Wednesday, July 20, 2011

depowering the nissan steering rack

There are numerous guides online that show you how to 'depower' your steering rack. The 240sx, Miata and other forums are full of folks who rave about the increased road feel and the telepathic like connection to the road. My steering rack was covered in oil and had been leaking for years though it had not leaked much recently. That was good enough reason for me to give it a try. I'll give my impressions of the swap at the end of this post.




Put an oil pan under the steering rack to catch the spill and undo the electrical connection and the two hose connections from the steering gear.




Loosen the tie rod nut and smack the knuckle with a 5lb sledge to dislodge the tie rod without ruining the boot.



Use your cool guy extension as much as you can. Here it is loosening the steering column connection. It is a good idea to lock your steering wheel in the center position before starting all of this.




Remove the bracket attached to the firewall that holds the power steering hose that comes from the power steering pump.




Wiggle the power steering hose up and out into the engine compartment.




Disconnect the other power steering hose from the reservoir that goes toward the radiator.




Connect the two hoses using a hose clamp. This procedure is called 'looping' the power steering hoses. On the Axxess, the power steering pump is not easily removed as it is part of the serpentine belt system which is hard to modify. Instead, looping the lines like this keeps the lubricating power steering fluid circulating inside the pump so it doesn't seize.
It may be possible to remove the fluid reservoir and all the hoses and make a much smaller loop or even seal the pump outlets while keeping the pump full of fluid. Removing the small paddle shaped vanes inside the pump may also be an option. There are probably better solutions like a custom idler pulley to replace the power steering pump or making modifications that allow rerouting the serpentine belt to bypass the pump.




If you loop the lines as we did above, there would still be fluid and a piston inside the steering rack that would mask the connection to the road we are seeking. It would also increase resistance making the car very hard to turn, according to the forums at least.
So instead we will remove the rack and remove the piston inside, repack with grease and seal it.
Remove the brackets holding the rack to the firewall. You will need to go at this from multiple angles with multiple tools. Here is the 'wobbler' extension on 1/2" breaker bar in use. Again, that twist handle ratchet would really come in handy on this one. One more excuse and I'll have to buy one.




The manual says to mark the steering position on the gear. This is not super critical as it will need realignment anyways. As long as the wheel is locked in the center and the tires are pointing straight when reassembling, the rest can be made up at the tie rod adjustments, and will need to be anyway.




Pull that puppy out!




Cut the old rubber boots off and clean things up. The tie rod ends should not flop around easily but as long as they don't rattle around they should be serviceable. The tie rod end needs to come off but first the retainer clip will need to be drilled out where it is 'staked' in place, two times on each side. You will not hurt the threads with the drill so go crazy.




You'll need two big, thin wrenches to undo the tie rod end. A large crescent wrench is probably too wide. This is a 30mm and maybe a 22mm.




Undo the 3 weird bolts with a regular socket and remove the cover.




Remove the pinon gear observing the paper thin washers and their orientation.




Remove the adjusting nut and plunger, spring and washer noting their positions.




Reach in with some pliers and remove the black bushing that presses against the steering rack which keeps it from wobbling and provides resistance. You will need to readjust this when reassembling to have a very slight pressure against the steering rack. Don't over tighten the lock nut as it's difficult to loosen when installed.




The steering rack tube must now come apart and it is also staked in place like the tie rod ends. The drill was tried at first but it left too many burrs which made it impossible to unscrew. In the end a grinder with a cut off wheel was used to remove the whole area cleanly. Be careful though, the grinder leaves behind a deadly sharp sliver of steel just waitin' to cut ya'. A file is advised to smooth the area.




A large vise and a monkey wrench were used to twist this bad boy apart.




And here is the culprit, the inner piston seal that must be removed to allow access into the true manual steering club.




Grind that puppy most of the way through on 2 sides.




Then smack it with a BFH. Ahh the sweet sound of success.




Grease up the rack with your favorite lube, moly grease in my case. Use as much as you think you need then add a little more. Grease up the pinion too. Slap the whole assembly back together and center the rack by counting gear turns or using the measuring method from the manual.




The tie rod ends need to come off to get the new boots on. Here they are marked with the side and number of threads showing to help with realignment.




New, cheap dust boots with decent warranty. The boots are easy to swap by just removing the tie rod end.




The holes are sealed with some RTV.




And here it is ready to be re installed. Now may be a good time to get some new steering rack bushings as well.




So how did it work? In a word, crappy.

Needless to say, it was very difficult to turn at slow speeds, requiring grabbing the wheel by the inner edge and cranking it hand over hand. It was manageable in parking lots as long as the wheels were moving before turning the wheel..which takes up space making everything a 3 point turn. Fine in a parking lot but not when flippin' a bitch on a busy narrow road with a truck coming.
At speed the steering was pretty good and I was feeling the improved connection with the road. I was pushing the speeds higher on freeway ramps and really felt as if handling was improved but in reality, my overall cornering speeds were slower than with the power steering and they just felt faster as the car was so much harder to turn. I also lost some confidence in my cars steering ability when approaching high speed corners as I just didn't know how it would react.
The car really wants to recenter itself without the power steering. Taking a long tight corner or navigating a traffic circle becomes a two handed death grip trying to keep the car at full lock, fun, for a while. The adjustable plastic bushing that presses against the steering rack can ease this recentering at the cost of overall resistance. A fine balance with diminishing returns. 

I drove the car like this for a few weeks and decided it wasn't safe for me. It was clear to me that quick, unexpected emergency moves would be difficult or impossible depending on my grip on the wheel. I also determined that in the case of a blowout, especially on a front tire, that I would be unable to keep the car straight and away from other cars or obstacles.
Because of these reasons, I decided to swap back to the stock power steering. I found a Stanza steering rack at the junkyard for $12 which is the same as the Axxess, and it had no leaks, just torn boots.

I was very happy to have my power steering back and will not try that agin, at least in an Axxess. I also own two rear engine cars that have manual steering and they are fine. I can imagine a RWD Miata or 240sx could benefit from depowering the rack in certain situations and i've even heard some Hondas and other FWD guys who love (or say they love) their depowered racks. Maybe it's just me or maybe the Axxess is just not the best candidate for this mod, maybe I'll try a turbo instead.

2 comments:

  1. Nice post. I appreciate your post. Thanks for sharing...


    Nissan 240sx

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  2. One of the most difficult things to design and build on a car is the steering mechanism. The steering mechanism is used to turn the car around the bends in the track. There are many different ways in which this can be done.Nissan cars come always with great reviews.Thanks for share this good one.
    Steering Rack

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