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Registered User
Join Date: Dec 2008
Posts: 108
'90-C4-Cab Top Disaster!

Had an issue with the Cabriolet Top Controller-Was not letting the top latching motors over the windshield engage or disengage all the time...pulled the controller from under the dash-() and dis-assembled it to find several cold solder joints on the printed circuit board in the location of the connector pins. Having been in the P.C. manufacturing business for well over 50 years, I am very familiar with this issue. I reflowed/re-soldered all the cold solder joints that were evident, re-assembled the unit, re-installed it(),turned the key and depressed the switch...Voila, instant gratification-works Every time now!

That's the Good News-Here's the Bad News-() While the top was being lowered,I heard a sort of "groaning noise" then a straining of the passenger side drive motor-The driver's side of the top seemed to retract normally while the passenger side was not.
At this point, I heard a loud "Snap" and I immediately shut the ignition key for fear that the dreaded "B-Pillar " break had occurred. I could not find any breaks in any of the linkage or bow parts but upon further examination, I found that the Cabriolet top drive arm on the raise/lower transmission-passenger side had snapped in half at the large 19 MM bolt hole. I believe there was a previous crack at that joint but I can't be sure.

I found a parts dealer not too far from me that has one at a fair price, so I am not totally "up the creek." I loosened the 19 MM bolt on the driver's side transmission so that We can operate the top in the "manual" mode with electric latching. My only concern is -What caused this?

Note: After this happened, I pulled both transmissions to find that the passenger side quadrant gear had frozen in place. I soaked the center bearing with "Blaster" penetrant
and was able to free up the gear so that it operated freely. Tested the whole assembly on the bench with the drive cable in my drill to operate it...went from one end of the travel to the other to be certain there was no binding. Temporarily joined the broken drive arm to test everything (Drive motors both worked and cables were operating-drive cable ends were extended proportionately.) Synchronized both transmissions to their respective indicator marks, made sure the micro-switches were in their proper position and got everything back together as was before this happened.

Gave it another try only to find the same scenario with the arm breaking again.

I dunno where to go from here-Any thoughts on this or has any one here had this happen? Any help with this issue would be Greatly appreciated!

Thank You!

Best Regards,

Old 07-17-2016, 06:10 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Join Date: Jan 2015
Posts: 127
I remember having a problem like this and what had happened was that the arm on the not cracking side was bent, which caused the synchronization to constantly be off. Your situation seems a bit more severe than that one but it may be worth a check!

Also that was on an earlier ('87) car, but I think the basic design of the tops is very similar...
Old 07-18-2016, 12:12 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
Join Date: Dec 2008
Posts: 108

Thanks Mucho for the comeback, Brother!

I am in the process of inspecting all the mating components in order to find the root cause
of this AGONIZING anomoly.

Will check back in when (And If) I find It!

Best Regards,

Old 07-18-2016, 01:22 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)

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