48 PM »
There's a Prince pump that has the proper specs, but I'm not finding a for sale listing. SP20PB14?200H4R
? is the GPM rating on the priority port from 1.5-5.0. I don't think I know how to make that choice. I just want every fluid ounce the pump can give me at my pressure setting to the steering valve, so probably 5?
SP20PB14P200H4R would work

Those full part numbers give me zero hits. I did find one place where I can request a quote, and as I found this morning when I got an RFQ back from a manufacturer for another OHLA: if I have to ask I can't afford it. (essentially the same as the zero-max linked above, for $640 each with a 6wk lead time)


Also, if anything kills the pump, I'm replacing 2 components at once because they're married. Pumps have so far been a wear item and part of the appeal of this is an interchangeable $100 pump. Even though it's different tech and should never die...
Quote from: etk300ex
oh lord!