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E85 / E86 Z4 (2003-2008)
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Old 12-06-2015, 07:08 PM
hwettersten hwettersten is offline
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Location: San Francisco
Join Date: Dec 2015
Posts: 4
Mein Auto: 2006 E85 3.0si
E85 Soft Top Hydraulics

Hi All,

I'm the new owner of an '06 3.0si E85 and the car I bought has the relatively common soft top drive failure. Mine was a little odd though because though the top wouldn't move, you could hear the drive motor running with a high-pitched whine. From what I understand the most common failure is that the motor is inundated with water and corrodes/shorts until it fails. Baffled, I decided to dig in.

Today I followed Shipkiller's awesome guide and pulled the top off of the car. As expected, the motor was bathed in water, but after a quick rinse and scrub with a wire brush it ran without an issue when hooked to 12v. It seemed that the real problem was somewhere in the hydraulic system. The oil reservoir was still half-full, so it didn't seem like there were any leaks.

Pulling the motor off the hydraulic pump revealed nothing out of the ordinary. The inside of the pump is spotless and all parts seem to be in good condition. Once reassembled, I applied power to the motor and it sounded distinctly different from before: where there had been a whine before there was now the sweet sound of a motor working hard! The top fired right up, extending fully to the "up" position, but when I reversed polarity to bring the top back down the motor went right back to the whine and the top slowly collapsed under its own weight - definitely not in the smooth and controlled fashion one expects of a hydraulic system. Trying to put it back up resulted in nothing more than the same whine and no motion.

I've managed to narrow the issue down to the valve that's used with the Bowden cable for the manual override. Has anybody else ever had an issue with this part of the hydraulic system, and if so, was there some trick to get it working again?

If not, has anybody done a soft top motor replacement and have an assembly sitting around with a dead motor but OK hydraulic unit? I'd be happy to pay to take it off your hands! I get the sense I'm in the minority here in that I have a working motor but a failed pump.


Last edited by hwettersten; 12-06-2015 at 07:10 PM.
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