DIY Electric Power Steering (1 Viewer)

[SteveH]

My minitruck PS delivers decent road feel, and some Saginaw setups I have driven do not (they seem grossly overboosted).

Any comments on road feel with the EPS, both on-center and off center? Many regular cars with EPS are criticized for crummy road feel, and I wondered how this compared. I know that we're dealing with FJ40s, but road feel is nice to have.

 

[x463]

@powthief19 - I'll try to find time this weekend to measure my setup.

@SteveH - depends on the boost level which is controlled with a rheostat control. I have mine set at maybe 1/3 boost - not numb at all. You can turn the system completely off as well. At full boost - pretty numb. You can spin the wheels lock-2-lock sitting still with 1 finger.

It's been almost a year with the system and no regrets.

 

[myquestoyota]

I just ordered the kit from Ken, what a stud. Thanks for the info guys.

 

[DieselFJ]

Thanks for sharing, I'm about to embark on this adventure myself. Would you mind sharing some rough dimensions on the length of your fabricated outer pieces? Looking for somewhat of a reference/gut check number to compare to.

Cheers, Chris

Chris, sorry I just ran across this thread again and noticed you needed some measurements. Did you still need those numbers?

Scott

 

[myquestoyota]

I'd like some measurements if you get around to it. Thanks

 

[x463]

Sorry about the lack of measurements...there isn't much I can measure without disassembly. The lower tube is obscured by the shaft collar I used (which I would do differently next time). The upper tube is covered partly by the plastic surrounding the upper column. I also noted in my 1st post I'd change the positioning of the EPS slightly and I made the overall length of my column slightly shorter (intentionally) past the EPS unit just for my comfort/ergonomics - I wanted the wheel slightly closer to the dash. I have measurements on paper somewhere....but can't find them. I can post when I do for reference but would hate for somebody to duplicate and have problems b/c there are various factors in play. Having built exactly ONE of these for a Dec/78 build date I can't vouch for my measurements working on other years of FJ40s nor on all EPS units.

It isn't hard to figure out yourself though.

Step 1 - prepare the EPS. Cut off the upper shaft and weld on a new splined end that Ken supplies. Measure the new length of the modified EPS unit and figure out the positioning of the EPS unit under the dash with the now modified EPS. The EPS units Ken supplies might have a standard length - check with Ken. Since I built mine it all depends on the cut/weld of the upper fitting.....EVERYTHING is based off this step!!!! (I may be exaggerating here as it is the upper part of the EPS that is modified - but I have no idea if all donor EPS units are identical in size, length, etc. It's possible that the lower shaft could be a "known" length applicable to other builds.)

Step 2 - once the EPS is modified - determine the length of the lower inner shaft measuring from where the EPS will mount to the steering box. You'll want it as close to the dash as possible. Start a little long and don't weld the fitting on the cut lower shaft yet. You can then tweak as needed by bolting the cut lower shaft back on the box and checking the EPS position - trimming the lower shaft little by little as needed. Pay attention to the brake pedal arm - this is where I had some minor clearance issues and would adjust slightly next time.

Step 3 - the upper shaft is then a math problem. Original TOTAL length - minus the length of the EPS - minus the length of the lower shaft you just figured out. I went slightly shorter with the upper shaft b/c I wanted the wheel a little closer to the dash.

Step 4 - The outer tubes are then just simple measurements once you have the other two shafts figured out (simplest way - you could do it via math as well but easier to measure). Assemble in the car and measure. For lower - distance from lower EPS to firewall. For upper distance from upper EPS to ignition housing. Pay attention to how the ends are "clocked" on the upper tube. I'd suggest using a sheet metal screw or tacking in place installed in the truck before doing the final welding on that upper tube.

 

[myquestoyota]

I am about to embark on this adventure on my '77 and will try hard to get some measurements and pictures as I go for posterity and the greater good that is this forum. My question is: Should I start a new thread or add it to this one?

 

[x463]

Should I start a new thread or add it to this one?

Makes sense putting it here IMHO. Not a lot of information out there and putting it all together with improvements or other ways of doing it makes easier to find.

 

[Shark56]

I'm currently working on a EPS install on my 74 with Fiberglass tub. I won't add any measurement's since the fiberglass tub's measurements are no where near a stock tub. Basically a one-off job.

First pic. is of the shafts parts bought from Epowersteering and the shaft I cut off the motor. It was cut right where the splines end.


The piece on the right is the pin that is inserted into the shaft after cutting. The center is the the spline that gets welded on pin,
the left is the mount that gets welded onto your steering shaft.

 

[Shark56]

Here is a pic of the upper parts welded. Like x463 says. Measure and re-measure, then measure again. Included is a picture of the shaft cover also. Direguard the ugly welds.They will be covered..

I made the plate that mounts to the EPS unit. This is on the steering wheel side shaft cover. I bolted it to the EPS the mounted the EPS on the dash with the steering column mount. Then I was able to get the measurement for the upper shaft and for the shaft cover. I was also able to get a rough measurement for the rag joint end.

This is the rag joint end part. 3/4 x 36 spline adapter.

 

[Shark56]

Picture of the rag joint side.

Once I had the upper shaft and rag joint shaft connections welded, I mounted the EPS to the shafts and mounted the unit in the truck with out the shaft covers. I was then able to get the measurements for the shaft covers. I used muffler pieces, slotted to get a little tighter fit. The 2 inch I.D. x 1 3/4 O.D. was a little loose on the stock shaft cover. I slotted this piece four times. When I welded it up I used a band clamp to get it tight on the shaft cover. For the upper side, I used a 1/1/2 inch I.D. x 1 3/4 O.D. adapter. The 1 3/4 end fits perfectly on the EPS. The 1 1/2 end fits better on the upper shaft cover but I still needed to slot it twice. I drilled a 1 3/4 hole in the plate I made to mount the column to the EPS.

 

[Shark56]

I ended up cutting off the main mount that would be used on the Saturn Vue or what ever vehicle. I was afraid it would cause interference with the brake arm when mounted. I ended up have to grind the brake arm a little anyway. I'm not sure if this would be needed on a stock body. Some have had too. some haven't.

Yeah I nicked the power wire a little. Just the cover though! I will be fixing that tomorrow when I work on the wiring for this unit.

 

[Shark56]

I will be working on this some more this weekend. Cleaning welds, sanding, painting ect.. I will get some more pictures up tomorrow.
I'm also starting to get parts together for a Saginaw install on my 1970. I'm certain that is going to be easier than this EPS setup.
A lot less measuring and thinking and more measuring and measuring again!
I was fortunate enough to have a spare column from an old parts truck so if i screwed up on measurements I had a back-up. I still wanted to get it right the first time. Before completely finishing it I plan on mounting it and cranking on the steering wheel with out the unit on to test the welds.
Thanks to X463 on starting this thread with his EPS build!

 

[myquestoyota]

How do you attach the ECU to anything? I see two threaded holes in the back of it, the back is not flat. I know I'll come up with something but a bit puzzled just looking at it. Thought it might have ears on it.

 

[Shark56]

I bought my EPS off ebay. I'm going to leave the Ecu box attached to the motor unit for now.
On my mock up mounting it is very visible but does not obstruct pedal usage at all.
Some where I saw where they mounted it where the trucks Ecu is mounted. Pretty slick but only for de-smog type stuff.

 

[x463]

I cut off those mounting "ears" on my EPS as well. I also remote mounted the ECU - but honestly don't know if it is worth the hassle. You have to be VERY careful extending the wires - which are very thin and fragile. There also isn't a great place to put it - at least not in a 78 w/ all the SMOG stuff intact. Mine is to the right of the radio above the plastic fresh air duct - not easy to secure.

I'm not sure you have enough penetration on your welds? Are you using MIG or TIG?

 

[Shark56]

(I'm not sure you have enough penetration on your welds? Are you using MIG or TIG?)

MIG. Some are two passes. I checked the welds today by turning the tires lock to lock several times on asphalt without the EPS on.
Nothing moved around. Not sure of any other way to test the welds.
Took truck for a test drive. Everything worked great. Definitely different driving with the power steering. I like it. About 1/3 on the adjustment feels about right for me also. Half way will easily turn 33 x 12.50 AT's on asphalt with a finger.

On final mounting I turn the unit just a little more clock wise, having the ECU box parallel to dash instead of the round motor. There is a little more than an inch clearance between the motor an the fuse block.

 

[Shark56]

My cost for this is around $325. That's not counting the time and welding material. I got the unit off Ebay, $125 shipped. Rest of the parts I got from Epowersteering.

 

[Rivalduke]

Been following this thread with interest. I am doing a DIY system but fitting the eps unit the engine side of the firewall ( there is just enough room ) . I will try and get some pics up the next week or so.
Modified column / modified bulkhead flange / modified steering coupler .
Looks stock from the cab side.

Cheers Andrew

 

[myquestoyota]

Interested to see how that works.