"POP" from front end somewhere when pressing brake pedal. Only certain speeds

Discussion in 'Fox 5.0 Mustang Tech' started by 281pony, Oct 9, 2010.


  1. 281pony

    281pony Active Member

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    my car decided to just take a big ol' chit on me today with issues out my ass. out of nowhere...

    anywhere in the range of 10-30 mph ROUGHLY. i can hear a "POP" from what sounds like the front drivers side of the car. it does NOT do this while stopped, below 10 mph again ROUGHLY or when over 40 mph.

    fluid is good, no leaking, good pads on it. everything is tight. it's only coming from one side that i can make out. booster? calipers, wtf causes this now?

    it causes the noise with the lightest application of the pedal. also, the pedal FEELS softer then usual. it might be in my head. the car literally developed like 5 issues today out of nowhere.

    thoughts?
     
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  2. 281pony

    281pony Active Member

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    nobody? caliper bolts are tight. calipers have equal "wiggle" on each side. nothing loose, out of the ordinary.

    it also does not do this in reverse. i got it up to speed in reverse for testing, no noise. i go same speed forwards, its there..

    i would chalk it up to nothing, but considering my pedal feels SOFTER, i dont want to ignore it. brake failures kinda suck.
     
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  3. project 87 5.0

    project 87 5.0 Member

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    i had the same issue about 6months ago, it was my caster/camber plate was loose. I would check that to start with.
     
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  4. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

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    Yeah, I'd look into it being suspension related and not brake.
     
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  5. 281pony

    281pony Active Member

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    The thing is though I can make it POP as many times as I want. All by touching the brakes? How could that be suspension? Balljoints are new with new control arms also. This ONLY happens when I touch the brakes.
     
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  6. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

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    Because when you hit the brakes, the weight of the car shifts forwards onto the front wheels as they push backwards resisting the car moving forward. In other words it's not the brake popping but the suspension as the wheel tries to slow down the car and something in the suspension moves.

    Being speed dependent makes me think this was well. Jack the front up and see if there is any movement of the wheel backwards or forward.
     
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  7. 281pony

    281pony Active Member

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    it does this with such light brake application. the weight of the car is literally not even shifting. ill have to take a video.
     
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  8. MFE92

    MFE92 Active Member

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    "How could it be the suspension?" Because applying the brakes causes torque to be applied on the horizontal axis through the caliper bracket to the spindle to the balljoint and strut and to the c/c plates, and the drag on the tire applies torque on the vertical axis to the tie rods, balljoints, and A-arms. That's pretty much every single front suspension component affected by merely applying the brakes, and not even counting compression due to weight transfer.
     
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  9. 281pony

    281pony Active Member

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    I completely understand weight transfers forward. What im saying is this happens before the brakes are even engaged. The very lightest touch of the pedal does this. The car is not even slowing its such a light application.
     
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  10. 2000xp8

    2000xp8 Mustang Master

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    281, i think you need to go into problems with a little more of an open mind.
    Each one of the issues you post, you have some type of pre-disposed notion of what the problem is, people give you the answers, then you debate it with them.
    You did the same with the fuel tank issue.

    Your problem in this case is suspension related more than likely if all your brake/rotor compoments are tight with no play.
    Just letting off the gas causes the weight of the car to shift.
     
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  11. MFE92

    MFE92 Active Member

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    Check your hubs for excessive play, which would cause excessive rotor runout, which would cause pad knockback, which would make for a longer pedal travel and potentially noise as slack is taken up.
     
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  12. 281pony

    281pony Active Member

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    i was walking in the mall on my phone and posted my last reply. im merely trying to say, that it doesnt seem to be suspension. im not arguing physics and the transfer of brake energy.

    i am doing this in neutral on roads with a tiny incline. i can let the car roll forward at slow speeds and get the noise to engage with every touch of the pedal. the brakes are NOT engaging at all, the car is not diving. not slowing, no hitting bumps, nothing. its doing this with no load at idle essentially. its completely speed related, so that might help narrow it for me. it's gotta be a moving part IMO.

    i've tried pushing on the front of the car thus far, and getting someone to listen to it while its rolling. they say its from the firewall area or a wheel. i was just hoping someone else had experienced this before. kinda burnt on wrenching, but ill look at it tomorrow.
     
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  13. 50sleeper

    50sleeper Founding Member

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    Same deal

    My car does the same exact thing.

    It IS the brakes. I can get it to happen everytime I back out of my driveway and then take off down the street, the first time I touch my brakes to slow down I get a pop on the front (drivers side I think but its hard to tell).

    I've got new Napa Ultra Premium rotors and Motorcraft pads on it I put on 2 years ago. I've also bled the brakes all the way around (twice) and am using new Motorcraft fluid.

    I can grab the outer pad and move it slightly as the pins that go through it on the ends are much smaller diameter than the hole in the ends of the pad. I think that is where the noise comes from but I can't seem to do anything about it. My brake pedal is nice and firm with no fade or mushy feel. I just have the stupid pop sound the first time I touch the brakes moving foward after stopping the car in reverse.

    It's really annoying but I've learned to live with it I guess.
     
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  14. 281pony

    281pony Active Member

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    thanks for the input.
    i havent looked at it yet, been working 16 hr days so i come home and sleep. about it lately :crazy: ill take a look asap and see what i can figure out. this started for me after the car sat for 6 days. no changes to anything.
     
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  15. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

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    What I can think of that the pads fit loosely on the pad support bracket and when you apply the brakes, they click forward slightly and make the noise as they move on the bracket
     
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  16. 281pony

    281pony Active Member

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    thats what i was kinda thinking too. ill check it out when i get time. just got home from work, 17 hours today. im done for the night :notnice:
     
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  17. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

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    Do you have the small clips on the pads that create a little tension. Iirc, with the cobra calipers, when you slide the pin in, you gotta press down onnthe caliper to put tension on the clips before you slide the caliper pin in and lock the caliper in.
     
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