Adding power steering on the 'Big D's' (and possibly others?)

[pacer 3,174]

I recently posted about adapting power steering to my D-180 using an electric power assist steering (EPAS) unit from a 02-07 Saturn Vue. I got one of the units in order to check if I would be able to 'stuff' it in under the dash of the D. You can get these things in different configurations, this one had the steering column attached (its not needed)

 

With this and Sarges recent post on improving the axle and its components on the D's, the dang thing will steer itself!!

 

 

After removing the wheel, I needed to try and get it to fit under the dash, with a bit of experimenting I found a near perfect spot!

 

So next we have to get the EPAS to function - It will not work since it no longer has the cars computer to "talk" to it. To fix this a fella on ebay has a 'controller box' that when wired into our EPAS it can work. His link is:

http://www.ebay.com/itm/Saturn-Vue-Ion-Chevrolet-Equinox-Electric-power-steering-controller-box-EPAS-/182283275302?hash=item2a70ee0c26:g:uVAAAOSw4GVYJv77

 

 

So then it was time to get the shafts cut to length and adapted to accept the shaft of the Ross system. The longer shaft is steering wheel side and is cut off pretty short to accommodate/adapt the D's wheel. I had a spare Ross steer shaft and cut the splines/threads plus about 1/2-3/4" excess and made an 'adapter' to mate it to the EPAS shaft using roll pins. The other sides shaft was already pretty short but I still lopped off about 3/4". I then bored out the square end of a 3/4" shallow 1/2" drive socket to fit over the other EPAS shaft, again using a roll pin to attach. This was in order to allow some leeway when I cut the Ross shaft to match up with the EPAS.

 

 

Next we have to wire the controller box into our unit --- and this part is critical for it to function! (I know because I messed one up) Mounted on the unit is a metal box (ECU) containing the 'brain' for it. This will have to be removed and "remoted" elsewhere and here is where caution is needed - there are 4 very small wires from the motor to the box (2 white & 2 blue) these are hard wired and will have to be cut or de-soldered. Re-connecting the sequence is critical!! With the wires being so small and short and not having any experience with small wires I had problems here (this is where I messed up)

 

 

 

Not a lot of room in the area under the hood - I finally figured out how to get the ECU mounted.

 

There is hardly any visible alterations to the external appearance of the tractor - just under the steering wheel is a short section of the EPAS visible, and the gauge for the transmission oil temp will have to be removed but thats it.

 

 

The ease of the steering on the D now is incredible, with the tractor sitting unmoving on concrete is one finger, and driving it is --- well, again, incredible! Course I dont have a FEL or plow, etc but I feel like this mod would also drastically improve the steering also.

 

Am not familiar with the other big tractors enough to comment on this mod being possible but you guys sure ought to do a little research on it.

 

I have a 4x4 Mitsubishi with FEL and thats my next venture with this, it doesnt look promising to fitting on it but it didnt look possible on the D til I got to tinkering with it!!

 

edit to add a late suggestion--

When you get your EPAS and the controller box from Portugal set it up on the bench hooked to a battery to not only make sure it works, but also to get familiar with how to get a feel of what/how it it does. I didnt do this and I believe it would have benefited me a lot...

 

Edited December 13, 2016 by pacer

[Sarge 3,464]

Excellent post and I'm sure it will help others or at least get the gears rolling for ideas - I'm leaning towards doing something similar since I run heavy v-bar tires on the newly modified front axle/hubs/wheels I did for the D-180 . I'm leaning toward a different setup that does away with the Ross steering box . I had found an obscure post somewhere in which a guy removed a Ross off of his garden tractor and replaced it with an electric/hydraulic steering box . Very compact unit and looked like it will fit inside the D's frame rails and possibly work on the smaller long frames to get rid of the weak and wear-prone fan gear system . The only possible issue I see is a lack of alternator power when going this route with electric units - they can draw over 40 amps at 12v , would take a pretty hard toll on even a larger automotive battery and run the stator system at wide open capacity constantly . Even though they are a demand-only system and don't run constantly it may become a problem . I suppose some creative work could be done to fit a bigger alternator to the pto side of the engine but if you use all the pto options on these tractors there just isn't enough room for additional equipment . There are very tiny automotive alternators that can be easily adapted since they use internal regulators and still put out some pretty good current . Shaft sizes are faily easily adapted to whatever is needed for pulleys but the limited room to install one is the still the main road block to an upgrade .

 

Still can't find that post I had found through Google on the steering mod with the electric steering box . The Saturn setup is popular for a lot of 4X4's and other stuff already and the purpose built electronics adapter is a nice addition to boot .

 

I'm leaning towards the idea of using a small , low volume orbital steering valve like a lot of the rock crawlers are using on their crazy buggy builds . Those guys have been key to finding cheap alternatives to a standard steering box and adding hydraulic assist systems for a steering cylinder on the axle for more power and leverage when in the rocks and trying to turn the wheels with heavy offroad tires .For awhile many were using a very small JD orbital valve from the older 2-row combines and using that with a standard Saginaw pump worked quite well and I even got to drive one in a Samurai on the street once . One finger , even stopped on 38x14 soft mud tires -  no problem . I don't think the Sundstrand or Eaton pump systems would have enough volume to use that type of orbital valve but there are other small ones out there - it's just their price tag that makes it tough to try to build something with that cost involved . I'll keep working on it over the winter if time allows , maybe I can find something easily scavenged off another piece of equipment to keep the cost down . The Ross box is a weak link due to it's design but for the space it takes up it was a good idea at the time . I'd like something that could be made to work off the tractors existing hydraulic pump with a tee in the system's pressure side , a simple shaft and bearing that can bolt into the dash to fit the existing steering wheel and a small enough cylinder to make either the stock bell crank work or one that could be mounted to the frame below the engine . Want a clean solution that would not interfere with the tractor's accessories , pto's or lift system and make it even tougher to work on the tractor for repairs .

Tall order , but it shouldn't be impossible , pacer is off to a good start for sure .

 

Sarge

 

[roadapples 6,983]

Great thread Pacer and Sarge... You guys never cease to amaze...

[R. L. Addison 299]

My brother put a Rotary Cylinder (I think is what he called it) type on a "D" with a loader for his wife to use and hooked it into the Sundstrand unit with no negative effects. It was a replacement unit for the old I H tractors, the H's & M's that he bought at a farm supply store. Looks to me like this might be simpler & cheaper if still available.

[GT14 243]

Great idea and nice conversion.

[bmsgaffer 2,046]

Awesome!

 

Do the D series have an ammeter? Can you tell how much current it draws?