When driving, there's a very audible thump against the driver's floor board. I can feel it and hear it. If I roll the windows down, it's extremely loud. The noise starts up around 15mph and gets progressively worse through 30mph. Accelerating to 40-50 mph actually helps the severity thud, but it never goes away fully.

Any ideas?

 

U joint going bad, exhaust heat shield loose?

 

Good point about the U-joint. I'll check it.
If it comes to that, how long does the swap take, generally? I don't have as much time as I should to spend on it as I'd like.

 

U joints are a pain. I would pull the driveshaft and take it to a driveline shop for replacement. That is provided you live in a town that has a driveline shop. If it is a bad ujoint go for the Spicer brand without a grease zerk. Those are the best.

 

Thanks Phil.

I took the H2 out again today to for a really short trip. No symptoms of the thump under the floor board, but I am hearing a clicking that I heard before (should have mentioned that).

Perhaps that's the heat shield?

 

Took it out again & now the break is acting funny...
It's missing the top mounting bolt on the driver's side. At least it's simple.

Is this the right bolt? (m16 x 2 x 41, 30 thread)

Dorman Brake Caliper Bolt/Guide Pin-Rear 14009 - Read Reviews on Dorman #14009

 

That happened to me as well. Rear brake caliper though. Now I loctite them. And tighten them 2x tighter than my tightest turn. I have to use a Johnson bar to get them off.