gciriani Posted August 9, 2012 Share Posted August 9, 2012 In the past week a noise on the front left wheel side started becoming every day more prominent. It goes at the same frequency as the wheel is rotating. The vibration can be felt on the steering wheel as well. Any suggetsion as to what it could be? The mechanic said it could be the axle CV joint, but probably not the ball bearing; it could even be the transmission in his opinion. The first time it was hoisted, moving the axle by hand didn't show any significant play. So we thought the CV was improbable. He injected some grease in the booth of the axle to see if this was going to change anything, but there was no change. Eventually we decided to try replace the axle, but as he started taking down the wheel and extracting a couple of pins, he became more convinced that the axle was OK, so he recommended that I take the car to the dealer to diagnose if it was indeed the transmission. When I left the mechanic's garage the noise had disappeared, and never came back by the time I reached the dealer. So I didn't go through any diagnostics as it would be wasted money. Any suggestion on what this could be, and what to check? The car is a 2003 Legacy SW with 118,000 miles on it, 2.5 L engine. This actually was the second time the mechanic had put the car on the hoist to check it underneath. He examined treads, brake rotors and axles. What I also asked them to do the second time was to turn on the car while on the hoist, put it in gear and spin all 4 wheels to at least 30 mph. First they spun the incriminated side without the wheel on; then because it was almost not moving (the differential transferring most of the rotation to the other wheel), they mounted the wheel back on and they spun all wheels again. I'm wondering if this has something to do with a problem in the differential that the uneven rotation hid away. I wanted to add further piece of the story which may or may not be related to what's going on right now. About a month ago a grinding noise started on the other side (front right hand side). It was at the same frequency as the wheel, and I thought there was something caught in the brake rotor, but nothing was showing after taking the wheel down. It appeared at the beginning of a 100-mile trip, and the next day was not there anymore. It had the same period as the clunking noise, but just grinding this first time. I could tell that it was metal on metal, and not with a lot of energy dissipated, but it was definitely there. The next day I went to the mechanic, and we couldn't find anything. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 9, 2012 Share Posted August 9, 2012 rotate tires front to back and see if the noise moves or changes. it is probably: 1. brakes or 2. wheel bearing brakes should simply be taken down to see if a pad is hanging. the caliper slides could be hanging up and the pad is dragging...or other issues. the caliper, pads, and clips should be pulled and inspected. wheel bearings on subarus can be really hard to diagnose, showing no symptoms at all when you inspect them but making noise while driving. a mechanics stethoscope around the bearing area or on the strut spring while turning the wheel by hand *may* reveal something. the infrared temperatures guns are really helpful and my favorite tool for diagnosing subaru wheel bearings. a failing bearing generates more heat and renders the front hub area hotter. comparing readings from one of those guns from drivers side to passengers side will show higher readings on a failed bearing. like 20 degrees or more hotter. you generally have to take a few readings though because the heat generated is so hot it's hard to stay consistent with distance from center, pointing the gun at an angle, etc - but with a couple readings it usually becomes notable that there's a difference between passengers and drivers side. and the nice thing about those guns is you could just go by one and have it handy in your car - test after an extended drive, etc. your description (which is limited in scope compared to seeing the car in person) does not lead me to think it's the trans or axle at all. Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 9, 2012 Author Share Posted August 9, 2012 Thanks for the reply. I do not understand though why you are suggesting a tire rotation if the problems resides with the brakes or the wheel bearing. The brakes (rotor and pads) where replaced 2-3000 miles ago as was the right-hand-side axle. The left-hand-side axle is still the old one, as it was judged to be still good. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 9, 2012 Share Posted August 9, 2012 tire rotation is easy to do so if you have a mysterious thump it's just an easy and free test you can do to rule out a bad tire - they can have a "thump" if they have internal belt separation, etc. i do not think it's a tire, just easy test. Even if the brakes were done they still need to be checked - what do you mean by "brakes were done"? for many shops that means: 1. replace rotors and pads. the caliper slides may not have been greased, the caliper clips are always have build up and sometimes rust that causes pads to hang...etc - were the slides greased and clips at least cleaned, if not replaced. for most shops/mechanics the answers to those questions are "no" and so it needs to be checked if you have an ongoing issue. i have seen 3,000 mile pads warn down to nothing because the pads hang due to a stuck caliper slide or hanging up on a rusted clip. Subaru OEM axles rarely fail...it's almost unheard of. I would be more suspicious of an aftermarket axle than the original Subaru axle with that low mileage on it. Due to the inconsistency of the aftermarket axle supply it is better to keep the original OEM axles - just keep rebooting them and never replace. Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted August 9, 2012 Share Posted August 9, 2012 If a wheel bearing is bad enough to clunk, it should show up in a wiggle test pretty easily. If it doesn't get hot, doesn't hum, and isn't loose, it's good. Telling you have a bad wheel wheel bearing is usually easy, on this it's figuring out which one that's tough. Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 9, 2012 Author Share Posted August 9, 2012 what do you mean by "brakes were done"?... Subaru OEM axles rarely fail...it's almost unheard of. The mechanic replaced both rotors and pads. I probably didn't explain the axle replacement well. Only the right axle assembly was replaced, and it was done at the same time as both brakes (rotors and pads), probably because the bearing or the joint had started to be noisy (I have forgotten the reason, but I trust the mechanic since I have along term relationship, and he often does stuff at no charge). The noise was periodic, like: clunk, clunk, clunk at the same speed as the wheel. It didn't sound like a caliper sliding on a surface. When it happened I could even hear it in the parking lot going 1 mph, standing outside the car and my wife driving in a circle. At that speed it was like: clunk, ... 1 second, clunk, ... 1 second. That is the clunk would last about 1/10 second, then there would be an interval of 1 second, and then again, clunk. So it was definitely in a particular position and it didn't seem caused by something sliding. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 9, 2012 Share Posted August 9, 2012 interesting - but jacking the car up and turning the wheel by hand offers no noises? nothing seems obvious to me hopefully someone else pipes up. since it is so closely associated with rotating and the description of the clunk, hub/bearing or axle seems suspect...but not sure... the axles are the same left to right so you could swap axles and see if the noise "moves" as a test. or you could buy a new axle and replace it. if it works then you're done. if it doesn't work then you have a spare axle to put new boots on next time one of your axles fails. if the boot has never been broken and the axle never replaced though i would be very surprised if it was the axle, Subaru OEM axles don't fail very easily. Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 9, 2012 Author Share Posted August 9, 2012 The mechanic, and I was there watching it, couldn't hear any noise turning it by hand. But I suspect that at that point the position of the suspension (hanging) made the difference. My further hunch is that spinning the wheels while hanging changed position of whatever it was, that was causing the noise. I'm still hunting for a rational explanation, and try to confirm it with some test, because something definitely was not right. The fact nothing feels wrong right now, only means that that "thing" may be lurking and wait to happen again. The boot I think it has a cut somewhere. Quote Link to comment Share on other sites More sharing options...
markjw Posted August 9, 2012 Share Posted August 9, 2012 I would look closer at the brakes. When the noise begins to happen, does applying brake pressure make it go away? If so, do as Gary said and pull the brake caliper, chk/replace the anti-rattle hardware and grease where it needs it. Don't forget the back of the pads. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted August 9, 2012 Share Posted August 9, 2012 Any speed related transmission noise would be a front differential problem. You can drain the fluid and check for metal in the oil and large metal particles on the drain plug magnet. Clean fluid and minimal very fine metal on the magnet will rule out the differential. Sounds like an axle problem. Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 9, 2012 Author Share Posted August 9, 2012 ... does applying brake pressure make it go away? ... There is no more noise now, I'm trying to diagnose what could have caused that for 4-5 days and then all of the sudden went away. But yes, applying brake pressure was making the noise go away, and so was constantly accelerating. The noise was at max while going in neutral, or with a very, very slight gas pressure. So it was torque dependent. Quote Link to comment Share on other sites More sharing options...
markjw Posted August 9, 2012 Share Posted August 9, 2012 I experienced clunking in the front end of my Outback this past winter. It was intermittent at first, but eventually was constant. My brake calipers were completely void of any grease. The backs of the inner brake pads were worn to shinny metal where they had been shifting rapidly against the caliper pistons in all sorts of driving conditions (except braking). I pulled both calipers and greased as recommended. Problem solved. Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 9, 2012 Author Share Posted August 9, 2012 ... I pulled both calipers and greased as recommended. Problem solved. MarkJW, Did you experience anything as I described during acceleration? With robust acceleration the clunk went away as well? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 9, 2012 Share Posted August 9, 2012 original poster doesn't seem inclined towards it but the caliper slide pins should be checked...i mean, it's hard to say not seeing the car physically, but they are notably poor design for early 2000's stuff, the ones that have a rubber bushing on the one calipe slide pins. the bushing swells (this happens all the time, i'm getting tired of them) and causes the pin to stick in the bore. thing is - it can happen after a brake job or get worse quickly after a brake job as the rubber bushing is exposed to less or more or different kinds of grease. so that you had rotors/pads changed doesn't really mean much and may even suggest that's a good place to look. i remove the bushings and throw them away, problem solved. Quote Link to comment Share on other sites More sharing options...
markjw Posted August 9, 2012 Share Posted August 9, 2012 MarkJW,Did you experience anything as I described during acceleration? With robust acceleration the clunk went away as well? I never experienced any clunking during acceleration. It was mostly on deceleration and being in a turn during deceleration. And of course, any bumps or dips in the road would bring it on, so long as I wasn't applying brake pressure. Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 9, 2012 Author Share Posted August 9, 2012 ... the caliper slide pins should be checked... Grossgary, Thank you again for the suggestion. I'll bring it to the mechanic, and we'll try it. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 10, 2012 Share Posted August 10, 2012 Grossgary,Thank you again for the suggestion. I'll bring it to the mechanic, and we'll try it. I was hoping someone else would chime in with some better options....but dunno? Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 10, 2012 Author Share Posted August 10, 2012 ...the caliper slide pins should be checked...... the bushing swells ... and causes the pin to stick in the bore GrossGary, I was thinking this over. How would the behavior you are referring to explain the noise I detailed in this post? Specifically a precise location during the rotation of the wheel at 1 mph the clunk would last about 1/10 second then there would be an interval of 1 second (about the time for a a full 360-degree rotation of the tire, and then again, clunk Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 10, 2012 Share Posted August 10, 2012 GrossGary,I was thinking this over. How would the behavior you are referring to explain the noise i really don't know what's happening physically but this brake issue is a very common 00-04 Legacy/OBW problem so it seems simple enough to check. but if you're reliant on a mechanic i can see where it would be nice to actually know. i've also had it happen immediately after brake jobs (i assume making that bushing swell or something). and you said it goes away when braking...strongly implicating brakes...though not ruling out other things of course! i think it goes something like this...but this is speculation, i usually just think of this as a common issue more than try to analyze what happens, but i can probably make something up!!...the rubber bushing is only in one pin per side and that pin is impeded or seized (probably a gradual process, not immediate - a bit reminiscent of your description of it going away). the other pin is able to move, but only has very limited range due to the other one sticking. so the pad has more range of motion on one end than the other. i can sort of picture a scenario where the pad is unevenly warn and slightly canted such that the pad is pushed, pulled, pushed, pulled..making a clunking noise. why it would be timed with tire rotation i'm not sure about. if memory serves me right i believe it is the inner pad that gets affected, i know it's just one that gets affected by this for some reason due to the geometry of the configuration. the ones that i have seen make more of a rubbing noise than clunk...so i'm equally unsure. applying brake pressure was making the noise go away, and so was constantly accelerating. applying brakes seizes the pads in place...acceleration may push a pad far enough off the rotor surface to mitigate the cause? who knows, i'm still calling my suggestions very rough guesses at best. hate to see you take it to a mechanic for a shot in the dark. Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 14, 2012 Author Share Posted August 14, 2012 Update: the mechanic said that last time I took the car there an he put it up on the hoist, he tightened the bolt on the disc. He hypothesized that this might have eliminated whatever source of play was causing the vibration. Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted August 14, 2012 Share Posted August 14, 2012 Tightened the bolt on the disk? Do you know which one he meant? Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 15, 2012 Author Share Posted August 15, 2012 I was watching him as he was doing it. It was the center bolt, the one for which one has to use an extractor (at least it was a large cylinder he was using). Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted August 15, 2012 Share Posted August 15, 2012 The big axle nut in the center? Whoever last had their hands on it goofed, it should never come loose! I wonder if the wheel bearing was loose because of that or if the noise was the axle slapping around or in/out. The wheel bearing on that side might or might not be OK, and might fail prematurely. Or maybe not. Quote Link to comment Share on other sites More sharing options...
gciriani Posted August 15, 2012 Author Share Posted August 15, 2012 The big axle nut in the center?Whoever last had their hands on it goofed, it should never come loose! It was not loose. The mechanic said it was not as tight with all the torque it is supposed to have according to the manual. Now, the same mechanic is the one who replaced the brake rotors and pads on both sides, and the axle on the side opposite from the side I'm having the problem with, 3000 miles ago. I don't know if he by mistake touched the bolt on this side. Quote Link to comment Share on other sites More sharing options...
KaraK Posted August 20, 2012 Share Posted August 20, 2012 So- the clunk is gone now? I recently had a similar clunk (under light acceleration) mine turned out to be the inner tie rods. Quote Link to comment Share on other sites More sharing options...
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