ausmini :: View topic - Riddle me this

Last car I saw and fixed with this problem (Monster Mini's) it was one steering arm a little loose on the swivel hub.
As TheMiniMan predicted. He was right again!

Last car I saw and fixed with this problem (Monster Mini's) it was one steering arm a little loose on the swivel hub.

It might sound like an odd question but whats it like in reverse ?

If you reverse hard in a straight line and back off does it still track true ?

I would remove the bolts on both the steering arms, and make sure the dowel bushes are not loose in either the arm, or the swivel hub (more common, these hubs are only cast iron). If hub is worn, bin it and fit another.

If the subframe has ANY twist in it it will do exactly ^ what you have described.

........and in those if I lift off, I have to be awake.

Author:	sgc [ Mon Nov 14, 2011 2:22 pm ]
Post subject:	Riddle me this
OK, so I've had this car for about 15 years now and whenever I've had the hydro suspension up off the bump stops, it's always done this, but I've never figured out why. Under acceleration and braking (any amount), it goes straight as a die, even hands-off. Transitioning from off- to on-throttle, the car turns right a little. Going on- to off-throttle, it turns left the same amount. When balancing the throttle just on overrun, the car squirrels around as it tries to decide where to go. This isn't a massive change of direction; I correct it subconsciously with maybe 5º or 10º of steering input, but it can be disconcerting if you're not used to it, and can make the car a handful in the wet. Since I've had it, I've almost completely replaced the front suspension -- adjustable lower & caster arms (including all bushes), tie-rod ends, top suspension pin on the LHS, it's had new engine mounts and steady bar bushes in addition to two lower gearbox steadies, new hubs/uprights and ball joints. It's been professionally aligned several times and always sets up properly, without play or slop. So yeah, I'm a bit stumped on this one...

Author:	Lillee [ Mon Nov 14, 2011 4:05 pm ]
Post subject:
Sounds like a steering rack problem?

Author:	74snail [ Mon Nov 14, 2011 5:01 pm ]
Post subject:
I,ll have to dig up the thread where Matt " I,m still here " MiniMan explains that one , at least I think I,m remembering what I think I am Wait a minute or three , maybe more oh and the other one was the engine rocking on the engine mounts and twisting and unloading on acceleration and braking , even more so if both the engine mounts and engine stabilizers are worn and you have only one or two exhaust pipe mounts and the rubber has gone allowing some forward/ backwards movement which of course would give the motor even more room to move and twist changing the weight distribution but you have replaced all that , so I,ll try to dig up the thread .

Author:	sgc [ Mon Nov 14, 2011 5:22 pm ]
Post subject:
Almost 100% certain it can't be engine mounts, and it's definitely not the stabilizer bars - it has 4, two top and two bottom, all with new bushes... The steering rack is the obvious candidate, but even when it was newly reco'd this still happened. But even then, why does it steer ONLY on the transition between on & off throttle, and only when the car is up off the bump stops? That's what has me stumped...

Author:	sgc [ Mon Nov 14, 2011 5:26 pm ]
Post subject:
Oh, and it only takes the faintest amount of throttle input either way from being perfectly balanced between on- and off-throttle and zip, it changes direction.

ausmini https://www.ausmini.com/forums/

Riddle me this https://www.ausmini.com/forums/viewtopic.php?f=2&t=74128	Page 1 of 2

Author:	drmini in aust [ Mon Nov 14, 2011 6:05 pm ]
Post subject:
Last car I saw and fixed with this problem (Monster Mini's) it was one steering arm a little loose on the swivel hub. As TheMiniMan predicted. He was right again!

Author:	74snail [ Mon Nov 14, 2011 6:14 pm ]
Post subject:
drmini in aust wrote: Last car I saw and fixed with this problem (Monster Mini's) it was one steering arm a little loose on the swivel hub. As TheMiniMan predicted. He was right again! That might have been the thread or similar I was thinking of , my search came up zip, nada , nothing It might sound like an odd question but whats it like in reverse ? If you reverse hard in a straight line and back off does it still track true ? If you reverse hard in a straight line is there a difference in steering left or right when you don,t back off ? I,m just trying to think through whats loading and unloading .

Author:	sgc [ Mon Nov 14, 2011 6:58 pm ]
Post subject:
drmini in aust wrote: Last car I saw and fixed with this problem (Monster Mini's) it was one steering arm a little loose on the swivel hub. Pretty sure these are tight (they've been done up and undone several times with all the suspension work), but I'll check it out. Thanks for the suggestion! 74snail wrote: It might sound like an odd question but whats it like in reverse ? If you reverse hard in a straight line and back off does it still track true ? That, sir, is an excellent question! I fang it backwards up the lane each morning, I'll see what it does tomorrow. Never thought about that one

Author:	sgc [ Mon Nov 14, 2011 7:04 pm ]
Post subject:
While I think about it, a little background and history... When I first bought this car and took it to be registered, I had to pass inspection at VicRoads (the Victorian RTA at the time, that's how long ago it was ) Toby at Mini Spares & Repairs in Seaford did the roadworthy on it for me, and part of that job was to pump the suspension up to legal height so it would pass muster. That was when I first discovered the problem; with the standard-geometry suspension it had at the time it steered pretty violently left and right coming on and off the throttle. Once I got the plates, I took it right back to Toby and told him to drop it down again, it was scary! It seems the adjustable arms have dialled lots of this behaviour out, but it's still there a little. Still can't figure it out...

Author:	drmini in aust [ Mon Nov 14, 2011 7:10 pm ]
Post subject:
I would remove the bolts on both the steering arms, and make sure the dowel bushes are not loose in either the arm, or the swivel hub (more common, these hubs are only cast iron). If hub is worn, bin it and fit another.

Author:	sgc [ Mon Nov 14, 2011 7:59 pm ]
Post subject:
drmini in aust wrote: I would remove the bolts on both the steering arms, and make sure the dowel bushes are not loose in either the arm, or the swivel hub (more common, these hubs are only cast iron). If hub is worn, bin it and fit another. Yep, I'll do that. As I think I mentioned above the hubs are new (or were so a couple of years ago) so I doubt it's them, but the arms were carried over, so that's definitely something to look at.

Author:	GT mowog [ Mon Nov 14, 2011 8:33 pm ]
Post subject:
It could be the total geometry being different from one side to the other, that is as the suspension works through it's full range of movement, remember that a wheel alignment is static and doesn't (usually) check it at all suspension arm positions. If the subframe has ANY twist in it it will do exactly ^ what you have described. Could also be in the rear subframe, I doubt it, but don't discount it.

Author:	sgc [ Mon Nov 14, 2011 9:47 pm ]
Post subject:
GT mowog wrote: If the subframe has ANY twist in it it will do exactly ^ what you have described. This has been my suspicion all along, actually. Since fitting the fully adjustable arms it's got a lot better mainly since I can balance the caster from side to side -- this at least has the car tracking straight under power and braking. It's just the sensitivity right on the point of overrun which I don't understand - it really is a very small margin of throttle load which causes the movement. It doesn't matter either how much steering lock I have on -- there are a couple of long 270º freeway on-ramps near my daily drive and in those if I lift off, I have to be awake. You can really feel and predict the movement too -- as soon as the engine weight shifts forward or backwards with the throttle: bingo, change of direction. Very sensitive.

Author:	adamstuart [ Mon Nov 14, 2011 10:21 pm ]
Post subject:
How much twist is too much twist? I measured how square my spare subby was today, and it was 8mm out of square Something like 30cm and 30.8cm front corner to opposite tower (obviously wasn't 30cm, but you get the idea) Is it too twisted to bother using? When Warrick Augustin put my moke together, he said my other subby was a bit out of square, but was acceptable What do you think GT?

Page 1 of 2	All times are UTC + 10 hours
Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/

Author:	GT mowog [ Tue Nov 15, 2011 4:05 am ]
Post subject:
sgc wrote: ........and in those if I lift off, I have to be awake. Check the rear wheel toe IN, but DO NOT have it checked wheel to wheel, but EACH wheel the the car centre line. You should want about 1/32" to 1/16" on EACH wheel to the centre line.