Is there a trick to restoring that new car solid "Thud" sound when closing the door? Internal bushings? Dynamat? Is there anything to tighten behind the door panels?

I have already replaced the rubber window channeling yet when I shut my door, instead of it going "Thud", it still goes, "SHKAPLANK!"

 

put square, firm, foam cubes on all the steel rods ( door lever actuator, door lock bar ) in fact anything behind there, even the wiring conduit if its not clipped well can make a rattle. a few of mine werent in very helpfull spots and i put a dab of silicon on them to hold them in place. other than that as long as your door rubbers are good and your glass is tight should be good.

 

My Vette is an all original survivor with 71k that I bought new. And the doors sound the same today when I shut them as they did back on 5/6/76.....

When you hear "SHKAPLANK" just think "FIBERGLASS".........

 

Check to make sure all the window mehanisms are bolted tight. I had a couple of bolts that held the window winding mechanism in place come loose and it sounded like a bag of bolts when I closed the door. Also, as said before make sure all the isolators on the linkage are there and working.

PS, it ain't ever gonna sound like a Caddy.

 

How's the weather stripping? This can make a big difference in the closing sound of the door.

 

There are anti rattle pads in there to keep the glass quiet, there are supposed to be the foam pads on the rods in the doors to dampen them. The rollers get worn and loose so the things rattle some. Best way to fix it is take the thing apart, clean and lube the rails, replace the rollers and pads, and new bushings in the hinges will get the door all lined up nice. With all that done they will Thud with the best of them

 

with all the above.

If all of the hardware is in shape with anti rattle protection as mentioned in some of the above then you will need to look at your door gaskets.

What I like to do on any car that I have replaced door gasket on is; install the rubber abount 1/8" from the jamb to give that nice tight feel when you close the door.

With the new rubber installed you will have a "crisp" closing sound and a nice "pop" sound when you unlatch the door.

 

As low as your are, its probably the sound of the door scraping the ground just before it closes!!

Back on subject, Id try checking the attachment stryker alignment. I have made a difference in previous cars by doing this - old camaros with long doors and worn bushings....

B......

 

Yes, the trick is about 40 or so hours of labor rebuilding the door innards which includes hard felt washers and set screw collars on all linkage, applying heavy wall heat shrink tube and poly wire loom mesh to the rods, reinforcing the inner metal stamping in a few select areas, redesigning the bellcranks with bushings and shims on a stainless shoulder screw, then reinstalling with stainless hardware instead of rivits, adressing looseness in the lock actuator and window mechanical systems, tedious work with the window felt pads and window adjustments, some dynomat, and lots of other things I forgot since last winter. Mine sound solid as a rock now...never a rattle except the rearview mirror from time to time at traffic lights. I also sound deadened the entire roll bar structure internally and all the metal and fiberglass around the door pillars(even this helped the doors sound more solid when closing), and ofcourse the entire back. I pulled the carpet and sealed and applied 1/4 inch thick felt to the entire front floorpan and tunnel about a month ago to wrap up the sound deadening. The difference is amazing and worth the effort and minimal $$.

As another poster pointed out already....alignment of the striker is crucial to a properly operating, and "proper sounding" door system.

The word "System" is actually key here....you just can't address one or two items and get a solid sound....everything interacts to some extent...either generating sound, or amplifying / modifying it.