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Old 04-07-2019, 12:50 PM
crosboe crosboe is offline
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Ideas on draining hydraulic fluid from Z4 ?

Hey guys,

I have a 2004 Z4. The roof stuggles to open and close. To the point now it works good in the beginning of the season and stops after a month or two all together.

This year it won't budge.

Latches work fine, and motor is whirring strong. I think it's a hydraulic fluid issue, but
every dealer I speak with wants to take the whole thing apart for thousands of dollars. It's just not worth it with the age of the car, to drop like 3 grand to fix the roof when the cars probably worth less than 9 grand now. And yes, I've read about all of the issues with the tops in these and am aware of them all.

I had just set the red ring in the boot to stay open and manually use the roof. I loved this!

My issue is the roof, is it's getting harder and harder to open and close manually. I'm 6'4" so easily can reach to open and close roof while sitting in the seat.

Pretty much i'm wondering, if I drain the hydraulic fluid, would I be able to more easily maneuver the roof up and down manually? I just want to use the roof manually from now on. It used to be so easy to manually open and close, but now, it take multiple pulls and pushes back and forth for about 20 minutes to close it.

Please correct me if I'm wrong, but hopefully draining the fluid will remove the resistance (beside the weight of the actual roof)?

What would the best way to go about easily draining all the fluid if I had no intentions of putting fluid back in down the line?

Thanks guys as always!
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Old 04-08-2019, 09:46 AM
crosboe crosboe is offline
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TLDR; How do I drain all of the hydraulic fluid for the roof, and will this make manual opening and closing of the roof easier.
 
Old 04-08-2019, 03:45 PM
wifesauto wifesauto is offline
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iirc i do not think you can access any of the stuff you want to unless you remove the whole top assembly
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Old 04-08-2019, 04:45 PM
targaone targaone is offline
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I don't know anything about your specific car, but I find it hard to believe there is not an access panel to get at the motor and drive mechanism. Worst case remove the lift arm from the hydrolic actuator and store those parts in a plastic bag for the next owner.
 
Old 04-08-2019, 10:56 PM
Rob2m Rob2m is offline
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Quote:
Originally Posted by targaone View Post
I don't know anything about your specific car, but I find it hard to believe there is not an access panel to get at the motor and drive mechanism. Worst case remove the lift arm from the hydrolic actuator and store those parts in a plastic bag for the next owner.
Yup, there is no access, the pump or motor and everything is mounted on a leg of the roof in the LH side. This was probably to make roof manufacturing and fitting easier and done away from the car.

To the OP, have you checked the bowden cable that is attached to the red ring is going fully home? If it remains slightly out it may be stopping the fluid pressure building up, if the motor is spinning the only other reason would be a leak and I'd expect you to find a small amount of fluid somewhere, maybe round the drain plugs somewhere in front of the rear wheels.
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Old 04-09-2019, 04:52 AM
wifesauto wifesauto is offline
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Quote:
Originally Posted by targaone View Post
I don't know anything about your specific car, but I find it hard to believe there is not an access panel to get at the motor and drive mechanism. Worst case remove the lift arm from the hydrolic actuator and store those parts in a plastic bag for the next owner.
then you do not know the ways of the evil elves from the enchanted black forest and how they design thinks in der father land
 
Old 04-09-2019, 07:31 AM
targaone targaone is offline
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I am here to learn a lot. And know know one more thing. Yikes.
 
Old 04-14-2019, 08:56 PM
filtercoffee filtercoffee is offline
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Quote:
Please correct me if I'm wrong, but hopefully draining the fluid will remove the resistance (beside the weight of the actual roof)?
The resistance is not caused by the fluid, but rather the fact that the fluid is coupled to the hydraulic pump and the actuators that move the top. When the pump moves, the fluid moves, the top moves. When the pump is still, the fluid is still, the top is still. Pulling the red hoop pulls on a lever which pushes a bypass button on the hydraulic pump, which allows the fluid to bypass the pump with no resistance. So I highly doubt the fluid is the issue.

Let us know if pulling the red hoop a bit more doesn't fix it! Maybe have a friend pull the hoop while you pull the top.

Last edited by filtercoffee; 04-14-2019 at 08:58 PM.
 
Old 04-14-2019, 09:09 PM
filtercoffee filtercoffee is offline
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Quote:
iirc i do not think you can access any of the stuff you want to unless you remove the whole top assembly
btw there's another way which involves only removing the rear "aluminum c-channel" which joins the rear of the soft top and the trunk area. However, it's still a large effort, and requires you to be able to move the top manually, so you can lift the c-channel up.

https://www.zpost.com/forums/showthr...1215892&page=2
and
https://www.bimmerforums.com/forum/s...ving-roof-DONE

At the end of the day, any way you do it, it's a PITA.
 
Old 04-14-2019, 09:26 PM
Andyz4 Andyz4 is offline
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Quote:
Originally Posted by filtercoffee View Post
Pulling the red hoop pulls on a lever which pushes a bypass button on the hydraulic pump, which allows the fluid to bypass the pump with no resistance. So I highly doubt the fluid is the issue.

Let us know if pulling the red hoop a bit more doesn't fix it! Maybe have a friend pull the hoop while you pull the top.
I agree, you may have a stuck bypass valve. If so, can be fixed without removing top. Google topic for more
 
Old 04-19-2019, 10:57 AM
crosboe crosboe is offline
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Thank you everyone. (My email was sending these responses for some reason.) I usually keep the red ring in the trunk permanently 'out and turned' so that the roof can be opened and closed manually. For some reason it's getting harder and harder. But if having LESS fluid would make it more difficult than it must be something else. I'll check on a stuck bypass valve or having someone manually pull the red ring even more while I try the roof. If none of this works maybe the aluminum C channel is the way to go.

I'll update when I check everything, thanks!
 
Old 04-19-2019, 11:14 PM
Andyz4 Andyz4 is offline
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Good luck Crosboe, I hope one day you can fish the dead top motor out of its watery grave and move it to its rightful location, the boot!
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