S320 W140

[pshawfocus]

Hi All

Virgin to all this so please be kind, gentle etc etc.

Recently splurged and purchased a fantastic S320, '96 on an N. Appears to have been well looked after, good MB service history and drivers pretty much faultlessly (can you feel the but coming along)...

This may well be my lack of experience of driving big cars with such big tyres (I've driven lots over the last 18 years including Senators, Citroen CX's, Scorpios, even the odd Jag) but I'm foxed as to the way forward on this one. The car has what appear to be standard sized alloys and tyres fitted. However, much as the car drives beautifully at speed on the motorway if you take it into town and drive at 30 or even on country lanes at 40-60 it gets very easily "deflected" by imperfections in the road. Apologies for the poor explanation but in some circumstances it feels a little as if the car is driving over a road made from snooker balls - as you fall/climb over bumps (on the left/right) the car seems to get pushed about and you have to make very conscious efforts with the steering to stay in exactly the direction you want to be. Nothing dangerous but it's a more a "peculiar" feeling, particularly as I'd expect such a heavy car to track true over even viscious undulations.

At speed its quite easily deflected by ruts on the inside lane of the motorway which is nothing unusual but it's more around town and up to say 50mph that the problem occurs - it feels as if you're driving around town but the sensation is as if you're at speed on the inside lane of a motorway? Normal bumps - e.g. you drive over a ridge on the left = no problem. It's only when both "sides" of the car are having to tackle different types of undulation - rises and falls on different sides at different times. Drive on a smooth/normal road and it's like a smooth limo again.

I wonder if it's low profile tyres causing the problem (are they actually "low profile"?) and this is just how the car drives or maybe it's the steering that isn't tracking true - it's slightly out of alignment when going dead straight.

As the tyres have maybe 4000m left in them I don't want to repeat the problem by going for the same make - what's the best choice for a fairly relaxed driver around town who likes to go with (e.g. lead) the flow on the motorway? And any suggestions as to the tracking or anything else that could be causing this odd steering?

Thanks in anticipation - next post will be a little shorter!

Gary

 

[jibcl500]

what size wheels and tyres are fitted?


jib

 

[42864]

If as you say you have Low Profile Tyres fitted this may well be your problem, these cars were never designed to be fitted with Low Profile tyres. I have been told by a couple of tyre fitters, DO NOT FIT L / P TYRES ON THIS CAR, apparently the car is "too heavy" to run on L/p tyres, infact I was once told to put commercial vehicle tyres on the car as they would last longer as the car is so heavy (2 Tons)

 

[jibcl500]

Some tyres are made specifically for the car type, Porsche for example have tyres rated for the rear to carry the extra weight on the back so fitting any old 255 on the rear could affect the handling.

Same applies to any heavy car, cheap nippon nevergrips could affect the handling, thats why my CL has conti 255x45 like it was meant too.

jib

 

[kth286]

Sounds like something not right.

A cheap way to get the suspension/geometry/joints/bushes checked is to submit it for an MOT at a Merc dealer/specialist that does their own MOTs and not farm it out.

The tester will know the weak areas and what to look for on the Merc.

 

[pshawfocus]

Sorry for delay. In actual fact the tyres look pretty standard, so I guess they're not low profile.

The size is 235/60 16 inches. The wheels are standard Mercedes alloys. The tyres are BF Goodridge.

 

[pshawfocus]

Thanks David. The car has a brand new MOT from Mercedes Benz of Macclesfield (I bought the car from Cheshire Classic Benz). The infomation on the MOT cert is from the Merc dealer so I'm guessing they do their own MOTs.

Gary

 

[jibcl500]

Well it could be possible the tyres have lost thier structure or shape, the tyres are pretty big and the wall quite tall but if the car has been sat for some time the weight on one part of the tyre couls change its shape.

Might be worth getting the tyres checked, dont forget the W140 S class have a wide track, wider than almost anything else on the raod and driving in the ruts left by trucks tends to pull the car left or right.

Might be worth getting all the suspension joints checked, are there any knocks whist driving?

jib

 

[pshawfocus]

Nope, no knocks or clunks whilst driving, neither is there any wheel wobble. The ride is pretty firm (compared to say a Jag or Lexus) although it doesn't feel "wrong". It deals with single rounded bumps better than hard edged stuff. Speed bumps are pretty ok but those plastic ridges used in car parks to slow you down create a thump (I don't zoom over them but even at low speed you are definately certain you've gone over one).

I wonder if it's the hard side walls as you say. Any suggestions for a Merc specialist garage in S London that can replace the tyres and check the bushes etc? I know from experience that Jags can suffer if their suspension bushes are in poor condition, I guess the same is true of the W140 due to the weight (instead of poor design/cheap materials as in the Jag?).

Either way I'm off to Skipton tomorrow and back via mid-Wales so will give the car a good chance to stretch its legs (and me loose my licence if I'm not careful!). I'll pay attention to the road surfaces/condition and report back anything which might give a hint to the specific solution.

Gary

 

[astradave81]

I'm getting a strange feeling when cornering, if you go round a normal corner its fine but if there is a slight imperfection in the road surface then the car seems to skip sideways as it goes over the bump. My car is a w210 e class. I know its the rear subframe bushes as i've checked them on the ramp at work, i'm just waiting for a day when i can be bothered to change them.. If the rear suspension is the same as on the e class then it could be these bushes also.

 

[pshawfocus]

Hi

Back from Skipton. I reckon it's something to do with the camber of the road - when the bumps/imperfections create a camber on one either side I get the same skipping feeling the Dave is referring to. As it effects my steering could that also mean the front bushes are in need of replacement?

Assuming this is the case any ideas on costs for the front and rear jobs - may as well do them both?

The car is having a drive shaft replaced at the moment to cure a faulty ABS sensor so I can ask the garage (Mercedes - it's a warranty job) to do that as well. I'll ask them to check to make sure our diagnosis is correct. Although if the dealer is going to charge the earth I'll look elsewhere. What do you guys reckon? Am I going to need to remortgage my house?

 

[type49]

Get them to remove & check the steering damper. This will take less than 5 minutes with your eyes closed. A damper costs about £30.