Popping noise while braking

[XLCOR_65]

Well, I did some searching on the forum and didn't find anything close to this little issue I am having. So, I will ask you guys if you don't mind.

I noticed that when I am coming to a stop and must apply moderate pressure, there is a subtle, yet distinct, popping noise that I can feel in the pedal and hear when the window is down. I thought it could be a wheel weight because the popping gets slower as the truck comes to a stop, then it stops.

(kinda like this: poppoppoppop..pop..pop....pop......pop.........pop.............pop............pop............pop.... ..............pop..............................pop)

It is drum on all 4 corners, I put new pads on it last summer, turned the drums, new wheel cylinders, new bearings, etc.

Any ideas of where I should look? The front end is decent, doesn't need new ball joints or tie rods yet, even though I plan on doing that this summer just as preventative maintenance.

Thanks for your input!

[Wrenchbender Ret]

Jack it up & spin the wheels one at a time. It could be a bad wheel brg. or a broken spring inside the brake.

[Mathew21]

I had that happen on my Suburban. It was a bad rear wheel cylinder.

[XLCOR_65]

Well, I pulled the drums last night and looked to see if maybe a spring had come off or was broken and everything was in place as it should be. I also put the drum back on and put a couple lug nuts on and spun each wheel listening for a grinding wheel bearing, but nothing came of that as well. I figured it wasn't a bearing since they are all new, but hey, never hurts to check. I also checked the wheel cylinders, but they looked perfect as they should since they are also new.

I drove it last night and also this morning to work and the noise is still there and I can still feel it in the pedal. Totally confused as to what it could be.

The only thing I noticed, was that on the driver's side, when I spun the drum, I could feel it drag the pad ever so slightly every half turn. Even though the drums were turned, could it be warped or oblonged?

[luvbowties]

Originally Posted by XLCOR_65

Well, I pulled the drums last night and looked to see if maybe a spring had come off or was broken and everything was in place as it should be. I also put the drum back on and put a couple lug nuts on and spun each wheel listening for a grinding wheel bearing, but nothing came of that as well. I figured it wasn't a bearing since they are all new, but hey, never hurts to check. I also checked the wheel cylinders, but they looked perfect as they should since they are also new.

I drove it last night and also this morning to work and the noise is still there and I can still feel it in the pedal. Totally confused as to what it could be.

The only thing I noticed, was that on the driver's side, when I spun the drum, I could feel it drag the pad ever so slightly every half turn. Even though the drums were turned, could it be warped or oblonged?

Answer to your ? is "Yes". Just trying to narrow down which/what is in error, I'd swap front drums & check before-and-after [the test u already did on front driver's side where u felt the slight drag every half-turn]. If that symptom changes sides, have an on-the-lathe check done on that drum.

That symptom could surely magnify in intensity AND frequency with increase in rpm's. If that drum has a 'hard spot' in the metal, the bit could fail to remove material there, skipping over it and resulting in a 'high spot', an out-of-round condition: meaning, buying a new drum.

A high spot would result in symptoms u related, even causing a pumping feel in the brake pedal, esp. at lower speeds, kinda like the feel in disc brakes with a warped rotor--and more a shuddering feel at higher speeds.
HTH,
Sam

[jtrichard]

The only thing I noticed, was that on the driver's side, when I spun the drum, I could feel it drag the pad ever so slightly every half turn. Even though the drums were turned, could it be warped or oblonged?[/QUOTE]

Short answer YES I would say you need to find out what is going on in that drum ..years ago a shop mis-chucked a disc and destroyed it had I to buy a new one the shop said it could not be what they did... well it was

[XLCOR_65]

luvbowties and jtrichard, thank you both for your insight. I think you are correct and I think I will just go ahead and buy new drums since they are cheap enough. Once I do, I will report back whether it fixed the issue or not.

[luvbowties]

Originally Posted by XLCOR_65

luvbowties and jtrichard, thank you both for your insight. I think you are correct and I think I will just go ahead and buy new drums since they are cheap enough. Once I do, I will report back whether it fixed the issue or not.

Sounds like u really wish to do things right--congrats on such an attitude! Just as a heads-up, often even new drums need truing(turning), as they can easily come to you in an out-of-round condition! A local industry recently received an order of several hundred drums for trailers they were manufacturing. Soon after assembling the first few and test-pulling and stopping them, they realized they all needed machining. A close friend of mine got the job of turning all of them--he even allowed me to turn a few dozen, on his machine.

Having said the above, u know I am implying that a good idea would be to have the new ones checked. When buying new drums, I like to buy locally, where the seller also has a brake-lathe, and he agrees to true them, if needed, at no additional cost to me. You may wanna weigh the cost of ordering PLUS cost of machining[worst-case scenario] vs. the cost of doing a deal as I described; and make your decision from there. I'm sure your finished project is gonna be a truck to be proud of!
Sam

[ChuckW]

I have had ball joints pop when load or direction of movement is changed. Not saying this is your issue but worth checking out...?

[old cool]

User name is "old cool" (newbie). Just picked up a '66 GMC SB. It's highly restored but noisy inside and do here some popping on left turns. I noticed that the front suspension has numerous grease fitting - control arms included. I'd take time and fill em up. I think dry sockets contribute to pings, thuds, pops, etc. Please keep posting on this. I'm presently investigating the extra whining noise coming through cab. Previous owner said ring and pinion possibly to tight, but I'm not ruling out tires, driveshaft, u-joints beaings, or, suggestions from members of this forum.

[evolve520]

Check your shims on the upper control arm. If they are missing you can hear a thunking kind of sound. I had a similar problem on mine caused by missing shims.

[spacedebris]

I just fixed a nearly identical problem on my Merc this past weekend. Although mine sounded less of a pop and more of a tap and I could also feel it in the steering. It also was only really evident under moderate to heavy breaking. Visually I couldnt find anything but I had the same issue where with it in the air, I would spin the wheel and feel it grab at one point every revolution. Turns out I had a drum out of round. Unfortunately it was too far gone to try and have it turned, I just had to replace it. So I ended up doing a complete break job. Problem solved. Hope it helps.