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Topic Review (Newest First)
02-11-2006 10:56 AM
pmurf1 The quickest and easiest way to do it is to just pull out the HP/bypass fitting and just drill out the two holes as big as the casting will allow. I pull out the screen too. We did one in Moab last year with a vise grip and cordless drill on AZtoy's rig when he didn't have enough pressure, took us less than an hour and it worked fine after that.
02-11-2006 06:42 AM
kjmcdaniel In the picture above, the piece on the right with the groove at the top....

Take two wrenches and take it apart. Inside, you will find a ball bearing and a spring. This regulates the bypass pressure of the pump. When pressure increases it pushes on the ball, compressing the spring and allowing fluid to bypass the pump vanes. I made a shim the same diameter as the spring, and about .070" thick, and put it in the bottom of the hole the spring goes in. At the opposite end as the ball.

Sorry, I don't have any pics, but if you have trouble, let me know, I'll try to explain better.
02-10-2006 09:37 PM
riksnacjnow So, you drill right through the little plate with the two holes? with a 13/64 bit? and I guess the notch adds a little more? Where does the extra pressure come from? I read a .070 shim will not explode the box but where does it go? Thanks
02-10-2006 08:50 PM
Originally Posted by riksnacjnow
I took the high pressure fitting out one of my pumps and where is the shim? I can't even figure where to drill the larger hole. I searched but can't find any pics. Thanks
This is what Erik B did to his I just drilled mine out. If you notice on the PSC pump, it is under-driven to make the pump turn faster at low speeds. That way you do not have to up the pressure of the pump by shimming!

02-10-2006 08:16 PM
riksnacjnow I took the high pressure fitting out one of my pumps and where is the shim? I can't even figure where to drill the larger hole. I searched but can't find any pics. Thanks
02-08-2006 01:52 PM
somebourbon If you dont feel comfortable DIY, then check out redneckram.com. They have the best prices for hydro assist that I've found.
02-08-2006 11:09 AM
kjmcdaniel Ok, we did a little experimenting last night. We tried various shims under the bypass spring.

I can tell you for a fact that .140" is TOO much! The pump would not go into bypass when you hit the steering stops. All it would do is slip the belt, and bog down the engine. The steering was WAY easy, until the pump burnt up! But, it did not blow the seals on the steering box.

After installing a different pump, we finally settled on a shim that was .070" thick. This would let the pump bypass when hard against the steering stops, but also provide enough pressure to steer with an open palm with almost no air in the tires, even when the drivers front tire was hard up against the lift arms in the shop. You could still turn the wheel with your open hand, it would just shove the rig sideways across the floor.

I don't know what the long term effect will be on the seals, but there is still no leaking after extensive testing in the shop. We cranked the wheel back and forth for about an hour with the 39.5 Iroks almost flat with no noticeable harm done to any components. We'll just have to wait and see what the real world throws at it.
02-07-2006 02:00 PM
kjmcdaniel I've read about and done the drilling of the restricter plate. Speed of the reaction of the ram is not my problem. I need more pressure. More force to turn the wheels.

You see, I am feeling inadequate. I've never broken a steering arm stud. Just joking. I run 39.5 Iroks aired down to 5 psi. I also have a terrible scrub radius, due to spacers and backspacing on the wheels. Turning, even with H.A. is verry difficult. I'm just looking for a little better push from the ram. I know it is possible, because I have driven similar set up rigs, which steer with the palm of your hand.
02-07-2006 01:24 PM
somebourbon You should find a pressure gauge and shim it little by little. Those pumps operate in the 1,000-1500 PSI range. Shim it too much and yes, you could blow the line, seals or the box. You can also drill the hole out where that ball check valve is and increase flow. Remember when you increase flow you decrease presure. If I were you I'd talk to an expert. I had once talk to Carl Jantz of Jantz Engineering. He's located in Poulsbo, WA. He's a mechanical eng, very experienced, and an extremely nice guy. Good luck.
02-07-2006 11:01 AM
CANYON KRAWLER MIKE i just took the brass washer out and stretched the inside spring a bit. but it is for full hydro and don't know if it is too much for the p/s box
02-07-2006 10:46 AM
JamisonWorkshop no answers except that PSC has a direct replacement pump for toys out now. that is very nice. Not sure how it compares to toy pump as I did it all at once.
02-07-2006 10:43 AM
turn up the pressure on power steering pump.

Ok, I've read through the FAQ and 48 pages of search results, and now I have a headache, but no answers.

I have read where you can shim the bypass valve on the power steering pump to bump up the pressure. I have also read where some have said if you do this you will blow the seals in the steering box.

What I would like to know is, what amount of shimming of the bypass spring produces the best results without blowing the seals?

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