I actually work for an aftermarket parts company so I can tell you exactly how it works...

You get pretty good fit and function up to about a 20 year old application but by that time there have been some consolidations to cover very low volume part numbers. After that, we're looking at vehicles that usually aren't classics, just old and still in service. New engineers consolidate down again without really understanding the application and you get a part that basically just installs in the hole but maybe doesn't work as well. Then the company gets bought and somebody eventually reproduces the part as another consolidation but based on the last available aftermarket part because they couldn't get an OE version. Kind of sucks but that's how it goes.

Quote Originally Posted by stab6902 View Post
I had the exact same issue several years ago when I replaced the center link and idler arm on my 1994 Fleetwood. If memory serves, I used Moog parts, which were the right part numbers for the car, but slightly different from original equipment. A quarter to a half inch difference here and there makes a huge impact on the geometry. I had to change the length of the passenger side tie rod assembly a lot to get the car to go straight down the road, and the ackerman was all jacked up because the tires squealed in sharp parking lot turns, which it never did before.



It was a high mileage daily driver so I lived with it, but it always bothered me. Let us know if you're able to find a brand of parts that fit right. I think the problem is partially sloppy quality control from the aftermarket and partially them trying to minimize the number of part numbers; as long as it bolts on and functions, they call it good enough, rather than really trying to duplicate all the subtle differences between model years and configurations.