Bilstein B12 Kit on 300CE Sportline

[rayhennig]

I’m starting this thread so that interested parties can share my experiences with the old 300CE. I sometimes get the impression that forum members are very active when they need information but dry up once they’ve solved their problem, depriving us all of the answer.

My car is a 1991 300CE-24 Sportline. I’ve had it since 1998 when I bought it from a Mercedes showroom in France with 135 K Kms on the clock. I’ve always had a bad feeling about the straight-line handling of this car and recently (early 2008) I have decided to do something.

All garages have reported ‘no fault found’ and the car has consistently passed its CT (MOT here in France). Members of various forums have made comments and recommendations that have been helpful and these are very gratefully received.

The general consensus has been that I should ensure that the existing suspension components are in good order and that alignment is correct on all 4 wheels before spending on replacement springs and dampers. So I’ve done exactly the opposite!

In truth, I have tried to solve the vague handling before replacing the springs and dampers but the garage here is adamant that there is no problem with the other components. Also, I do accept that, in all respects, the car is better now at 320 KMs that it was when I took delivery with its 1 year European MB warranty and that this is due to the efforts of my local garage. Whether this garage is right or wrong, only time will tell. I am treating them as innocent unless proven guilty!

I do intend to get a second opinion when I’m next in the UK with the car. I’ll approach Colin Ferns (if in London) or Oliver Stoner (if on the south coast) and request an in-depth check and alignment. My thanks go to both for their helpful comments to date.

So, I recently selected a Bilstein B12 spring and damper kit to be the replacement for the original Sportline setup. I was careful to calculate (using Bilstein’s recommendations) the points value of my vehicle and to select the correct kit.

That’s where the first question arose. My front points value was borderline between the heaviest duty front springs and the next ones down. I chose the heaviest springs because it felt like a safer bet. Not only that but a UK MB specialist (Colin Ferns) kindly calculated the value himself and arrived at a higher figure. So, the kit SE5-8172 was chosen and, oddly, turned out to be about £30 less than all the others in the W124 Mercedes range (why, I wonder?).

11 April 2008
Car goes to garage with more instructions to ensure all suspension components are in good order BEFORE installing new springs & dampers.

15 April 2008
Collect car after installation of B12 kit and inspection of all suspension/steering components for wear. I am assured that all suspension components are fine.

I test car on local roads (narrow, twisting, undulating and bumpy country lanes). The verdict:

1. Immediate impression is one of surprisingly little change.
• Ride height very similar – garagiste estimates 10 mm lower.
• Ride quality similar – no greater roughness.
• Slight tendancy (very slight) to pull to the right. Wouldn’t notice this without taking hands off wheel. A separate issue, perhaps.

2. Start to ‘press on a bit.’
Appears to corner flatter.
Turn-in seems more immediate and more ‘confident’ if that word’s relevant.
Feeling in corners is more positive. I’m beginning to WANT to corner more quickly. There’s less slack in the handling.

3. I do seem to be driving more quickly! Is this a good thing?

4. We hit a familiar straight, narrow, bumpy section around 2 kms long.
Suspension feels positive so I accelerate.
Bumps absorbed nicely and no feeling of harshness. Springing over this poor surface is not uncomfortable.
Towards 130 kph. We maintain a straight trajectory with no weaving. I want to believe that the old motorway/sidewind stability problem’s solved but it’s early days.

5. Slower now and into corners. I do feel there’s a greater degree of confidence.
Hairpin bend taken nicely and another very low speed one taken smoothly.

Conclusions - 15 April 2008

1. Lack of drama has come as a shock but perhaps this is a good thing. We’ve got a lot of rough roads around here and we could do without rock hard springs.

2. I want this car to be useable and not give grief over speed bumps, so lack of drop is good.

3. We need a high-speed run next.

More as it happens!

[mrnickleye]

So I was wondering about this. I live in the high desert in Calif. High winds are common. My Toyota Supra sits tight on the road, and I never feel any concerns for stability.

But I just got this 1990 300CE 3 months ago. It tends to be a bit 'drifty' in the winds.

It has new heavy duty bilstein shocks. All new steering linkage ends, steering shock, etc. New performance tire on
17" wheels. recent 4 wheel alignment by the best shop in town.

Everything is tight, and handles great in all other areas.

I figured it was because the aero-dynamics aren't as good as the Supra, but after reading your post, I am thinking its just the way this car will be.

[rayhennig]

I've grown used to this over the years but I don't accept it.

Next week the car will be with a UK specialist and I may have some answers.

Watch this space.

RayH