Editing Replace the steering rack (section)

==Reconditioning==
[[File:Elise Steering rack exploded.jpg|thumb|Exploded diagram for rack with plastic bushes]]
The rack is made by [http://www.titan.uk.net Titan Motorsport], and they will sell all parts to the public on the condition of a £25 minimum order value. And to be honest, they are very helpful too!

I removed my rack as there was play, which I suspected to be the nylon cups at the inner end of each track rod.

I ordered 2 of the cups (£3.50 each), 2 of the springs that sit behind the cups (£ ), 2 of the locking pins that lock the cups to the locking nuts (£ each), and 2 gaitors (£4.50 each).

[From Titan Motorsport, March 2007: A1161611200A3 - £3.35EA - Nylon shoes, A1161610900A3 - 52p - Spring, A1161916700A3 - 28p - Locking Pin.  Note: There is a minimum charge fee of £25]


This seems to be the most common cause of play in the rack.


You will need to source grease to re-build your rack.  The "rocol MTS1000" is now know as "rocol Sapphire hi-pressure bearing grease" and the "scheerol mpt2 grease" is actually called "spheerol mp2".  [A recent thread reports Titan use MTS1000 which is slightly different from the Sapphire product and still available. Spheerol MP2 has been replaced by Spheerol EPL2.]  I sourced this from RS but there are other places that sell them.  Note 400g is a lot but that was all they had at the time I ordered.
   RS Stock No. Qty Unit Price Goods Value Description 
   198-3136 1 £2.82 £2.82 Spheerol MP2 bearing grease,400gm 
   330-6288 1 £14.15 £14.15 Sapphire hi-pressurebearing grease,400gm 
   288-4793 1 £6.00 £6.00 Pocket spring balance w/hook & ring,30kg 
  Running Total £22.97   
  Delivery charge £4.95   
  VAT £4.19                  Order total £32.11   


Start by removing the cable ties that hold the gaitors on and sliding the gaitors back to the track rod ends (I left the track rod ends in situ, the theory being the tracking wouldn't be too far out when I put it back together).

This exposes the inner ends of the track rods and the cup joint that they sit in.

You will see that the cup joint has a locknut. Between the lock nut and cup joint body there is a small locking pin (roll pin) that needs to be carefully drilled out (using a 2.5 / 3mm drill bit).

Once the locking pin it removed, it should be possible to (carefully) clamp the rack bar in a vice and undo the locknut using a 32mm spanner.

Once the locknut is released, the cup joint will unscrew from the end of the rack.

Remove the cup joint noting the nylon cup and spring that are in there.

Repeat for the other track rod.

Before reassembly (using new sockets) you need to hone the new sockets to the ball surfaces using a light grinding compound. If this is not done the required load setting will be lost within a few hundred miles.

Upon reassembly the two joints should be tightened to a point where a load of 3 to 4 Kg, applied 152mm down the track control arm from the centre of the ball in the joint (ie right near the end), is required to move it. Lock at this point, re-drill, and pin. A centre punch on the end of the locking pin will spread it slightly, securing it. 

At this point, I'd noticed that my rack preload seemed far to loose, in that I could turn the pinion shaft with just my finger and thumb, and that when I did this the rack, to my mind, sounded "noisy". There was also one point in the travel where it went "tight".

I made the decision to strip down the rack and re-lube it.

First step in doing this is to remove the pinion. To do this, first undo the Rack Bar Thrust Pad bolt locking nut using a 36mm spanner, then back out the thrust pad bolt using a 5.5mm allen key. Then remove the circlip that holds the pinion assembly in. You can then gently tap out the pinion, for example by mounting the pinion in a vice and gently tapping the housing with a rubber mallet. It doesn't need very much force at all. The pinion will come out with a bearing still attached. This will need to be pressed off if you want to replace it.

Carefully withdraw the rack from the end of the rack body. Finally you can push out the second bearing and the alloy blanking plate. Finger pressure is enough.

You can then carefully withdraw the rack from the end of the rack body.

After a bit of cleaning and degreasing, I found that the internals were pretty much fine, with the exception of a marked tooth on the rack which was causing the tight spot I'd noticed. I just dressed this with a fine file.

Upon reassembly the Rack Bar Thrust Pad should be adjusted to give a preload that allows a horizontaly mounted rack to be pulled along its entire length by a force of 50 - 70 N.

Here you find some pictures of a dismantled rack: http://silverdreamracer.de/steeringrack/index.html