monte carlo popping front end

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HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
one of my best customers brought in a 1996 monte carlo, they had replaced front hub assemblies as the bearings were roaring. after this the car began popping when the wheels were turned and the car was in motion. a test drive immediatly sounded like cv joints when they begin going bad, even though the boots were intact, we installed a used set from a local yard, same noise. this time a reman set were picked up and installed just in case a second set of bad used ones had been installed, still same noise, sounded worse if not the same. the customer stated he was unsure if he could have damaged the hub assemblies during install so as a precaution and since no noise was evident prior to the bearings being installed we put in 2 new hub assemblies. still no change, tie rod ends and balljoints were next, and even a new set of struts, no change. it cracks as if the joints are binding and then letting go "pop" I laid on the hood and had my employee drive the car slowly and I can visible see the wheel jerk as it pops. we checked torque on lugs and even substituted wheels from another quiet car just in case a wheel had a crack, no change in sound. I swear its cv joints, my part supplier sent me a BRAND NEW (not reman) axles and low and behold no better, we even removed the brake rotors and calipers to eliminate them as suspect, still no change, I am at a loss. the car will pop mostly with wheels turned sharp, although it has done it while straight. it has to have the weight on it, while on stands it will not do it, it does not need to be in gear , rolling in neutral will also cause the noise, forward, reverse does not matter. very simply, the car must be rolling with vehicle weight on the suspension, can anyone help, I have nearly $ 600 in parts not counting labor and still no fix in sight, no tsb's have been found, other than a scrunch noise while turning from a faulty jounce bumper but that is not this noise. any suggestions ? thanks Bob Phillips Bob's repair and welding Kodak TN

posted by  bobcat7

I suppose it's too late to tell you to actually diagnose and isolate the cause instead of throwing parts at the car. :doh: Control arm bushings on that car tend to get noisy at about 100k miles and they make a popping sound only under load. At this point you have nothing to lose AND you've already replaced everything else.

P.S. Next time try using sentneces and paragraphs. It's really hard to read a block of text.

posted by  vwhobo

I appreciate your response, and will certainly try to be more readable from now on, frustration does strange things to ones sense of editorial skills.

Now, as for the control arm bushing theory, I have already thorght of that, and have been under the car with a prybar and wrench tightening everything and looking for loose parts, soft bushings etc. really nothing notable. One thing did come to mind based on your reply, I should more clearly describe the popping. It is not a single pop as a bushing would make, but it will repeat 5 or 6 times per wheel rotation. as in pop, pop, pop, pop . probably every 30 degrees or so of rotation. which is mostly why I suspected cv joints.

The process of removing the rotors and calipers,substituting other wheels, as well as removing load from the wheels, rolling the car in neutral as as opposed to under power in drive then reverse were all process of attemptimg to locate/ isolate the noise. we have spent 6 days trying to isolate this noise. ball joints and tie rod ends were shot anyway just hoped to eliminate them from the equation. I still would say it was cv joints if I were to be seeing this car for he first time. however, assuming it is, I cannot understand what would cause now 4 sets of axles to do this. there is no sign of collision damage, alignment is ok. no reason for the alxes to flex more than they are designed to thus damaging each set.

i suppose tomorrow I will remove both axles, and reassemble the front suspension less axles, then push the car and see if it is quiet.

one other possibility enetred my mind, try to follow along, im thinking out loud here. it seems to occur more frequently while turning right or left, could there be a problem in the differential? while trying to compensate for different axle speed, something binds up. then snaps loose. the sound would then travel along the axle, which is under pressure and resonate through the wheel, which would act as a large speaker, so to speak? could explain why i see the wheel jerk as it pops
has anyone ever heard of anything like this????
thanks for your ideas bob

posted by  bobcat7

Okay, so the customer is absolutely sure the noise wasn't there prior to replacing the hub assemblies. Is that correct? It sounds strangely from the additional description like you have a bolt that is too long and it's intermittently hitting a stud flange on the back side of the hub. That would also explain the jerk from the steering wheel.

posted by  vwhobo

he says the noise wasnt there, my experience has proven him to be up front & honest as long as i have known him.

there are no bolts hitting the back of the hub. done checked that. I just wonder if he forced the axles into the trans and maybe chipped a spider gear or something.

posted by  bobcat7

The spider gears are stationary when rolling in a straight line, so it should be quiet. Also, why would the axles come out to replace the hubs? I think you're gonna have to wait till tomorrow and try rolling it without the axles installed as you suggested. Just make sure you have the hub/wheel bearing assemblies supported so you don't damage the new ones.

posted by  vwhobo

good question about why the axles would have come out, they dont, that doesnt mean he didnt take them out though. ill call him tomorrow and without asking , ask. hes a young guy , very mechanically inclined, but just not much actual knowledge, he calls me 3 or 4 times a day to ask commom knowledge questions. he and his father in law have a used car lot, he tries to get all the stuff ready to sell, he maens well, but doesnt know what hes really doing. good job security for me!!!!!

posted by  bobcat7

have enough power steering fluid?

posted by  azkid110

Good idea. Being low on power steering fluid often causes a popping sound to emanate from the fornt end of a car, especially when the car is being pushed. I'm going to write that down and post it at my shops to help my newer techs. :thumbs:

posted by  vwhobo

today I took both wheels off, "locked" 1 wheel and rotated the other, both sides, no noise. tried with the car running and foot on the brake to add artificial load to the turning wheel. no noise. My help didn't come in today so I wasnt able to push the car with no axles yet, ill try that tomorrow. I guess at this point I can add that the noise isnt constant. for example, you might drive it in circles 10 times around no noise, then all of a sudden pop pop , might be silent again for a few more feet then pop pop pop. By the way power steering resivior is full. and car will pop without input to the steering wheel anyway. definitly sounds like cv's but 4 sets?????????

posted by  bobcat7

today I took both wheels off, "locked" 1 wheel and rotated the other, both sides, no noise. tried with the car running and foot on the brake to add artificial load to the turning wheel. no noise. My help didn't come in today so I wasnt able to push the car with no axles yet, ill try that tomorrow. I guess at this point I can add that the noise isnt constant. for example, you might drive it in circles 10 times around no noise, then all of a sudden pop pop , might be silent again for a few more feet then pop pop pop. By the way power steering resivior is full. and car will pop without input to the steering wheel anyway. definitly sounds like cv's but 4 sets?????????

Oh yeah i spoke with the owner, he says he never had the axles out, so im less sure about the diff gear theory.

posted by  bobcat7

You should not have posted that. If I break down in TN, I will not go to you.

posted by  What?

Glad you were watching, In truth, my name is Achmed, I own the "other" shop in Kodak, and this is merely a campiegn to lure all business away from my competitor, Bob's Repair. he is a good for nothing honest fair reliable shop owner who has stolen all of my hard cheated customers by being so damn good. May the fleas of a thousand camels infest his armpits!!!!!!!!!

Just dont tell him I said that. and besides its not like i was asking a stupid question like "what size tire should i put on my Yugo?"

posted by  bobcat7

I hope you stick aroudn at carforums for a long time. I had a similar popping noise to what you desribe on my comet when I first purchased it. Mine only ocurred when turning left. I had the struts replaced and the noise went a way.

posted by  Aondor

Struts on a Comet? Think, type, submit. :doh:

posted by  vwhobo

EXACTLY WHAT I WAS THINKING!!!:banghead: :banghead:

posted by  glagon1979

Hi there, first off Id like to once again thank those of you who took time to answer in a responsible fashion. I hope I can do the same for you at some time in the future. A very wise teacher of mine said "there is noone smart enough to have all the answers, true smarts comes from knowing how to find them." Forums like this one are but a tool one can use to draw on the experience of others and gain help. and there is no shame in asking for help.

Now on to the solution. we pulled the axles and bolted the thing back together, put a large bolt and nut thru the bearing to keep it from seperation and pulled it with a tractor, still same noise, I swear it sounded just like cv joints when at a full turn, but the axles were gone!! hmmmmm.

the only still moving part was the bearings, which by the way are what had been replaced that started this whole mess.

we removed the hub assy. and compared it to a factory gm hub assy from another car, believe it or not they shared the same critical dimensions, fit in the same hole etc, but they were constructed differently. the aftermarket bearing, (both sets as my customer had replaced them and so did we to eliminate the chance of defective or damaged bearings) had an extra external spacer/ race where as the gm bearings were more like a one peice encapsulated unit. this extra spacer/race would be the part that contacts the cv part of the axle and holds the bearing tight toghether when installed. this spacer was created in such a manner that it didnt fit tightly against the installed axle thus letting the bearing parts work loose when installed. we put in the old factory gm units and noise is GONE.

I called my supplier and discussed the problem with them. the bearings ordered were (both sets) a generic store brand part, even though they carried a BCA number. my supplier apologized for the whole thing and has filed on my behalf a claim to reimburse me for my labor related to this ordeal. Thumbs up for Oreilly auto parts,

I suppose there is a moral to this story, I suppose there may be many. 1 keep in mind that because a part is new dont mean its good. 2 the BCA brand part cost nearly 2 times the store brand part, you get what you pay for.

again thanks for all the input,

posted by  bobcat7

are you telling me i don' have stuts cause Im just going to pos pictures then you can Think type submit tm

posted by  Aondor

i didn't see him stutter.... :screwy: no, you don't have struts on your comet...

...and before you take a pic of your shock and post it...

http://en.wikipedia.org/wiki/Strut

posted by  dodger65

wow Im a big DB

posted by  Aondor

db?

...stupid letter counter...

posted by  dodger65

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