Strange thumping sound...

krb · **Posted:** Wed May 20, 2020 1:01 pm

So I'm driving around 50mph and upon deceleration start hearing a thump thump thump, sounds about the same rhythm as the tires rotation. Seems like it's coming from the rear driver's side. Even sounds like a flat tire or tread separation - but it's not exactly constant.

I pull over and investigate and find nothing. Tires are fine, a quick shake says bearings seem fine. Shocks aren't loose nor are the u-joints. Breaks aren't hot. So I pull back out and accelerate and all is well - until I let off the pedal, thump thump thump. If I slip it in to Neutral the thumping almost goes away but is still there, kind of off and on. Pull over again - nothing obvious.

Drive a few more miles to my destination all while repeating the thump, no thump depending on accelerating or decelerating. I don't feel it in the steering and braking doesn't seem to affect it.

I haven't a clue at this point until I can get it home and start removing wheels to further investigate. Any ideas???

ebbnflow · **Posted:** Wed May 20, 2020 1:40 pm

You can really only tell u joints are bad by removing the drive shaft from the vehicle. Your problem sounds like u joints to me.

krb · **Posted:** Wed May 20, 2020 2:02 pm

Could be, hope to further investigate tonight. Could be a binding joint and not worn out maybe.

Just drove it home 12 miles to swap Jeeps and got to experiment more. Braking seems to affect it some but not much. When coasting, if I apply just a little bit of throttle it goes away. Driving the last bit home on our little country road I could hang out the door and it's definitely in the rear and sure sounds like it's at the wheel. Kinda sounds like the roar/grind of a bearing but not constant like I'm used to. Definitely got worse/louder too.

When I get back tonight, if I have time (and it's not raining - my daughter's RAV is in my shop while she's replacing the timing belt) I'll remove that wheel and see what I find.

In the mean time, back to town to run errands before the river cuts us off...

krb · **Posted:** Wed May 20, 2020 7:15 pm

Well not sure if I found my problem or problems...

Didn’t notice it before but one wheel lug was missing. Jacked it up and could barely turn it so it appears I have a sticking caliper even though it didn’t seem hot when I checked it on the side of the road.

Weird part is the remaining lug nuts were just barely tight, didn’t have to break them free. What makes it weird is while the Jeep was down for the past two years for head gasket etc work that was a slow leak tire so I had it repaired. I know I torqued it to specs otherwise I wouldn’t have put the tools away. But what I’m pretty sure I didn’t do is re-torque after driving it a bit since the tire fix was like 18 months ago.

So, could the fact that I didn’t retorque allow the lugs to loosen enough and the ever so slight slop cause the noise? And the dragging caliper be secondary (or are they always that tight on these things)?

Taking it out for a quick spin to see if I hear the noise now that the wheel is properly torqued - if the river isn’t over the road yet...

krb · **Posted:** Wed May 20, 2020 7:47 pm

Well joy, no more thump thump thump.

But lesson learned and now I get to experience the joy of replacing a wheel stud. I assume I’ll need to pull the axle but not checked the FSM or stickies yet.

Never smelled any brakes so I’m assuming the tight caliper is “normal”? Dad’s started smelling so he had his replaced and his has fewer miles than mine.

TKB4 · **Posted:** Sun May 24, 2020 2:12 pm

I have had wheel lugs from a spacer get broken off etc when a tire company didn't torque correctly putting tire on and the wheel holes also got wallowed out on two wheels making them unusable. BTW I have a Willys 1955 CJ5 with the F head engine. I am sure calipers or warped rotors could do that but I haven't had any malfunction.

krb · **Posted:** Wed May 27, 2020 7:15 am

I miss my 3B with the F head. Is yours running and driving?

TKB4 · **Posted:** Thu May 28, 2020 9:23 pm

No the transmission kept popping out of third gear and I took it out with intention of correcting the problem but then all kinds of distractions and I only used it on hunting land left it out there so it didn't ever get the attention it needed bought it in college had every part of it in the family room a little at a time got it in pretty good shape and drove it when didn't need pickup for about 4-5 years as main vehicle then real life took over and relegated it to part time weekend use . I am sure engine would start but it isn't going anywhere . It also has a Koenig PTO winch which came in very handy a bunch of times.

krb · **Posted:** Sat May 30, 2020 7:20 am

Cool.
I bought mine when I was 18. Threw a rod driving it home. While searching for another block me and my dad took the body off and cut out all the rust and welded in new metal. I sandblasted & painted the frame. Found another F-head in a FC Jeep and put that one in.
Drove it throughout college and used it on the farm. It had the front & rear PTO but I never used it. Then about 9 years later I got married and we moved to my grandparents farm. Dad used the Jeep some, then it sat, for years...
A friend asked about it, was wanting to make a rock crawler. I knew I hadn't the time or money to re-resurrect it so I sold it to him. Oh well...

Strange thumping sound...

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