I recently replaced the front struts on my 2007 GM W body.  I utilized a complete strut kit from Monroe, so everything between the knuckle and the upright is brand new.

Shortly after install I started hearing a popping/clunking noise that was directly correlated with the nose attitude (accelerate and the nose rises, clunk.  Brake and the nose falls, clunk.  Accelerate gently and no change of pitch attitude, no racket.  Decelerate slowly, no noise.)

I investigated and it appeared to be that the spring mounting flange was slightly larger than original and was perhaps catching the splash guard.  I opened up the splash guard to afford more clearance - that was not it.

The lower control arms are relatively new, ball joint is good as well as the bushings.  Sway bar end links are good, as are the sway bar bushings.  Tie rod is good.  Wheel bearing is good.  CV axle does not display failure modes (it is quiet in turns, in fact the aforementioned noise is NOT present in turns.)  It is not the intermediate steering shaft, and in fact can not be felt in the wheel.  The suspension components have been checked by me, a friend and finally a state inspector (it passed.)  In a moment of head scratching, I liberally applied spray lubricant to every component of the strut I could get to, just in case it was a spring rub or something - this had zero effect.  

I have searched the internet for similar issues, and while there seem to be a LOT of hits for "strut makes noise after replacement" and similar queries, I've been able to find very few cases where a resolution was given.  

My question - has anyone encountered this with new complete strut kits?  I'm looking to see if I have a one in a million issue on my hands, or if this is a far more common issue. To be very blunt I am not impressed with the quality of these units I've seen thus far.  

I think I'm going to install the old strut this weekend (it was fine) and that will tell me for sure what's up.

Just because it's new doesn't mean it's good. That's why we have warranties.

Well now... that much I've somehow managed to figure out, but I guess I was hoping for some "real world" accounts... particularly since I did read about many similar issues seemingly without resolution.

Such data could answer some random questions, like:  Is the brand that I bought known for being junk?  Do strut kits have more issues compared to shop rebuilds due to the quality of the other components, like thrust bearings?

Monroe is garbage and most likely culprit. Did you replace the bearing at the top mount? Did you use a good one?

I upgraded to Bilstein 1500's last year.  I thought it was just me too.  After they were installed my truck went in for an alignment, and 100k service.  Nothing said by any techs that crawled over it, and was happy that I did a good install.  But they were so loud.  I could take rr tracks without slowing and no noise.  But at low speed a 1" pot hole was loud as hell.  I kept looking under my truck to see if anything was loose.  I finally interwebbed it and discovered it is one of the more common complaints.  Otherwise I love them.  Also put new tires on this Monday (Nitto terra grappler g2 295/60/20 LT ), and they said everything looked good when I asked.  So I am just going with it.  
So I am not saying you do not have a problem. But I hope I answered you request correctly.

Usually that noise is the bearing plate. Either bad or strut shaft nut not tightened down all the way.

Did you put the spring isolators back on right?

This was a complete strut kit, it came 100% assembled with new spring, thrust bearing, boots, spring rubbers, the whole damn thing.  All I did was spin the nuts on the top mount and reinstall the mounting bolts on the knuckle.  

I'm also changing my position a little and I no longer think it has to do with the deck angle but rather minor shifts in camber and or castor when the wheel is under load.  I say that because it doesn't make noise when simply bouncing.  Note that the caster is not adjustable on this vehicle, and the camber is not adjustable without the use of aftermarket eccentric knuckle mounting bolts that I don't have.  

Replacing it with the old unit will give a definitive answer.  I'm still just stumped as to why so many people have similar issues.

Did you check the torque specs on the lower mounting points on the strut?  A lot of times these bolts are interference bolts with an out of round nut to hold them tight.  Even though you think it is tight, its really not.  My son had that issues when he swapped struts and wasn't paying attention to what he was doing.

Not that anyone cares, but I thought I wouldn't be like everyone else on the internet and actually post a follow up.

To answer the post above me, the mounting bolts WERE tightened to specifications.  

Last week, I decided to un-do the last thing I did before the noise started happening, so I re-installed the old strut.  Nothing wrong with it other than it wasn't quite like new (the other side was bad and what prompted the replacement.)

Immediately, same BS - so it was NOT the strut.  This was starting to drive me nuts and make me doubt my own mechanicin' skills.  I drove it for the week, with thoughts of trading it in because it was really starting to piss me off.  Otherwise, I was starting to think rack bushings, motor mounts or subfarme bushings - all of which looked fine, and I'm not about throwing parts at problems.

Anyway, on Friday I popped the hood to double check the top mount bolts - they were (still) fine.  However, something caught my eye - there is a brace that runs from the strut tower to the core support.  There is one bolt at the strut tower, and two at the core support.  The one at the very end was loose, the other two were snug-tight.  Also running to the core support?  Torque struts/ upper motor mounts.

As the torque from the engine pulled on the core support, the bracket was binding against the loose bolt and making the popping noise.  I torqued everything down again and she shut right the hell up.

Here's what just blows my mind - I replaced the radiator and torque struts in early January.  I replaced the struts in late January and I did not touch the affected fasteners at that time.  It didn't make a peep until a couple of days after replacing the strut.  

Next weekend I'll re-install the new strut and hope my luck holds

Attached File

Where the bushings in the links between the sway bar and control arm or strut ok?

Glad you found it!  In my old '95 Mustang GT, I had a similar noise after I did a spring/strut install.  It was a God awful knock/banging that really showed it's ass on a dirt road with the wash board surface.  I hunted and hunted that damned noise for months and never could fine it.  

A few months later I was at a shop getting new gears put in the rear end.  I walked under the car on the lift with a flash light inspecting everything very carefully and found it!   It was my transmission cross member bolts to the isolator mount  at the tail shaft of the trans.  It was more of those interference bolts that had come loose over time.  And being that the car was a convertible, there was a lot of flex in the suspension.  What I was hearing was the mount studs sliding back and fourth in the slotted holes of the cross member.