Steering rack play?? and solution??

[Griff]

In the process of removing the engine to sort out the clutch release bearing/arm problem, I decided to investigate further into the apparent "play" in the steering. It's not bad but is more than I would expect.

 

1) Ball joints and tie rods all OK

2) No play in the column, UJs etc

3) Quick release has the usual small amount of play

 

The play seems to be at the pinion and searching the archives I see several comments referring to an allen screw plus dire warnings about setting the right

end float, not over-tightening etc.

 

The cure is to loosen the big locknut on top of the rack above where the pinion enters and adjust the central allen screw to remove some slack then retighten the lock nut. If you do it too much then the rack goes tight.

 

BUT...when I remove the big nut on top of the rack there is just a plastic plate below this, no allen screw or anything else that appears to be adjustable. Does this plastic plate flick out or am I missing something obvious and fundamental?

 

Regardless of the play at the pinion, when I peeled back the end rubber gaitors and gave the end of the rack a good shake (or wiggled the wheel) you can detect a bit of lateral play in the rack. I'm not sure if this is due to a loose pinion or if there are bearings that are damaged/worn.

 

With track day season approaching I'm only going to repair if this is a simple and straightforward process, otherwise will order a new rack.

 

All advice gratefully received.

 

Cheers,

Mike

[James_Russell]

Are you sure the play isn't at the inner trackrod ball joint(s)- where the track rod enters the rack? Every time one of my racks has developed play it has been cured by tightening these ball joints (well, actually my dad does it for me because I'm scared 😳 )

[Phil B]

Mike,

I had some play in this area and traced it to worn bearings supporting the pinion.

 

You need to take the rack off to replace these, but its not a difficult job, the bearings are a standard size available from bearing factors and cost me around £15-20 the pair. You will need to split one of the inner ball joints to slide the rack bar out of the way to get the lower bearing out.

 

Phil B.

[Griff]

That was quick - thanks both.

 

I've just checked again and 100% sure the play is in the rack/pinion, not the tie rod inner or outer ends, nor in the column itself. So perhaps the bearings supporting the rack are a possibility - but here's an odd one?!

 

On checking both ends, at the near side there seems to be a bearing or at least the rack housing comes right to the end and prevents the nut and tie rod housing/nut from entering the rack body.

 

At the off-side the housing is larger and the tie rod housing/locknut go inside at full lock. There doesn't seem to be any bearing in there and this also seems to be the end with the most lateral "play". This begs the question, should there be a bearing and if so what does it look like? Anything too thick will restrict full right lock and I also don't see any means of securing a bearing (circlip etc), so perhaps it's not meant to have one?

 

Phil - when you slid the rack back out of the way, did you have to release the tension from the pinion via the allen screw under the big nut on top of the rack? I'm referring to the screw I don't seem to be able to find unless its under the plastic plate? Did you do this job in-situ or with the rack removed?

 

Does anyone have a set of photos showing a dismantled rack? That would be a great help.

 

Cheers,

Mike

[Phil B]

Mike,

If you e-mail me on philblagden(at)aol(dot)com, I will dig out an article and drawing i found relating to overhauling an Elise rack, which is a Titan unit so very similar to that used by Caterham.

The bearings I refer to are 2 ball races which support the pinion, so they are in line with the steering column. They do not support the rack bar itself, but if they are worn they will allow the pinion to effectively wind itslef in/out across the rack bar which gives a small clunk as you rock the wheel. MoT tester spotted it for me as a small movement of the universal joint, but he is a friend no worries.

 

Phil

[Griff]

Thanks Phil - I've emailed you.

[Stationary M25 Traveller]

BUT...when I remove the big nut on top of the rack there is just a plastic plate below this, no allen screw or anything else that appears to be adjustable. Does this plastic plate flick out or am I missing something obvious and fundamental?

The big nut is a lock nut around a smaller screw, which has a socket in the outer end of the screw. Maybe it all came out together and looked like one piece ? Look under the crap and see if you can find the socket, so you can hold it and turn the nut. May be easier off the rack, on the bench ?

 

I just did mine, and it solved the play. Screwed the inner screw in by hand, and held it while I tightened the lock nut. Cleaned all the threads up while apart and used CopaSlip.

 

Did it with the front wheels off the ground, so I could check the steering travel from lock to lock. Also removed the inner (rack) end cable tie from the offside gaiter, so I could apply lots of grease and oil.

[Griff]

The shame...

 

I tracked down a 36mm AF socket and managed to remove the "cap" after a little struggle. Close inspection showed this was indeed two pieces, the female top and the thin locknut. Not that you'd know with the 5 layers of bitumen it had been liberally painted with.

 

After removing the worst of the paint the thread above the nut was revealed and the nut could then be eased further up. The little "airhole" in the middle turned out to be the missing hex socket, nearly sealed with paint. A quick trial refit later and I was able to find the perfect point between zero play and tight rack.

 

So this evening's first job is an easy clean up and final refit...the second is to take the engine out and sort the clutch arm and CRB, not quite as quick and easy.

 

Sorry to make a drama our of a crisis

[Stationary M25 Traveller]

Hurrah

[samsul]

Are you sure the play isn't at the inner trackrod ball joint(s)- where the track rod enters the rack? Every time one of my racks has developed play it has been cured by tightening these ball joints (well, actually my dad does it for me because I'm scared  )

Hi, I have the same issue. Could you explain exactly what needs to be tightened on the rack please? Thanks, Sam

[SM25T]

Holy thread resurrection Batman !!

[SamC]

Sam, 

I had the same issue and it was solved by changing the rack and pinion preload. At the bottom of the column where it joins the rack there is a bung that adds the preload and a large hex locknut around it to lock It. 
 

Mark a line on the centre bung through the lock nut and onto the housing with a sharpie. The only lines you're interested in are the centre bung relative to the housing. Slacken the locknut, do a 5 degree turn of the bung then tighten the lock nut. This will likely move the bung too. Check If you still have play by turning the column with your hand. If you haven't, take the car from a drive and check that the wheels can self centre ok. It's an iterative process between backlash and self centring. Took me three or four run outs to be happy. 

If the play turns out to be the ball joints on the rack then I believe only Titan can sort it.

[samsul]

Sorry for thread resurrection!

The play is only on the passenger side track rod. I removed the gaiter on that side and confirmed the play is definitely in the track rod / rack interface, so assume it's the ball joint/bearing. I am not too sure where to go from here. Will do some ringing round tomorrow!

Thanks for all the help, Sam