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Hydraulic pump bypass jammed open

Discuss problems you have had or are having with your Z4
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Rudi
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Joined: Mon May 22, 2017 12:44 pm

Hydraulic pump bypass jammed open

Post by Rudi » Mon May 22, 2017 1:02 pm

Hi I bought an 05 Z4 a few weeks ago and the roof needed a push to get it to open although it closed fine. I did a bit of research on this forum as a guest and as a result relocated the pump and motor to the boot. The motor was all gunged up so ran it in diesel for 20 mins and works fine now. The opening was still needing help and i reckoned maybe the pump bypass was slightly open so I took off the bowden cable activator and i discovered the bypass gold ball seemed to be seized. i pushed it in but now it wonr spring out again! it seems to be seized so now i cannot open the roof with the buttons only manually! Any ideas for to free up the bypass ball or will I have to get a new pump? Any advice would be much appreciated. I'm new to this forum but having viewed as a guest I think it has a host of good ideas and experience.

Dietcokeman

Hydraulic pump bypass jammed open

Post by Dietcokeman » Wed May 24, 2017 10:52 am

Just try lubing the ball and mount and work it in/out with a round ended implement,so you don't damage the ball, and it should free up.

Rudi
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Joined: Mon May 22, 2017 12:44 pm

Hydraulic pump bypass jammed open

Post by Rudi » Thu Jun 01, 2017 12:29 pm

Hi
Thanks for that. It worked and ball is now free. However the roof is still not opening without some assistance.
Its closing fine. hydraulic pump not losing any fluid. Any ideas? Could the motor be weak or could the pump be faulty?
any suggestions would be appreciated.
Thanks.

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mac27040
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Hydraulic pump bypass jammed open

Post by mac27040 » Fri Jun 02, 2017 1:18 pm

i have the very same issue, i have replaced the motor and still the same :headbang:
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Dietcokeman

Hydraulic pump bypass jammed open

Post by Dietcokeman » Fri Jun 02, 2017 7:42 pm

Ok so if the roof un latches and the windows drop but the pump won't push the roof down then I'd suggest either the motor is weak in one direction or you have a kink in a hydraulic line .

If the motor has been relocated this is possible , to check if the motor is at fault swap over the hydraulic pairs of pipes and see the the roof now opens easily but struggles to close. If this is the case then the motor is probably the cause, I did have a new recon motor that was like this once , if it's still the same then you have a linked or blocked hydraulic pipe .

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