Nissan and Infiniti door detent mechanisms (a.k.a. door check straps) are poorly designed. The doors like to close on your legs when you're trying to get in and out of the car. A new part is $80.00 and must be purchased from the dealer. I have devised a modification or fix for the problem.

The detent mechanism shown is for a 2005 Infiniti G35 2 door coupe. The same part is used on Nissan Maxima and many other Nissan and Infiniti models. To remove the detent mechanism you have to remove the door panel. Then remove the speaker (3 Phillips 10mm hex head screws). With the door fully opened remove the 3, 10mm hex head bolts in the door jam that mounts the detent mechanism. Reach in through the speaker hole and pull out the detent mechanism.

pic1 pic2 pic3 pic4 shim 

Once the detent mechanism is removed mark the top position of the cover and the housing (Pic1 and Pic2). You will want to reassemble in reverse order. Pry open the 4 locking tabs so you can remove the cover. Inside you will see 2 pieces of nylon and 2 rubber pieces compressing the nylon inserts into the detent bar (Pic3). Make a small shim from a piece of sheet metal 1.5 mm thick (Pic4). Pry out the top piece of rubber and cut and grind the shim until it fits evenly in the housing. For easier installation, taper the back of the shim almost to a knife's edge. Put the rubber piece back into the housing and lubricate the shim with some soap or wax. Press the shim in between the housing and rubber. It will not go in easily, you will need to use vise grips or channel lock pliers. Once installed, the shim should fit flush (Pic5).

pic5 stock radius pic6 squared off radius

I decided to modify the detent bar because the radiuses were too rounded from wear. I used a 1/8 inch carbide cutter to square off the radius. This makes it more difficult for the nylon pieces to slide over the detent bar. Pic Stock Radius and note the difference after modification (Pic6).

Reassemble the cover. I bolted the cover together with 2, 10 mm head bolts and washers to align and hold the cover to the body. Then I bent the locking tabs back over the housing and tapped them tight with a small hammer.

Reinstall the detent mechanism through the speaker hole in reverse order.

You will notice a big difference in its operation. Let me know how this modification works out for you. I'm checking into making my own nylon inserts for the detent mechanism and I will make them over size so shims will be unnecessary.