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P/S pump modification

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Understand that this is an article I threw together a while back. The idea was I'd have a hydro-assist part that would go with it, but it just hasn't happened. So, this part is here to be picked on.





How-to: DIY Power Steering Pump Upgrade.


Applicable to: Most late model jeep power steering pumps, an XJ/MJ model is shown and this article is written with them in mind.


Purpose: A cheap and easy way to get a little more out of your power steering; to aid in turning with both stock steering setups and hydro-assist.


Tools Needed:


-Basic wrenches/sockets

-Drill/Drill bits

-Vice (and soft jaws, or some hose)



These mods can be done with the pump in or out of the vehicle. I did it to a removed pump as I was in the process of swapping out a dead pump at the time. I would suggest having some clean rags around as well as a tray or piece of cardboard to set the parts out on. A few of the piece are very small and if you lose them you will be in big trouble! Also, a can of brake cleaner works wonders for cleaning up all the pieces. You do not want to re-assemble a pump with dirt or other foreign material in it.




Step 1:


Remove the high pressure hose from the pump housing. It may be VERY tight depending on how long it has been there. To avoid problems I would throw a little penetrating oil on both the threads and the centre of the fitting before attempting removal.


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At this time if you wish to remove the pump you should also undo all the other relevant bolts and lines.



Step 2:


Remove the output fitting from the pump. This is the fitting that the high pressure hose threads into. It too can be very tight. This fitting actually acts as a restrictor valve, and we will be taking care of it later.



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Step 3:



Looking down in where the fitting is removed, you can see the pressure regulator.


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It has a spring behind it and might just pop out on its own. Or you may need a small magnetic jobby and some wiggling to get it out. Or if the pump is removed, you can flip it upside down and shake it a bit. Be careful not to lose the regulator or spring behind it.


You do not need to remove the spring from behind the regulator, but if it falls out you might as well clean it and set it aside until re-assembly. It will not be modified in this article.



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Left to Right: Output Fitting, Regulator, Spring.




Step 4:


This step is only really necessary if you have hydro-assist steering. You can however do it with stock steering; there just might not be any gain. The purpose of this is to increase the flow output from the pump at lower RPM. With hydro-assist your steering may feel sluggish at or around idle. This mod will often correct this.



Mount the output fitting in the vice. Or a drill press if you have one.


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Then select a drill bit to increase the size of the restriction valve. 3/16" is as large as anyone should realistically need. Drill through the small opening that is at the bottom of the fitting (looking down).


And it'll look something like this:


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Not a huge visible difference, but it really increases the amount of flow.



Step 5:


Now we are going to deal with the pressure regulator. This will increase pump output pressure and will be beneficial to both stock and hydo-assist steering. I will warn you right now that small modification to a regulator can produce a wild pressure increase. If you go too far you will split hoses and blow seals...


The regulator comes apart quite simply - just remove the nut on the end of it. This is where you need soft jaws for your vice, or a piece of hose. Mount the fitting in the vice and remove the nut:


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Be cautioned that there is a spring and a ball in there. You don't want to lose either!



Exploded it will look this this:


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Left to Right: Regulator body, spring, stud, ball, shim, cap/inlet.


There may or may not be a shim/washer. Of both the pumps I did, one had it and the other didn't.



If there is a shim, the first step would be to throw it out. You can stop there as it will mildly increase output pressure.



If you want more, you need to put a washer inside the regulator housing. A #4 machine washer works, and is thicker (more pressure), and a 3mm will work and provide less pressure. I personally haven't tried both so I'm not sure how much difference there is. The inside of the washer should be drilled out so that the limiting stud can fit through it, or the stud can be trimmed down slightly.



Drilled-out washer inserted.


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Step 6:


Put it all back together! Hook up the lines and fill the reservoir with fluid. Then bleed the system by turning the engine on and cranking the steering back and forth a couple time, while checking the fluid level and making sure you've not got any leaks. If it all checks out go for a test drive. Hopefully there will be an improvement. If not, you can go back and try a thicker washer.

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3 hours ago, ShrumpagonXJ said:

Hey I’m late to the party like 12 years late dirtyMJ! This doesn’t have photos anymore. Any chance you could send me the photos as they were in your original post to me? 4oh8 six42 zero964 thanks DirtMj

Use the quote button otherwise the person  you are addressing may never know you posted in his thread. Seeing this thread has been drug out from the crypt.

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On 3/11/2019 at 2:22 PM, ShrumpagonXJ said:

Hey I’m late to the party like 12 years late dirtyMJ! This doesn’t have photos anymore. Any chance you could send me the photos as they were in your original post to me? 4oh8 six42 zero964 thanks DirtMj


I don't have them anymore.  Photobucket ate them and most of the other stuff I had.


And I would buy a legit 01+ V8 WJ pump instead (not some reman that is the wrong one), assuming you're doing this because you have hydro assist.  Better upgrade, as it is actually a higher displacement pump.

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I attached instructions on modifying saginaw pumps I downloaded a long time ago from WTOR's site, I hope no one minds me reposting this info.  The pump shown in that document is a Saginaw P-pump but the internals are very similar to the TC on the MJ/XJ/ZJ/WJ.  I did the 01+ WJ V8 pump swap and the high pressure fitting that comes on the pump has a really large bore, much larger than 3/16" and isn't compatible with the stock high pressure line.  If you do use this pump you'll need to use the XJ/MJ TC pump high pressure fitting and you can drill that for more flow, IIRC a 3/16" drill didn't actually remove any material on my original TC high pressure fitting.  I opened mine to about 0.200" on the drill size for the high pressure fitting.  I think I used a late model XJ high pressure line to fit around the WJ pump reservoir.


Here is what the TC piston looks like and what I did to get it apart:





There weren't any shims but rather the threaded fitting you see here was glued in place such that some space was left between the threaded fitting and the piston body to mimic a shim.  I cleaned off the old glue and then re-installed with some loctite red and screwed the fitting all the way into the piston body to bring the operating pressure up.

I'd shy away from adding small machine washers underneath the spring inside the piston to further increase pressure, I believe I blew a P-pump apart that way - twice, although I did also try opening up the high pressure fitting to 5/16" at the same time, so maybe that contributed as well.  First time I blew the back of the pump out and after I fixed that, the pump shaft broke on round 2...  At least it didn't explode the PS gearbox and had not rolled out of the shop...  Maybe I just had a defective or worn out P-pump, it was the original pump on my van with 177K on it at that point...  The P-pump is different than the TC so that's another variable...  Try closing the gap/removing shims (if present) first before adding shims under the spring in the piston, didn't work for me on the P-pump but maybe the TC is more tolerant?  The attached instructions also have you take some off the limiting stud if you do decide to shim the spring inside the piston.

The WJ V8 TC pump for the hydraulic fan setup runs a really large hole in the high pressure fitting so my best guess is shimming the spring in the piston is what put my P-pump over the edge.


upgrade saginaw pump.pdf

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