Hey guys,

On my '91 500SL, I've been having an issue with the front top latches/locks. Specifically, the passenger (right side) one. With the hard top on, even the slightest bump in the road causes the dinging noise to appear again after tightening the latch manually. Part of the issue may be that I can't lock the hard top down with the hydraulics since the rear cylinders are leaking heavily. I have not used the soft top and don't plan on it until I have time to take the car apart to send all the cylinders out to Top Hydraulics.

I had the issue when I first bought the car, however, after tightening it down manually it would be fine for 50ish miles or so. The car sit for around a month while I did some work on it and after starting to drive it again it apparently has gotten much worse. I plan on taking the car on a 1300 mile trip up pacific coast highway in a week and a half. Is adjustment of the switch inside the latch/lock adjustable or is there a way to get it back into spec?

I referenced this thread: hardtop beeping noise
But the information seemed kind of vague on how to adjust the switch by bending some kind of spring in there. Is there more to it that I should know before attempting to fix it or is it that simple? Would buying a new OEM one (right side part 129-800-08-74 for $358) be the real solution? I'm assuming buying a new one would be the "best" solution, but realistically would trying to repair it by adjusting the switch fix it permanently or would the same thing happen again 200 miles into the road trip? I am hoping to get this resolved before the trip coming up in the next 11 days so any help would be appreciated.

Thanks!
Austin

 

Very likely not, in my opinion.

If you remove the latch you will see that a microswitch is secured in place with a set screw which can be loosened to allow adjustment. I think it is completely intuitive how to proceed. If not, post a picture of the switch.

By the way, the switch is a "normally closed" type. That means mechanically when the switch is depressed (you hear a "click"), electrically its contacts separate and break the circuit. So, if I remember correctly, you want to adjust the switch in a manner which ensures the microswitch can not become depressed when the latch is locked.

 

Thanks! You were correct that the adjustment is intuitive. Once you see how the switch assembly works it makes a lot of sense. No need to over think it. Mine did not have a set screw but adjusting the tab about a millimeter with some small needle-nose pliers and gentle force was sufficient to correct the gap between the tab and the switch. All is well now!


For anyone referencing this later, I made a quick video showing how the latch works and what you need to do to fix it. It is very simple and should not take more than 10 minutes to take the windshield header cover off and bend the tabs real quick. A few philips screws, pull the cover back toward the rear of the car, and the latches are easily accessible.



Hope this information helps someone else out there.



Here is a link to the video:

[MEDIA=youtube]NmNY4IRyiXc[/MEDIA]



Here are some other pictures I took:



With the latch in the open position, turn the latch to locked/closed position by pushing down on the latch with a screwdriver and simultaneously rotating the 6mm latch hex bolt with a socket or the factory tool.









Latch now in the closed or locked position:









The tab should be high enough so that it does not push down on the button-like micro-switch below it. When the latch is locked, the tab rides OFF of the switch. With the latch open (top not present), the tab rides ON the switch. With the latch closed, you should be able to push down on the tab with your finger and not be able to hear the clicking noise the switch makes when activated. If you do, you need to bend the tab up more. It only takes a very slight adjustment with some small needle-nose pliers to correct the gap. Be careful to not damage the switch with the pliers and try to grab the tab down as far as you can with the pliers.

 

Well documented with the photos! Thank you This clarification may be very necessary since the weather soon will let us doff our tops!