Call Ssnake Oyl at 800-284-7777. They are located in Texas and specialize in restoring seat belts. They can just to a reweb or can do a complete restoration - rechrome, new moving parts, etc...
They can replace your webbing with the correct weave, which doesn't meet current safety standards, or with "modern" webbing that is stronger.
Act quickly, I just sent them my front belts and the backlog was 6 weeks. They get very busy in the spring.
Sunlight degrades plastic. Seat belts are made of nylon, which is a form of plastic. If your belts need to be redyed because of exposure to sunlight, it is likely that they need to be replaced, even if they look and feel ok.
Also FYI, I have read that you should get your seat belts repalced after you have been in an accident. The belts are designed to stretch on impact and do not return to their original length. Thus, they are designed for one use. Once they are stretched, they lose their strength.
[This message has been edited by gheatly (edited 01-13-2000).]