I have been experiencing a clunking/popping noise in the front end (passenger side) lately. It only occurs while braking and at slow speeds (less than 20mph), and even then it is not always consistent. It only seems to happen when I'm on the brakes lightly, such a riding the brakes a little in a parking lot or something like that. If I am on the brakes harder, it doesn't happen, or it stops. This also doesn't happen just driving down the road or while going over bumps. I had my Blazer into the local garage a while back for other work and the mechanic thought that the popping sound that I've described (he drove it too and heard) was that the right-front rotor was warped and this could cause the caliper to jump a bit. They removed the front passenger wheel and put it into drive on the hoist and played around with it and noticed that the rotor was a little warped and they think this was causing the popping sound. I had them take a look at the ball joints along with everything else, and it all looked OK...so this was their diagnosis.

I'm just wondering if that could be the case, it sounds pretty bad when it happens and I'd think it were a more serious problem that something like a warped rotor. I've tried the general test of slowing down quickly from about 60-70mph to check for significant vibration, and there is none, which to me suggests that the rotors may not be the problem...is this something anyone has heard of before, or does it sound like it may be something else? Also, this is a 99 Blazer 4WD incase that helps. Thanks.

 

There has been lots of discussion about popping and clunking noises lately under the Suspension section of the forum. Check there under the topic "popping noise", and there might be similar discussions in the past if you do a search. Not that we've reached any definite conclusion about what usually causes this, but you might get some ideas.

 

I checked out the above mentioned forum and posts, and it seems that my problem is a little different from the rest of those. The ones mentioned in those posts dealt with a pop during turning the wheel...my situation occurs when going straight more often that while turning, and it's only at low speeds when I'm on the brakes.

Any other suggestions?

 

Hmm....... Mine happens typically when braking, but sometimes when not braking, and sometimes when going straight, and not turning, like when slowing down or speeding up somewhat abruptly, and usually, but not always, at slower speeds. I'm getting the idea that Blazers have lots of popping noises that are very hard to pinpoint! No mechanic I've taken it to yet has been able to observe it happening, so they haven't taken it very seriously, and everything under the car has looked OK to them. It's happening much less often now, so I'm less worried, but still concerned.

I do know that on another vehicle, a Subaru, I had a very pronounced pop or clunk that would only happen when braking, and not every time. It sounded like from the rear but I could feel it in the brake pedal with my foot. It happened the worst when backing up, but also when going forward at driving speeds. I had had a complete brake job not long before it started, including new rotors in the front and shoes in the back, new calipers, etc. The guys who did the brake job could find nothing wrong and concluded that it must be worn bushings that were near the rear brakes, and that it hadn't done it before the brake job because the brakes were worn and weren't stopping the car with as much force. That sounded fishy to me, so I took it to another mechanic who took the brakes apart and put them back together but could find nothing wrong, and could see nothing noteworthy about the bushings. And he never heard the noise because it wouldn't do it for him, so he thought I was nuts! I never did find out if it was the bushings or what it was.

Sorry for the long story and that I can't be of more help...... I hope someone else can shed more light on your problem!

 

I have a somewhat simular problem.

For awhile the right front of my blazer would start to hum when slowing down and when I stop it clunks. It stopped after I got a few things fixed on it 2 weeks ago but that was the starter,a gasket,and fixed the idle.

It started again yesterday and it sorta bugs me. I talked to a buddy of mine about it a month or two ago and he said it was something but i forgot anyway he said his truck does it too. He is good with vehicles and said it doesnt hurt anything. If it doesn't it still bugs me.

Any idea?

 

There are numerous things that can cause a pop/clunk in the front end. Of those, I'll list off the most common.
[ol][*]Ball joints - both upper & lower, but the lowers generally go bad before the uppers [*]Shocks - a worn out shock can cause a clunking sound to be heard whenever the suspension moves or makes sudden moves. This is commonly caused by excessive play in the shock valving. If your shocks are that bad, you will also notice that the front end will bounce all over the place [*]Control arm bushings - on higher mileage vehicles and older vehicles, these bushings can deteriorate causing excessive play in the suspension. This type of a failure will also be associated with other concerns (unusual tire wear, bad handling, pulling to one side while driving) and would normally be caught during a safety inspection.[*]Hood pivot bolts - a very unusual source to be sure, but on the newer body style S10 variants, the pivot of the hood near the windsheild can cause clunking noises while going over bumps that sounds very similar to a loose/wornout shock or bad ball joints. GM knows of this problem and has released a provision in the form of a spring washer that gets installed between the head of the hood pivot bolts and the rest of the brackets. Total cost of around $5 from the dealership and it's an easy 15 minute job to install them.
[/ol]

 

Thanks K, this has been driving me NUTS! Atleast I have some things I can ask my mechanic to look for now (I need prices from him).

 

No problem. Like I said, there are a ton of things that can cause a clunking sound in the front end, but the most common problems are those listed above.

 

I had a similar problem in a 2001 4X4, changed the ball joints, and clunk was still there. I remembered a wheel alignment done months earlier, torqued the upper control arm bolts to spec, and the noise is gone. [8D]

 

I am no mechanic but have you checked your break calipers, sticking calipers could also make a popping noise?