W126 420SEL front suspension.

[RT 420SEL]

Hi folks, I am hoping for some advice/clarification on 420 SEL front shocks.
I have a 1986 420SEL that has a very smooth/comfortable ride. Also a late 1989 420SEL of which the ride is distinctly firmer than the 1986.
I plan to change the shocks on the 1986 first but want to identify the correct Bilstein B4 model.
Part numbers for Standard shocks: 24-011839.
Part numbers for HD shocks :24-005012.
I cannot find any info relating to the suspension type on the car apart from removing a shocker to identify a part number. The 1986 is a far superior ride with the 1989 being quite harsh.
Ideally, I would like both cars to have the same smoother/comfortable ride as the 1986. How can I technically confirm whether the cars have standard/HD front suspension apart from the ride quality itself?
Any thoughts or info? Thanks. Rich.

 

[c107]

They both should be similar.
Do they both have the same size wheels on the car? I bought a W126 with 17s and the ride was very harsh. Only the full hydro cars would have a good ride with wheels over 16".

Also, sounds simple, but have you checked the tyre pressure? ride is much harsher at 40psi than 30.

Those shock part numbers look right to me. If the shocks are old, its probably worth replacing the fronts in any case. personally I would go with standard if it were my car - I'll be doing the fronts on my 560SEL early next year to replace the pedders garbage on there.

Have you also checked the other suspension components for wear? E.g. control arm bushings and so on?

 

[Styria]

If your two cars have self levelling suspension units at the rear, it could then be possible that the Air Pressure Cells (if they have them) are not functioning correctly. Perhaps you could advise or clarify if you have an Oil Reservoir located at the right hand front as seen from the front of car. Regards Styria

N.B. As C107 correctly stated, tyres can dramatically affect ride comfort as can tyrepressures.

 

[RT 420SEL]

Thanks Bryce & Styria. Both cars have 16" wheels, good tyres with correct pressures.
They also have rear SLS which operates well with adequate fluid.
The firm ride is from the front end definitely & the difference between the 2 cars is noticeable.
I had planned to replace the shocks on both cars but want to ensure I purchase the correct type-standard or HD. Both front ends are in sound condition, with work done recently on the 1986.
Looks like I may have to find the part number on the old shocks to confirm. I thought it would be listed on the spec plate or owners manual.

 

[c107]

Thanks Bryce & Styria. Both cars have 16" wheels, good tyres with correct pressures.
They also have rear SLS which operates well with adequate fluid.
The firm ride is from the front end definitely & the difference between the 2 cars is noticeable.
I had planned to replace the shocks on both cars but want to ensure I purchase the correct type-standard or HD. Both front ends are in sound condition, with work done recently on the 1986.
Looks like I may have to find the part number on the old shocks to confirm. I thought it would be listed on the spec plate or owners manual.

The bilsteins you buy direct are slightly different to shocks you get if you buy them from Mercedes-Benz. Mercedes set their own parameters and Bilstein are not allowed to sell these shocks to the public. They have their own offerings that are very similar, but slightly different. The closest to the factory shock is the comfort model. If the shocks are still original, they probably have the MBZ part number. Its likely they were changed at some point though.

The only exception I can think of is if your car has the options ticked for rough roads and was sold originally in Africa. Doesn't seem likely.