About Us

Coach · 08-23-2010, 03:41 PM

Ok this is driving me crazy. My '67 GP was a total basket case when I brought it home. I have been over every square inch of the car when I built it and I thought I had it all right.

Here is the issue I am having. When I do anything that heavily shifts the weight on the front suspension I am getting a clunk out of the front end. This includes accelerating, backing out of acceleration, or hitting the breaks.

It almost sounds like something is binding and then releasing. I have checked the A-arms, and all the moving parts and cannot find anything loose. The steering has no noticeable slop in it, and when it "clunks" it does not seem to change the handling at all.

I thought maybe motor mounts, but those look OK. I thought maybe my exhaust but it sounds like it is coming from the front end, not under the car. Without a lift this is really a pain in the butt to diagnose.

One thing I was wondering about, if I did not get the springs in the pockets correctly, could that be causing the sound?

If anyone has any ideas I would really appreciate it. If I cannot figure it out this week I will have to take it into an alignment shop and I really dread leaving the car with someone who will have to "test drive" it.

Thanks in advance, -Harry

PS: In case I don't find anything do any of you Chicago area guys have a front end shop you would recommend?

ryan389 · 08-23-2010, 05:08 PM

I had this problem with a 67 gto i had, I found it was the springs that was not properly installed in the pocket, drove me crazy!
Does it do it going left and right?
Check the springs.
Hope this helps.

PMDRACER · 08-23-2010, 08:17 PM

On a buddy's '68 GTO, he had the same thing. Ended up being a lower ball joint rocking in the lower a-arm.

Coach · 08-23-2010, 08:58 PM

Thanks guys, I'll double check the ball joint, but they are new and I am pretty sure I got them in correctly. The springs I am not so sure of.

Can someone tell me how to get them set in the pocket correctly?

Best, Harry

GStage1 · 08-23-2010, 11:55 PM

The springs get seated in the lower A-arms with the end just before the oblong hole in the A-arm.

Had the same knocking/clunking sound on 2 of my A-body cars and one in my 84 Silverado.......all of them had the same problem....bad lower ball joints....one was new and only had 5 miles on it before I had to pull it out and swap it.

Charlie Brengun · 08-24-2010, 06:31 AM

I had a loud clunk like that in my '73 caddy. same symptoms as you had, had a friend sit in the car and turn the steering wheel full lock to full lock and you could see movement on one of the upper a-arms.
Turned out it was the bolt that holds the upper a-arm to the frame that was worn out so I had a shop fix it for me and that solved the problem. So perhaps have a look at the a-arms..

Coach · 08-24-2010, 09:47 AM

Again, I appreciate the feedback. I had my wife turn the wheel stop-to-stop with the front end in the air and saw no flex in anything. I have replaced all the bushings and such on the front end, that's not to say I might not have screwed it up or gotten a bad component.

This weekend I will get into the springs and see if I have them set correctly in the lower pocket. Any tips on how to check the ball joints while the car is jacked up?

Thanks,
Harry

Coach · 09-01-2010, 10:22 AM

Well I wanted to bring this one full circle.

Lessons learned:

1) Sound travels - when sitting in the drivers seat, that clunk you hear from the right front wheel could be coming from anywhere in the car.

2) When you deliberately leave a set of bolts loose during a multi-year restoration, TAG THEM. Use anything you need to, but put a note on there reminding you to look at them in 3 or 4 years when you button up the project.

3) When trying to find a loose suspension component, it is MUCH easier to do it on a four post, drive up lift, then it is laying on your back with the suspension hanging in the air.

I finally broke down and took the car over to a friend's garage, he got in the passenger's seat hung his head over the side of the car and said it sounded like the noise was coming from the rear of the car, not the front. We got it up on his four post lift and sure enough when we started to bounce it up and down I could see the bolts shifting on the rear end struts. I now remember not torquing them down as I was thinking about swapping out rear ends and didn't want to fight them later. We spent 20 minutes going over every bolt on the suspension and motor/trans mounts, these seem to be the only ones I left loose.

The car is now silent to drive, the "looseness" is gone on the road, and life is good. Well pretty good, the voltage regulator when wacko on the ride home, so I have to figure that one out, but at least I can drive the car without wondering if the whole front end is going to fall off!

Again, thanks for all the support,
Harry

Hunter98TA · 09-01-2010, 01:18 PM

Boy Harry, you now have me nervous. #2 is something I SHOULD have done.

Oh well, you found the problem, fixed it for no additional $$ and taught me a lesson at the same time!!!!

Thank you Sir!!!
Matt

schlitzman · 08-13-2011, 03:10 PM

I have a similar situation to that of Coach. I have a '67 GP convert. Had it now a year and this horrible "clunk" sound developed. Seemed to coincide with my upgrade to a 1.25" front sway bar. First I thought it might be the end links. No, it wasn't. I've isolated the sway bar, shocks, tightened all bolts and motor and body mounts and can't find the source. The sound occurs usually at low speed when the car weight shifts, like going up/down a drive way or making a low speed turn. It sounds like the front springs are "catching" and releasing. Driving me crazy.

I'll bring to my suspension mechanic and ask him to reseat the springs. Can I use a rubber hose as an isolator? I will also check all bolts in the rear, too. Only ones left. Any help or advice would be most appreciated.

Coach, thanks for your initial description. Very helpful. Also nice to know I'm not alone with this problem. Sometimes you think you're going nuts.

Regards,

Schlitzman

Pontirag · 08-13-2011, 03:32 PM

Name that clunk

lets call it PITA

PMDRACER · 08-14-2011, 02:46 AM

Make sure it's not the upper arms shifting because the bolts for the shim are loose.

HaloMedic · 08-14-2011, 08:08 PM

Quote:

Originally Posted by PMDRACER

Make sure it's not the upper arms shifting because the bolts for the shim are loose.

Or missing shims I had a clunk in the front that i chased for a year , turned out it was missing a few shims

Evil Stu · 08-14-2011, 08:14 PM

Front coils have a top and a bottom. If you install them upside down you get a loud click/clunk sound when the front suspension travels.

Stu

schlitzman · 08-15-2011, 11:51 AM

Thanks, Stu,

How do I tell the difference between the spring top and bottom? Also, can I install an insulator, like neoprene or Tygon tubing?

Thanks for the info.

Bruce

IOWA552SLOW · 08-15-2011, 10:30 PM

just got done fighting a similar noise in my lemans. ball joints less than 2 years old, tie rods as well. i did find worn control arm bushings, and a weak lwr ball joint as well. i did replace those parts as well as everything else in the steering. i agree with all of the advice everybody else has to offer, check bolts and maybe even the new parts, could be bad out of the box.

Evil Stu · 08-16-2011, 11:21 AM

Quote:

Originally Posted by schlitzman

Thanks, Stu,

How do I tell the difference between the spring top and bottom? Also, can I install an insulator, like neoprene or Tygon tubing?

Thanks for the info.

Bruce

I don't know. I put mine in wrong and had an awful noise. Somebody told me what I told you, so I changed 'em and now they're quiet.

Stu

schlitzman · 08-16-2011, 05:10 PM

Silence, at last!!!!!

Finally found the problem after three days of trial and experiments. I would eliminate or isolate a function stepwise so I could check out the systems and actually find out what caused the "clunk".

It was the TH400 transmission cover. It was not properly seated and would catch on the front mount every time the car would flex.

I did find out the springs were properly installed and aligned. My wheel bearing were in bad need of service. Body mounts were all torques to spec. Rear sway bar needed tightening, but wasn't loose. Exhaust and header bolts needed retightening.

The advice from all of you was very helpful and useful. Thanks much. Hope my experience helps others, too.

Schlitzman

Silver Judge · 08-18-2011, 07:57 PM

Quote:

Originally Posted by Coach

Lessons learned:

I finally broke down and took the car over to a friend's garage, he got in the passenger's seat hung his head over the side of the car and said it sounded like the noise was coming from the rear of the car, not the front. We got it up on his four post lift and sure enough when we started to bounce it up and down I could see the bolts shifting on the rear end struts. I now remember not torquing them down as I was thinking about swapping out rear ends and didn't want to fight them later. We spent 20 minutes going over every bolt on the suspension and motor/trans mounts, these seem to be the only ones I left loose.

It's good to have the clunk gone I bet !
Do you mean the rear shock mounts? I'm confused by what you mean when you use the word struts

Wild Bill · 08-28-2011, 09:27 PM

Quote:

Originally Posted by schlitzman

Thanks, Stu,

How do I tell the difference between the spring top and bottom? Also, can I install an insulator, like neoprene or Tygon tubing?

Thanks for the info.

Bruce

the top of the spring is ground flat and sits inside the frame.

the bottom coil is just cut and sits with the cut end in the "step" formed in the LCA

Menu

About Us