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Front end knock

So I’ve got a very soft knock that only appears on slow <10 mph turns, both left and right, that is coming from somewhere in the front end of my 1997 Ford Taurus (120k).



I’ve jacked up the car (both sides & one side at a time) and can find nothing loose. There is no play visible in the steering (the second you push on a tire, the steering wheel jerks to that side). The right side outer tie rod was replaced a week ago, the left side outer was replaced ~3 years ago. Struts and mounts are 3 years old, drivers side control arm and sway bar links/bushings replaced early this year. Everything else is original.



Any ideas?

Did you check the boots on the CV joints?

yep… they’re all intact. The knock I should clarify is just a single pop or two on a turn, not a consistent popping sound, and doesn’t happen on all turns.

You might want to check for worn ball joints.

Place a floor jack under the control arm of the ball joint to be checked, and raise the vehicle so the tire is 5"-6" off the floor. Take a 5’-6’ long pry bar or 2X4 and place one end under the raised tire. While someone watches the ball joint, pry up on the tire and release repeatedly. If the ball joint is worn it’ll be observed moving up and down in it’s socket.

Tester

Those seem tight, too… :S

Still no idea what it was/is, but 3 days of quiet now… maybe I just had some debris jammed up in a strut mount or something like that…

Car’s been great except for these suspension noises, but then I’ve hit countless axle-deep potholes on the abysmal roads around here.

It is quite possible to have a faulty joint on a halfshaft or a ball joint with an odd wear pattern which can cause a noise like this. It’s also very possible that the joints may feel perfectly fine with no looseness but that does not mean the joints are good.
The same thing applies to driveshaft U-joints. They can be perfectly tight and yet completely bad.

Sometimes it requires disassembly of the component and a thorough inspection by feel with all stresses removed from the part before this can be detected.
That gets into the area then of whether to replace the parts due to age/mileage since it’s apart anyway.

So short of disassembling the entire front end and replacing it all in the hopes that one of the replacements would work, what would your suggestion be?

It sounds like you’re advocating blind replacement of parts. I’d personally lean towards watching it carefully for noises/looseness until the source can be more clearly identified…

Could it be a bad wheel bearing, proper diagnosis for a proper cure I agree. cvc joint shirley could be a cause also, yes things will get worse not better in all probability, Is the money better spent searching for the problem, or waiting until the failed part is so obvious and may take other parts with it is a tough call.

The problem I have is that two different mechanics (one of which gets fantastic ratings on this site) could find nothing wrong in the 4 days or so it was making the noise. Neither could I. Now for several days it has made no noise at all.

I’m just averse to replacing parts because there is a random chance they might be troublesome.

No I’m not advocating blind replacement of parts. That’s something I never do or advise.
I’m only pointing out that with many items on a car being tight does not necessarily good and sometimes it make take disassembly to know for sure.

Suspension components, U-joints, halfshaft CV joints, you name it. Even wheel bearings may come across as fine when trying to detect a bad one by hand. Place a load on that bearing and it changes completely.

Fair point… thanks for the advice… :slight_smile:

When I had to replace the half-axle on my Camry, it was worn as you describe - not loose by hand, but worn badly when you ripped it open. But it also made noise much more consistently (and considerably louder).

I once pulled a rock about the size of dime out of my front strut (wedged into the mount) that made a noise like you describe. Couldn’t see it for the life of me, but it was there.

Solved!

Finally got a mechanic to recognize and find the noise - he said he struggled and was only able to isolate it using a stethoscope. He verified that everything is tight and safe, but that the noise is coming from the strut mounts. Figures. Lousy replacement parts (it seems like 75% of my repair costs on this car have been replacing previously replaced parts)…

He says that the mounts are nice and tight, but just not moving smoothly. I have no memory steer issues at this point, and he advised that I should probably just drive the car as is for awhile until I couldn’t take it anymore or they actually started loosening up.

Best part? He charged $0 for the diagnosis.

Thank you for posting back but I sincerely hope your mechanic is correct and that the problem is not related to a ball joint.

It’s possible for a ball joint noise to reverberate through the entire steering knuckle and strut and since a ball joint is a part that can kill you PDQ I hope the diagnosis is spot on.

Thanks for trying to keep me paranoid, ok4450. :S

I’ve tested the balljoints and can’t get them to move or make noise, and neither can any mechanic I’ve taken it to, but now I’ll probably have it back up on the jack this weekend triple-checking that. :slight_smile:

Strut mounts wouldn’t surprise me, though… neither car can keep a pair of replacements working for more than 2 years, it seems… and this doesn’t sound that different than when the Taurus blew through its original mounts (those lasted 9 years).

My goal at this point is just to get another 12-18 months out of this thing. At that point, with a 15 year old and a 14 year old car, it will definitely be time for replacement.

PS - hope that didn’t sound “snarky”, ok4450 - I certainly appreciate your advice and you certainly give out some of the best advice I see around here. :slight_smile:

No, it’s not snarky at all. I only get antsy about ball joints because some years ago I had a car here that I suspected of a RF ball joint problem. No amount of checking could detect any looseness in this joint.

One Sunday afternoon I decided to pop the suspension apart and not only was the joint bad, to my surprise it was one of the worst, most worn out joints I’ve ever seen. I could move the ball socket on that thing a good 1/4". It just stunned me that one with this much slop in it would not allow the wheel to move around. Even having someone doing some prying while I carefully watched it revealed no movement at all.

The engineer in me would love to have seen that balljoint. I’m struggling to envision how you couldn’t get the wheel to move around with that much slop… must have been a truly bizarre wear pattern.

It was definitely a strange one. The RF wheel was perfectly tight; no movement at all in the 6 and 12 positions or at the 3 and 9. Prying up on the tire/wheel revealed nothing.
The symptom was a little wandering and an occasional knock sound on a bump.
Even the wear indicator on the joint showed normal.

When it was apart and I saw the amount of slop I was just flat stunned that it could be that loose (about to break actually) and yet maintain a tight wheel. I think I’ve still got that joint in the scrap metal pile. Get a chance I might dredge it up and post a pic of it.