Lubricant for steering? (Potential solutions for Mirage's lack of self-centering)

[cyclopathic]

I'm interested to hear if other Mirage owners have the same characteristics as I do. There is a dead area from having the steering wheel about one-eighth turn to the left and to the right. In this area, the wheel does not self-centre. Beyond that area (as when doing a 90 degree turn) there is a strong self-centering force. The result is that no problem is noticed during city driving, but there is constant need for correction during highway driving. I do not notice any "stickiness" in the movement of the wheel that one poster mentioned on this or another thread.

Dead center you describe is due to toe-in. If you want to reduce this reduce toe-in

[cyclopathic]

Like I had said earlier, my Toyota changed with miles.
The difference between 2k and 10K was astounding.
It went from horrific, to O.K.
Ball joints, rod ends, bearing plates, steering rack, column bushings and U-joints, EPS parts (?) what have I missed...
All that stuff loosening up with miles...allowing the steering to freely float when centered ???
Sure feels different now thats for sure, hopefully the Mirage's will do the same.

This is likely due to tire wear. Was your Corolla spec'ed with Yoko tires? They are known for dreadful no center feel when new

[foama]

Quote:
With regards to post #25 of foama, How did you managed to loosen the locknut on the steering rack? Special tool maybe?.

Yes, special tools. All especially made. You need something like a spanner of the size (40? or 43? dont remember), but it actually has to be the form of a nut. Probably you could take a very large nut, do some welding and modifications, etc. With that you could loosen the locknut. Observe: That locknut has four sides to it, not six!
Removing the two rear brackets of the rubber holders for the front sway bar gives you somewhat better access.
Then you loosen the crown nut. If its too loose, the steering will rattle on uneven roads. If too tight there is too much friction, and the known steering problem gets worse.
If the crown nut is loosened all the way, and re-tightened with your fingertips so it just touches the rack, you need to turn it more inwards by about two-thirds to 3 quarters of one turn. The exact amount is crucial.
Then do a careful test drive before re-fastening that locknut. I put a dab of 1-component PU on to help secure it.
Of course, all at your own risk. If you don’t know exactly what I am talking about, and aren’t certain you can cope, better leave your fingers off. Sorry, this is only for experienced mechanics!

Question:
Looking at the actual worm-gear the electric motor is mounted on, is there a way to loosen the pressure of the worm onto the associated gear? Maybe this is where we can get rid of some of the much too high torque?

[foama]

Bump!

Question:
Looking at the actual worm-gear the electric motor is mounted on, is there a way to loosen the pressure of the worm onto the associated gear? This is certainly where we can get rid of most of the much too high torque?

Thanks to ThreePot for the image!

[MightyMirageMpg]

Bump!



Thanks to ThreePot for the image!

Are you asking if you can you alter the quantity of assist?

Cool image. How heavy is the assembly with the motor?

[foama]

Quote: Are you asking if you can you alter the quantity of assist?

Answer: Definitely no!




Summary: There are two inappropriate factory adjustments causing the much too high torque within the steering.
I will identify these below. And yes, the assist motor does compensate it when the initial unassisted torque (Layman calls it "sticking of the steering wheel" or "dead non-selfcentering spot in the middle") has been overcome. However this is at the price of creating the "sticky" steering and lack of self-centering.
All in all this is stupid rubbish that I don't want to put up with. For no difference in cost whatsoever, it could have been built properly. You could call this an unfinished part of development, or just plain sloppy engineering at best.


Problem 1 (solved):
The permissable "Steering gear total pinion torque" as described in the FSM on section 37-72 is too high set at 0.6 to 1.25 Nm. It can be reduced to normal levels (max. 0.5 Nm) such as common in other small cars by means of a simple adjustment, but this is only for those who certainly know what they are are doing, nothing for laymen. This adjustment by itself already makes a big noticable difference for the better.
The FSM does not even mention the adjustment possibilities!
For details, see the how-to in post 73 within this thread.


Problem 2:
The overtight wormgear. This problem still persists, that being the question of post 74.
Knowing the pressure the worm is pressed onto the gear is responsible for this gear's torque, there must be a way to correct the overtight factory adjustment. Here the FSM states a max value of 1.25Nm, but no more than about half would seem correct. This is the core of the unanswered question repeated below:


Question:
Looking at the actual worm-gear the electric motor is mounted on, is there a way to loosen the pressure of the worm onto the associated gear, and thus reduce the torque required to turn it?

[Ranny]

Thanks for the details, foama. Unfortunately, sounds like an 'un-doable'. Certainly I don't want to tackle it and with the need for custom fabricated tools, even a good front end shop probably wouldn't want to do it unless they were paid a small fortune. Pity. I'd love to get some self centering and a little reduction in the 'dead on center feel'. One adjusts to the lack of self-centering, but it would be a nice quality to have.

I've also seen a post about strut bearing lubrication. Sounds a lot easier to accomplish. Has anyone tried this and found improvement?

[MightyMirageMpg]

maybe i missed it, and if so appologize..

but how has it been decided the gearbox is the issue, and more specifically, the tension of the gears together?

obviously the worm cannot be driven by the spur, which is the reason for lack of self centering (steering jacking is cause of self centering, which is a product of not a single suspension geometry, but, mainly, rim offset and caSTer) and therfore the weight of the vehicle is attempting to drive the worm. this is kind of obvious, and GM has patents for technology too combat this.

so... has anyone removed the worm gear or am i completely misunderstand everything you guys (and gals?) are talking about?


edit; i should note it sounds like there's a lot of knowledgeable people in this thread, and lots of good information with only speckles of misinformation, but its like we're all dancing around the ugly truth, or I'm talking about something completely different lol

[foama]

@ mighty mirage:
The FSM lists both the torque (the resistance to turning forces) of the steering gear, and also of the power steering assembly. See the FSM for details.
Compared to similar sized cars, these torque values a ridiculously high, at least twice as high as usual. This is what makes the steering so numb, makes it "stick" and prevents the self-centering forces from reaching the steering wheel.

I have conquered the first part of the problem within the steering-box (rack and pinion gear), and it has helped a lot. See problem one in a previous post.

The second point (problem two) to tackle is to reduce the torque within the steering column. This is caused by the excessively tight worm gear.

Question:
Looking at the actual worm-gear the electric motor is mounted on, is there a way to loosen the pressure of the worm onto the associated gear, and thus reduce the torque required to turn it?

[MightyMirageMpg]

i see, and now i understand. i don't know. sorry your having problems

would love too know the weight of the gearbox and motor, though, if anyone has one handy