window alignment/freeplay adjustment process - how does it work?
 

Hello everyone! I am still searching for my C4 cabrio's driver's side "door thunk" that happens when I hit big bumps in the road. I thought I had it figured out, but only half-way I guess.

Initially, I found the L-shaped bracket that holds the front part of the black window frame/guide down at the bottom of the frame within the door (make sense?!) had cracked in half. I could grab the black window frame at the top of the window and rock it back and forth as a result. Well, I welded that piece back together and fixed that problem.

Today, I noticed that I can grab the window in the rear-most corner when it's in the up position, and pull it up and down just a bit - maybe 5mm to 10mm or so. I cannot do that on the passenger side. So, that appears to be my problem. So I disassembled my door again, and found that when the glass is pulled up and down, I can see the window move up and down against the rear-most guiding rail within the door. It's a gold-colored rail that runs down the length of the back of the door. It appears to have two allen-head bolts at the top, and one at the bottom (which was so tight I could not remove it).

Ok, now to my questions!!!

1. Is the reason my driver's side window can rock up and down due to the rear guiding rail being incorrectly adjusted? Can it, if possible, be adjusted? And how?
2. Is the rear rail within the door supposed to be lined with a rubber material like the front rail to insulate and/or hold the window better?

Thanks so much for any input! I greatly appreciate it.

If I remember correctly, the windowframe cannot be adjusted.

It is the "scissors" that lift the window up and down that can be adjusted, but just a bit via the gold irridium plated allen bolts (take a 5mm allen) and if you have your door panel off, you can see about 3-4 locations that have elongated holes to allow for such adjustment.

My guess is that one of these allen bolts are loose, this allows either your electric motor, the "scissor" mechanism or the rail that holds your window at the bottom to move up and down in it's adjustment holes??

Check it out.

Along the latch side of the door, there are three allens that hold the window frame in, it appears you've already figured that one out. :)

Along the front of the window frame, there is two allens that hold it in, forward of the triangular window, right above the top hinge...all the aforementioned allen bolts are accessible once you remove the plastic plugs that conceal them in the doorframe.

Okay, there are two more allen bolts that hold what I will refer as the middle rail, or the forward rail that actually holds the windowglass in. One is located right underneath your doorlock console (the black piece that runs along the top of your door panel. The other one is down INSIDE the door, you would have to remove the door panel and punch through the plastic sheeting to get to it. Just imagine how that rail runs down all the way to the bottom of the door, just as your rear most rail does, to hold the moving window glass in...at the bottom, there is a clamp mechanism that holds it to the internal sheet metal of the door.

Here is a cruddy pic that I just happen to have available on my hard drive...I made markings where most of the allen bolts are that hold the window rail in - hopefully this helps...if not, lemme know, I'll get you a MUCH better pic from my archive CDs that I created when I tore my car down to pieces last Winter.

I apologize for the crappy pic, but it's late and I'm not too good at making those "neat" markings on photos via my mouse! :D

http://forums.rennlist.com/upload/crappydoorpic.jpg

Hey Jeff, thanks for the response! I think I'll try to adjust the scissor mechanism - thanks, you answered my question about the unadjustable rails!

There are a lot of points to adjust the scissor - so I'll have to figure out which one to adjust to lock the window in a tighter position against that rear guide-rail. Would an adjustment of the scissor to hold tighter against the rear of the window affect its travel in other ways?? I hate to get the thing way out of alignment!

None of the allen bolts were loose when I inspected them, but I know the previous owner had a shop adjust/fix the door locking mechanism several months ago before I bought the car, so they may have messed it up.

Thanks again for the assistance.

Here's pic I took when Arjan & I (mainly Arjan ;) ) replaced my window regulator in September:

http://members.rennlist.com/rgranaas...Adjustment.JPG

Hopefully, Arjan will follow-up--as he really did do most the work. But, these allen head bolts are adjustable.

If you can't find any loose screws or bolts, you may simply have a worn regulator. In my own case, the window would rattle in the track when it wasn't fully up. It also had a tendency to stick fully up on occasion.

Wayne Dempsey's "101 Projects for Your Porsche 911" explains exactly how the window regulator is installed on our cars, with the exception of our cars having a torx-head bolt in one place, where the earlier car in Wayne's book used a conventional bolt.

Good luck!

Yes, I will folow up. The adjusment of the window needs to be adjusted near the window motor. This is the end position of the window regulator. Adjus it with little steps, and if you are done, tight the bolt well!!!
May be Randall has a picture of that. Its on the left door above the door speaker, aproxx. in the middle. I think it's a metric 13mm bolt, which goes thru a aluminium bracket.

The picture Randall showed above, is the adjustment of the guide rail for the widow regulator to hold the window straigt in one line. Yes, you can adjust that also.

Goos luck

Thanks for the great information and pictures. I will have to take a look and see if adjustments will help. I am afraid that adjusting the scissors will move the window, making it fit differently with the roof weatherstripping.

How long are regulators supposed to last? My 92 C4 has 47000 miles on it; my 65 has 94000 and it still works fine!!!

My last question to the masses, is: should the rear rail that supports with window and runs along the "latch side" of the door, should it have a rubber or felt insert like the front guide rail?? I could check my passenger side, but I wanted to check with all of you first. Thanks!

Hey,

//Update: I eneded up removing the screws holding that part in and I managed crimp it slightly in place with a G clamp and put lots of grease there and it seems that the rattle has now gone//


Just kicking this thread off again in the hope there is a fix or a part I can replace as I have a rattle and probably in the same place as most have.

From the picture I hope you can see which part is rattling..

After going bumpy roads and sticking my hand under the window I beleive this is the cuplrit.

Is it that the wheel has worn or the rail and are these parts replaceable?

Can I take just this part out to inspect it?


https://cimg4.ibsrv.net/gimg/rennlis...9ceb23f1a.jpeg

Cheers

Alex