hello all. I am working on my Kubota conversion, in my XJ body jeep Cherokee. and I would like to not have to make a extra belt drive system and pump mount for power steering..
I have been seriously considering a electric power steering conversion. I know there are some folks out there that have done this. I think a popular unit is the Toyota MR2. one of the Kubota guys is using a Volvo unit. I have just seen a reasonably priced electric unit from a Nissan Pathfinder.
Then I saw just the electric motors from some of the other units for sale, and that got me to thinking about just mounting an electric motor to my Jeep Cherokees OE power steering pump. I have a lot of different electric motors laying around. I tried 2 of the smaller motors, and they both turn the pump whilst not pumping fluid. a little problem for me though is that both of the motors I tried ended up running a little under 20 amps. the first motor was a 12vdc starter from a 40hp Yamaha outboard. This probably is not too good for continuous duty. the other was a little 110vac 1/5th hp pump motor, and by the time I ran it through my inverter it also was pulling little under 20 amps.
My alternator/vacuum pump is only 70 amps. So power consumption is a factor.

So does anyone want to discuss these or other options?

 

would a remote electric water pump motor work? A lot of guys run them on the street in a continuous duty environment. How much HP does the pump take to operate correctly? Would one of the 12v scooter motors work? There were a ton of 250w sized little kid scooters out there, still a 20 amp draw I would guess running fully loaded.

My Escape has EPAS but it's on the rack itself and controlled by the body control module. I'd rather have a manual rack. Have you looked at putting a manual steering box on the Jeep or is that out of the question?

 

i put a used manual steering gear box on my Mercedes jeep. it does work, but I would prefer power steering. Plus on my benz jeep, the used box I bought is worn out, and a new rebuilt manual steering box for the jeep is $300 or so with a $100 core charge.
These EPS units are less
Lets stay on topic of Power steering please.

 

thought I was on topic - wasn't trying to discuss stereos. Sorry, just wondering about the manual. There are a lot of questions up there besides that one. What are you limited to for current draw? Do you know for sure what the requirement of the pump itself is? The only two kinds of systems I know about are on the rack (EPAS) where the computer controls it or remote mount motor where your concern will be constant duty, although limited time at "full power" as you probably aren't driving in figure 8's, and potentially high current draw. Also don't know but I suspect the Jeep box is a variable ratio and what impact that will have on current draw at varying load?

 

I guess as they say water and oil don't mix. Maybe I misunderstood, and you were talking about re-tasking a electric water pump to run the PS pump. if so sorry about that
Yes the newer chevy style electric assist will not work.
I just bought a "returnable" Nissan electro hydraulic pump for a reasonable price. I can not find much info on it as it is from a 2013 and it is still a dealer item I guess. The seller could not tell me about the hydraulic connection. From some other limted discussion the full load amps on these units is pretty high 70 amps ish, but the cruise consumption is a lot less in the 3-5 amps area. Yes power consumption is a factor as I only have a 70 amp alternator.

So in other words, I decided to not adapt a new e motor to my existing belt drive pump.
We will see how it works out. I just hope I can get the thing to work without its required " body control module"
I also wonder what the flow requirements are from I assume the Nissan's power rack and pinion compared to the jeeps Saginaw style?

Red are you out there. how is your Volvo unit working???

 

that is what I was talking about, putting a motor onto the existing pump... I misunderstood what you were saying you already had (Hybrid unit).

The 70a max draw is a pretty temporary load, how big is the battery in your Jeep? I could see an issue when Off-road but I suspect the 70a alternator would keep up with it fine otherwise?

Nissan PR documents show the involvement of a torque sensor on the steering shaft, then the ECU for the steering being included in the "power pack" (pump, resorvoir). I'm guessing the torque sensor is sending a +5 to -5v signal to the ECU to indicate how much pressure to generate. I'd be surprised if it didn't also want a VSS signal to provide better "feel" (less pressure) at speed so it didn't drive like a 70's Lincoln.

Do you have the part number for the Nissan pump?

Edit - something else I saw earlier poking around the Speedway site looking at their dirt car power steering stuff, Thunderbird rack and pinion and GM/Saginaw boxes being a "high pressure" and the Ford type boxes being "low pressure" design units, for what it's worth. I'm not sure where Nissan falls, checking to see if I can find out anything on that.

 

I get a p/n of #49110-3KE5A and a interchange p#553-59239 14829. I think from what I saw on the MR2 conversion, the fellows are just hooking the pump connections to 12vdc 80amp breakers, and not bothering with the control side of the wiring. Then the fancy one put a dash switch in the circuit so they don't have the pump running at engine start. But that is a older Toyota MR2, not a almost brand new Nissan

 

Sorry for going AWOL, I took a week off work and was off the grid...

The pump is working ok. The brakes are great, and steering is good under normal conditions, but it doesn't seem to have enough flow for extremely quick steering inputs. This doesn't seem to be a problem with emergency maneuvers (tested for safety reasons) or off road, but I've actually only encountered it with quick full lock turns like parallel parking.

I can see a voltage drop spike when this happens, so it may benefit from a larger gauge wire, second battery, or possibly a capacitor. Physically, the guts of these pumps are a common pump used for belt drive applications, and it should flow fine...

I'm using 8G wire with a fusible link off of the PDU stud. It has a relatively long run from one side of the engine compartment to the other though, so I probably should have just gone with a larger cable.

I'm not familiar with the Saturn unit, but most GM cars with electric power steering are purely electric, just an electric motor directly powering the steering shaft. I've actually considered retrofitting one of these steering shafts, and may still if I don't reign in my imagination... It looks like the hot rod crowd is just starting to sink their teeth into these retrofits.

I don't know the HP or wattage of the motor. It's an electronically controlled brushless DC motor, so you'd have a really hard time matching the power and efficiency in a similarly sized package. Starter motors are typically high torque, high current motors that won't live long in constant use.

MR2
The older (MK2?) MR2, as well as the Subaru XT used stand alone pumps that were much more simple than the newer units. They were also noisier and took more power.

The MK3 MR2 (Spyder) pump is very similar to mine. Most (if not all) of the new style pumps are made by TRW, and are very similar. The biggest concern is whether they have the same fail-safe parameters that allow them to be ran without the CAN bus. The Volvo unit is programmed so that if it has power to one of the pins, and no CAN bus detected, it runs stand alone.

 

Hey Red, thanks for the reply. I received the EPS unit yesterday. and sent it back today for a refund. I called Nissan dealer today to try and get some wiring info. my unit HAD I think 8 pins, with the open end of the connectors facing me, 2 big spade lugs in one plug, on the right, and I think 6 small connections in the other connector on the left. The dealer said the pin 1 was pos, 2 neg, and 5 ign switch pos. So I hooked it up like that and got nothing. Also no luck just hooking up 1 to pos and 2 to neg. That is with the reservoir pointing at me, and the #1 lug is on the far right. #2 next to the left.
Lets hope I get my credit back. and it will be back to the drawing board. The Dealer also said it would not work without the full body/engine control module talking to the EPS unit.
Red if you are still out there. How many wire connections does your pump have? Now I am curious to see if yours was like mine. The one I had was from a 2013 Nissan pathfinder, and the dealer said there was a change from 2012 to 2013. Also interesting to know that new list price is wait for it!!! $1500.
Maybe I should have tried a bit more to get it too work.
I really thought if this one worked it would be a good fit, as I am not using hydro-boost, or big tires, I would guess that the OE tires on the new pathfinder are bigger than the old Cherokee.
I will just keep plugging away at it and see if I can find some thing that will work

 

Mine has two plugs, one with large male spade like pins for the main positive and negative, then the second plug has three pins. I think two are bus, and one is ignition power. If you give it ignition power, it waits a couple seconds for bus communication, then starts running automatically if it doesn't detect anything.

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