NA Steering Play

[zacMX5aus]

Hi,

I have a 1991 NA MX5 with manual steering and have noticed there is quite a bit of play in the steering when at center. I didn't think it was a big issue until my friend drove it and said it was much more play than he had experienced in his own miata with power steering and with a depowered rack. Has anyone had a similar issue before? Any tips on how to eliminate the steering play?

Thanks

[93_Clubman]

Loose steering on a '94: https://forum.miata.net/vb/showthread.php?t=283747

Front end clunk by cujet with answer by flintzis: https://forum.miata.net/vb/showthread.php?t=54743

[3gress]

In non powered racks the adjuster bolts push down on a spring that loads a concave bush with a roller wheel that travels along the rack. Sometimes enough muck can get in the rack somehow to allow the roller wheel to sieze and start wearing out as well as wearing a groove along the rack itself. This is a worst case scenario thing but any adjustment will just exaserbate the wear leading to more trouble.
If you're going to be playing with the adjustment and lock bolts it may be wise to take them out being careful to pay attention to any shims and remove the spring and bush to inspect for wear on the roller and rack shaft.
I've rebuilt a number of manual racks and found two that were worn beyond repair thanks to the roller seizing. Just be careful to note the sequence of parts during removal to help with reassembly.
Also check your inner tie rod ends, very rarely do they muck up but just to be thorough.
There are needle bearings at the very bottom of pinion that locate it securely in the rack housing. Sometimes these can find a way out (dont know how they do it but they do) and this can lead to the pinion end pivoting about that is felt up the steering shaft as slack in the steering.
If you have checked your wheel is secure, had the bushes, tie rod ends and balljoints inspected you are right to suspect the rack being the culprit.

[93_Clubman]

Ta - useful to know about the roller wheel & needle bearings.

[3gress]

Pic of the adjustment mechanism to tension the pinion against the rack.
The roller inside the bush is just visible. Sometimes this siezes and a flat spot forms. Also visible is the convex end cap that the spring sits in and pushes against the roller. Wear is evident on the end of this cap but still servicable.

Note the shims that are stting in sequence of diassembly. Be sure to reinstall these in correct position.

Post script, sometimes if the car has had a history of modification, the steering wheel boss splines can be worn and result in steering play. You can check for this by engaging the steering lock and trying to turn the wheel. Fixed only by replacing the steering column.
The bolts holding the wheel to the boss can be loose also.

[3gress]

Roller wheel in picture shows flat spot worn after seizing.

Note right end of pinion. This fits down into the needle roller bearings in rack housing.

[zacMX5aus]

Thanks for the lengthy response 3gress, I think I will have to remove the rack and have a look at what the component conditions are and go from there.
You mentioned you have rebuilt a number of manual racks.. do you have any notable resources that might help if I wanted to go down that path myself? any list of components that will be required?

Cheers

[3gress]

The only parts I've had to chase up are the clips that secure the inner tie rod ends to the rack shaft and inner tie rod end boots. I either order from the local Mazda dealer for the clips and miataroadster for the boots.
Spare racks are always good to have about.
You can remove the adjustment components without removing the rack. I pulled my adjuster parts out from my installed rack to take the photos, and dug through the parts pile to find the worn roller wheel.
It is a bit of trial and error to find the right tension after reassembly. I have the car up on stands and tighten the adjuster bolt down until the rack starts to become tight to turn and then back off a quarter turn or so.
Steering play is more likely to be caused by worn tie rod ends or ball joints so visually inspect for tears in the rubber boots or binding while turning the steering with the car on stands.
If unsure have a mechanic check over the front suspension for any obvious issues as it is not something to mess with!!

[zacMX5aus]

A few weeks later and I'm in the process of rebuilding a manual rack to replace my troublesome one.

Do you know where to find replacement dust caps like this one?

IMG_20180116_194359.jpg

Also, is it a good idea to remove the pinion on manual racks? I wasn't sure if this nut is locked into place or if it is okay to remove it.

IMG_20180116_194426.jpg

Thanks

[zacMX5aus]

P.s. I only had one washer under the tension adjusting bolt, is there meant to be three there?

[3gress]

You can remove the outer lock nut and then the inner threaded bush with the proper tool which allows removal/inspection of the rack etc for wear.
Be careful to note number of shims and where they sit. The number of shims vary from the factory it seems.
Also make sure not to lose spring or cap.
Get everything clean, inspect for wear on the roller, the spring cap and rack itself.
To adjust tension of pinion to rack reinstall in car and attach to steer wheel but leave the tie rods free.
I usually tighten the pinion adjustment bush down fairly tight and then adjust the roller bush against the rack until it is as best as i can get it. I then loosen the pinion bush a quarter turn or so to see if rack/ pinion mesh engagement improves. It takes a bit of messing around to get the rack/pinion engagement smooth but it is not hard to get a feel for it.
Hope this helps a bit.
Pic of depowered rack but helps to point out what i mean.
1: is Pinon adjustment bush. Tighten this down first.
2: is roller bush. Tighten this second then loosen first slightly for good engagement. A bit fiddly but...yeah.

[zacMX5aus]

Thanks for the write up 3gress. What is this 'proper tool's you speak of?

There is currently no play that I can feel in this rack I'm rebuilding, so I'm tempted to leave the rack and pinion alone for now, maybe just stick some new grease in where I can and just replace the tie rods. I'm likely to do more harm than good taking the pinion out haha

[3gress]

If there is no wear on the roller wheel that you've pulled out already you need not disturb the pinion.
The tool i use has two pins that fit in the slots on the pinion bush. I bought it from a mower store from memory but you can find them in autobarn or bunnings also.
The rubber cover you asked about can be cleaned with soapy water and then a tiny bit of brake fluid to restore it if it is not too perished or deformed. I'd suggest Amamaya or a Mazda parts counter maybe for acquiring a new one if necessary?
Brake fluid is awesome for restoring unpainted plastic parts like the engine bay undertray for example.
Adam from revlimiter wrote up a diy on restoring his dash with brake fluid and i tried it with great results. Now a standard cleaner i use where possible. I recently cleaned my radiator fan housing and it came up great using brake fluid.
Let us know how it goes with the rack eh'?

[zacMX5aus]

I've been slack with this rebuild but finally getting to putting new tie rods on.
Question though, do you have any images of the needle bearings you talked about? I was turning the pinion by hand and it reached the end and it felt as though the rack disengaged from the pinion. I was able to realign the two and it feels normal now, just wondering if I missed anything up...

[3gress]

Apologies on tardy reply.
Needle bearings fit around this end of pinion housed in the rack body. If they were an issue the pinion would have a noticable galling and weird rotation as soon as you turned it.


If you didn't remove the pinion then the needle bearings would be ok.
Assuming you didn't turn the pinion with superhuman strength it would've just reached the end of the teeth on the rack and would be fine. You could wind the rack along and out one end which would have you messing around trying to get the rack back in and meshing with the pinion teeth again but the pinion wouldn't be able to move upwards out of place disturbing the needle bearings.