I’d say the play is normal.  Inside the input shaft of a power steering box or a power rack and pinion there is a spring steel shaft that actually deflects a few degrees when you give it steering input.  It is part of the magic that ports the oil to the right places to make it power steering.

If your alignment really is 0-.5 degree negative camber, 3-5 degrees positive caster and a little toe in I don’t see that as a problem- that sounds about perfect.

How are all the other parts?  Ball joints?  Upper control arms?  Everyone tight?

Only suggestion I have is to second check alignment and tightness of every fastener.

My 2 cents.... Bump Steer.  It happens when the tie rods are not parallel to the  lower control arm...I think.

lowercasesteve wrote:

My 2 cents.... Bump Steer.  It happens when the tie rods are not parallel to the  lower control arm...I think.

  I was thinking that to on the bumps.  Doesn't explain the wander.  I was debating on buying a bumpsteer kit and see what happens. 
 

Steve69 wrote:

  Have a 69 Mustang with a Unisteer rack that I installed  8 years ago. When driving the car  it Wanders.  Going over bumps is kind of scary at times.  The steering wheel will be completely straight and when I hit a bump the front tires go where they want to go. 

Is your front end lowered? When I lowered mine it put the angles of the control arms send steering arms out of whack for proper angles with little or no bump steer.




I measured and drew out the control arm and steering arm locations to determine how much of a drop the outer steering arm mount needed to be lowered for proper angles. This drawing is grim when I had a 2 inch Shelby drop. I've since changed it back to the normal 1 inch drop.



Some people don't like the bump steer studs on the steering arms due to the increased leverage in play. I don't experience any unwanted steering manners at low or high speeds, bumps or no bumps. I had it up to 133 mph the other day and it required little effort on the wheel.

Steve69 wrote:

Bearing Bob wrote:

My guess would be the rack is not positioned correctly. If the rack is not mounted in the right spot in height and also front to back, it will cause too much toe in and out over bumps and during acceleration and braking. Too much toe out causes an unstable feeling in the steering.

  There's two bolts that hold the cradle up where the old crossmember goes. Really no way of  having it in the wrong position. 
 

 
The bump steer stud might fix your problem, but I mentioned the rack mount because you have a rack and pinion. I've never used R&P on a Mustang, but I thought id read that there was play in the mounting where it could be adjusted.

Thanks for the diagrams Bearing Bob and the info TKO.  Im going to call Unisteer and see what they say. From what I gather there should be very little play with a Rack.  Ill let you know what I find out.  

Thanks Steve69

Bearing Bob wrote:

Steve69 wrote:

  Have a 69 Mustang with a Unisteer rack that I installed  8 years ago. When driving the car  it Wanders.  Going over bumps is kind of scary at times.  The steering wheel will be completely straight and when I hit a bump the front tires go where they want to go. 

Is your front end lowered? When I lowered mine it put the angles of the control arms send steering arms out of whack for proper angles with little or no bump steer.




I measured and drew out the control arm and steering arm locations to determine how much of a drop the outer steering arm mount needed to be lowered for proper angles. This drawing is grim when I had a 2 inch Shelby drop. I've since changed it back to the normal 1 inch drop.



Some people don't like the bump steer studs on the steering arms due to the increased leverage in play. I don't experience any unwanted steering manners at low or high speeds, bumps or no bumps. I had it up to 133 mph the other day and it required little effort on the wheel.

Steve69 wrote:

Bearing Bob wrote:

My guess would be the rack is not positioned correctly. If the rack is not mounted in the right spot in height and also front to back, it will cause too much toe in and out over bumps and during acceleration and braking. Too much toe out causes an unstable feeling in the steering.

  There's two bolts that hold the cradle up where the old crossmember goes. Really no way of  having it in the wrong position. 
 

 
The bump steer stud might fix your problem, but I mentioned the rack mount because you have a rack and pinion. I've never used R&P on a Mustang, but I thought id read that there was play in the mounting where it could be adjusted.

Bob Bolles book I see. I have the same one

I am super curious what you will find.  It is weird to me that  Unisteer stated the input was a solid connection.  I have never seen a power box or rack that does not have some sort of torsion bar in the control valve.

If you have 8 minutes watch the whole thing- if you don’t start around 3:40.  This guy does a pretty short and sweet explanation of a rack and pinion power steering setup.

https://youtu.be/amTnNkAhWgQ

Bentworker wrote:

I am super curious what you will find. It is weird to me that Unisteer stated the input was a solid connection. I have never seen a power box or rack that does not have some sort of torsion bar in the control valve.

If you have 8 minutes watch the whole thing- if you don’t start around 3:40. This guy does a pretty short and sweet explanation of a rack and pinion power steering setup.

https://youtu.be/amTnNkAhWgQ

The guy does a pretty good job of explaining what is going on.

Thanks great video.

I like the grinder too.😂

Last edited by Nos681 (5/21/2020 5:12 PM)

**Im happy as a clam!  Took the day off Friday and jacked up the car to take a look at the rack.  So I pulled on the u joint attached to the Rack and there was no play and solid.   I went up to the upper U joint and there was no play between the U joint and the steering column.  So everything was good.   So I pulled the complete U joint off the Rack, Shaft and U joint on the Column.  Major PIA.  I have a Z bar and AC lines so there isn't much room to work with.  After inspecting the U joints and shaft everything looked good and tight.  No play.  So I lined everything up on the bench like Unisteer had  in the link I posted with phasing the U joints.  Something they added well after I installed the unit in 2012.  I drew a black line with Marker all the way across the U joints and shaft.  I installed everything how I marked it on the bench.  A 3 day process.  I would work a little bit here and there and take a break.  Added locktite and torqued to 40 pounds.  Guess what no play. When I turned the steering wheel lightly the wheels turned too. Before there was at least 1" of play before there was movement in the wheel.  So I pulled my new steering wheel off and had the nut on loosely so I could pull the steering wheel off to get it centered.  Pulled the car over on my drive and pulled the steering wheel off to get it centered.  8 years of wander and shimmy over bumps  and its finally fixed and feels safe.  Drives really nice. No excess play.  Going over bumps I have full control like I should have.  Very happy I took the time to trouble shoot instead of wasting another $150 on front end alignment that wasn't going to fix this problem.   Now on to the next problem! Why my electric fan would only kick on when the AC compressor was cycling...LOL  I think I knocked a wire off the prong while working on the U joints.   Thanks you guys for your help and input!   

Steve69

Last edited by Steve69 (5/24/2020 2:27 PM)

Steve69 wrote:

**Im happy as a clam!  Took the day off Friday and jacked up the car to take a look at the rack.  So I pulled on the u joint attached to the Rack and there was no play and solid.   I went up to the upper U joint and there was no play between the U joint and the steering column.  So everything was good.   So I pulled the complete U joint off the Rack, Shaft and U joint on the Column.  Major PIA.  I have a Z bar and AC lines so there isn't much room to work with.  After inspecting the U joints and shaft everything looked good and tight.  No play.  So I lined everything up on the bench like Unisteer had  in the link I posted with phasing the U joints.  Something they added well after I installed the unit in 2012.  I drew a black line with Marker all the way across the U joints and shaft.  I installed everything how I marked it on the bench.  A 3 day process.  I would work a little bit here and there and take a break.  Added locktite and torqued to 40 pounds.  Guess what no play. When I turned the steering wheel lightly the wheels turned too. Before there was at least 1" of play before there was movement in the wheel.  So I pulled my new steering wheel off and had the nut on loosely so I could pull the steering wheel off to get it centered.  Pulled the car over on my drive and pulled the steering wheel off to get it centered.  8 years of wander and shimmy over bumps  and its finally fixed and feels safe.  Drives really nice. No excess play.  Going over bumps I have full control like I should have.  Very happy I took the time to trouble shoot instead of wasting another $150 on front end alignment that wasn't going to fix this problem.   Now on to the next problem! Why my electric fan would only kick on when the AC compressor was cycling...LOL  I think I knocked a wire off the prong while working on the U joints.   Thanks you guys for your help and input!   

Steve69

You want the fan on when the AC is on.  There needs to be airflow through the condenser at all times.  If there isn't bad things happen.