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Front end clunking noise on my 05 STS -- think it's somewhere in the brakes

12K views 26 replies 13 participants last post by  dannyquest 
#1 ·
Looking for some comments or suggestions to help me track down and fix a problem. I replaced my brakes about 9 months ago, and recently I started to hear a "clunking" noise coming from the front of the car. I followed what some others had suggested / done in some other threads here (see http://www.cadillacforums.com/forum...012/194735-how-replace-rotors-brakes-je5.html for one example), and put Hawks on the front and Akebono's on the rear. Used Centric rotors all the way around. I started noticing the noise a couple of months ago, and I was finally able to find the right "bumpy" road to do some testing. The noise goes away when I put a slight drag on the brakes, and comes back when I release the drag. So I went looking for the noise. I pulled the front wheels and did a visual inspection for loose parts, and found none. I then tried to rock the calipers, and saw that they had a fair amount of slop in them. I was able to rock them back and forth and get the "clunking" sound on both sides, but there seemed to be more play in the driver's side than the passenger's side. I've searched for people reporting similar problems, but no luck. Right now I'm guessing that I didn't put enough grease in the caliper pin bore when I put them back on, and loading up the bore with more grease should fix the problem. Thanks in advance for any feedback.
 
#2 ·
I am actually having the same problem right now with my 05. It started on one if the front calipers and has spread to 3 of the 4 calipers. I am planning to replace the caliper brackets in the next couple of weeks. I think it is more of a design flaw than a lack of grease. The bracket is aluminum and the bolt is steel. Since steel is harder than aluminum, the bracket hole stretched open from heat and stress. I suspect that this will become a hot topic on this forum as more of these cars get higher in milage.
 
#4 ·
Your guess sounds as good a mine, but we're both just guessing :) .

These are not new cars, and in my searches of this forum I didn't find any other reports matching this one. So I'm more inclined to think "user error" rather than design flaw, as I put the brakes on myself. As a shade-tree mechanic I'm not ruling out the possibility that I did something wrong.

Hopefully we'll both get some pointers before we go randomly replacing parts. Sometime in the next couple of weeks I'll pull the front wheels and re-grease the pins to see if that changes things. Perhaps a little bit of my time and some grease will make the noise go away.

(BTW, not sure which type of grease to use yet, but I'll add that when I update the thread with my results.)
 
G
#14 ·
Just had my driver's side lower control arm replaced under GMPP. It would clunk when I first started out in the morning and applied the brakes. After a while it would go away. I also thought it was in the brakes.
 
#7 ·
Having exact same issue. Can shake front calipers and hear metal to metal noise in them. Its more herd from the LF than anything. When over bumpy road the noise is there like a light metal loose component sound, slight drag on the brakes the noise is gone completely. I really think its the caliper bracket and pins are both worn. The play that the caliper has seems excessive. Car had just had brake job before I bought it, 2 months later the noise is there.
 
#8 ·
i bet they put the pins in the wrong holes...

The upper and lower caliper pins are NOT the same.

My creaking noises went away when i did my brake job, did all 4 wheels (rotors and pads).
My pads also came with new rubber seals for the pins (the old ones were a b¡tch to remove) I did replace them and applied a generous amount of caliper pin grease and haven't had them make any noise since.
 
#9 ·
i bet they put the pins in the wrong holes...

The upper and lower caliper pins are NOT the same.
The postings that I used as references mentioned that the pins were different. While changing the pads / rotors I thought I kept track of which one when where, and put them back in the same place. But who knows .....

Are there any markings on the pins that would help me to identify which pin goes where? What's different in the two pins (my recollection is that they looked the same to me)?
 
#12 ·
This is not an issue with the pins or pin placement. When I first started hearing this noise, I actually purchased new pins and rubber rings from GM. I measured the diameter on the new and old pins and there wasn't any sign of wear. I went ahead and replaced the pins and rubber rings anyway and used caliper grease during the install process. This didn't change the slop in the calipers and the noise has stayed the same. After that waste of time, I removed the caliper brackets and measured the inside diameter of the pin holes. It has in fact become enlarged and my next stop will be to order new caliper brackets.
 
#17 ·
I haven't been driving the car too much in the past 3 months, so it's been easier to ignore the noise instead of tracking it down and fixing it. I think my problem is more along the lines of what ishoothsts and Brent Messing describe -- The noise seems to go away when I put a drag on the brakes.

If I read things right, the noise happened for KRSTS and EChas3 when they applied the brakes (and my noise goes away when I apply the brakes).

I'm not saying the car doesn't have front suspension slop, as something has to wear out of spec after almost 9 years and 100K+ miles on some poorly maintained roads. But I'm still hoping the fix doesn't require major $$$. Weather has been very warm and dry out here in Northern California. Maybe I'll get around to re-greasing those caliper pins this week and see if it changes anything.

I measured the diameter on the new and old pins and there wasn't any sign of wear. I went ahead and replaced the pins and rubber rings anyway and used caliper grease during the install process. This didn't change the slop in the calipers and the noise has stayed the same. After that waste of time, I removed the caliper brackets and measured the inside diameter of the pin holes. It has in fact become enlarged and my next stop will be to order new caliper brackets.

Brent Messing -- did you ever replace your caliper brackets? Did it get rid of your noise?
 
#15 ·
I have a very slight clunk when i go over roads that are just right. It's easy to confuse with the usual sound of hitting bumps, but it's a bit higher in pitch. If it turns out to be brakes, that'll be great, but i'm feeling like i'll be putting a ball joint or bushing on it at some point...
 
#18 ·
A clunk noise would lead me to believe the LCA (lower control arm bushing) issue, I had what I would call a crunch or a creak noise in mine which went away after I did a brake job.
I replaced all pads and rotors and the rubber gaskets around the caliper pins and gave them a good lubrication and also applied this to the back (non-rotor side) of the pads and the noise has not returned.
 
#20 ·
I have had both the issues with the lower control arms and the calipers. The easiest way to tell the difference is to softly apply the brakes over a rough patch of road. If the noise is goes away, it is probably brake related. If not, you probably will need to replace the lower control arm.

I have two recommendations based on experience. First, if you have to replace on of the lower control arm, replace the both. That way you don't have to pay for and alignment twice. I wish I would have fine this because they wore out about 6 months apart. Second, you shouldn't have to replace the caliper brackets like I did if you just repack the caliper bolts with lots of proper caliper lube. I had more severe issues from driving and braking really hard.

I hope this helps.
 
#21 ·
Well, I finally got around to re-lubing the caliper pins. It does look like they were under-greased, as there was plenty of slop in the pins before I added more. So I'm hopeful that this will stop the rattle I was hearing.

Unfortunately, I must have mixed the pins up when I originally changed the pads and rotors, as the one with the rubber ring at the end was in the top hole on one side, and the bottom hole on the other :confused:.

Does anybody know which choice is correct? I tried checking ALLDATA, but the diagram didn't show which pin went where.

Car's still up on jackstands, and I'll finish putting it together tomorrow. Hopefully somebody will have an answer before then so I don't have to guess which one was right :bigroll:
 
#25 ·
Thanks Brent -- I managed to get your update before I buttoned things up.

The area that made the most noise was the side that had the pins reversed. I don't know how I missed noticing that one of the caliper pins had a rubber grommet on the end when I did the brakes, but somehow I did. :thepan:

I now have the pins in the correct position, and they are loaded with grease (instead of just coated). So far, so good! I've put about 50 miles on the car after making these changes, and the noise seems to have gone away. Back to the nice old "caddy quite" while driving on a rough road.

So, I made two mistakes when I originally did the brake job:
  • Caliper Pin in wrong place: I read in the forums that the caliper pins were different, but I didn't see that the difference was the rubber grommet at the end of one of the pins. So I reversed the pins on one side by mistake. The pin with the rubber grommet goes into the top-most location of the caliper bracket.
  • Insufficient grease on Caliper Pin: I didn't use enough silicone grease on the caliper pins. I should have realized that these pins float the same way that wheel bearing pins float -- not enough grease on them and your wheel would rattle. I added grease until there was enough back-pressure to push the pin back out about a half inch. Anything more and I couldn't compress it in enough to put the caliper back on.
It's said that true knowledge comes when you learn from your mistakes. But somehow I don't feel very smart after this adventure.

Thanks to all that gave me pointers along the way!

Larry
 
#23 ·
I had my experience with that "clunking sound".
On my 07 CTS it happened and I asked my mechanic friend about it. He put it up on the lift and took the tires off, fronts, and took the calipers off and used a needle gun to clean every bit of rust off the pads and backing plates, he even showed me a snot of rust that was probably the problem.
It seems this is common at slow speeds, no disc is perfectly true, so when it tips a couple of thousands one way, then the other way as it turns, the pad and/or backing plate will rock ever so gently on the snot piece of rust.
He added a small amount of squeak stuff to the back of the pads and problem solved.
This may not be the answer to all "clunks", but just a reminder to clean well when doing your brakes.
 
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