Steering Rack In/Out Play

[AKimball92]

I am experiencing a weird play in my steering rack. While driving there is no vibrations, like I experienced in the old rack that came with the car. While in a corner the steering will shift when steering under load. It can be anticipated. The shift is not a clunk or vibration but a smooth sliiiiide over a few degrees. It happens in both directions back and forth. after the slide the steering wheel can be a few degrees off center one way then the other. You can predict it under moderate load going through the twisties but it suuure doesn't boost confidence to make it out the other side.

I got under the dash today to look and I notice a definite in/out motion of the column to the rack of about 3 mm. The wheel also moves this in/out forward/back motion compared to the plastic cover or column mounts. If the rack and pinion is helicoil in nature i think this would just be the pinion gear sliding up and down the width of the rack.

Is this just an adjustment to the steering rack shims? From my understanding to tighten the rack I just need to remove a shim #4 in the image attached. Or could it be shim #12 and/or the upper #11 and lower #10 bearings being worn or out of spec?

 

[AKimball92]

Looking more closely at the diagram I think I more than likely need to increase the number of shims #12 on the pinion itself. no matter how tight the rack/pinion is there I don't think there should be any in/out play in the pinion. I will probably need to get a new pinion gasket #3 and pinion seal #13 to open it up.

 

[Ics19]

3mm seems a lot of play for the pinion - are you sure the pinion is moving and it's not just the column bottom clamp joint that is loose?

You may not have the steering rack type pictured - that's an early version - the later ones (maybe '82 on?) have a big staked nut (2 variants I believe) to secure the pinion and do the adjustment, rather than the simple shim type in your diagram - @Rupunzell did an excellent write-up on the later type as the big nut needs carefully milling/un-staking to avoid ruining the thread.

But yeah, I think the top pinion adjustment is where you need to look, if it's looking like a rack issue - the yoke rack adjustment Y as pictured won't effect the in/out movement, just the contact pressure between pinion/rack - the pinion should always be in the same place

 

[Dr.Jeff]

Keep in mind there are two styles of X racks. And the adjustments are different between them.

Ooops, @Ics19 beat me to it.

 

[AKimball92]

I just measured from an edge on the bottom (furthest forward) u-joint to the sheet metal lip before and after pinion movement and got a difference of about 2.5mm.

My car is a 78 by parts, '79 by title. I purchased this rack from MWB and have it installed.

4327717-R

Steering Rack and Pinion Assembly (Fiat X1/9 1976-82 + 1973-75, 128 All) - REMAN-4327717-R------

MWB Steering Rack and Pinion Assembly (Fiat X1/9 1976-82...)

This looks to be an early type fitting my car's model year.

Looks like I should swap out to the other one I had issues with as I cannot remember if fixed the vibration issue at the time. I believe I have a new right inner bushing in it already. And also see if I can identify why this installed one is sliding in and out.

Does anyone sell these shims or do I have to make them? I have a friend with a mill he is working on getting together. A simple shim should be an easy first piece.

 

[Ics19]

I just measured from an edge on the bottom (furthest forward) u-joint to the sheet metal lip before and after pinion movement and got a difference of about 2.5mm.

And you can definitely see the actual pinion moving along with the U-joint?

This looks to be an early type fitting my car's model year.

Yes, it has the M14 track rod ends (pre '82), but it's actually the "later" type pinion as it has the big top nut, so not the pinion shim adjustable type as per your workshop diagram - of course the one you received may be different. How many miles have you done with the replacement rack - worth a chat with MWB perhaps?

EDIT:
You can see a side by side picture of the two rack types in this thread:

New 82 and under steering rack and tie rods. No longer for sale.

Brand new steering rack and set of outer tie rods from Midwest Bayless. I goofed and ordered the wrong one. this one is for years prior to 82. Not sure how much to ask. I bought the rack for 238.79 American and 47.58 American for the set of tie rods. make me a fair offer.

xwebforums.com

 

[AKimball92]

I've probably barely done a 2000 miles since full rebuild. Certainly no more than 3000.

I will look closely to see what differences I can find in the racks. Between my two and the above threads.

 

[johnph]

Did you check the plastic/nylon rack end bushings? They wear and you can get some slop. When they pop out, there is a huge steering wheel vibration when going thru the caroussel at Sears Point when cornering at over 1 G. It can happen

 

[JKIDD]

Have you checked your torque rod bushings? Something happened similar on my 79 Celica back in the day. Ended up a faulty bushing would allow the lower control arm move under harder cornering. Drove me crazy until a mechanic found it.

 

[Kendall]

And you can definitely see the actual pinion moving along with the U-joint?

Before you get really deep in this, I think you should check this out. A little bit of a dummy check, but when you installed the steering link to the rack, did you make sure to push the end coupling down far enough so that the bolt aligns with the radius cut out on the rack pinion? If you didn't you would have only clamped into the splines of the pinion, it could move and shift around. The bolt is intended to prevent in and out play. If you have 3mm of play in your rack it wouldn't steer for **** and you would have noticed it when the rack was out of the car.

 

[Kendall]

Sorry for the second reply, I was just thinking, how can your wheel also have 3mm of in and out play? Is your steering column not secured under the dash? There is some adjustment, I think for slight differences in steering linkage lengths, but when it's all together your steering wheel should not move in and out.

 

[Dr.Jeff]

EDIT: Please see my additional comments in post #15 below.

The adjustment shims are available from EuroSport. I believe they have some for each type of rack.

The pinch bolt cannot be installed if the U-joint is not all the way on.

Things like tie rods, trailing arms, susp bushings, etc, will not effect this type of movement. It must be coming from something like the rack itself, the steering shaft, etc.

 

[Dr.Jeff]

EDIT: Please see my additional comments in post #15 below.

I should also add, if the U-joints are bolted down then they cannot slide on the splines. So any movement there will be from the actual joint - which can be worn out.

The movement of the steering wheel makes sense because the steering shaft is solid. So if the shaft is moving at the rack end, then it will also move the same at the steering wheel end....assuming the U-joints are good.

 

[Jonohhh]

My 85' actually does the exact thing Andrew described, but I haven't gotten anywhere near troubleshooting it yet due to the other, larger issues - so I have just assumed it to be something sloppy in the front suspension (despite feeling nice and tight when testing). Even the racks end bushing is nice and firm...not really sure how, to be honest. I say it feels like suspension, but it sure does feel very "connected" to the wheel...hard to describe, but it feels like whatever compliance or movement is happening is very coupled to the steering wheel itself.

Curious what the cause ends up being. Can you replicate the compliance while at a stop, while loading up the steering? If not, perhaps try testing again while one wheel at a time is elevated to create a differential force (left to right) to more realistically simulate road conditions - I have found this to reveal otherwise hidden steering system compliance in the past.

 

[Dr.Jeff]

Jon's comments made me realize I wasn't clear in my prior two post (#12 and 13). I was speaking specifically about the "in and out" movement of the steering shaft, and not the sudden shift in steering under load. Sorry for the confusion. It was intended to only reference a later post by Andrew and therefore misleading. Hopefully I understood all of Andrew's commonets correctly.

 

[Rupunzell]

Three are a few places where excessive play in the steering can happen.

Most common is the plastic bushing for the rack gear inside the steering rack has come undone or died (most common failure, the three plastic tabs bust off). Idea replacement is to make a bushing from SAE bearing bronze or replace it with the stock FIAT plastic part. Making this bushing out of aluminum per the PBS "race" book is not good as aluminum is a horrid bearing material unless properly alloyed to be a bearing material.

Check the ball joints at the ends of the steering rack gear.

Check the ball joints at the end of the steering rack that connects to the front upright's steering arm.

Check the front wheel bearings for slop.

Check the lower ball joint for excessive slop (unlikely).

There is a needle bearing U-joint drive shaft between the steering column to steering rack's piñon gear, these can and do wear out.. and the splines on both ends must be proper and the M8 bolts clamping then together must be properly seated.


Bernice

 

[kmead]

Three are a few places where excessive play in the steering can happen.

Most common is the plastic bushing for the rack gear inside the steering rack has come undone or died (most common failure, the three plastic tabs bust off). Idea replacement is to make a bushing from SAE bearing bronze or replace it with the stock FIAT plastic part. Making this bushing out of aluminum per the PBS "race" book is not good as aluminum is a horrid bearing material unless properly alloyed to be a bearing material.

Check the ball joints at the ends of the steering rack gear.

Check the ball joints at the end of the steering rack that connects to the front upright's steering arm.

Check the front wheel bearings for slop.

Check the lower ball joint for excessive slop (unlikely).

There is a needle bearing U-joint drive shaft between the steering column to steering rack's piñon gear, these can and do wear out.. and the splines on both ends must be proper and the M8 bolts clamping then together must be properly seated.


Bernice

Nice to see you here. We have missed you.

 

[AKimball92]

A little bit of a dummy check, but when you installed the steering link to the rack, did you make sure to push the end coupling down far enough so that the bolt aligns with the radius cut out on the rack pinion?

Even without the pin in place through the groove property or not I can physically see the pinion move with the steering column. Both are moving together through the "firewall".

Sorry for the second reply...

Don't feel bad. More comments makes me feel popular

If you have 3mm of play in your rack it wouldn't steer for **** and you would have noticed it when the rack was out of the car.

I wish I would have checked that before install but didnt think to question a freshly purchased rebuilt unite from one of our trusted suppliers. Also in the car you definitely have to supply a force to get it to slide. I can make multiple turns without it shifting and it's not so loose to shutter or vibrate while driving. The small moment arm or griping the splines bare handed on the workbench might not have been enough then or even now to move it.

 

[AKimball92]

EDIT: Please see my additional comments in post #15 below.

The adjustment shims are available from EuroSport. I believe they have some for each type of rack.

The pinch bolt cannot be installed if the U-joint is not all the way on.

Things like tie rods, trailing arms, susp bushings, etc, will not effect this type of movement. It must be coming from something like the rack itself, the steering shaft, etc.

I agree with each of these points. The pinch bolt maybe if worn or forced enough might be able to be off but I remember it sliding home easily enough when I matched up the splines correctly.

The only thing I could see causing the pinion movement other than the rack itself at fault would be the rack mount bolts loose or firewall flex but I checked the bolts and certainly not enough force to flex the sheet metal.

 

[AKimball92]

The gray TRW unit is the one I removed due to a vibration issue but a total overhaul so I honestly cannot remember what fixed it. The black installed unit is the MWB rebuild. This looks to be inverse of Mike's experience.