Popping from front end, don't think it's CV
 

Hi all, I've been doing a lot of searching but I'll just save some running around and get specific. I have a 2000 or '01 protege with a popping noise that gets faster as I accelerate then suddenly stops. It sounds like its coming from the front driver's side. The thing is it only happens when I am driving straight which steers me away from a CV joint. I've read that a bad wheel bearing will make more of a humming or grinding sound. Also, when I brake and come to a stop I hear(and feel) a louder POP that feels like something giving or shifting somewhere around the wheel. Caliper maybe? What do you fellas think?

Many thanks
Wes

Check your ball joints and tie-rod ends, jack up the car and stick a long bar under your tire and lift, if it moves and makes clunking your ball joints are shot, next grab the tires sides and wiggle left right left right, if it clunks then its a tie-rod or possible bearing. A bad tire is also a possibility but a remote one I think, could even be a bad shock/strut as well.

X2 fwiw. It might be a strut also?

Thanks for the replies. I conveniently had to plug the same tire where the popping comes from so I wiggled it and it seemed fine. I didn't want to pry up on it however because I was using the original jack on gravel and didn't think it would be a good idea. I did however put it in neutral and turn the tire just to see if it would pop and no dice. I'm guessing it either has to have weight on it or actually being turned by the motor.

That's a puzzle. But I like puzzles.
I am thinking it could be that the caliper sticks enough to create the popping and once the pads have been pushed back the sound disappears.

Are wheels balanced? Unbalanced wheels can cause some strange things. Rotate the wheels and if nothing changes you eliminated the wheels as a potential cause.

When you apply the brakes the momentum of the car is putting forces on the struts and the lower ball joint. Considering the age of the car I guess the struts are done. Check the ball joint as MazdaTirol suggested.

The sway bar links tend to go quickly. And that could be the key: when you go straight they are not loaded. When you steer the sway bar gets loaded and the popping stops. Let is roll straight on an unpaved road or on grass and you will probably hear that popping pretty good. The soft ground will muffle every other sound.

I bet it's the sway bar links.

Tan

Thanks tan for the reply. I forgot to mention I had a broken sway bar link a while back and replaced both of them hoping to fix the issue. Now I'm pretty sure the shock/struts are in need of replacement, but I wouldn't think tha would cause the pop perfectly in time with tire rotation. Now if it IS the caliper, what is the prognosis? Replace it?

Thanks
Wes

Oh and I will rotate the tires jus to be sure.

"but I wouldn't think that would cause the pop perfectly in time with tire rotation"
You are thinking correctly. Let's see what rotating the tires will do. While you have the wheels off push and yank on the caliper. They should move in and out on the sliders with little effort. But they should have no play in the same plane as the tire rotates.
I am slow and deliberate when it comes to replacing things. On my '98 Protege I cleaned the sliders and the rubber parts. I sanded the rust off where the pads move relative to the caliper and I replaced the stainless steel anti rattle shims. I put hi temp grease on all the moving parts and replaced the pads, springs and rotors.
Use a long screwdriver or piece of wood between the studs and rotate the hub with the wheel off. Just look at everything and feel out if there is something happening every 360 degrees.

good luck!

I have to periodically tighten the upper strut nuts on my tribute. I think it's because of crappy roads here in Tulsa. I've only seen calipers "lock up".

the brakes are almost new. so i put the car on jack stands today and put it in drive and let the hubs spin. it didn't make so much of a popping sound as just an awful racket. i made a video, is there any way to post that here? or can i link to youtube? don't wanna break any rules.

thanks
wes

hope everyone had a good thanksgiving.

the popping has been happening since i received the car. i did the sway bar links and brakes out of necessity, but also hoping they would fix the problem. anyway here are the links to two videos. the first is the noise from outside the car, and the second from within. instead of a popping sound this time, it's more of a clunky grinding. i dunno, tell me what you think.



thanks
wes

wes:

I looked and listened to both videos. Of course on Youtube it is not like being there. The outside video is more telling, and I am afraid it is major. I would have placed a hand on the caliper, on the hub assembly and on the transmission feeling for a bump or hit. That would have told me where to look further.
I think I saw a wobble on the half shaft near the transmission.
I suggest taking appart the brake assy, hub assy, take out the half shaft and look feel inside the transaxle where the half shaft inserts. I think you will have to take it all apart anyway.

Ditto what Tan said, looks like you have axle issues.

Mmmm. not good news. i have mechanical skills but not exactly mechanic skills. it doesn't look too complicated but is this something i may end up sending to the shop? i mean, if i can replace radiators and water pumps and brake cylinders, is this something i can tackle? i may have the day off tomorrow anyway, so i may just go for it.

In your case I would take it to a shop, if you dont have the right tools you will ruin parts (ball joints, tie rod ends etc.) Plus your looking at 4-5 hours at least if your good and all your parts are correct from the shop. A shop will also give you a warranty on the work for some time whereas you cant warranty your own work except with your wallet.

well i was going to go ahead and give it a shot. then i stopped and thought, i need to figure out where the sound is coming from first, right?, i mean if it's not in one of the cv joints, then it's coming from the transaxle, and that's way beyond my capabilities and pulling the axle off would just be a wast of time. am i correct in thinking this?

Yes but you can check by hand and wiggle the axle itself and see if its the joint or something deeper inside. With the engine off of course!!

When I wiggle the axle it has a little play much not so much that I would think is not normal. Then again I don't really have a reference. Anyway this is what I did today. I removed the caliper after about an hour of struggling with the two bolts that hold it on. This also leads me to believe that I DIDN'T do the front brakes because I didn't even have a large enough wrench for the bolts (17mm I think.). These things were so tight I had to put a ratchet on them and then use the car jack to push the ratchet handle up. Oh, let me back up and say I ran the car again and really felt like the noise was coming from either the caliper or hub assembly. Ok so I took the caliper off and ran the car again and what do you know, no awful noise. The hub however was turning faster and the noise seems to be more prevalent with slower movement. Then I put the rotor back on and with the car in drive I slowed the spin down using my foot. Still no noise until I threw it in neutral and thought I heard a knock. Put it back in drive and I can just barely hear a constant knock, not so much a pop, but a knock. I also can't really tell how deep it is either. But, the caliper thing really has me confused. Pads are full of life and rotors are smooth with no grooves on either side. Really crazy. Sorry for the long post I'm at the bar ;)

No not crazy, but confusing. See, calipers don't have return springs. After applying the brakes the calipers get opened by the rotor. No rotor is completely round and true. There is always that 1000th mm (or whatever) of thickness variation. So the thickest portion pushes the caliper sides apart. But that only works right when the sliders are friction free. So you need to have a good look at the sliders, remove any corrosion with sand paper, grease them with high temp caliper grease and reassemble them. There is also some anti rattle hardware consisting of a M-shaped spring and maybe some tiny stainless steel shims. New springs and a clean surface for the shims are needed. When you do one side you should do the other as well.

Ok so I can't get a good pic right now but I'll try my best to explain. I pushed and pulled on the caliper on the driver (affected) side and also the passenger. The passenger side had a lot more play. The caliper would move back and forward with the play on the rotor. (Picture I'm facing the rotor and pushing and pulling to and from my body). On any disc brakes I've ever changed, the bolts had to be fed through a rubber accordion-like section before catching threads. These calipers don't work quite like that. The little rubber pieces were attached to a little cylinder type piece that is built in to the caliper. Are these the 'sliders' you mention? If so, on the driver side they are practically stuck. Hitting them with a hammer barely achieved any movement. I'll post a pic tomorrow to better explain what I'm trying to say.

Thanks
Wes

after a little more research i see how this works now. i've never done brakes where you just rotate the calipers up to change the pads, i've always removed both slider pins. so on this vehicle apparently the top slider pin is frozen and i need to remove the bottom (hex) pin and then convince the top one to slide out so i can either replace it or at least grease it up. then i will put it all back together and see if that eliminates at least some of the noise.

Yes, those cylindrical sleeves are the sliders. On my '98 protege they have grooves at their ends and on the upper sliders small rubber boots sit in these grooves. On the lower slider a long rubber boot runs through the hole in the caliper and the slider sit in that rubber boot. Use a little penetrating oil and tap the sliders in and out so they move easier. Remove them completely and remove all rubber boots (2 small one's and one long one.) Use a wire brush and sand paper to get the sliders really clean and smooth. Make sure the holes in caliper are free from rust. In my case moisture managed to get behind the rubber boot and promoted rust on the caliper. That caused pressure on the rubber and made the slider stick.
A professional mechanic would replace the caliper to save time. A do it yourself mechanic would rather spend elbow grease than money. I wound sand paper around a wooden dowel and sanded the rust out. I coated the inside of the hole with grease before putting the rubber boot back in.

On reassembly: The rubber boots may have been stretched so much that they cannot be properly seated. Good thing you may be able to buy the rubber pieces separately. Do an online search.
Use Permatex hi temp grease to lube the rubbers and sliders.

update. i greased up the sliders, put everything back together, and put her in drive. that god awful grinding noise from the videos is gone. i believe it was coming from the caliper. now i thought i still heard a slight popping as the axle turned, but wasn't really sure. i did notice however that when i left it in reverse i was getting a grinding noise that i could hear better inside that car than out. not really sure of where it is coming from but i would venture to say transaxle. next i put the tires back on and drove around the neighborhood trying to recreate the original pop. i only heard it once and it wasn't for long. i'm going to just drive around for a couple days and see how it does. it come and go depending on temperature, who knows.

i haven't driven the car since the initial test run but when i do, i'll post back...