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Help me diagnose scraping sound

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  • Help me diagnose scraping sound


    Hi - Ive been trying to track down an intermittent scraping sound coming from the front left side of the truck for a few weeks. The scrapping sound only lasts for a second or two. Its not repeatable, but Ive noticed that it mostly happens when Im slowing down. Sometimes at 5, 10 or 20 mph. The sound doesnt speed up or slow down depending on the speed. It can happen in straight line or while turning. Happens more frequently in the morning when the engine is cold. I really thought it was the alternator bearing so I had that rebuilt (no luck). Then I was convinced it was the brakes. I did a complete brake job on all wheels and that didnt help. I checked the metal deflectors for rubbing on the rotors and could not detect any issue there.

    Im wondering if its a collapsed bearing or something else in the drive belt or timing belt circuit. In the last year, I had an idler pulley fail so I replaced both of those and the drive belt tensioner. I plan on flushing the power steering system tonight. I also plan on checking the play in the suspension or bearings tonight. I did lube the pivot points in the suspension to attempt to eliminate a dry bushing or something with no luck. All links, ball joints, CV boots are intact... The sound is not a typical clunk or squeek. It really sounds like a bearing or metal on metal sound. Im tempted to dig into the timing belt even though I changed that 40k miles ago. If a bearing fails on that circuit that could be the end of the engine.....

    Any ideas before I dig into the timing belt are appreciated.


  • #2

    I get the same after having new front wheel bearings installed. I thought it was the brake deflector aswell. But having checked that i am none the wiser either. But i only get it with nearly a full wheel lock and accelerating out of a corner. Then it stops. Only lasts a second or 2. If i get an answer i will let you know.


    • #3

      I was sure the sound was drivers side. Got under this morning and using the handle of a large screw driver found it to be the passangers side brake deflector was loose. A quick trip to the mechanic today who installed the bearing and will be fixed. Hope this is of some use to you.



      • #4
        I checked both heat deflectors and they are not loose. I think Im going to pull the wheels and check front wheel bearing play next....


        • #5

          When you done the brakes did you put the anti rattle plates back in?? Just a thought?? Or maybe done a rubber bush in the swing arm?? Know it not helpng much but trying to think outside the box


          • #6
            Thanks for the suggestions. THe new pads both had plates riveted to the back of the pads. I am assuming that the rattle plates are integrated into the pads. I use plenty of brake grease on the back of the pads and on the guide pins (actually replaced a set due to corrosion). When I check bearing play, I think Im going to remove the heat shields just to eliminate that from the equation. Today (subject to change tomorrow) Im thinking its the bearing. I tried looking at play of the hub but I didnt have the dial indicator set up right. I checked the mitsu manual and thought of another way to check play that will be much more accurate. According to the manual there should be no detectable play between the hub and the upper A-arm! I know I was seeing play, but because I was rushed, could not get a reliable number. I will post the amount of play for both front wheels tonight.


            • #7
              If I were you I would start a process of elimination, put your truck on four jacks, start the motor, no noise eliminates motor, first gear rear wheel drive only, no need to floor it as you are on jacks. No noise rear drive ok. Put in 4 wdh and let the motor idle in gear and inspect closely for noise, if there is noise remove front wheel and repeat with a careful ear. Just make sure the car is on jacks securely. You can get your Mrs or friend to apply brakes slowly to elimate them. And dont forget to spin front tires while not engaged in gear to elimate heat shields. Hope thid helps you find your problem.

              Loving the PAJ
              |04 NP DiD GLS|Manual|ARB Bullbar|Lightforce lights|Dual Batteries|Snorkel|


              • #8
                Major breakthrough

                Well I took off the heat shields and also checked the bearings for play. The bearings looked good (absolutely no play between suspension and spindle when pushing and pulling on it with my hands) so I buttoned everything back up. This morning I start the truck and apply the brakes without moving.... and the sound was back...

                But it was the breakthrough I needed. I found that when the truck is cold, I can get the metal scraping sound when applying the brakes hard without the truck moving. Come to think of it - when I bled the brakes a few days ago, I noticed small metal particles coming from the first caliper I bled (farthest wheel from master cylinder). Ive never seen that before on any car, but in retgrospect should have been a big clue for me.

                I looked online and it seems that the brake accumulator (4630A011) is a potential cause for the metal on metal sound Im getting. I read that a metal screech with no loss of brake function is typical failure mode. I really hope this is it - Im looking and the rest of the brake system is big bucks. The particles I saw is still concerning however....
                Last edited by tj90; 13-12-13, 07:39 AM.


                • #9

                  I know that my paj had the recall done on the brake accumulator. Something to do with the nitrogen reservoir. Have a look for the recall sticker. Or take it to a dealer and get them to search to see if it was done when the recell was issued.
                  I did the latter as i was there getting another part.
                  Hope its an easy fix. And keep us posted.



                  • #10
                    I took it to a dealer today and they told me that my 03 Paj was not part of recall. Actually I have a silver accumulator (4630A012) that apparently replaced the black bulb version (4630A011). Apparently mitsu replaced the 012 for the 011 brake accumulator for '03 and later. (I assume it was due to all the issues with the original design). The only other part to replace is the entire hydraulic brake system that is almost $2000 USD! I really hope its the $180 USD accumulator!

                    I called a high volume mitsu parts company - they told me that even though the 012 version is less failure prone, they do fail. Out of almost 300 shipments for brake issues, only one needed an entirely new brake system versus just the accumulator. I took the guys word for it and ordered a new 012 accumulator. Ill have it in about a week. At least I know that I can still drive the truck while I wait.

                    The particles I saw during brake bleed are still a mystery. It may have been grime in the bleeder screw (lost the rubber caps long ago) so I wont loose too much sleep.

                    BTW: Here is a helpful link for anyone who has brake noise:

                    A video in the above link illustrates the exact sound that I was hearing:

                    Can you see how I was fooled into thinking it was the heat shield rubbing a rotor? Never would have guessed an accumulator!
                    Last edited by tj90; 13-12-13, 07:52 AM.


                    • #11
                      Not the intercooler bash plate rubbing again a control arm when you're turning?

                      2003 NP DID Exceed with a bit of lift and a hunk of steel on the front with some stuff hanging off it


                      • #12
                        Originally posted by smwhiskey View Post
                        Not the intercooler bash plate rubbing again a control arm when you're turning?

                        Definitely not. I can put my hand on the accumulator and you can feel it knocking. THe piston inside must be sticking or something....


                        • #13
                          Originally posted by tj90 View Post
                          Definitely not. I can put my hand on the accumulator and you can feel it knocking. THe piston inside must be sticking or something....
                          im selling my

                          4630A012 brake accumulator as i ordered it instead of


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