unit91

Took a ride in a 67 convert that was being sold at a car show. My wife & I were in the back seat - I was on the driver's side. While we were riding around I noticed a squeak near the top edge of the driver's door. I put my finger between the door edge and the rear quarter panel and could feel movement between the two. After that I drove the car and my wife sat in the front with me, no one setting in the back, and there was no squeaking. I put my finger between the door and the rear qtr panel again and could not feel any movement between the two. I visually checked for frame damage/rust but didn't see any. Is this a weak frame issue, weak rear springs, etc.???

67mustang302

Or the door wasn't shut all the way.

2+2GT

It is normal for the door gap to change very slightly while moving, since there is no upper striker on Mustangs. However, if the door gap pinches closed, it's a likely sign that the inner rockers are rusty and losing strength, and should be checked.

Oxnard Montalvo

Are you and your wife a "plus size" couple?
Kidding.
It's a big investment so it's worth getting a little dirty over...Lie on your back and look at the torque boxes and frame rails. Make sure the door to body gaps are even and there's no visible body sag.
As said, some movement is normal, it' going to flex.

unit91

What's a striker?

2+2GT

The DOR390 and DOR392 are striker wedges that keep the top of the door gap from closing when the body flexes. Mustangs don't have these.

MustangFTW

convertibles have less support then coupes too, since they have no roof to hold it together as good.

JMD

IMO, this PROBABLY explains everything.....

A certain amount of flex in these cars is just going to happen. Subframe connectors would probably help some though.

scottybaccus

it's called cowl shake. The cowl forward (including door hinges and anything hanging on them) shimmys from side to side in the opposite direction as the rear quarters. All this twist is going on in the floor pan and rockers. Very normal for a convertible, even today. They usually beef up the undercarriage of a convertible to minimize this, but I've never seen one any bigger than a Miata that was without any shake at all.

Subframe connectors and an X brace added to the space between the rear wheel houses is a big help, but not likely to rid all of it.

2+2GT

The Mustang had "cowl shake" when introduced. In mid-65, tubular braces were added.

A Mustang convertible with solid, or freshly replaced, structure is quite firm. Most are in some stage of deterioration, and rust-thinned steel isn't very stiff.

Convertibles had a LOT of extra bracing. Front torque boxes, inner rockers, one-piece seat platforms, lower seat platforms, B pillar braces, rear seat braces, transition panel brace, even the rear crossmember was doubled.

Subframe connectors were mentioned. Think of inner rockers as The Subframe Connectors From Hell. No subframe connector I have ever seen even comes close to the strength of the inner rocker.

Any Mustang that's not a trailer queen should have an export brace. And not the cheap crappy one, either, the thick, deeply stamped repro.