rack and Pinion movement

I installed a brand new T-Bird Rack and Pinion and bushings in my 40 ford truck. Its powered by a GM pwr steering pump with reduction valve installed.
With the tires on the ground I get what seems to me a lot of movement of the rack when I turn the wheel. ( engine running). ( Yes everything is tight as can be)
At the first knuckle/ end of output shaft of the rack there is movement of about 1/4" to 3/8" up and down. All is tight, I can't budge it by hand no how.
What is wrong with this ?
Is it supposed to be like that ?

I'm confused. If you can't move it by hand, how do you know that it moves up and down. Are you having someone turn the steering wheel while you look at the rack? Not familiar with the T-bird rack, but no rack that I ever owned moved up and down.

.

Your talking about the rack/joint and not the housing?

Is the rack input shaft bent maybe?

Quote:

---

Originally Posted by jerry clayton

Your talking about the rack/joint and not the housing?

---

Yup I'm talking about the rack /joint. I'm turning the steering shaft by hand on the 1st segment of the steering rod just before it gets to a Heim joint thats bolted to a bracket on the frame. The housing stays put for the most part, its just the outer limits of the rack out-put shaft that moves. Of course the housing must be moving a little bit or the shaft wouldn't move. Should have taken a picture, my pictures communicate better than I.
The shaft is not bent.

Navy, looking at the rack there are the two threaded "steering rods" that attach to the spindles, and then there is the splined shaft that you turn to affect movement of the steering rods. When you say "output shaft" are you talking about the splined shaft that attaches to your steering via DD u-joints, and saying that it moves in & out radially from the rack housing, basically the shaft pushing back towards the firewall 1/4" to 3/8"? Just trying to understand what you're trying to communicate.

Quote:

---

Originally Posted by rspears

Navy, looking at the rack there are the two threaded "steering rods" that attach to the spindles, and then there is the splined shaft that you turn to affect movement of the steering rods.
When you say "output shaft" are you talking about the splined shaft that attaches to your steering via DD u-joints, and saying that it moves in & out radially from the rack housing, basically the shaft pushing back towards the firewall 1/4" to 3/8"? Just trying to understand what you're trying to communicate.

---

Ok I found a picture of the rack with out the pump installed.
Its not moving in and out but up and down. The splined shaft and the housing move together, its like its rocking on the rubber bushings, but only when turning the wheel.
http://i990.photobucket.com/albums/a...psatipwqlb.png

Is the angle too steep on your u joints?

Quote:

---

Originally Posted by 36 sedan

Is the angle too steep on your u joints?

---

No thats not it, there is only a short shaft coming off the rack that I turn by hand to turn the wheels at this time.

Have you checked the gear lash adjustment?
Rack-and-Pinion Service

Navy, I'm having a hard time understanding how a force can be generated to cause the whole rack to rotate against the bushings. Unless I'm wrong the rack & pinion are both simple straight or spiral cut spur gears which don't cause any torque load. The gear lash adjustment on the rack & pinion is only to deal with excess play in the wheel, as I read about it (at the very end of the link 36 sedan posted above).
The only thing that makes any sense to me is that maybe your steering arms are describing a vertical arc as they turn, imparting a "twist" on the rack? I'd try loosening the lock nuts on the threaded steering rods to allow them to rotate a bit as you turn and see if the housing movement disappears. If so you may need to tweak your steering arms for better alignment? Does that make sense to anyone else?

I'm sorry, I missunderstood, I thought he was saying just the input shaft was moving?, not the rack itself.
I believe a power steering rack operates differently without fuild and pressure and could be torquing on its bushings due to this, JMO.

I suspect that a number of small items are adding to this pile---------

Incorrect bushings and/or improper mounting--check out a T bird ( maybe also Lincoln) to see EXACTLY how they are mounted-probably against a crossmember that can't twist or flex.

If the steering/suspension geometry has even one little varient incorrect it will take a significant amount of force to turn them and that will cause the back feed that will necesstate enough torque to twist the housing(applied thru the spiral/bevel to rack will cause rotation in that direction mentioned.

And -------are you setting down????? If the power steering is powered it will generate the force internally in the box and this won't happen-I don't think you have a problem

In Navy's original post he says that

Quote:

---

Originally Posted by Navy7797

...Its powered by a GM pwr steering pump with reduction valve installed. With the tires on the ground I get what seems to me a lot of movement of the rack when I turn the wheel. ( engine running). ( Yes everything is tight as can be)

---

He also says in the post with the picture,

Quote:

---

Originally Posted by Navy7797

Ok I found a picture of the rack with out the pump installed.

---

This says to me (could be wrong) that the system is totally plumbed, engine running, pressure to the rack unit when it twists, which adds to the dilemma. With that I'll await the next installment from Navy.

Quote:

---

Originally Posted by jerry clayton

And -------are you setting down????? If the power steering is powered it will generate the force internally in the box and this won't happen-I don't think you have a problem

---

That's pretty much what mine does and, when you operate it manually (without power) it messes up the fluid balance inside the rack and will not operate correctly until you rebalance (bleed as some call it) the fluid inside. Usually all it takes to rebalance the fluid is to crank the steering wheel under power left to right (full stop to stop) several times until it starts driving correctly.

Quote:

---

Originally Posted by rspears

In Navy's original post he says that

He also says in the post with the picture,

This says to me (could be wrong) that the system is totally plumbed, engine running, pressure to the rack unit when it twists, which adds to the dilemma. With that I'll await the next installment from Navy.

---

WOW! I missed that too! Gotta start reading better, lol....

Quote:

---

Originally Posted by Navy7797

I installed a brand new T-Bird Rack and Pinion and bushings in my 40 ford truck. Its powered by a GM pwr steering pump with reduction valve installed.

---

Here's a thought, is the rack set up for a GM pump without using the pressure reduction valve? Mine is set to run with the GM pressure.

I have new rack and pinion bushings and I'm wondering about the amount of slop with the bolts and inter steel bushing . There's 45 thousands difference and that seem loose to me but I never had one apart before. Does it even matter after all when things get tightened down ? Thanks for the input.


Rember this post?????

Quote:

---

Originally Posted by jerry clayton

I have new rack and pinion bushings and I'm wondering about the amount of slop with the bolts and inter steel bushing . There's 45 thousands difference and that seem loose to me but I never had one apart before. Does it even matter after all when things get tightened down ? Thanks for the input.


Rember this post?????

---

Yes that rings a bell, but the bolts are not moving, the housing is moving on the rubber bushings. I'm going to take a video and post it. It maybe the the rubber bushing are just to dam soft ??

Quote:

---

Originally Posted by 36 sedan

Here's a thought, is the rack set up for a GM pump without using the pressure reduction valve? Mine is set to run with the GM pressure.

---

I already had the valve installed from my old rack so I just left it in the pump. I don't think less pressure would cause this problem. it turns smoothly, its just movement at the spline output shaft that has me concerned.

How about a couple of fender washers on the bolts to better contain the bushings from bulging out? Just a hair brained thought....

Are the tie rods level from the rack to the control arm, or do the slant up or down when the car is at ride height?

Quote:

---

Originally Posted by Henry Rifle

Are the tie rods level from the rack to the control arm, or do the slant up or down when the car is at ride height?

---

I agree, I'm still where I was on the forces you're seeing -

Quote:

---

Originally Posted by rspears

Navy, I'm having a hard time understanding how a force can be generated to cause the whole rack to rotate against the bushings. Unless I'm wrong the rack & pinion are both simple straight or spiral cut spur gears which don't cause any torque load. The gear lash adjustment on the rack & pinion is only to deal with excess play in the wheel, as I read about it (at the very end of the link 36 sedan posted above).
The only thing that makes any sense to me is that maybe your steering arms are describing a vertical arc as they turn, imparting a "twist" on the rack? I'd try loosening the lock nuts on the threaded steering rods to allow them to rotate a bit as you turn and see if the housing movement disappears. If so you may need to tweak your steering arms for better alignment?

---

Does it rotate one direction ( up/down) when you turn the shaft one direction and the other way when you turn it the other way? this would indicate mounting issues to the crossmember-

I see that the rack your using only has 2 mounting points----------there were some that used 3 and early ones even a u-bolt around the right side

Navy, I have used several Mustang II racks which might be & do look similar to your setup, on a set of bushings I recieved from Heidts the rubber on the bushing was much longer than the metal insert that the bolt goes through and is tightened with a nut to the crossmember mount, I had to trim off a small amount of that rubber as it folded over and was pinched when the rack was mounted, making the rack & pinion wobble and not mount firmly in mockup. I did this build in 2006 and never found any info on those bushings as I remember looking but after the trimming its been on the road since then with no problems. I hope this helps. Matt

Here's results from my pwr steering work.
I took apart the bushings and found that the metal sleeves in the rubber bushings were longer than the rubber so there was no compression of the rubber leaving things to move around to much. I cut down the sleeves about 1/16 th and tried them again and while I still have some movement its very little, problem fixed I hope.
http://i990.photobucket.com/albums/a...psmjpbtbfu.jpg