eps steering rack.... delvin into the deep!

[britlude]

as it was a pleasant day i got a chance swap in the steering rack....

! started at about 10:15....
IMG_20190330_101753 by jon sutherland, on Flickr

once i had the car on the front axle stands, i fashioned a simple tracking gauge to mark the current alignment (a laser pointer taped to a stick that sat against the front wheel edges, and put a dot on a bit of tape stuck on the rear wheel, when marked, this gave me a reference to get everything basically in the right place with the new/old rack!)....i also marked the input shaft and seal to show me where the exact centre point is!

.....and an hour later....

IMG_20190330_111942 by jon sutherland, on Flickr

and another hour and a half it was all back together....

pleased to say it's all working as it should, no play, slack spots, tight spots, or anything else untoward! took it out for a test drive, wary of the 'won't self-centre' scare comments, and all was well, no knocks or unusual noises!

so, if you have any of the mechanical symptoms, they are, touch wood, cureable, as they are essentially a basic mechanical system that's just bearings and gears!!

[britlude]

update, now its been in a week....

when i put it together, i set the preload clamp bolt ( the one that presses the rack onto the input shaft) as per the honda service manual instructions, tighten to 4nM, release, do it again, back off 20 degrees and tighten the lock nut.

the weight on the input shaft was then checked as per manual at 3Kg at 100mm lever length (ie. gently clamp on some grips on to the input shaft, measure out 100mm from shaft and pull at that point with a spring balance...) so i double checked it was about that, it was, and fitted it all in....

if this is how it's supposed to be, then no wonder auto cars get a bad press with 'dull' steering.... it's like driving in treacle.... yes it all does what it's supposed to but its heavy going.... i expected it to be tighter, as there's more drag on the shiny new motor bearings, but the motor assist will offset that...so a bit more investigation....

the eps rack, according to the service manual is set to a load of 3kg on the 100mm lever....
the manual rack is set, according to the book, at 1.5kg... so it's half the turning force when there's nothing connected to start with!

i then checked the rack i removed, which was comparable to the original rack when i swapped it in..... 0.7kg!!! no wonder Sarah thought it was really light when she drove it!

fortunately the rack clamp bolt is easily accessible under the car, so a quick jack up, back off the lock nut, do the double torque up, and back it off about 40 degrees, check there's no play or issues, there's not, so all back together... i did a spring balance check on the steering wheel before and after, and i suspect i'm closer to 2kg/100mm now, not as loose as the manual rack, so splitting the difference!

the result, much nicer

so, lost the knock going over bumps, the other rack had a small dead point when you rocked the steering (probably a combination of the torque sense mechanism getting sticky and play in the ball screw mount as well and hence this whole investigation) so obviously lost that, and lost a 'knock' from the input shaft every 360 degrees (probably that loose plastic gear related)

so that's the steering rack sorted!

...and i've got the one i took out to go through too..... at my leisure!!

[Heineken]

All thumbs up for the work, I'm truly, truly impressed!

PS: My rack got serviced at KSP when the car was still in Japan (google translator version of their procedure here).

[pralognan]

I'm also impressed and want to thank you for sharing this with us. Can I ask for comment on my power steering?
Its a 1991 UK car,all original. When I bought it I thought the steering was heavy when cornering at moderate speeds,but felt fine whilst parking. I read an old 1991 Motor Sport road test,"The steering felt light and deft whilst parking but any kind of cornering effort felt so heavy that we thought the power steering had failed. Over a thousand miles it became less disconcerting....."
Car magazine in 1997 said that "at speeds of more than 87mph assistance is virtually nil"
Has anyone else had similar experience and is there any adjustment possible?

[Pride]

I'm also impressed and want to thank you for sharing this with us. Can I ask for comment on my power steering?
Its a 1991 UK car,all original. When I bought it I thought the steering was heavy when cornering at moderate speeds,but felt fine whilst parking. I read an old 1991 Motor Sport road test,"The steering felt light and deft whilst parking but any kind of cornering effort felt so heavy that we thought the power steering had failed. Over a thousand miles it became less disconcerting....."
Car magazine in 1997 said that "at speeds of more than 87mph assistance is virtually nil"
Has anyone else had similar experience and is there any adjustment possible?

If your car is a totally original 91 manual transmission NA1 then you DON'T have power steering.
Electric power steering was only fitted to auto transmission models but from 1995 all NSX's except R's were fitted with it.
Hope this helps.

[RedCarsGoFaster]

If your car is a totally original 91 manual transmission NA1 then you DON'T have power steering.
Electric power steering was only fitted to auto transmission models but from 1995 all NSX's except R's were fitted with it.
Hope this helps.

IIRC the 1991 Motor Sport review was of an auto; the 1997 car reviewed by Car magazine would have had EPS. If you do have a 1991 manual, these comments are not applicable to your car.

However, if you do have a 1991 auto and therefore have EPS, that experience sounds normal.

The steering is set up to have more assistance the slower you go. As such parking is easy, but yes, steering loads will increase significantly at higher speeds.

I've seen several different speeds quoted for the point at which assistance is effectively switched off and I'm not sure which of them to trust. My car (1995 manual - see above) certainly feels like assistance switches off a long way below 87!

As regards tuneability of assistance, no idea. Per the OP's adventures there is some tweakability, but adjusting the speed at which the assist comes in and out sounds like a different challenge.

[pralognan]

Thanks for your responses. Yes my car is automatic,so I tend to follow Britlude's adventures.

[NZNick]

If your car is a totally original 91 manual transmission NA1 then you DON'T have power steering.
Electric power steering was only fitted to auto transmission models but from 1995 all NSX's except R's were fitted with it.
Hope this helps.

Not quite true Clive - your statement applies to UK cars, but not to JDM, as EPAS became an option from the introduction of the NA2 with C32B engine. All Type T (targa roof panel) cars (& all NA1 automatics) have the EPAS, but coupes (excluding the Type R & S Zero) could specify it and most did.

[philboo]

Not had much time to read the forum or even get out in my car this year but reading this I love the skill and enthusiasm of the members here to fix and share their knowledge. Thank you for the time taken to share this. Thumbs up