​Adding Electric Power Assist Steering (EPAS) to An Ascona A wagon

This article will document the installation of Electric Power Assisted Steering (EPAS) into my 1972 Opel Ascona wagon.

The EPAS:

I purchased an EPAS from a 2007 Saturn Vue for a local yard for $50.

This unit requires an input from a sensor on the wheel to determine the amount of assist needed. There are several aftermarket controllers available to workaround the speed sensor. I ordered one on eBay from bruno_steering .

epowersteering sells complete kits and components for this conversion. Their accessories page include couplers and other components.

Connecting the EPS unit to the Opel steering column

Here is the Saturn EPS next to the Opel steering column. The splines on the EPS are 3/4-36 on the steering wheel side and 16.5mm-36 on the rack side.

Wheel side connection: I will be going back to the yard and pick up the upper column to use those components for connecting the wheel side. That will give me more flexibility for this mod.

Rack side connection: An epowersteering coupler connected to the lower Opel shaft. Keeping the collapsible shaft may be a challenge.

Under dash: The lower left side of the dash will need to be trimmed and a quick measurement shows that the EPS motor will be able to be rotated up under the dash. The biggest challenge will be making a mounting bracket to support the EPS and keep it from rotating.

11/07/19 Update

Picked up the upper Vue steering column. It came complete with the air bag. I can probably sell the extra parts of of it and recover most of my costs!

The column has a tilt mechanism. Might be worth a look to see if that can be used.

I found a nice leather Momo steering wheel and adapter in my parts stash. It will be replacing the Manta B wheel that is in there now.

The controller module arrived today and the other components will be here in 2 days.

11/09/19 Update

The 16-5 mm-36 to 3/4 smooth coupler for the rack side arrived today. Picked up a 3/4" wooden dowel to use to determine the length of the output shaft.

Stripped down the Vue column and saved the input support and shaft. The input shaft is important as the Vue is tilt adjustable and the length of that shaft and the long spline on the EPS allows for flexibility in setting the steering wheel location. The support and Opel column cover have the same O.D.

Also removed the Opel column and dash. This gives me the chance to clean up some of the wiring that was just tucked behind the dash and see about EPS motor clearance before trimming the dash.

11/13/19 Update

I used a 3/4 inch wood dowel attached to the lower column coupler to locate the EPS motor's position.

A bracket was fabbed using a 6 inch wide piece of 1/8 sheet stock. That piece was heated and bent to an angle that centered the dowel in the hole in the floor.

Using this setup, I was able to determine that there is enough clearance for the EPS with the motor placed at around the 10:00 position. The EPS front mounting tabs location was transferred over to the bracket and the EPS bolted in place.

With the EPS in this position, its ECU was in a 6:00 position and could interfere with brake and clutch operation.

I relocated it to a location on the firewall above the fuse box.

The ECU used the EPS assembly to dissipate heat so a 2" x 3 1/2" heat sink will be placed on the top of the unit.

The collapsible portion of the lower column was retained and the length determined using the wood dowel.

Installation complete. Here's a Video.