disco_al Posted July 2, 2012 Share Posted July 2, 2012 Right, here's a good one. Mates 90 has developed a bit of a rear steering issue. Everything underneath has been changed - new springs, shocks, bushes, track rods, A frame ball joint & bushes have been changed as well. It's on a Terrafirma medium duty setup, with castor corrected hockey sticks, and corrected trailing arms as well. But - it's crabbing. The best description i can give is that it feels like it's turning again half way through a corner, but not all the time - if that makes sense. Example, your followng a constant radius curve in the road, so the wheel is at a particular angle, then halfway round, the vehicle moves, and you have to correct the steering. Following him down the road, you can see that it's crabbing, but on level ground, everything measures up ok, so it only appears under load. The only thing left to change now is the panhard rod bushes, would those make such a large difference if they've gone soft? (It was fitted with orange polybushes throughout - but now has the harder blue ones from Bearmach installed - apart from the panhard rod) We do have a RTC steering damper to fit, but i don't think that it will alter the way things are feeling. It's not wheel/tyre related either, as he has tried it with one set of wheels with worn tyres, and another set with virtually new tyres on < 500 miles on them. Any ideas oh wonderful forum guru's???? Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted July 2, 2012 Share Posted July 2, 2012 As they've been changed, I would be looking at the tightness of the bushes. Things like A-frame bushes need to be ridiculously tight to not move about. Quote Link to comment Share on other sites More sharing options...
Diff Posted July 2, 2012 Share Posted July 2, 2012 Apart from panhard bushes, I would also check the tracking. If the tracking is not set correctly (too much toe out most likely), it can cause the mid corner handling problems described. Regards, Diff. Quote Link to comment Share on other sites More sharing options...
robertspark Posted July 3, 2012 Share Posted July 3, 2012 A frame ball joint sticking? How did he press it in (not via hammer)? Thought I'd ask. Is there anyway to pull over when it happens (gently) and have a look and shake thinks about. Seems like something may be binding, ...... something like over tight / stiff trailing arms to axle bolts + bushes, maybe need a bit or wear / copper grease? Just guessing here Quote Link to comment Share on other sites More sharing options...
Tanuki Posted July 3, 2012 Share Posted July 3, 2012 You did remember to reassemble everything 'loose' then tighten the nuts/bolts to the final required torque only when the vehicle has its weight fully on the wheels? If you tighten everything up with the vehicle jacked/wheels hanging/suspension at full deflection, you will have all sorts of odd and undesirable pre-loads in the suspension bushes. I'd suggest slackening the bolts where the hockey-sticks attach to the axle-bushes, do the same for the A-frame-to-chassis bushes and the panhard-rod at the front, then drive *slowly* forwards and backwards a few times (5-10MPH is all it takes) so everything can settle. Then park up on level ground, and torque all the nuts/bolts to the specified values. Pedants would add a 175-pound weight to the driver's seat before doing the final torquing. I've never bothered. --Tanuki Quote Link to comment Share on other sites More sharing options...
Briarston Posted July 3, 2012 Share Posted July 3, 2012 Crabbing is usually due to the axles being out of alignment. Change of turn radius suggests to me that one of the axles is moving on the radius arm bushes. Does it "self steer" when changing from power on to over run throttle? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.