Steering: Electric Power Assisted Steering (EPAS) - consider all the factors

[PackardV8]

Yes, EPAS is being used in almost every current production car, so incorporating it into the steering column is a means of getting rid of the impossibly clunky Bendix PS units Studebaker used '57-'66, or to add PS to a non-PS Studebaker; EPAS conversions in Studes are becoming more common and we're seeing some problems arise, along with the benefits.

We've seen several conversions which worked as advertised and produced the desired results. However, there are factors to consider:

1. Studebaker steering gear boxes, especially the smaller Ross units, were not very strong when new; sixty years and many miles have taken their toll. We saw one K-body conversion where the shop the owner paid to install the EPAS either didn't notice or ignored that the gear box was worn out, to the point the output shaft would move vertically 1/4" and the seal wouldn't hold lubricant. The EPAS worked fine, but the steering gear box soon failed.

2. Modern wide radial tires can put too much strain on the old gearboxes. One owner, proud of his EPAS conversion, used the now-easy steering as license to install 7"-wide wheels and wide radial tires. Too much force at the steering wheel and too much resistance at the tires shredded the internals of the steering gear box.

3. The Studebaker frame may not be strong enough to handle the forces. Again, the force the EPAS can apply to the input of the steering gear box and the resistance of wide low profile radial tires is beyond what the frame was designed to bear. A '50s C-cab, again with wide passenger car radials, was twisting the frame rails where the steering gear mounted. It was a race as to whether the steering box or the frame would fail first. We welded the K-member to the left side rails and fish-plated the gearbox mounting area.

Bottom line, always begin with a rebuilt steering gear box. We prefer the later Saginaw box as the one to use. Consider reinforcing the gearbox mounting point of the frame rail. And finally, drive it like it doesn't have PS; at every possible opportunity, have the vehicle moving before turning the steering wheel.

For the good of the order, please continue the feedback here on your EPAS experience; what worked and what you'd do differently.

jack vines

[clarkwd]

I have installed a Toyota EPS unit in a 53 with radials and Ranger wheels. The combination of the radials and the offset makes for a better handling car and improved stance. It does however add to the steering box input torque required to turn. I totally agree with point 1. Don't try to do the EPS with a worn out box. On points 2 and 3, the force into the box to turn the wheels in exactly the same with or without the EPS unit. The EPS unit is just helping to turn the steering shaft. The difference is without the EPS unit, you might not want to grunt enough to turn the steering wheel, but the EPS unit is gonna turn it anyway. Not just the box, but all the front end should be in good shape before adding the EPS unit.
In order to try to have more centering, I reworked the A frame locations and have 4 to 5 degrees of positive caster. I screwed up and used a Ross box. Even with the extra caster, the wheel does not center after a turn. I have not tried it, but I expect the centering might be better with a Saginaw box, or better yet the Saginaw box from a late model Lark with a lower ratio. Other than the box, I'm OK with what I did. The Toyota unit was about $50 from a local U-Pick-It and I had all the shaft welding done by a professional. The steering jacket changes took some trial and error, but I ended up with the stock steering wheel and made the signal lights and horn all work. I'd like to find a late model Lark box.

[6hk71400]

One of our chapter members 30+ years ago put a Vega steering box on his 56 Transtar. One of other members due to a right shoulder injury just ordered a new Vega steering box and installed it on his 59 Deluxe truck.

I know this is off topic but I am curious it the box is an alternative to a possible expensive change to the system. I just got our newsletter with an article on the swap with pictures. If anyone is interested I can post the article and if someone thinks this should be posted as a new topic let me know

[r1lark]

Yes, off topic from Jack's intent with this thread for sure!

[Simonjohnwilmer]

Id be very interested to see also

[yeroldad]

Yes, I'd like to see the article and pics. I'm sure others would also. New topic would be good.

[DEEPNHOCK]

(opinion)

EPAS does nothing to change the forces applied to the steering box, or the frame, or the suspension.
What EPAS will do is 'possibly' change the initial rate of rotation speed of input to the steering box input shaft.
But even that is minuscule, but understandable, due to the difference between human torque applied to the input shaft (steering column), and the torque being applied 'faster' due to an electric motor being used.

Agreed that the steering box needs to be in good condition when EPAS is installed, but that condition should always be maintained, or repaired irrespective of power, or no power steering..

EPAS is not a band-aid for a troubled, poorly maintained, or neglected steering gear SYSTEM.
EPAS does put an additional electrical load on your electrical supply SYSTEM.
Adding EPAS to a generator, or even a 'stock' alternator equipped car will strain it quite a bit.
The amps required to operate the EPAS motor are quite large.

My last experience installing a new EPAS system was on a Transtar pickup.
In my opinion, this was the perfect application of an EPAS.
No crazy modifications to the beam axle, reach rods, or steering box were required (other than shortening the seeing column shaft).
Many happy miles driven several years after the install.
That install was not for the timid or inexperienced. It was done with the engine out, which made steering gear/colum access easier.
Mounting the EPAS unit was not a simple bolt in. The torque support strap placement was tricky inside the cab under the dash.

I liked the EPAS experience. But it was not 'simple' and if one has to pay for the installation, then the actual costs need to be discussed and agreed to well ahead of time.

Measure twice, cut once....
Jeff

[PackardV8]

(opinion)EPAS does nothing to change the forces applied to the steering box, or the frame, or the suspension.

Agree, Jeff; none of the forces change. What does change is with an EPAS installation there is then no feedback as to how much the tires are resisting being steered. With the old manual box, one always recognizes from the force required at the steering wheel, it's better to have the vehicle moving slightly to assist the process and/or how much wide tires affect the effort required.

In the two instances I mentioned, the owners installed wide tires and then thought they could just crank lock to lock, because it was so easy.

jack vines

[JoeHall]

Sounds like wide tires aren't a good match with EPAS.

[Jeffry Cassel]

One thing that worries me is that when the electrical system fails (and don't say that never happens!) and you have electric steering , the steering must fail. We have a UV with electric power steering and it is nice, But it has always had this habit of sudden electrical failure. Just goes dead. Stops cold. And the steering stops too. I've never had this happen in a Studebaker but I have had it happen in a Ford. I've always liked the PS on 56-7 -8 Studebakers and have never (knock on wood ) had any trouble with them The later ones with 17 hoses running this way and that, were a poor replacement. But if you can EVER get them to stop leaking, they are fairly reliable ,also. I've never felt big fat wide radial tires were a very smart idea. And they are really ugly.

[r1lark]

One thing that worries me is that when the electrical system fails (and don't say that never happens!) and you have electric steering , the steering must fail. We have a UV with electric power steering and it is nice, But it has always had this habit of sudden electrical failure. Just goes dead. Stops cold. And the steering stops too. I've never had this happen in a Studebaker but I have had it happen in a Ford. I've always liked the PS on 56-7 -8 Studebakers and have never (knock on wood ) had any trouble with them The later ones with 17 hoses running this way and that, were a poor replacement. But if you can EVER get them to stop leaking, they are fairly reliable ,also. I've never felt big fat wide radial tires were a very smart idea. And they are really ugly.

So Jeffrey, are you saying when the power going to the EPS is taken away, the steering locks up and the steering wheel cannot be moved at all?

[4NStudy]

So Jeffrey, are you saying when the power going to the EPS is taken away, the steering locks up and the steering wheel cannot be moved at all?

I can't speak for anyone else; in my case if there is no power to the EPAS it simply behaves like a normal manual system. An EPAS should not make your steering inoperable

[Jeffry Cassel]

I was pretty sure that was the case. But, in hydraulic failure in some commercial aircraft the default position of the elevator is full downward deflection. Lost ps in our old Chevy truck and it was a real challenge to steer that thing. UV doesn't lock up but it does get real hard to steer. (Just because you can do something doesn't necessarily mean you should.) (Silly Americans tend to attribute competence to engineers and architects. ) Think "Space Shuttle" They were both lost to incredible, mind numbing, incompetence. Concorde- they failed to consider FOD! Battleship "Maine" (coal bunker adjacent to munitions. ) There are a million cases of people injured or killed by engineers and architects.