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Title: steering rack Post by: tonylanciabeta on December 20, 2008, 11:52:19 PM From: budgerian (Original Message) Sent: 22/09/2008
I seem to have too much play in the ZF power assisted steering rack in my HPE VX. When I wiggle the front wheels from left to right I can clearly see unwanted forward and backward movement in the center of the rack. Obviously this makes the car a little more unpredictable and stable then it should be. Can this be fixed without replacing the entire rack? If so how? Is the bush that beta boys sell only for the TRW rack, or for my ZF rack? What is it's function. I have not yet looked at the internals of the rack, so I have no idea what causes the play. All I know is that there is no play in the track rod ends and no play whatsoever in the steering column. Any help or advise will be deeply appreciated. Roger From: hutch6610 Sent: 23/09/2008 First things first - the rack bush you talking about Part no: BBB08 by chance - if it is i haven't a clue where it fits either, it looks like a bush that fits into the steering column - please put me out of my misery somebody? Anyway lets forget that - if you have play when you wobble your wheels with the car on stands and you see the track rods moving in the centre, check that they are nice and tight first - remove the safety clips (if still fitted) and tighten the two bolts up - mine were loose! Check the rubber bushes on the track rods themselves, they do wear out being fairly close to the exhaust - and these were worn also on my car! Also check the rack is not moving on the bulkhead - just chucked that in to make double sure. If the bushes are good and the bolts are tight then the chances are that you could have wear in the rack itself and i would not advise you to attempt to fix it at the best of times. Shimming is involved, seal kits etc etc - better take it to the professionals and have it overhauled. Its usually caused by age or running the car with the protective boot split, dust and muck gets in onto the "rack" itself and the inevitable happens The rack is supposed to have grease smeared on the the teeth and this is what lubricates the pinion also where they make contact - so you can imagine what would happen if dust/grit were to get in. BUT you "should" have play in the steering column also from what you describe - while the car is on the road, hold the wheel with your palms and rotate any free play in the wheel, can be anything from 1 - 5mm. I have about 1.5 - 2.5mm play and it does not inspire confidence when you throw the car around bends or doing about 100mph on the motorway does it? Oh ... one last thing, check the universal joints in the steering column itself - you never know. From: Omicron Sent: 24/09/2008 They slide in the end of the steering rack (non-pas). From: hutch6610 Sent: 24/09/2008 13:46 Thanks allot - clears that up. So wont be any use for your power assisted rack. From: budgerian Sent: 28/09/2008 19:50 Thanks for the info guys. Hutch, I hope it's one of the things you mentioned, I'll have to check when I'm able to put the car up on a ramp next weekend. Where are these rubber bushes situated that you mentioned? Are they inside the rubber gaiters? Are these the ones I read about people replacing them with a piece of coolant hose? I have yet to find an exploded parts diagram of a zf steering rack, to clear up what could be causing the play. If anybody's got one, could you put a picture up here or mail it to me at ramegens@home.nl ? Giving the general condition of the entire suspension, the steering gaiters and the track rod ends, I'd be surprised if the rack itself is faulty, but one must not assume ofcourse.. Roger From: hutch6610 Sent: 28/09/2008 I should have made myself a little clearer about the bushes. First set to check are the ones on the track rods themselves - that's the rods/arms the track rod ends are attached to - Just follow them inward toward the steering rack and you will see them bolted to the middle with 19mm bolts if i remember correctly. There are two metal clips to stop them coming loose - prize them off with a screw driver carefully and don't loose the little "rivets" that hold these to the reinforcing plate. As i said, tighten them up with a ring spanner or breaker bar and socket, you may have to turn the steering a little to get the tool on correctly. Now the other bush i mention actually goes around the rack itself and a metal "D" shaped plate secures it to the bulk head - its just to insulate the rack and allow a little "give" to save your mechanical components. If you are a aero modeller you will know about the cushions used on servos to save wear and tear on the gears inside - does exactly the same for the rack on the car. I have a decapitated HPE bulkhead with the rack bolted to it - to convert earlier manual rack cars to power so i will dig it out this week and take a couple of photos - i think its easier than trying to explain. |