Popping noise from front when braking.

[DooMer_MP3]

Hi there,
2001 MP3 with ~60k, SPOOL springs, AEM intake and OBX header. When I am coming to a stop under light-moderate brake pressure, there is a popping noise that comes from the front of the car. It only happens when braking. If I were to glide to a stop in or out of gear, no. If I slow down to where the popping begins, and then switch to the e-brake (rear brakes), no.

I removed the pads and regreased the area where the front pads go with brake grease, and re-greased the bottom slides where the allen key goes on the caliper. My next step is replacing the front swaybar bushings since they already creak in the cold. This problem happens in cold, warm, dry or wet.

Any ideas? Could it be control arm bushings? Motor mounts? CV joint? I rule out CV joint since it only does it when braking which shifts weight to the front, hence my belief its the suspension...

Chris

 

[BiGx5MurF]

Try torquing down your rims while they're still in the air (up on jack stands). I had this same problem when I last changed my pads. It seems I didn't torque the rims in well enough while they were still in the air, I didn't torque them until I lowered it.

hope this helps.

 

[DooMer_MP3]

Thanks, but the noise just kind of appeared out of nowhere. Then I jacked it up and greased the brakes and it still did it.

 

[vindication]

ball joint?

 

[DooMer_MP3]

What/where is the ball joint?

 

[DooMer_MP3]

Ok, looked it up in the shop manual... s***, that looks hard/expensive to replace, with all of the Special Service Tools the manual recommends. UGH.

 

[apexlater]

Eh, I vote for your front sway bar bushings. Mine does that a little too under hard braking. You should torque your wheels when they are on the ground. You do however want to make sure that the lugs are seated while off the ground, but use a torque wrench after you've lowered the car back down. Re-torque them after a couple hundred miles also.

 

[DooMer_MP3]

Yeah I always get the lugs torqued pretty tightly while up in the air using the crisscrossing star method for 5 lugs, and then lower it down to where the wheels touch the ground and have enough load for torquing them to proper spec. Then recheck when completely off the jacks. I'll be doing the bushings soon (next week or 2) but the noise is getting really bad and starting to worry me.

 

[GhostLinker]

Sounds like it can also be a wheel bearing. It is not uncommon.
Do not try to change it yourself unless you have the right tools (Mazda special tools).

Check the manual in section 3-11.

 

[apexlater]

wheel bearings tend to grind and vibrate, especially while turning. He says it only happens during heavy braking, probably most often when he "stabs" the brakes. The front swaybar bushings will get squished and mangled up, causing more bar movement and it will bang against the lower control arm.

I did my front wheel bearings myself, I had a shop press the old bearings out and the new ones in, but other than that I did it all myself. You don't "need" the right tools, unless you are talking about the giant press that is needed. The manual is very helpful though.

 

[DooMer_MP3]

Ok, just a slight update on the symptoms. It is getting worse right now, so its easier to test when things happen. It happens under light-moderate braking, not heavy. It also does not happen when you brake when going in reverse. I had my fiancee drive forward and brake for me, and from the outside it sounds totally different. Maybe because its so less bassy, but it sound like more of a clicking noise coming from somewhere by the wheel. Definitely from the driver side, couldn't tell if it was doing it on the passenger side (might have been hearing the driver side).

I tried turning the wheel all the way side to side with the car at a stop. No noise. I also turned the wheel all the way to a side and drove at a slow (5-10mph) speed. No popping. Tried it all the way to the other side, and no popping.

Its got to be something rotational, but its so weird that it only does it going forward. I still haven't ruled out brakes either. I might just take it to a shop and see if someone will do a suspension check for cheap.

Any other ideas?

Chris

 

[apexlater]

Maybe pop your hood and check to make sure the strut top bolts are tight?

 

[CDNMSP]

I think i have the same problem as you. Only under light braking towards the tail end of the brake period. Sound comes from the front end. I cannot figure it out either.

 

[DooMer_MP3]

I've scheduled a suspension and brake check for next Tuesday at my dealer ($40). However, my fiancee's dad is coming up for her birthday this weekend, and he's a mechanic. We'll be jacking the car up and seeing if he can figure it out. If he can, I can save the $40+...

 

[DooMer_MP3]

I think i have the same problem as you. Only under light braking towards the tail end of the brake period. Sound comes from the front end. I cannot figure it out either.

Exactly. If you were going 30, it probably wouldn't start until your speedometer dipped below 10, under light-moderate braking. If you stab the brakes pretty hard, it really doesn't do it.

 

[CDNMSP]

let me know how it goes. cause i can't figure it out. My winters are scheduled to go back on next week. I plan to take a better look when I have the wheels off. I tried tightening the lugs but maybe I'll find more when the wheels are off. I also have about 60K (90K km's).

 

[AznXstazy]

yup i got the same problem from driver side. did u ever try turning while braking? does it sound louder...? when i do that i hear a crackling, poping sort of. try that n tell me if u hear it, i think it might be the lower control arm.... not sure though.

 

[DooMer_MP3]

I'll give that a shot. I've definitely done it but wasn't really testing to see if it was louder. It definitely seems driver side based.

 

[AznXstazy]

ya mine does it mostly when i turn, idk if its louder, but it does make the noise more if i turn n brake.

 

[DooMer_MP3]

Well, I believe my fiancee's dad and I figured out the problem. Even with the history of suspension noises, he firmly believed it would be a problem with the brakes. In fact, he pretty much called it when he said "It could be rust deposits on the rotor kicking out the pads". Well, we jacked up the front driver side and inspected the suspension (control arm, ball join, cv dust boots etc) and all were fine. We then re-greased the caliper again, but then he noticed it.

On the inside part of the rotor (the part not visible to you without getting under the car, on the inner diameter of the rotor, there was a bunch of rust deposits of varying thickness. Its basically where the pad barely touches. For a quick fix, we just used a flat headed screw driver to scrape off the rust and a little sandpaper.

After putting everything back together, I still heard some popping. But after lots of testing, it was noticed to be totally gone from the driver side, and now only heard from the passenger side. I took that apart tonight, and did the exact same thing. This side had a lot of rust deposits as well.

My sound was totally gone, but I didn't have much chance to test it. I also need to be sure its dry, because it took a lot longer for the problem to surface when it was raining yesterday, and it was pouring tonight. But as far as I can tell after numerous braking, it is gone.

I'll give my final results tomorrow if its not raining, and will hopefully be able to cancel the appointment at the dealership.

Later,
Chris