Cab body flex
09-08-2017, 12:29 PM
#1
Rennlist Member
Thread Starter
Cab body flex
If I had to choose between owning just one 968 it would be a cab. I think the coupe is better looking but for driving, I just love putting the top down. It adds so much for me.
That said, I had an interesting discovery on cab body flex this week. I had the Wimbledon car in the shop to have the top re-powered. The tech did the job while the car was on the lift. bad idea. When I picked up the car and went to put the top down it unlatched showing it was under tension. When I went to put the top up, no way would it close. the tech had to redo the job while the car was on the ground to get the alignment correct. Works great now but interesting. I know Porsche did a lot of extra work to stiffen the cab body but obviously, there is still a good amount of flex. FYI.
That said, I had an interesting discovery on cab body flex this week. I had the Wimbledon car in the shop to have the top re-powered. The tech did the job while the car was on the lift. bad idea. When I picked up the car and went to put the top down it unlatched showing it was under tension. When I went to put the top up, no way would it close. the tech had to redo the job while the car was on the ground to get the alignment correct. Works great now but interesting. I know Porsche did a lot of extra work to stiffen the cab body but obviously, there is still a good amount of flex. FYI.
09-08-2017, 01:20 PM
#2
When raised on the typical swing arm type automotive lift, the doors of most cabs are in a bind to the point that they cannot be opened. I typically open both doors of a cab before I raise the vehicle so that I have access to the interior and so that no added stress is applied to hinges, latch, etc. No issues opening the doors of a coupe
09-08-2017, 03:00 PM
#3
Burning Brakes
Good to know about the top alignment, although I 'm surprised the car was on a lift for aligning the top, but maybe other work was also being done.
I have experienced the same issues on coupes, both Porsche and domestic.
While there may be slightly more flex in a cab, all of the bodies flex.
When you compare the vehicle's suspension attachment locations on the body to completely different points where the lift is applied, any unibody structure will flex unless the lift is supporting the suspension. The degree of flex is affected by where the lifting force is applied and the rigidity of the body structure.
Body shops are well aware of this issue since panel replacement and body repairs should be done with the body supported on it's suspension or at support locations that minimize structural flex.
I have experienced the same issues on coupes, both Porsche and domestic.
While there may be slightly more flex in a cab, all of the bodies flex.
When you compare the vehicle's suspension attachment locations on the body to completely different points where the lift is applied, any unibody structure will flex unless the lift is supporting the suspension. The degree of flex is affected by where the lifting force is applied and the rigidity of the body structure.
Body shops are well aware of this issue since panel replacement and body repairs should be done with the body supported on it's suspension or at support locations that minimize structural flex.
09-08-2017, 04:09 PM
#4
Rennlist Member
Thread Starter
09-08-2017, 05:36 PM
#5
I believe it is standard shop procedure on a Mercedes soft top to have the doors ajar.
the W140 sedan cannot be lifted with the supplemental underdash supports removed or the windshield may crack
the W140 sedan cannot be lifted with the supplemental underdash supports removed or the windshield may crack