This is more of a two-part explanation of a common problem found on the 100 Series rear doors accompanied by
solutions to this problem and an
upgrade for the 1998-2002 owners.
1. The 1998-2002 door check problem (rear door carnage/failure)
The old check assemblies had a steeper 'ramp' or slope to them which, in my opinion, may be the cause for so many
rear door failures on the 98-02 models.
Combine a steep grade with old age, dried up grease, and lack of use (many owners may never have opened the rear doors but once in a blue moon) and the perfect storm emerges to create problems such as these (see photos below):
Above, left: 1999 Lexus LX470 rear door sheet metal cracked beyond prevention
Above, right: 1998 Lexus LX470 rear door showing early signs of cracking (check your rear doors!!!)
It is possible to prevent further damage to the doors (seen at left) by installing the
reinforcement plates I've designed (next batch expected 2 weeks from 8.16.24) but once it starts it can degrade within a matter of days!
It's the act of closing the door that puts pressure on the rollers inside of the check assembly. That pressure is transferred to the sheet metal of the door and creates stress fractures from and around the square hole in the door.
Above, left: 98-02 check assembly (68640-600xx, 68630-600xx) disassembled- observe rust on springs (Arizona truck)
Above, right: 98-02 check assembly rollers after being lubricated - some rust still present
Above: (68630-60050 superseded by 68630-60051 and 68630-60070) - observe crusty condition of the roller surface
Continued in next post...