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  #1  
Old 12-17-2001, 10:48 PM
Robert Boyer
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W126: lowr front end than rear.

I think some of my front-=end discomfort is because the front rides higher than the rear-end, and this distributes too much weight to the front and compresses the springs somewhat. Here's my theory as to why:

A few months ago, I had the 'bright' idea of putting Bilstein HD's on the rear, and Comforts on the front.

Do you think if I put the HD's on the front as well, that this would improve the situation? I mean, I could try to adjust by putting thicker spring pads in the front to raise it an inch or so. Which approach (or both) do you think is best?
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  #2  
Old 12-18-2001, 11:49 AM
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Join Date: Dec 2001
Location: Plattakill, NY
Posts: 137
not sure about this exact application but rear has more general effect on the ride comfort than front. I would not think it would be a good idea to mix types of shocks unless it has been tried before. (and with the price of these shocks I would not be the one doing the experimenting!) If the ride is uncomfortable I would think the likely culprit would be the rears. Of course those are the ones that are more expensive! Not sure I under stand how "front rides higher than the rear-end, and this distributes too much weight to the front and compresses the springs somewhat." If the front is riding higher then the springs are compressed less not more. It could be a result of the different shocks. If you are finding the ride to harsh I would think the answer would be to change the rear to comforts (assuming they are softer). It may feel that the harshness is coming from the front but it usually comes from the rear. It could also be somthing else perhaps a good shop could clear it up.
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Currently
1991 Mazda Miata 174000
1991 Subaru 189,000 Winter beater

got rid of:
1984 VW Vanagon 195,000
1976 350SE Euro 185,000 KM
1973 280SE 4.5 (boy do I regret that)
1980 280SE European W126 4 speed manual (miss it)
1989 BMW 735iL 119000 (good riddance)
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  #3  
Old 12-18-2001, 11:54 AM
Robert Boyer
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Sorry!!

I meant that the front is riding LOWER than the rear.

So you think changing the rears to comforts is better than putting HDs on the front or thicker spring pads on the front?

The only thing that makes me hesitate to changing back to comforts in the rear is that they have drmatically improved handling on a car of this size.
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  #4  
Old 12-18-2001, 12:02 PM
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Join Date: Dec 2001
Location: Plattakill, NY
Posts: 137
actually it makes sense as the hd has higher gas presure than the comfort. (I believe it is the pressure or the valving) If you like the way the hd's handle then I would go with them up front but it will come at the cost of some ride comfort. unfortunately we cannot have our cake and eat it too. I personally am not interested in the handling of the big sedan as I have a Miata for that kind of fun and really enjoy a soft and cushy ride. We have really bad roads in upstate NY and any kind of performance suspension can get real harsh. But I would think it would make sense to have the shocks match. Have you had any change in over/under steering? Funny thing is the Miata all I want to do is change it but the Mercedes just stays stock, except I want to add some stereo stuff, now that is a can of worms best left unopened!
__________________
Currently
1991 Mazda Miata 174000
1991 Subaru 189,000 Winter beater

got rid of:
1984 VW Vanagon 195,000
1976 350SE Euro 185,000 KM
1973 280SE 4.5 (boy do I regret that)
1980 280SE European W126 4 speed manual (miss it)
1989 BMW 735iL 119000 (good riddance)
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  #5  
Old 12-18-2001, 12:14 PM
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Join Date: Dec 2001
Location: Plattakill, NY
Posts: 137
Come to think of it you may have nothing to loose to try the spring pads as they are likely much cheaper than shocks and could resolve the issue but I doubt it would help much but may be worth a try. If you do not like the results you may be able to return them if you get them from the same place you are going to get the shocks from, as an exchange. would not hurt to give it a try! good luck
__________________
Currently
1991 Mazda Miata 174000
1991 Subaru 189,000 Winter beater

got rid of:
1984 VW Vanagon 195,000
1976 350SE Euro 185,000 KM
1973 280SE 4.5 (boy do I regret that)
1980 280SE European W126 4 speed manual (miss it)
1989 BMW 735iL 119000 (good riddance)
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  #6  
Old 12-18-2001, 12:17 PM
Robert Boyer
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Thanks, Boat. But why don't you think the higher spring pads wouldn't help? wouldn't that relieve some of the compression on the front springs from the rear being a bit higher and resultant offset in proper weight distribution?
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  #7  
Old 12-18-2001, 01:53 PM
PaulC
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Robert,

I'm assuming the lower front ride height is the result of sagging springs. While higher spring pads may restore the ride height, bear in mind that the springs will still be shorter than normal, and will not offer you a full range of travel, particularly under compression. Age, use and possibly corrosion has caused the spring (compression) rates to change. Handling and ride will not return to Mercedes specs simply by the addition of the pads.

Other than under heavy braking, I can't see how a difference in front vs. rear ride height would have any material effect on dynamic weight distribution. Obviously, static weight distribution would not be affected.

Another matter to consider: Like most modern cars, the front suspension is designed to allow the wheels to move slightly rearward when the front suspension is under compression. This rearward motion allows the suspension to absorb some of the shock of hitting a road defect (pothole). If the chassis of your car is not perfectly parallel to the road surface (as it would not be in the event of sagging front springs)the wheels would move in a more vertical plane than intended under suspension compression, with loss of this shock absorbing ability. There goes the ride.

As an aside, other elements of the front suspension geometry (caster, camber)would be affected, causing a decline in handling abilities. If my preceding thoughts are less than clear, imagine this: an entire front subframe and front suspension (absent the rest of the car) moving down the road at speed, reacting to bumps and corners as designed. Now imagine tilting the subframe, and therefore the front suspension, forward a few degrees. Think the suspension will still perform optimally? Not a chance.

This is my long-winded way of concurring with your idea to restore front ride height, but not by rubber pads, by buying 4 new springs.
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  #8  
Old 12-18-2001, 03:34 PM
Mattman
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If you are going to change the spring pads you would be advised to change the springs at the same time. The labour cost to change the pads is the same as it is to change the springs. Pick up a set of front springs from a dismantler near you. Go and have a look at a wrecked 420 and get some springs from it if it looks okay. In your last posts you were talking about front ride height. From what you have said in your earlier posts I don't believe that the front is the problem, I think it is probably the rear that is causing the harsh ride. Certainly the rear springs could be sagging, combined with the harder valved shocks and the standard front this could be causing all your problems. I would message the clearance of the front and rear wheels on both sides and post here, hopefully someone with a 420 can respond and confirm which end is not at the right height. I would also guess that the cd should have this info so someone could look it up for you.

Cheers
Matt.
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  #9  
Old 12-18-2001, 03:42 PM
Robert Boyer
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Thanks. I think that new springs all around are probably in order, even if that isn't clearly the issue.

By the way: My ride clearance i9n front is about 31/2 inches between top of tire and opening on rt. front, 1/2 inch less on left front; rear has about 31/2 inches clearance on both sides - which may be a touch high. What do you think?
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  #10  
Old 12-19-2001, 12:56 AM
BigPimpin
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Hey- thought I'd help out. '88 420SEL ride height:

Front Left- 3"
Front Right- 3 1/2"
Rear Left- 2"
Rear Right- 1 3/4"

These measurements are with a sagging rear end, before I got new springs in the rear only. The springs raised it about a 1/2" on each side I think, and improved the ride and handling significantly.

From what I've read, the rear subframe mounts tend to go bad on 126's, can anyone comment on this?
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