10 replies to this topic

[roblightbody]

Hope someone can give me some guidance.

My Mini is just back from getting a thorough going-over by a long established Mini expert, but I'm left with one long-standing issue.

When at speed (maybe 50+) the car starts to feel more and more vague on the road, until i have to really concentrate to avoid swerving. Its hard to describe. I *think* it might be because there's no response to small steering wheel movements. At slower speeds it feels absolutely fine.

Its on the original Rover alloys, on good Yoko tyres all round, with camber, caster and tracking all checked and correct all round.

I've been driving Minis most of my life, so have encountered most problems, and don't remember coming across these symptoms before.

My Mini expert, who I'll not name here, thinks it could be because the rear shocks are too firm. Its on gas a just ones from Mini Spares - a mild upgrade on standard I thought.

Edited by roblightbody, 27 November 2020 - 02:39 PM.

[sonscar]

Rear radius arms worn,loose,badly adjusted perhaps?Steve..

[Stevie W]

Hi Rob,

 

Also worth checking the steering rack “U” bolts & nuts are nice and tight. If these are loose it will give you the feeling your getting of the car wandering about on the road.

 

Cheers, Steve.

Edited by Stevie W, 27 November 2020 - 03:56 PM.

[cal844]

Also make sure there isn't any side to side movement of the rack and then inner components

[Spider]

I'd say there's not enough Toe Out on the front wheels and / or possibly not enough Toe In on the rears, but I'd say it's the fronts.

[Cooperman]

I'd say there's not enough Toe Out on the front wheels and / or possibly not enough Toe In on the rears, but I'd say it's the fronts.

 

That is exactly what I was thinking, Chris. It could be a very slight toe-OUT on the rears which can cause exactly this symptom.

OP check front & rear tracking again. If work has been done on the rear sub-frame or radius arm brackets the setting might be slightly out. It doesn't take much in respect of either front or rear track to cause a steering problem in a straight line. Whilst you are doing tracking, you might want to check the camber of the rear wheels. Ideally you want zero to -0.5 degres negative on the rear.

[roblightbody]

Thanks guys.

I'm told that it's now got 1/2 a degree negative for rear camber and parallel or a small amount toe in on the rear tracking, and the front tracking is correct (don't know the measurement though).

The rear camber was badly out before he fitted adjuster brackets and corrected it as above. Fixing this helped my cornering but hasn't changed the vague feeling.

It's got zero advisories on it from the MOT centre my mini guy used so I genuinely don't think it's something routine.

Sorry for being naive but do steering racks just wear out at some point? The car although fully rebuilt ten years ago, has got over 100k on it and I'm guessing it's the original rack.

[sonscar]

Not all MOT centers are equipped or have the knowledge to correctly test old cars as some only see newer models.(part of the reasons for 40 year exemption)plus some assessment of wear is subjective(worn to excess)this does not mean a "dodgy" MOT.Some cars are more susceptible to wear,Chect carefully with wheels on ground as far as you can.Good hunting,Steve..

[richmondclassicsnorthwales]

I had this with one of my Minis

 

What I found was that you seemed to have to steer the car to get it to do what you want, and that the car seemed to have a bit of a mind of its own

 

I found that the top suspension arm bearings were very stiff, and I mean "Stiff" This was more so on the radiator side

 

Just thought I would drop this one in - You never know. Just ideas for the pot

[Spider]

I'm told that it's now got ,,,,,,,,,,,, parallel or a small amount toe in on the rear tracking, and the front tracking is correct (don't know the measurement though).



Sorry for being naive but do steering racks just wear out at some point? The car although fully rebuilt ten years ago, has got over 100k on it and I'm guessing it's the original rack.

 

 

The Rear Tracking needs to be more than Parallel or 'a small amount'.
 

And yes, more than the Rack could be worn, though, usually with a worn rack, the car will tend to pull right on power and left on the over-run (in a RHD Car), but other parts, particularly the Suspension Rubbers will have deteriorated in that time and with those miles on it.

 

As the car increases in speed, the tracking forces on the wheel increase and can be in a big way. Certainly on your Rear, with Parallel Tracking, just with the minute play that will be in the Swing Arm Pins and Wheel Bearings the tracking will pull Toe Out as speed increases. Also, there is well enough forces in play here at 50 mph (and more) to flex the rear arms, they are very springy and surprisingly flexible, which is part of the reason why Minis appear to have a lot of Rear Toe in, to ensure that under all driving conditions and speeds that there is always Toe In. As speed increases, because of the design and layout of the rear swing arms, they naturally want to go Toe Out.

As Cooperman mentioned, it only needs the slightest Toe Out on the rears for the car to become vague.

[roblightbody]

Thank you for all replies so far, really interesting thoughts from everybody.

 

I will come back to this topic once i figure it out, but I think it will be next year now, the car is away in the garage for a few months.