Here's an option to give your rear axle a softer landing. It's a GM foam jounce bumper that gives a more progressive response at full compression. Not only is it nicer on the spine, it won't upset the car as much during cornering. I haven't heard or seen evidence of any contact in the rear, and that's with running B&G lowering springs over Michigan roads.

There's a catch, however: The welded-in stud is the correct 10mm diameter, but the wrong pitch. I cut it off, drilled it out, faced off the stud head, and used the original screw that mounted the Mazda hard rubber bump stop.

 

Hey - interesting discovery! thanks for the Share-

Stu Aull
80GS
Alaska

 

That's interesting. And makes me ask: I've got an 83 GSL with 32K, all stock springs, shocks seem decent. Is it normal that when I hit a reasonable bump in the road, that the rear end of the car gives me a thunk sound and jumps as I go over it? Or is that bad springs or bad shocks?

 

I can't answer your question since I haven't driven a stock suspension car in a very long time. But you could try the mod and see if it helps. You can always switch back to the OEM bump stops if you don't like it.