Typical and Optimal backlash in steering

[Moparfiend]

Whats an acceptable amount of backlash in my steering? Is the typical source of backlash in the gearbox? If so is there any adjustment or is a rebuild in order if the backlash is too much?

Is backlash the right term? Is it measured typically in degrees or total travel in inches?

Thanks for responding in advance….
MF

 

[1 Wild R/T]

One more time....
Steering boxes are unique in that the gears only mesh to a close tolerance within a small window generally less than 1/4 turn and the closest tolerance is just the center point... That 1/4 turn is total, so only 1/8 turn right or left from center... When the steering is off center the pressure created in the steering linkage by feedback from the caster of each spindle forces all backlash to be taken up & it can't be felt in the steering...

So when setting steering back lash it's absolutely critical the steering gear is meshed at it's tightest point... If you set the proper mesh backlash, but set it off center.. Not when you get the steering on center the mesh is to tight & if excessively tight it might bind... But more common the steering doesn't bind, instead it comes up to the center but won't stay there, it snaps past center.. Then you try again to hit center but again it snaps to the other side... This leads to the car driving down the road needing constant steering correction...

So, sloppy on center needs to be tightened but getting the mesh to tight is worse... Plus to tight will quickly chew up the gears in the on center (most critical) part of the gears...

 

[R413]

why do you ask, are you having a problem?

Power or manual? Mopar power steering is very sloppy with the engine off, or pump disconnected.

do you have a factory service manual? It outlines adjustment procedures and what is normal.

tight or sloppy it will not compare to a modern car or a rack & pinion steering system.

 

[Moparfiend]

why do you ask, are you having a problem?

Power or manual? Mopar power steering is very sloppy with the engine off, or pump disconnected.

do you have a factory service manual? It outlines adjustment procedures and what is normal.

tight or sloppy it will not compare to a modern car or a rack & pinion steering system.

I am just getting the car back together after 3 plus years. I just installed the steering column (factory power steering set up) and noticed slop in the steering (maybe +/- 25 degrees?). This is with the car not running.

Wanted to know if this is typical or if I need to tighten it up.

Yes I have the FSM

 

[Moparfiend]

One more time....
Steering boxes are unique in that the gears only mesh to a close tolerance within a small window generally less than 1/4 turn and the closest tolerance is just the center point... That 1/4 turn is total, so only 1/8 turn right or left from center... When the steering is off center the pressure created in the steering linkage by feedback from the caster of each spindle forces all backlash to be taken up & it can't be felt in the steering...

So when setting steering back lash it's absolutely critical the steering gear is meshed at it's tightest point... If you set the proper mesh backlash, but set it off center.. Not when you get the steering on center the mesh is to tight & if excessively tight it might bind... But more common the steering doesn't bind, instead it comes up to the center but won't stay there, it snaps past center.. Then you try again to hit center but again it snaps to the other side... This leads to the car driving down the road needing constant steering correction...

So, sloppy on center needs to be tightened but getting the mesh to tight is worse... Plus to tight will quickly chew up the gears in the on center (most critical) part of the gears...

I guess ill wait until it’s running to fully evaluate the backlash. I am not there yet but hopefully soon.

 

[1 Wild R/T]

Yeah power steering & engine off means lots of slop... Get it running..

 

[Kern Dog]

An RB Big Block with headers makes adjustments with the engine running a bit too close for me. I've had the engine off and adjusted, started it up and tested the feel, then shut it down if it was good enough. The headers make lots of things difficult when the engine is hot. I remember guys telling me to "read the plugs" when trying to determine if I was running rich or lean but that has to be done after a hard run....The pipes are still quite hot and capable of melting skin within a second of contact. Screw that...I bought an air-fuel meter!
More on topic though:
To repeat, I make slight adjustments, (maybe 1/8th a turn of the Allen center screw) test it, repeat until the steering feels like it is binding, then go back half way to the last adjusted point, then test again.
Completely unscientific but this isn't as critical to be dead nuts precise like bearing clearances and piston ring gaps.

 

[Steve Garner]

As was said, steering box gears are cut with a high spot in the centre. This does not mean that only in the centre all the lash should be gone. The lash should be gone off centre and with that you get added resistance (tightness) as you roll through the straight ahead position.
Mopar doesn't adjust them this way, but to give you the best explanation, when setting up a GM box you adjust preload on steering shaft bearings so that it takes around 5-8 inch pounds of torque to turn the shaft. You then install the pitman shaft and adjust it so that the effort to turn the shaft increases by 4 to 10 inch lbs as you go through the straight ahead position.

The purpose of this tightness at the centre is to hold the wheels in the straight ahead position and reduce driver fatigue.

On the 69 Mopar ps box the Mopar engineers instruct that you adjust pitman off centre by just removing all of the lash in the turned position. This will result in the correct resistance as you pass the high point.

Boxes are never adjusted with the engine running or by feeling the amount of "looseness". The steering shaft (input) is not a solid shaft. Built into it is the valve that controls oil flow. It has to be able to move. How far the valve moves before the wheels start to move is a function of the centring spring tension.