TECHNICAL SERVICE BULLETIN FOR BMW Z4
SI B 54 03 03
Special Roofs
August 2003
Service Engineering
SUBJECT
Convertible Top Hydraulic Pump Damaged by Water
MODEL
Z4 E85
SITUATION
Some vehicles may experience a failure of the soft top hydraulic pump, and when the pump/ motor assembly is removed from the plastic housing, it is found to be damaged by water.
CAUSE
The plastic housing is not adequately sealed, allowing water to enter and eventually build up to the point that it destroys the pump motor.
CORRECTION
The sealing system to prevent water entry into the housing will be improved in production shortly.
The improved sealing method may be used on earlier cars that experience this problem to prevent any repeat failures.
PROCEDURE
If a pump/motor assembly has been damaged by water, replace the assembly as described in Repair Instructions, Section 54 34 005, and seal the housing as described below prior to reinstalling the top assembly.
Note: In order to clearly show the placement of the sealants, the illustrations below do not include the hydraulic lines and electrical wires. When performing this repair, use care when installing the pump assembly so that the seal around the wires is continuous.
As illustrated, run a single piece of butyl cord (2), part number 81 22 9 407 639, around the lower section of the housing (1) on the lip. Note that the butyl is not run in the area between the arrows where the hydraulic lines clip to the housing.
Install the top portion of the housing (2), and press the two halves together so that the retaining dips snap into place. Some of the butyl cord will squeeze out from the joint.
Fasten a strip (3) of black cloth tape or black duct tape to the housing starting at the retaining clip on the mounting side and continuing around to the mounting flange. Press the tape firmly into place on the housing and on top of the wires and hydraulic lines.
Fasten a second strip (4) of tape over the first, starting at the mounting flange and continuing all the way around to the other side of the mounting flange.
__________________________________________________
Here is a picture of a damaged top motor from water:
