Almost done
The steering rack came off on Monday, and the biggest problem was three of the four bolts used to attach it to the chasses snapped. I had soaked them well in WD40, but they were completely stuck in the rack. In hindsight I should have worked a bit more on them, but I guess I was a bit anxious to get the rack off. The track rod ends came off easily with the tool I bought, so getting the rack out was easy once the bolts were off.
I then stripped the rack and found the failing bush. Interestingly, it showed no obvious signs of wear, but putting my finger in it, and pushing it back and forth, revealed the play it had. I think the rubber has just detoriated/softened up over time and wear. The bronze bush inside was without signs of wear. For some reason I thought both sides of the rack contained this bush (even though the drawing didn't show), but there's only one. The other side is fixed by the spindle.
The first photo, where I'm pushing the bush on one side, shows the narrow gap between rack wall and bush.
Another thing I didn't realise, was that the new bushes which I got from Simon, are complete with inner sheell and rubber, but molded in plastic in one piece. Oetker sent me a used bush with metal inner shell which was without play, but I decided to use the new bush anyway since I think this (newer) construction is as good or better than the old one made of solid rubber, vulcanised on the shell.
With the rack completely stripped, I needed to attend to the still-stuck bolts. With the help of fellow Murena owner Jan and good amounts of heat, I got the remains out. One bolt was a little tricky, but once it was out by a little, the top of it could be cut off with an angle grinder and it could be pushed out.
Unfortunately, while beating the bolts with the rack suspended in the vice after heating, the aluminum broke in two places. This was quite unfortunate, but not critical at all. But if you go the same route as I, take care to suspend the rack in such a way that the aluminum is not torn.
Reassembling the rack was easy with grease applied liberally. One note has to be made regarding the rack tensioning system, which is adjusted by the bottom nut.
The workshop manual says to adjust it so there's no knocking sound when turning. My experience is that with no weight on the rack, you won't hear any knocking, so there's no way to make the adjustment with the rack off the car, or even with the wheels lifted off the ground. Fortunately, the nut and bolt is accessible from the front compartment, if you lean your body well down and reaches under the rack. Have a helper (e.g. a son!) turn the steering wheel for you, and adjust it until there's no knocking. Then give it 15 degrees more. Lock it with the lock nut. Take care not to turn it to the bottom, as the tensioner will then be locked on the rack with the spring not able to "give" it the play it requires. If you feel it reaches the bottom, loosen it until it starts knocking again, then start tightening again.
I left the original tie rods on the rack (I only removed the LH side to get the rack off), but the RH tie rod end had a slight amount of play, so that is being replaced. Unfortunately, finding them here in Denmark, isn't that easy, but a local shop managed to find one in sock somewhere in Aarhus, and it's now with the a mechanic who's fitting it and adjusting the toe in.
By the way - when the rack has been disassembled, the steering wheel will no longer be pointing straight. The steering takes a full 3 1/4 turns lock-to-lock, so the way to set the steering wheel right is to turn go to the full stop, then turn 1 5/8 turns back. Take the steering wheel off the column, and refit it pointing correctly. Then adjust toe-in to make the car go straight.
My initial feeling is that the handling is improved, but I'll let you know when I get it back from the mechanic.
The last picture shows the rack installed. Note that I've fitted the four bolts upside down compared to the factory. It's easier this way, and if the new bolts get stuck, it won't matter. The top right one, however, has been fitted from the underside. And yes, I did fit the distance plates correctly under the rack - this is an important point as I know of no way to adjust the rack to sit horizontally.