Strange steering problem when lifting off the gas

[Steve A]

When i take my foot off the power the car pulls quite a lot to the right and when i put my foot back down it pulls a little to the left. If i dip the clutch and brake it brakes in a straight line. Under constant power it seems to drive straight enough, its just when you take your foot of the gas and the gear slows you it seems to be at its worst? It does it most of the time. Any ideas what to check first?

[InimiaD]

Check the tie rod/s front mounts first. Are your nuts tight. (should rephrase that really).

[Steve A]

I could do with getting it on a ramp really but i thought if they were loose it would happen under braking as well but it could be a possibility. Might sound odd but could it be the diff causing it? Its a cross pin diff if that means anything?

[InimiaD]

The diff was going to be my next suggestion.
Something to do with biasing if my memory serves me correctly. It needs to be shimmed properly and preloaded.
It's a long time since I rebuilt a box, so excuse the vagueness.

[Steve A]

I am a complete novice when it comes to gearbox's but i had it rebuilt 120 miles ago. It is a 1128 casing with close ratio gearset and hardy spicer outputs. It had a new cross pin diff fitted along with 3.1 final drive and new baulk rings. I imediately had a problem with a weak gearchange and unless careful it crunches when shifting down into 3rd. As the engine had been rebuilt at the same time i was going to put 3 or 4 hundred miles on it before fetching it back out to sort the gearbox. When i picked the gearbox up from being rebuilt i noticed that the washer and nut were not right the way home properly on one of the output shafts so was told to loosen it off sit the washer correctly and tighten it back up. I am now wondering if there is something sinister going on with the diff?
If the steering problem is due to tie rods or some movement somewhere surely this would happen under breaking? It seems to happen mostly under deceleration?
Could it be a driveshaft problem? though i don't know how?
Incidently the hub assemblies are all new and i did have the steering arm work loose after 100 miles for no apparent reason as the locktabs were still in place, this was subsequently nipped up.

[66S]

I reckon this might be a diff problem too. Put the car in 1st gear and rock it back and forth. There should be very little free-play but I reckon yours may have quite a bit. I've struck it before.

Al

[Steve A]

How much is a little and how much is a lot?

[Steve A]

Just tried it and doesn't seem a lot but i have nothing to compare it to?

[66S]

I thought you might ask that !! I can measure it at the weekend using a car that I know is fine. This test is by no means definative but just trying to come upo with a way you can quickly check it.

Al

[guru_1071]

sounds like the diff pin is about escape through the back of the case.

might be worth draining the oil out to see what you find

[1071 S]

"...but i thought if they were loose it would happen under braking..."

So you brake without lifting off first??

Maybe the easiest starting point would be to cup the tie rod end in your hand (make sure you're holding the tie rod and subframe bracket) and push the car back and foward (about an inch will do). Is there any movement in the tie rod end???? You will feel movement that may not be visually obvious.....

No movement ? OK, now look somwewhere else...

Having had a tie rod end come adrift (at about 10 mph) I can assure you - this is somewhere you do not want to go.....

Cheers, Ian

[guru_1071]

id jack the front up and put it on stands, then get someone to grip one wheel whilst you try and turn the other back and forth.

then if you both 'back and forth' the wheels - but one going back when the other goes forth, you will be able to judge the amount of backlash thats in the diff.

if you get a pair of mates to wobble the wheels whilst you listen up near the diff you may hear the clonking.

sounds like whoever built the box didnt do a very good job

[Steve A]

It had been mentioned when the engine and box first went in that the diff sounded a little noisy but it has gone quieter now the problem has started odly enough. I am really p--sed off with the gearbox to be honest as when i asked the guy to rebuild it he asked me the spec and if i wanted a cheap job or a proper job and i said i wanted a proper job as i didn't want to fetch it out again, he said you won't have to. Famous last words. He has however offered to help with removal and strip the gearbox down and sort it out which is fair enough. I just want to find out what this weird steering problem is first in case its nothing to do with the box and i'm barking up the wrong tree.
Its going on the ramps tommorow and i'll have a good look and report the findings cheers Steve

[Frogeye61]

I for one am very doubtful that a diff could cause this steering problem.
I've worked in garages for more than 20 years and whenever this type of steering problem show up, it's inevitably tie rod ends. Though I one time had a 911SC with a defective rear tire that caused a similar result. Ball joints or other looseness in the front suspension could also cause this.
Happening only on acceleration and not deceleration or braking indicates nothing more than that the suspension is in the "normal" position when both decelerating and braking, and pulled out of normal position when accelerating. (or vs.vs)

[Steve A]

It seems to happen on deceleration only when NOT using the brakes. As soon as you lift off the gas in fact. Under braking it is straight no problems. It's going on the ramp tonight so I'll post my findings

[Steve A]

Mystery solved.
Got it on the ramp tonight and couldn't beleive it, there was movement in the drivers side steering arm so we undid the two bolts holding it to the hub and removed to find there were NO locating dowels fitted! I had previously found a little movement in the passenger side but just nipped it up thinking that was all it needed.
These hub assemblies were new and built up by my local mini specialists who will be getting a piece of my mind when i see them next. Negligent and downright bloody dangerous i would think .
The only thing i can think of was during deceleration different forces are applied than when braking?
The mini specialist doesn't feature on this forum so not to confuse them with more qualified traders on here.
I am now going to check every nut and bolt they have touched as its not the first thing i have found.
Thanks for everyones help and suggestions and hopefully a lesson to be learnt here.

[InimiaD]

We take for granted that (supposed) Mini specialists can do even basic maintenance and repair tasks on our Minis. It beggars belief that these so called experts can make a dogs dinner of putting a front hub together properly.

Thankfully the problem was found before any serious harm came to you, your Mini and any third parties.

[rolesyboy]

Sounds similar to the situation I had re steering arms. It is such an easy thing to overlook when you have a million parts in front of you. Glad you found the problem and so glad it wasn't an expensive and time consuming engine out job. Mark

[Steve A]

I have had good experiences with mini 'specialists' but unfortunately not this time . Thankfully there was a happy ending but it makes you wonder and a little nervous especially as i do like to 'drive' mine
The car is now a joy to drive i must say just got to get some miles on it to run it in. Just hope the weather is kind in the next couple of weeks.