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mg_zs
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Discussion Starter #1
My ZS has always been a lot twitchier than my last one since i've had it either because of the suspension or the CV joints on the old one being worn, but since getting it back from the service i've noticed it drifts slightly on one direction or the other under acceleration or deceleration (NOT braking).

It tends to go to the right more than often so is this normal behaviour or do you think I need to change the transmission fluid because the differential is sticking.

I have always been used to the way the car follows the road but this is more noticeable than usual.

Note: I have installed 135 cams but given the engine is doing this at around 3500-4000rpm in 5th and 4th I wouldn't have thought it something that the cams would make the slightest difference on.
 

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You don't say which engine or gearbox.

What mileage is the car?
Manual gearbox fluid needs changing at 90k IIRC.
Not sure about autos.

ZS's don't normally suffer from torque steer.
What condition are the tyres in?
What pressures are you running?
What make are the tyres?
 

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other_manufacturer
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id start by checking track rod ends and ball joints , and general condition of the front suspension areas.
and as above check gear box oil .
 

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mg_zs
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Discussion Starter #4
1.8 petrol manual

about 75,000 the clock.

I'm gonna check the CV joint covers to see if any are leaking.

There's nothing major going on here but it's noticeable enough to wonder if something needs looking out now before it costs a lot later on. My first thought would be transmissiony to be honest. I doubt the engine is doing anything here by itself, which is why my first thought is the differential.

Tyres are all brand new and either Michelin primacy or Yokohama (equivalent tread spec) all tyre pressures checked (one was 34psi the other 33psi)
 

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Worn suspension bushes / balljoints are the most likely cause. Don't forget to check the rear trailing arm bushes too.
 

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mg_zs
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Discussion Starter #6
Appears to be my ABS reluctor ring which my mechanic said was cracked but "shouldn't give me any trouble" despite me asking him to replace it during the service.

I guess this also explains the buzzing noise I keep getting from the right hand side wheel occasionally. (which btw still is there when rolling down a hill with the engine switched off and clutch disengaged).

The CV joints are only a year or so old with no wear or cracks on the gasket and the calipers have both been replaced within the last 3 months so it's going to have to be the ABS reluctor ring just falling apart.
 

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rover_400_95_99
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I suggest you check the reluctor ring yourself - just remove the wheel and look behind the disc. I would be surprised if this was rubbing without affecting the ABS.

As for pulling to one side, if this is transmission related, I'd expect something to get hot.
 

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mg_zs
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Discussion Starter #8
I suggest you check the reluctor ring yourself - just remove the wheel and look behind the disc. I would be surprised if this was rubbing without affecting the ABS.

As for pulling to one side, if this is transmission related, I'd expect something to get hot.
I've got a feeling it may be the wheel bearing. Only happens when I run the engine forward. Doesn't sound like a CV joint would if it went and I've tested it on a hill with no clutch and no engine power so it's happening regardless of torque input.

The ABS ring looks ok tbh and isn't giving me any problems with braking since changing the bound caliper 4 months ago(beyond the usual ****ty ABS you get with all ZS's, I hate ABS in this car and i've driven several. Even when working it still behaves horribly when you need straight line braking).
 

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mg_zs
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Discussion Starter #9
As for pulling to one side, if this is transmission related, I'd expect something to get hot.
Realised what I feared it might have been.

When I last had the cam cover off I dropped a bolt into the engine bay.

Couldn't find it and worried it might have fallen in.

Only just checked it with a stronger light and found it sitting below the water pump pulley.

It's been grinding away at it and that's what's causing the buzzing noise.

Taken the bolt out now. No visible damage to the pulley but it was obviously stuck down there rubbing which explains why it stopped rubbing when I put the brakes on but was still intermittent.
 

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mg_zs
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Discussion Starter #10
Ok, so the problem has exacerbated enormously.

First of all the steering has become lighter and the other day I ended up spinning the car on an exit ramp smashing the front right and pointing the wrong way down the road.

At the time I put this down to the road surface and camber and me just being too aggressive with the driving but since then i've still noticed a that corners i've driven 100x are causing me to uncontrollably drift into the adjacent lane at speeds well below what i'd usually take them at putting not just me at risk now.

The car is driving like it's on ice at high speeds so i'm going to strip out the rear suspension and replace it because the car is now just too unsafe to drive unless i'm doing 50mph everywhere.

It almost feels like the wheels are coming off but they are completely fine. The pressures are all fine, the brakes are fine, i'm even changing the bearings to be sure.

At least my ego has a little less bruising from the crash, but if i'm honest that was still my fault for driving too fast.
 

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rover_400_95_99
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Before you do all that, try borrowing a pressure gauge, or even asking someone else to check the tyre pressures. Personally, I have two that agree with one another (although one is hard to read). I used to have another that was way out - they are not all accurate!

Also, look at the wear pattern on each tyre - a significant issue is guaranteed to show up as uneven wear. Also, depending on the nature of your spin, the problem might be at the rear - specifically, the rear trailing arm bushes are a known weakness.
 

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mg_zs
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Discussion Starter #12
Before you do all that, try borrowing a pressure gauge, or even asking someone else to check the tyre pressures. Personally, I have two that agree with one another (although one is hard to read). I used to have another that was way out - they are not all accurate!

Also, look at the wear pattern on each tyre - a significant issue is guaranteed to show up as uneven wear. Also, depending on the nature of your spin, the problem might be at the rear - specifically, the rear trailing arm bushes are a known weakness.
All tyres are brand new and were balanced and checked within the last month professionally.

It's not the tyres. I've been keeping an eye on them and the change has been progressive not sudden.

Tyre pressure wouldn't cause the car to drift into another lane uncontrollably at 60mph. Not on this corner. I've driven that road over 100x on various tyres and pressures. This car just turned like the differential was locked solid. i.e. tramlined.

Short of turnign so hard that the car spun it wasn't going anywhere.
 

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Worth looking more closely at the rubber?

.......... drifts slightly on one direction or the other under acceleration or deceleration (NOT braking). . . . . . . .
I've had this exact same issue on my 2012 STi. While it would consistently pull right under acceleration and then left under engine braking, it would also pull up dead straight on the brakes.

I swapped the mismatched front pair of tyres (1 pirelli, 1 el cheapo fantastico) for the matched (budget) pair at the rear and the problem went away. I don't know if it was due to the different tread patterns or the fact that one had worn more than the other.

I know you've discounted the possibility of tyres being to blame, but this is my recent (expensive - new pair of P Zeros bought!) experience, albeit on a completely different car :D. Maybe worth another check?

Regardless of what's causing it, I hope you get it sorted quickly (and cheaply!)

Gary.
 

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Did they fit the tyres with the run out stripes correctly compensated. Seen a lot of fitters who have no idea what these lines mean and they can cause issues in the steering pulling to one side.
 

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Did they fit the tyres with the run out stripes correctly compensated. Seen a lot of fitters who have no idea what these lines mean and they can cause issues in the steering pulling to one side.
Had to google this, I had no clue what the coloured lines were for! :) - thanks Stu.
 

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mg_zs
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Discussion Starter #16
I had originally put it down to tyre squirm as I had stress tested them on several roads I knew very well what the limits were and got an extra 10 mph out of them before progressive loss of grip. No major slip.

But this came on out of the blue almost a few weeks later.

Having spun out and crashed the car in the wet I discovered the dampers are basically.....******...both rears.... The left is the worst.

With the new car I have new bearings to fit and sususpension that feels way more stable son the car is getting stripped.

I imagine the dampers won't have any give to them when I take the wheels off.

The car drifted into another lane by itself soon after I had got over the crash.
 
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