Suspension - Shock/Strut Replace Guidelines

Suspension - Shock/Strut Replace Guidelines
Date: June 4, 2008
Order No.: S-B-32.25/19e
Supersedes: P-B-32.25/19d and T-B-32.25/20b dated October 18, 2007
Group: 32
Revision History
Revision Date Purpose
2000 Mercedes Benz Truck ML 55 AMG (163.174) V8-5.5L (113.981) 334
e 6/4/08 Replacement Procedure & Applicable Models Updated
d 10/18/07 Paragraph 1 Updated (statement of Tech. Documentation and EPC)
c 7/18/07 Addition of Note Pertaining to 211 / 219 Airmatic Struts (Section 1)
b 5/5/06 Applicable Models Updated
a 3/15/06 Applicable Models and Replacement Procedure for ABC Struts Updated
- 12/30/04 Initial issue
SUBJECT:
All Model 124, 129, 140, 163, 164, 170, 171, 201, 202, 203, 208, 209, 210, 211, 215, 216, 219, 220, 221, 230, 251 and 463 Vehicles
Replacement Procedure of Shock Absorbers and Suspension Struts
It has been noted that shock absorbers and suspension struts are repeatedly being replaced in pairs for no justifiable reason. When a repair
requires the replacement of a shock absorber or suspension strut, only replace the damaged part, unless otherwise noted in technical
documentation or the Electronic Parts Catalog (EPC).
Note:
There will be increased focus on the compliance with these rules when performing warranty parts inspection. DO NOT replace
non-damaged shock absorbers or suspension struts. Warranty claims will be denied in cases where a shock absorber or suspension strut
was replaced needlessly.
1) Guideline for Airmatic air suspension struts (Model 164, 211, 219, 220, 221, 251), ABC suspension struts (Model 215, 216, 220, 221, 230),
and ADS suspension struts (Model 129, 140, 210)
Note:
Not applicable to AMG 211 and 219 Models (211.076/077/276/277 and 219.376/377)
Damage to one suspension strut does not justify the simultaneous replacement of the opposite suspension strut. This also applies to complaints
of noise, such as thumping. In such cases, thorough diagnostics to such cases, thorough diagnostics to determine the responsible suspension
strut should be performed by driving each side of the vehicle on a road surface corresponding to the customer complaint. Only the affected
suspension strut should be replaced.
Prior to replacing the suspension strut in the semi-supporting systems ABC, Airmatic air suspension, or ADS, relieve the tension on the
respective suspension strut to check whether this remedies the noise complaint. To do so, loosen both the upper and lower mountings on the
rear suspension struts and retighten to the prescribed torque with the vehicle resting on its wheels.
Experience has revealed that for the front suspension strut, it is sufficient to carry out this procedure on the upper mounting only.
Since it can be assumed that a new Airmatic/ADS suspension strut installed in a high mileage vehicle, would not match with the used
suspension strut and thus impair ride comfort and or vehicle dynamics, it is then recommended that these components be replaced in pairs only
after the vehicle has reached a mileage of at least 50,000 miles (~ 80,000 km). In the cases where a strut may have been previously replaced,
the mileage differential between struts must be at least 50,000 miles (~ 80,000 km) in order to replace in pairs.
In contrast to Airmatic/ADS suspension struts or conventional shock absorbers, the ABC suspension struts do not have to be replaced in pairs
at high mileages (50,000 miles / 80,000 km) as the damping of the vehicle body is taken over by the active actuation of the plunger.
2a) Guidelines for conventional shock absorbers (Models 171, 203, 209, 211 and successor models)
Damage to one shock absorber does not justify the simultaneous replacement of the opposite shock absorber. This also applies to complaints
of noise, such as thumping. In such cases, thorough diagnostics to determine the responsible shock absorber should be performed by driving
each side of the vehicle on a corresponding road surface. Only the affected shock absorber should be replaced.
Since it can be assumed that a new shock absorber installed in a high mileage vehicle, would not match with the used shock absorber and thus
impair ride comfort and or vehicle dynamics, it is then recommended that these components be replaced in pairs only after the vehicle has
reached a mileage of at least 50,000 miles (~ 80,000 km). In the cases where a strut may have been previously replaced, the mileage
differential between struts must be at least 50,000 miles (~ 80,000 km) in order to replace in pairs.
2b) Guideline for conventional shock absorbers (Model 124, 129, 163, 164, 170, 201, 202, 208, 210, 251, 463)

For these models, there exist various shock absorber variants. Thus requiring that the conventional shock absorbers be replaced only in pairs.