Instead, a torque sensor tells an electric motor to turn the wheels when the steering wheel is used. The idea is improved fuel economy, as the steering is not a constant drain on the engine's power.
Personally, I think Honda's EPS feels unnatural. From personal experience (before following excellent advice to spray a little lubricant in the torque sensor area), it can be notchy and reluctant to return to centre. At the time of writing, an innocuous google search for "honda civic eps" brings up more complaint than high praise - click the thumbnail to zoom in.
Poor lubrication can result in noise in the EPS rack when steering, stress on the electric motor, wear, and big headaches and bills. There are guides to replacing the rack once it's worn, but I'm not comfortable extracting the entire rack from the engine bay, or resetting electronics or tracking. I'd rather regrease the EPS in situ as much as possible while my steering is still fine, as a preventative measure.
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To give a short overview of what this involved, I lubricated as much of the rack sliding surface as possible by first pulling back the rubber accordion gaiters on either side of the EPS slider, and shoving grease in there. To get access to the rubber gaiters, I first removed the resonator box and airbox from the engine bay; to pull back the rubber gaiters, their steel retaining clips needed to be cut off.
- an 8mm socket (for removing the airbox).
- a 10mm socket (for removing the resonator box and airbox).
- socket set extender (for an awkwardly placed resonator box bolt).
- axle stands (for raising the wheels off the ground; moving the steering wheel side to side helped with distributing the grease evenly).
- a small set of cutters, to remove the original retaining clips (bellows bands).
- a small crimping tool (to fit new bellows bands to the rubber gaiters).
- A new driver's side bellows band ("Band A"), Honda part number 53449S5AJ01.
- A new passenger's side bellows band ("Band B"), Honda part number 53448S5AJ01. This has a larger diameter than the driver's side. £8 for the pair at a dealership; why so expensive? More on these bands below.
- General purpose grease, despite the rubber gaiters. Honda make a dedicated power steering grease - part number 08C35-B0534L - but the shop manual specifies normal multipurpose grease during overhaul of the EPS rack:
I found it a great help to have the front wheels off the ground, so that they could be easily steered with the engine off:
Attempt nothing without gloves!
I've never come across these "bellows bands" before. Judging by the old ones, after fitting, the only way to remove them is to cut them off, so they are single-use. The raised area seems designed to prevent you cutting into the rubber gaiter by accident. When fitting the new bellows bands, I crimped the raised area in the same fashion as the old ones had been; this tightens the band securely.
In the photo below, the tabs circled in green slot into the holes circled in red. Then the raised area, circled in blue, is crimped tight. To later remove, the raised area is cut, releasing the band.
Following this introduction,I've split the EPS regrease photographs into stages:
- Removing the resonator box (only four 10mm bolts to unscrew)
- Removing the airbox (only two captive 10mm bolts to loosen, a hidden 8mm bolt to loosen, and an electrical socket to unplug)
- Regreasing the rack sliding surfaces at either side of the EPS slider guide
See you in the next one, have a good time.