P/S Tie Rod Adjustments

[DSM90AWD]

When I originally installed my P/S rack I didn't have it completely centered and have re/re it a couple times now and it's still not centered (it's very close now.. but going right 1.5 turns and left has 1.30 turns). Stupid me returned the core before I could match them up

I'm taking it in for an alignment tomorrow so was wondering if I could just pull the steering wheel and re-install a couple degrees to the left so when they adjust the tie rods the travel would even out? I've done this once before and seemed to work... but don't know if this screws up anything else in the process (i.e limiting the range of the rack itself)

Also.. (if anyone has checked recently) how many threads are exposed on the tie rod on each side? Are they even on both sides?

Thanks!

 

[DE91TSI]

Whats up man just checkin the board on my day off. If you have the rack pretty much on center dont worry about it we can staighten out the wheel for you they do that on evey alignment anyway.

 

[DSM90AWD]

Actually the wheel is centered now.. but the turns lock-to-lock are uneven left-to-right.
If the tech sets the wheel a few degrees left and does the alignment.. that should even it out.. I could then re/re the steering wheel so it is correctly centered.

 

[giester2]

The alignment will help to make the turns even. An alignment will not affect the total turns of the rack. On your car you can always remove the coupling, center your steering wheel, and then reattach the coupling (and like the guy said some alignment shops do that anyway).

As far as how many threads should be showing on the inner tie rods....it varies from vehicle to vehicle but they should be almost equal on both side (within 1-4 threads or turns)

 

[turbotoad]

You should take some measurements of the actual steering rack components instead of a lock-to-lock estimate. Measure the distance from the center of the outer tie-rod pivot/ball-joint to the center of the inner tie-rod pivot/joint. These measurements should be VERY close to identical on both side of the vehicle. Like Geister2 said, the tie-rods should show nearly the same amount of threads on both sides.

If the measured distances are uneven your rack is not centered and can cause handling issues even if the alignment is dead nuts perfect. This is because now your tie-rods ends are traveling along different arcs as the suspension compresses/rebounds. Creating what I believe is refered to as "orbital steer".

Think of your car going through a fairly large dip in the road. The front suspension compresses causing the knuckles to move upwards relative to the steering rack. If the rack is centered and the tie-rods are an even length, the change in toe (toe in or out depending on suspension design) will remain constant/same for either side of the suspension. If, however, the tie-rods are NOT equal length, the change in toe angle will be different from left to right and will cause the vehicle to pull in one direction or the other.

Of course the amount the rack is off center has a lot to do with how much this effect is actually felt in the vehicle. A few millimeters off center isn't going to hurt much, but if the rack is off by 5 millimeters or more then it could really start effecting the way the car handles.

How much rack travel does your .2 difference in turns equate to? If it's more than 5mm (.25 inch) then I would suggest re-centering your rack. This will most likely require a total re-alignment of the front wheels and possibly the re-centering of the steering wheel to get it "centered" relative to the rack (not the wheels).

 

[DSM90AWD]

So the best way to tell the Rack is centered is to measure from the Racks input spline (where connects to steering gear) to the end of the inner tie rod ends (outers removed to take that variable out of the equation) and make the distances equal on both sides?

Currently the threads on the Rod Ends are very close so assuming the rods themselves are of equal length.. should now be pretty much centered.

My question was more.. instead of going thry the PITA process of re/re the connection of the steering gear to P/S input shaft to center the rack.. pulling the steering wheel off instead + centering the rack then reattaching.

 

[turbotoad]

So the best way to tell the Rack is centered is to measure from the Racks input spline (where connects to steering gear) to the end of the inner tie rod ends (outers removed to take that variable out of the equation) and make the distances equal on both sides?

No, not from the input spline, but from the "ball-center" of the inner tierod (where it attaches/pivots at the rack) (inside of the rack boot) to the "ball-center" (pivot) of the outer tierod (where it attaches to the knuckle). The outers ARE part of the equation. Basically the overall length of the inner and outer tierods combined should be the same on either side of the vehicle.


Perhaps there is some confusion with the term "rack". The "rack" is actually the splined/toothed rod that travels back & forth within the steering rack housing and to which the tierods are attached. The input shaft (pinion) is part of the housing. This housing does not neccesarily need to be centered in the vehicle (within reason). But the "rack" itself (the rod inside of the housing) does need to be centered in the vehicle. Thus forcing both tierods to be of equal length.

Once you establish that the rack itself (steering rod) is centered yet the steering wheel is not, then you may re-center the wheel by either removing the wheel and rotating it, and/or disconnecting the input shaft and rotate the wheel untill it's centered.

I hope that makes sense.

 

[DSM90AWD]

Thanks for the clarification.. wish I had a blowup diagram of the rack handy .

On other question.. is the Rack-Side tie rod end threaded? If not.. does spinning the rod in/out affect the P/S unit as a whole other than the outer tie rod end?

 

[turbotoad]

Thanks for the clarification.. wish I had a blowup diagram of the rack handy .

On other question.. is the Rack-Side tie rod end threaded? If not.. does spinning the rod in/out affect the P/S unit as a whole other than the outer tie rod end?

Yeah, I wish I had a pic or diagram too! Anyway, yes the inner tie-rod does thread onto the rack end. The inner tie-rod has one end that is a ball-&-socket type end fitting. The part that threads onto the rack is the "socket" part of the ball-&-socket. This "socket" is then staked/locked onto the rack so that it will not un-thread under use. The "ball" part (e.g. the rod itself) is then free to pivot for suspension movement and ajusting the alignment.

Rotating the inner tie-rod ONLY effects/moves the outer tie-rod. Toe ajustments are made by loosening the jam-nut on the outer tie-rod, then rotating the inner tie-rod. This rotation moves the outer tie-rod up or down the shaft of the inner tie-rod via the threads. Thus increasing/decreasing the overall length of the entire tie-rod asm and toeing the wheel in or out.

 

[DSM90AWD]

Rotating the inner tie-rod ONLY effects/moves the outer tie-rod.

Ok that makes more sense. I was concerned that there was adjustment on both ends of the rod (which would of made my thought process much more difficult)

Thanks again for the help. When I first looked to center the rack all found was advice to "spin the input shaft until it pauses".. which I tried over and over never finding the "pause" point. Maybe if I'd done this for years I would have figured it out.. but your method bodes better with my inexperience with P/S racks and experience with a tape measure