W168 ASR, ESP and stability - where exactly is the problem?

[dtr]

My little A class handles well at normal conditions on good well-surfaced roads.
Unfortunately, the car is in Bristol and not in Germany. As you have guessed there are not so many good roads here (thank you Bristol council). The surface is very bumpy, almost as if the tarmac was damaged by tree roots and moles. A class doesn't seem to like that and the steering wheel starts to wobble out of the bumps. It almost feels like the car is doing it itself. Slippery white road markings seem to have some effect too. When that happens I have to hold on to the steering wheel and try to keep it steady.

I did a hard breaking test from 50-60 mph (only did once so far just to test it when it was clear behind me), and the steering wheel starting twisting and pulling the car to left and then to right. I had to balance it myself with quite a lot of force.

Yesterday, I disabled ASR when moving, and I *think* stability clearly improved back to "normal". ASR comes back on after a couple minutes so the workaround is not very practical.


Any ideas if such behaviour can be treated - or is it "normal" for a Merc?

 

[A140driver]

That sounds completely normal in a W168, swb especially, I'm afraid. Ride quality is poor in the A-class, generally. If you hold the steering wheel properly it's not too much of a problem, and you do get used to it. I can't say I've ever felt the W168 is unstable, though it is very sensitive to road surfaces.
In terms of the ASR, it comes back on automatically at 30, and there's really not any point in switching it off. How you drive it will affect the way it rides too. Any car will be affected in some way by such a poor road surface, and in these cases, you've just got to be careful. Roads around here are awful, but you've just got to adapt your driving to them. If you drive quickly over bumps in an A-class, you'll soon be looking at new rear springs and new rear trailing arms.
Your braking issues could be due to warped discs, or just a poor surface.
The classic, and Elegance models do tend to ride better than the Avantgardes though.

 

[dtr]

That sounds completely normal in a W168, swb especially, I'm afraid. Ride quality is poor in the A-class, generally. If you hold the steering wheel properly it's not too much of a problem, and you do get used to it. I can't say I've ever felt the W168 is unstable, though it is very sensitive to road surfaces.

Your braking issues could be due to warped discs, or just a poor surface.
The classic, and Elegance models do tend to ride better than the Avantgardes though.

I have Avantgarde . I can hold on to wheel, but I don't have any trust in the car, and have to go really slowly if I feel there is any danger ahead... more so than with my first car - clio II 1.2.

The discs were described as 'slightly worn' in the last MOT. It may be time for a replacement then. Which are better (more efficient) - plain or etched / drilled ones? I don't care about the looks.

The previous owner put crazy 17" AMG alloys on it. They may look "cool" but I bet it doesn't add to the ride quality, or affordable tyre selection. Is there any merit in swapping for 15" alloys with quality new tyres? Somebody may want to "upgrade"? The current tyres are some budget hungarian brand with some thread left, but some uneven wear (just been tracked in Kwikfit). I don't think I would even remotely consider new quality tyres for 17" wheels (£700 that could be better spent elsewhere).

Finally, front suspension is raising me some suspicion. When I break, the car leans forward, and then bounces back... Is it time for new front shock absorbers?

 

[A140driver]

The 17" alloys will definitely be a contributing factor I'd say, as they have a very low profile, and are unlikely to be the wheels your car arrived with. If you can find some correct 15" Avantgarde items for your car, it should make quite a difference, and I imagine that you'll get a good sum for the AMGs. I assume that the car doesn't have AMG bodystyling and that the current wheels were fitted by a previous owner. Uneven wear will certainly have an effect on the way the car drives.
In terms of brakes, the standard items aren't too bad, but make sure you go for decent quality ones, ideally MB, as they're cheaper than some unknown brands, from what I remember.
Easiest way to assess the front shocks is to push the front of the car down, and if it bounces back up and stays there, then they're fine, but if it continues bouncing, then they are getting worn.
Any photos of the car with its current wheels?

 

[dtr]

Any photos of the car with its current wheels?

I don't think it has any AMG styling, unless I missed something

 

[Howard]

The A classes were offered with 17 inch AMG's from the factory , so not that crazy.

Tyres ( Falken 452's ) for those wouldn't set you back more than £300 ish.

I suspect you may have something wrong with the car , as ours doesn't pull violently from side to side under even heavy braking. The fact that you have uneven tyre wear points to something not being right.

 

[A140driver]

Is there any accident damage?

 

[dtr]

Is there any accident damage?

Nothing major. An old guy recently dented the rear door, but that was far too weak to have caused any component damage, according to my local mechanics. I have no idea what the previous owner did to it, but there are no signs of accident repair.

 

[Howard]

Have you had it tracked properly ( not at Kwik Fit ) ?

It will lean forward when you brake heavily , as the weight transfers , but it should return after one 'bounce' not keep going.

 

[dtr]

Have you had it tracked properly ( not at Kwik Fit ) ?

It will lean forward when you brake heavily , as the weight transfers , but it should return after one 'bounce' not keep going.

It does return after a single 'bounce' and steady up.
The only tracking was done at Kwak Fit, as as I have a few vouchers after their last royal f*** up with breaks on my previous car .

P.S. Where exactly do I need to look to stop that fuel smell? I can't find the source of the leak.

 

[Howard]

At the back of the engine , under the airbox are two rubber pipes .

Have a read of this , this helped me to cure the smell in our car.

Bert Rowe's Mercedes-Benz-'A'-class info. Fuel Flap lock, Fuel Filter, Fuel lines, Petrol Tank, Petrol Pump, Fuel Level Sensor.

 

[derin100]

Rather than re-start a whole new thread I discovered this thread and would rather resurrect it.

I've recently purchased a little '53 plate W168 A140 for the kids to learn to drive on. It's a very clean, relatively low mileage vehicle with only 41K miles on the clock.

I too have noticed that under "firm" but not even really heavy braking that the car feels unstable just as the OP described. It lurges forwards but also the front "squirms" left and right and I have to hold on to it to try to keep it straight.

I'm a quite experienced driver and I'm aware of it but I'm worried the kids might not be able to react to this.

I don't normally have any FWD cars. Is this "normal" for a W168 or is there something wrong? It almost feels like some weak bushes at the front end or weak shocks?

Thanks in advance