Volvo EPAS Conversion

[PetroleumJunkie412]

After the Trail Ride, I realized with the encouragement of @AgPete139 , @Jim Oaks and @bobbywalter that I really need to get this article finished. Posting the incomplete version for review. Want to get it finished up over the next few days. AgPete and @lil_Blue_Ford drove it. They can report the difference in road feel for those that are curious.


Volvo EPAS Power Steering Conversion
Original Poster: PetroleumJunkie412

Difficulty: 4 out of 10

Time to install: 4 – 6 hours, depending on amount of stuff you’ll need to relocate

Disclaimer: The Ranger Station.com, The Ranger Station.com Staff, nor the original poster are responsible for you doing this modification to your vehicle. By doing this modification and following this how-to you, the installer, take full responsibility if anything is damaged or messed up. If you have questions, feel free to PM the original poster or ask in the appropriate section of The Ranger Station.com forums.

Brief Explanation: The Volvo EPAS (Electric Power Assisted Steering) pump is a hydraulic pump built by Ford and used to remotely run the hydraulic power steering in some Volvo models.

It is a microcontroller controlled hydraulic pump that produces somewhere in the neighborhood of 1700 psi and 4.4 gpm on 12 volts and 7-79 amps, depending on amount of pressure called for/load. In some of the models that the pump is installed in, the driver has the ability to manually set the pump rates based on preference, and in others the ECM sends CANBUS commands to adjust the pump pressure based on road speed. This adjustment gives the driver more or less resistance to their steering and thereby increases or decreases ‘road feel.’

For the purposes of adapting the system to an RBV, we will be using the pump in standalone mode. If you’re a CANBUS wizard, I’m certain you can gain full control of the EPAS unit; I'm still experimenting with this one. When wired correctly, the microcontroller in the pump will enter ‘limp’ mode at startup and base its output on load. In ‘limp’ mode, the EPAS pump will run at approximately 70%-80% of its maximum capacity, and flow a constant volume based on detected load. Pump pressures will increase according to resistance, and volume will stay the same.

You will be using your stock power steering box for this mod, and deleting (or removing, as I did) your power steering pump from your accessory drive.

All of this translates to CRAZY AWESOME UNICORN POWER STEERING THAT FREES UP POWER AND MAKES YOUR RBV FEEL LIKE A FIGHTER JET MADE OF BICPES.

In reality, it makes your steering feel firm and controlled. I can now run comfortably at highway speeds in excess of 75 mph in a first gen with 235/75/R15 tires, worn out bushings and ball joints, etc. Wind gusts caused by tractor trailers no longer affect control of my vehicle, nor do potholes, heavy winds, etc. The steering senses fast, jerky movements and cuts power to the assistance due to sensed ‘unsafe’ conditions, allowing the vehicle to maintain its course. It only responds to slower, controlled movements. Additionally, for the off-road crowd, the pump will use your battery as a power reservoir instead of your accessory drive. This means that your battery will supply power to the pump, and that you will not lose power and stall when turning against obstacles. Since the pump draws power from your battery, the charging system will gradually replenish your battery, and your steering will operate with much greater power when the engine is at low RPM. Like I said, crazy awesome unicorn power steering.

Most Volvo cars build from 2005-2009 will have this pump located in the lower portion of the front bumper. An incomplete list includes:

VOLVO	C30	2008-2013
VOLVO	C70	2006-2013
VOLVO	S40	2005-2011
VOLVO	V50	2005-2011

Mazda 3 also uses an EPAS pump, but not the same one, as well as Mini Cooper S, and a few others. Best way to locate them is through rock auto by using part numbers, and other automotive forums. I learned this mod from the Fox Body guys and DIY Electric Vehicle crowd. I attached some links for further reading.

Some important notes about pulling them from junkyards like I did:

Make sure when you pull yours, that you get the COMPLETE pump. This includes the mounting bracket, hose, and a length of the wiring harness with pigtail connectors. I would cut at least 6-12” of harness with both pigtail connectors out of the donor. Additionally, I would recommend at the very least cutting the rubber portions of the hose and retain the undamaged metal ends. This will allow for much easier conversion. More on that below.

Tools Needed:
- Drill and bits
- Wrenches and sockets
- Soldering iron, solder, and heat shrink

Parts Needed:

- Volvo EPAS pump, pigtails, and hose end
- Wiring connectors
- You will need to have a custom hydraulic hose made for the pump. Mine was $90. I did not mind spending this as I sourced my pump for $14 from the U-Pull it yard

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Steps 1:

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Steps 2:

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Steps 3:

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[Jim Oaks]

I really want to do this. I'm tired of my truck sounding like a sick cow every time I turn the wheel.

 

[Dirtman]

I really want to do this. I'm tired of my truck sounding like a sick cow every time I turn the wheel.

Then how would you know you're driving a Ford?

 

[Dsetz]

Yeah, excited for this article. Seems much easier than modifying the steering shaft(as in other electric steering mods). Awesome contribution!!!

 

[fastpakr]

How would this keep you from modifying a steering shaft?

 

[PetroleumJunkie412]

How would this keep you from modifying a steering shaft?

It's plug and play. Hook the Volvo pump to the Ford box, wire it in, and you're done. Even the Volvo and Ford hoses are the same thread.

 

[fastpakr]

Wasn't questioning that, just referring to dsetz's question.

 

[adsm08]

I wonder if I could use one of these on my tractor. I need a manual diverter valve that can switch the direction of the flow.

 

[PetroleumJunkie412]

I wonder if I could use one of these on my tractor. I need a manual diverter valve that can switch the direction of the flow.

I honestly can't see why not. As long as you use a deep cycle, you'll be fine.

 

[bobbywalter]

shit...it would have took me 3 months to write that...


thanks for knocking it out. great work!.

 

[SenorNoob]

For curiosity's sake, how would this work powering steering and say hydroboost?

Obviously as it varied so would the brake assist, but how much?

 

[tinman_72]

Is it just me or is there no write-up. I only see Steps 1:, Steps 2, and Steps 3.

 

[Dsetz]

It's a placeholder for him to finish it. When he does it will go up as a tech article.

 

[Jim Oaks]

I priced one of these pumps new on Rock Auto. $199.00.

 

[BlackBII]

This is interesting and a good alternative to using an inline electric power assist motor in case you want to keep hydraulic assisted steering. Can't wait for the article to be finished.