Problem with Top Hydraulics - HELP!

[mdooling2]

2007 Z4 top stopped working. Rear motor would run, but no movement.

Hydraulic motor was sitting in water like everyone else's. The hydraulic motor was replaced. Top functioned with new motor while on shop floor.

Once installed, top would not move, although motor running strong. Motor was detached from frame while top was still attached to car, and the top worked. Re-assembled, top not working again.

Something is up with the hydraulics. Do you think it's the manual bypass cable? Is it so sensitive that shifting the position of the motor could change the tension and put it in manual mode? Any ideas?

[wonkydonkey]

It sounds like it's bypassing or the reservoir is low on oil.

1. On each of the two occasions where the new motor did work correctly, was the bypass valve operating cable connected or not?

2. Were the plastic housing and lever arm fitted to the pump body or removed?

3. Has the motor been fitted back down in the body cavity or has it been relocated to the boot? If you went with the latter option (therefore making it accessible), try removing the plastic housing and lever arm associated with the bypass valve (three small allen screws). Now try your roof. Still no joy? Press the brass bypass valve in a good few times (it should return by itself each time you let go). Now try your roof.

The bypass valves can get sticky and need freeing off with WD40 or similar. Mine sometimes partially bypasses when I'm operating my roof, so I need to give it some attention.

[mdooling2]

Wonkey Donkey - you got it right. The manual release cable was sticky. Shifting the motor positions was causing the cable to change tensions, which explains the intermittent operation of the motor. Thanks for you suggestions!!

[wonkydonkey]

Wonkey Donkey - you got it right. The manual release cable was sticky. Shifting the motor positions was causing the cable to change tensions, which explains the intermittent operation of the motor. Thanks for you suggestions!!

Good result!