My 1998 Z3 convertible top has stopped working with the switch. The motor runs but the top goes nowhere. I can lower the top easily just by lifting it at the windscreen and it will continue to the completely down position. Raising the top also doesn't work with the switch but after pushing the raise position on the button for a couple seconds, the top can be pulled to the up position with only a little effort. Any thing to check???? Thanks for any help.
You've lost hydraulic pressure. There is a leak somewhere. That's why the hydraulic ram (driver side, next to soft top frame main pivot) doesn't stop it from dropping. When raising it, you are fighting the weight of the top and whatever resistance the ram is still capable of, so running the pump helps reduce the latter. Mine did this some years back.
You can find the problem and repair it or pop the hydraulic ram out and put in a manual "assist" gas ram, like what is in the trunk and hood. That's a (much) cheaper alternative if you can live without the power. You can also just disconnect the ram entirely and handle it 100% by hand.
The top was originally manual. A gas strut and ball pin attachment points were introduced in spring of '97 to reduce the effort, and a few months later the strut was replaced with a hydraulic cylinder powered by a pump and motor.
If the fluid level in the pump's reservoir is below the bullseye, top it up.
If the pump or motor has failed, turning a little Tee thumbscrew on the pump will disconnect the hydraulics and allow easier manual operation.
https://www.bimmerforums.com/forum/s...7#post29223657
The hydraulic cylinder, pump and motor can all be repaired or replaced.
https://www.ecstuning.com/b-genuine-...t/54347114081/
https://www.tophydraulicsinc.com/en/
https://www.tophydraulicsinc.com/bmwz3removalguide.pdf
https://www.bimmerforums.com/forum/s...Soft-Top-Motor
When accessing the cylinder, be careful as the plastic and hard rubber parts that you must remove can easily break.
https://www.bimmerforums.com/forum/s...1#post29224601
It is said that aftermarket roll bars fit with the hydraulic cylinder if the base of the bar's mount is trimmed.
Last edited by Vintage42; 09-21-2018 at 07:28 PM.
BMW MOA 696, BMW CCA 1405
Vintage 42 gave good advice. If you've got a leak, it will be found either in the trunk or in the B-pillar on the left side. If there is no fluid to be found in the trunk, I can almost guarantee that the foam under the carpet under the left seat has been soaking up hydraulic fluid. My had that and it's difficult to clean, once you've managed to get the carpet out. Top Hydraulics fixed the cylinder nicely. The top is so easy to run manually that I nearly didn't have the cylinder repaired.
Wayne
1998 M Roadster
1994 Honda ST1100--sold
2017 Yamaha FJR1300ES
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