Front end thump

miller · May 13, 2018

That's on my 64 Ply SF. I have a whopping 33 miles on it.

What's happening is, for any and every little bump, getting a thumping sound from the passenger side suspension. It seems, the farther I go, worst it gets, sounds like a loose part, or fastener. With the car in my shop, I can push up and down on the front, and get it, too.

Completely rebuilt the front end myself, years ago...only has sitting in the shop time, on it.
I have re-checked every nut on the suspension, and made sure all parts are seated in place. Do not find anything loose...
Both wheels are tight, no movement. When I built the front end, changed to disc brakes up front, via the old school way, using all Mopar parts.

What the heck am I missing? Need ideas, guys.
Refuse to drive it, until I find the answer.

WileERobby · May 13, 2018

Both ends of the strut rod tight ?

PurpleBeeper · May 13, 2018

re-grease the lower ball joints? Are you SURE the ball joints and control arm bushing bolts are tight? Find someone to push up & down on the fender while you listen for the sound and try to pinpoint it.

miller · May 14, 2018

WileERobby said:
Both ends of the strut rod tight ?

Yes, both are tight.

PurpleBeeper said:
Are you SURE the ball joints and control arm bushing bolts are tight?

Yes. All my front end ball joints/bushing are new Moog. Shocks are Monroe HD.

It at least appears to only be up and down movement. I've put a hand on all the parts, feeling for side to side play...nothing. And, I ran the car through the lube shop, just to get it done. Also re-checked my K-frame bolts.
Thinking about it last night, today I'm going to put a prybar on each ball joint. Never know, even with new parts, right? Thinking of pulling all the dang cotter pins, and put the wrench to each nut. If I can't find anything, I'll pull the shocks, and check them, off the car.

Going down the road, thing sounds like something is trying to come apart. Getting looser with each hit. Hell, you'd think something like that would jump out at ya!

AR67GTX · May 14, 2018

Hard to equate it to a thump but in the process of rebuilding my front end I became convinced that the noises I was hearing out of mine before, was probably due to the LCA shafts - one of which was too worn to lock down tight in the K-frame. I had to use vice grips to hold it to remove the nut. Possibly it was catching & releasing as the suspension moved up and down. I'm just guessing but the LCA mounting design on these cars just looks ripe for strange issues to occur in.

miller · May 14, 2018

AR67GTX said:
Possibly it was catching & releasing as the suspension moved up and down.

Thanks! They are tight, but I'll look again for movement, while bouncing the front.

I've built a handful of these suspensions...never any problems. I am curious if I have a ball joint breaking apart (getting loose). First 15 miles on the car, to get it inspected, was all good. Second 15 miles, the thump started, getting worst, farther I went.

Yesterday, had the wife bounce the front, while I did the flat back, trying to look, pick something out. Seems aft of the passenger wheel...not much there. Up on jack stands now, so I can even get under the car.

68gtxman · May 14, 2018

My guess is the welded tube in the K-frame for the LCA shaft broke free. I suspect a similar issue on my passenger side but haven’t pulled it apart yet to check. Mine is not getting worse with each suspension hit though. Good luck!

miller · May 14, 2018

AR67GTX said:
was probably due to the LCA shafts - one of which was too worn to lock down tight in the K-frame.

Actually, my shafts were in good shape, bushing a good fit, inner and outer...had to press it all together. That's something I'm pretty particular about. It was all done about ten years ago. Yeah, I know, I'm slow.

miller · May 14, 2018

68gtxman said:
My guess is the welded tube in the K-frame for the LCA shaft broke free.

I'll look! I have been making a point to look things over, for cracked parts, or broken welds. There's no tellin'.

68gtxman · May 14, 2018

FWIW, I broke the lower ball joint in my first car (1969 Plymouth Belvedere taxi) and the tire just folded up under the car (like a plane’s landing gear). It didn’t cause any additional damage - just scrape marks on the tire sidewall. It (passenger side) failed when I made a right turn. It seems that it should have failed in this fashion while doing a left turn, but it didn’t. So maybe you could test yours in an empty parking lot and do some right turn donuts? Do some left turn donuts too for good measure.

khryslerkid · May 14, 2018

68gtxman said:
So maybe you could test yours in an empty parking lot and do some right turn donuts? Do some left turn donuts too for good measure.

^^ Please don't attempt this ^^

All you have to do to check the lower ball joint is to place your floor jack under the LCA. Jack the tire off the floor just enough to get a three or four foot bar under it. Try lifting the tire/wheel with the bar to see if there's any play in the ball joint.

miller · May 14, 2018

Don't have a working floor jack. I did use a prybar, to check for any play in the joints...none...though it's on jackstands, right now.
Also looked over the torsion bar sockets, welds in good shape. Frustrating.
If I can't find anything, later this week, I'll get my youngest son over, to give me a hand. Twice my weight, be able to bounce the thing around pretty good!

Also will re-check the ball joints, once back on the ground, to see if there's any difference.

miller · May 14, 2018

Not going to make the call, but finally found something a little loose. The bolts/nuts at the lower shock mounts, not fully tightened down. Old and senile, too much beer, or something like that. :monkeyleft:

Still looking...won't know for sure, until it's on the ground.

threewood · May 14, 2018

miller said:
Not going to make the call, but finally found something a little loose. The bolts/nuts at the lower shock mounts, not fully tightened down. Old and senile, too much beer, or something like that.

Still looking...won't know for sure, until it's on the ground.

That will do it. Thump thump.
I had a slightly loose tie rod nut and that was a pop pop . Loose upper control arm bolts go pop as well.

khryslerkid · May 14, 2018

threewood said:
That will do it. Thump thump.
I had a slightly loose tie rod nut and that was a pop pop . Loose upper control arm bolts go pop as well.

PurpleBeeper · May 15, 2018

miller said:
Yes, both are tight.

Yes. All my front end ball joints/bushing are new Moog. Shocks are Monroe HD.

It at least appears to only be up and down movement. I've put a hand on all the parts, feeling for side to side play...nothing. And, I ran the car through the lube shop, just to get it done. Also re-checked my K-frame bolts.
Thinking about it last night, today I'm going to put a prybar on each ball joint. Never know, even with new parts, right? Thinking of pulling all the dang cotter pins, and put the wrench to each nut. If I can't find anything, I'll pull the shocks, and check them, off the car.

Going down the road, thing sounds like something is trying to come apart. Getting looser with each hit. Hell, you'd think something like that would jump out at ya!

Good idea miller. I've had plenty of new parts that were bad AND I've had idler/pitman arm bolts that "seemed" tight, but the ball was just spinning in the socket... a little wedge with a pickle fork + impact wrench tightened them up more.

miller · May 16, 2018

It was the lower shock mount bolts. Had them bottomed out, but not tightened. Usually do that, once wheels are on the ground. It's fixed, now.
Thanks, all, for the ideas!

miller · May 25, 2018

I'm BACK!

And, ur-uh, thumping again. :wtf:

Didn't like the way the front shocks were acting. A little more driving, the passenger side thump started coming back! So, the hell with it, got another pair of new shocks, mounted them up, then a test drive. Thump still there, a little worst.
Rantin', guys...get 'something' done. It sure ain't the damn shocks.

Front end on jack stands, pulled half the cotter pins, checked those nuts. Tighter than Dick's hatband. Dammit...what the hell.
I'll check everything, including play in the ball joints, today. Real frigging irritating!!

Boy is dropping by Saturday, for the extra eye.

Ski 61701 · May 25, 2018

Could it be the pressed in bushings are loose in the control arms ? Maybe put a witness mark on the bushing and control arm and have someone push on the car to see if the bushing isn't rotating in the control ams

miller · May 25, 2018

Ski 61701 said:
Could it be the pressed in bushings are loose in the control arms ?

Appreciate that, Ski. But, have to doubt that. I've always put the bushings in myself, and would never use a loose hole. Still will look 'everything' over. Both upper and lower ball joints test good. It has to be something...just haven't found it, yet.

Front end thump

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