Steering rack input radial play

[digger]

Has anyone else ever noticed radial play on the e46 racks and seen any symptoms? i think it is root caused by operation with worn or incorrectly installed steering coupling causing binding that increase the radial loading.

I have heard that rack rebuilders don't replace the pinion bearing (hard to find the correct part) but claim this doesn't matter, but when procuring a reconditioned rack this is not something i would like as on cars where i have seen this you can hear a slight knocking when you move the wheel CW and CCW back and forth quickly even if the steering doesn't feel vague it may cause a slightly vibration with the steering wheel (atleast IMO basd on not being able to find any other cause).

The "play" only shows up upon change of direction as the radial load changes direction if you load the steering one way and then increase load the same way play doesnt come into it as it is already taken up

Thoughts?

[PSUEng]

davidinnyc is your guy here...

[bigjae46]

I could see how a worn coupler could cause the bearing to fail but how do you incorrectly install a coupler? I thought that was one of those jobs I could never screw up.

Being a certified youtube engineer...I would think that it would be unlikely the bearing would fail. It is not seeing high RPMs, high heat or high loads. I'd guess the most likely issue would be contamination due to failed pinion seal.

[sapote]

1) Has anyone else ever noticed radial play on the e46 racks and seen any symptoms? i think it is root caused by operation with worn or incorrectly installed steering coupling causing binding that increase the radial loading.

2) I have heard that rack rebuilders don't replace the pinion bearing (hard to find the correct part) but claim this doesn't matter, but when procuring a reconditioned rack this is not something i would like

1) The radial plays on the steering wheel caused by 2 sources: the plays on the external coupling, and the plays between rack / pinion. The biggest load on these parts happened when turning the wheel with engine off with zero power assist.

2) why blaming the pinion bearing? Unless the bearing has bad radial play or axial plays (which for sure can cause oil leaking very soon) and this is easy to detect by rocking or bush/pull on the shaft.

[digger]

I could see how a worn coupler could cause the bearing to fail but how do you incorrectly install a coupler? I thought that was one of those jobs I could never screw up.

Being a certified youtube engineer...I would think that it would be unlikely the bearing would fail. It is not seeing high RPMs, high heat or high loads. I'd guess the most likely issue would be contamination due to failed pinion seal.

if you install an aftermarket coupling that is fairly rigid (no compliance) then you can phase it wrong and some designs are adjustable in length and if you dont minimize the shaft angle it causes binding that isnt taken up by the non existent flex coupling

[digger]

1) The radial plays on the steering wheel caused by 2 sources: the plays on the external coupling, and the plays between rack / pinion. The biggest load on these parts happened when turning the wheel with engine off with zero power assist.

2) why blaming the pinion bearing? Unless the bearing has bad radial play or axial plays (which for sure can cause oil leaking very soon) and this is easy to detect by rocking or bush/pull on the shaft.

i am blaming the pinion bearing because it is radial play at the input end of the shaft and the rotational play is non existent in the rack

when an assistant turns the wheel back and forth i can hear a slight knock when under the car and i can feel the input shaft moving radially and if i remove the steering coupler i can move the shaft by hand and hear the same noise (tie rods removed from knuckle)

[davidinnyc]

Sorry it took so long for me to respond, but in my experience this play you’re referencing is generally found at the pinion gear / steering rack teeth junction or at the coupler.

By design, the valve body on the pinion shaft has less than 0.5MM of clearance (probably even tighter clearance) between the inner pinion shaft of the rack tube and the valve body + Teflon rings. This creates a pretty firm seal to flow hydraulic fluid between the valve body orifices.

The INA needle bearing is pressed into the pinion shaft cap that sits atop the valve body. There is also a seal that is sandwiched between the bearing and the upper cap housing. These two work together to keep the pinion shaft from moving radially. Unless the needle bearing itself is damaged, there’s no place for the roller bearings to be dislodged or move too far one direction to create play.

Finally, there is another bearing below the valve body that is pressed onto the pinion shaft just above the pinion gearing with <0.5MM clearance inside of the tube, and then just below is another seal that sits against a lip on the inside of the tube.

I’ll draw up a diagram tonight, but unless you have significant play then I’d argue it to be the coupler. After checking that connection for fit, I’d then tighten the rear steering rack lock (the 12-point lock) 1/4 turn at a time and check for binding. If you do reach the point of rack binding, take off 1/4 turn.

If these two checkpoints fail, then I’d say it’s time to open up the rack to see if your pinion gear and/or the steering rack teeth are damaged, or if the needle bearing has worn down.

David

[sapote]

if i remove the steering coupler i can move the shaft by hand and hear the same noise (tie rods removed from knuckle)

"Move the shaft by hand", rocking up/down left/right, or rotational motion?