The Stovebolt Site Forums The Shop Area Driveline clunky rattling sound on slightly rough pavement

So I have a '49 3100 which I bought as a pile of parts with a title to bail out a friend whose wife said that he had one too many projects.
I already had a project of my own in progress, but what are friends for. All I had to do was lie to my wife and keep it hidden from her.
Anywho, My original plan was to assemble it, new brakes and in running condition with era correct parts, and sell it as a project for someone else, and make some money to finance the project that I was already in the middle of.
I fixed obvious drivetrain components, but didn't go over it with a fine tooth comb. It was intended to be sold as a project truck.
Well that all changed, as I lost my mind and decided midstream to do a full on, resto-mod, trophy queen.
There's 7500 miles on it now and I has developed a clunkety clunk going on while driving on uneven road surfaces. I jacked it up and wrestled with the tires and banged around with a dead blow hammer, but could not replicate the conditions to make the noise I was hearing on the road.

Rather than finishing my story to tell everyone what I found, and how I found it, I thought that it would be a good exercise for y'all to ponder this issue and see what y'all would do under such circumstances to troubleshoot this.
Feel free to ask questions just as though I am stumped (I truly was stumped until this evening).

Hah, I’ll bite

Check the Cab mounts?

Chuck

Beer bottles on the floor under the seat?

loose exhaust pipe banging on the frame or floor, or spare tire or carrier under bed?

Nope, but I was headed in that direction next.

Nope. I throw those out the window when they get empty. You can get a ticket for having empties in the truck. Something to do about how that got empty I reckon.

All the noise was up front. I could feel it in the steering wheel.

Steering component(s) not tightened properly, loose brake caliper?

Broken shock / mount ?
Or broken leaf spring.?

/ Bushing


George

I had a 59 that had metal bar welded between the spring and frame .would be more of a hoppety hop than a clunk though.

You are getting warmer.

Did you leave a tool resting on the frame somewhere?

Maybe the e-brake rod is banging against the top of the frame rail...there's supposed to be a rubber "guide" for it to rest in which I wouldn't have known about until seeing it when the cab was off.

radiator support bracket loose

Prior owner had welded a box between the U formed by the frame and had filled it with gold Krugerrands.

Busted spring mount/bushing or a lot of gold and your now rich and avoiding this thread

What's the knee shock hitting on a hard bump?
Or... is it bottoming out? Is the rubber bump pad missing?

Winner winner chicken dinner.
Severely worn rear spring bushing and pin of the left front spring.
Now here is how I found it.
I jacked up the front end and put jack stands under the front crossmember to allow the front axle to hang freely with the front tires about 2 inches off the floor.
I then used a long pry bar under the tire and lifted up on it repeatedly and listened for the racket. Sure enough. There was a good 1/4" up and down play at the rear spring pin /bushing. I pulled the pin and there is considerable wear on it. I ordered pins and bushings for both sides.
I have my finger crossed that the pin did not wear all the way through the bushing and got into the spring eye.
Taking all of the weight off of the springs by letting the axle to hang was the key to finding where this racket was coming from.
Thank y'all for playing along and wishing for me to find hidden gold bars.

Unloading the suspension and using a long pry bar under the tire is the same way we checked for worn ball joints and bushings in an independent front suspension system. It took a while for some of my students to understand that concept. Leverage can be your friend in a lot of situations.
Jerry

The clunking seemed to only be happening on the rebound of the front axle when driven over a bumpy patch of road, thus floating momentarily
causing the pin to float a bit before resuming the down position on the loose bushing resulting in the clunk.
I could not make it clunk any other way than by relieving the weight of the truck off of the springs and lifting the axle (via the tire) with a pry bar.