2008 Uplander Two Issues - Vibration and Noise - Front End

Hi, I've been experiencing some nagging issues with this 2008 Chev Uplander with about 83,000 kilometres on it (just over 50,000 miles), for some time. VIBRATION Last year, it pulsed and vibrated while braking hard, almost scary at highway speeds. So last year I replaced the rotors and pads all around with Raybestos premium ceramic pads and top of the line Raybestos rotors. I also replaced the rear calipers as I could not squeeze them with the special turn and push tool. The pulsing and vibration disappeared and the van was braking beautifully. Now the vibration is back but it has no pulsing, and is not as bad as last year, yet. I have looked at the brakes on all the wheels. I found that the front wheel brakes look good with evenly slightly worn pads across each pad and the same thickness on both sides of each rotor. I checked the sliders, all are clean, lubed, and free. I checked the calipers, I was able to squeeze both with ease. The rear brakes also looked OK, with clean, lubed, and free sliders, and evenly slightly worn pads across each pad. I noticed the rear right inside pad was worn a little more (a bit thinner) than the outer pad. On the rear left they were the same thickness on each side of the rotor. Unfortunately I did not squeeze the calipers as I did not have the special tool to turn and squeeze the rear calipers with emergency brake cable attached. I replaced both calipers on the back last year when changing the pads and rotors as neither caliper would squeeze, so these calipers are less than one year old! Could it be that the rear right caliper has seized again? Should I borrow the tool to check it? This is the only thing I see that could cause the vibration when braking hard, but does not appear to be that bad and wonder if it could be caused by the second problem that follows! CLUNKING NOISE The vehicle has been making clunking noises at the front end for quite a long time which are progressively getting worse. The other day I jacked up the vehicle and supported it on two jack stands to try to nip this problem in the bud. I tapped on all sorts of parts to see if anything sounded strange and grappled at various components to see if anything was loose. All I could find was a tinny sound coming from the lower joint on the left anti sway bar end link. All four joints on the end links were low on grease and sealed, so I ordered a pair of very nice Moog units with grease nipples to replaced the old ones. That done, the problem persists. It clunks usually when starting out from a stop, but not usually when turning or going over bumps, occasionally lately it started doing this clunking thing also when slowing, and the noise happens more frequently. I also checked the wheels for play to check for worn hub and bearing assemblies and steering joints, but neither wheel has any play. When driving, the steering wheel is taut. To check for any issues with the CV joints, I inspected each CV joint for cracks of the boots or leaks from the boot areas, and could not find any problems there! When cruising the vehicle drives well with no veering to either side and no noises, just runs smoothly. Any and all ideas as to what may be causing either issue will be appreciated. Thanks, quickcurrent

Hmmmm..these issues seem to be confounding for everyone here as they are for me, huh? Any ideas? There are no bad ones!

After waiting for what seemed to be forever for one of my local parts suppliers to get its caliper retracting loaner tool set back, I ordered my own from Amazon and received it yesterday. Today I was able to squeeze both rear calipers (with integrated emergency cable so they have to be twisted and pushed :-( ) with it. The calipers seemed to have a little dirt and corrosion around the seals and it may have been that that prevented the brakes from working well. I'll take it for a drive soon and see if it still does the vibrating thing.

The noise problem remains, even if the vibration is gone!

Hi, I've been experiencing some nagging issues with this 2008 Chev Uplander with about 83,000 kilometres on it (just over 50,000 miles), for some time. VIBRATION Last year, it pulsed and vibrated while braking hard, almost scary at highway speeds. So last year I replaced the rotors and pads all around with Raybestos premium ceramic pads and top of the line Raybestos rotors. I also replaced the rear calipers as I could not squeeze them with the special turn and push tool. The pulsing and vibration disappeared and the van was braking beautifully. Now the vibration is back but it has no pulsing, and is not as bad as last year, yet. I have looked at the brakes on all the wheels. I found that the front wheel brakes look good with evenly slightly worn pads across each pad and the same thickness on both sides of each rotor. I checked the sliders, all are clean, lubed, and free. I checked the calipers, I was able to squeeze both with ease. The rear brakes also looked OK, with clean, lubed, and free sliders, and evenly slightly worn pads across each pad. I noticed the rear right inside pad was worn a little more (a bit thinner) than the outer pad. On the rear left they were the same thickness on each side of the rotor. Unfortunately I did not squeeze the calipers as I did not have the special tool to turn and squeeze the rear calipers with emergency brake cable attached. I replaced both calipers on the back last year when changing the pads and rotors as neither caliper would squeeze, so these calipers are less than one year old! Could it be that the rear right caliper has seized again? Should I borrow the tool to check it? This is the only thing I see that could cause the vibration when braking hard, but does not appear to be that bad and wonder if it could be caused by the second problem that follows! CLUNKING NOISE The vehicle has been making clunking noises at the front end for quite a long time which are progressively getting worse. The other day I jacked up the vehicle and supported it on two jack stands to try to nip this problem in the bud. I tapped on all sorts of parts to see if anything sounded strange and grappled at various components to see if anything was loose. All I could find was a tinny sound coming from the lower joint on the left anti sway bar end link. All four joints on the end links were low on grease and sealed, so I ordered a pair of very nice Moog units with grease nipples to replaced the old ones. That done, the problem persists. It clunks usually when starting out from a stop, but not usually when turning or going over bumps, occasionally lately it started doing this clunking thing also when slowing, and the noise happens more frequently. I also checked the wheels for play to check for worn hub and bearing assemblies and steering joints, but neither wheel has any play. When driving, the steering wheel is taut. To check for any issues with the CV joints, I inspected each CV joint for cracks of the boots or leaks from the boot areas, and could not find any problems there! When cruising the vehicle drives well with no veering to either side and no noises, just runs smoothly. Any and all ideas as to what may be causing either issue will be appreciated. Thanks, quickcurrent
When you put your wheels on, how tight are you making the lugnuts? You have to make sure the mounting surfaces of your wheel and hub are clean. Wire brush. You also have to be careful how you torque the lugnuts. I always put them on by hand and tighten each as much as I can by hand first in the correct sequence, wiggling the wheel around as I tighten them. Then I tighten with a lug wrench further in sequence. Finally, I give them the final torque, in sequence. If this is not done carefully, the shape of the rotor will get distorted and cause pulsation during stopping.

When you put your wheels on, how tight are you making the lugnuts? You have to make sure the mounting surfaces of your wheel and hub are clean. Wire brush. You also have to be careful how you torque the lugnuts. I always put them on by hand and tighten each as much as I can by hand first in the correct sequence, wiggling the wheel around as I tighten them. Then I tighten with a lug wrench further in sequence. Finally, I give them the final torque, in sequence. If this is not done carefully, the shape of the rotor will get distorted and cause pulsation during stopping.

Thanks bud, but I am quite sure it's nothing like that. I've been taking wheels off and putting them back on for decades, and do them in the same fashion as you suggest. I've never ever had a problem like this!

When I replaced the rotors last year the car was pulsating because I had been taking it to the dealer, where they always use that damn air wrench and apply uneven torque - that's what warped the OEM rotors. I have never warped rotors with my manner of doing it. They are not warped since I have no pulsating. What I have is a vibration that shakes the entire vehicle. I thought the rear calipers may have seized so I purchased a rear caliper turn and squeeze tool set and have squeezed the pistons. They squeezed fine, fairly easily, but I did notice that a fair bit of dirt and rust dust came off the area around the piston seals, so I thought by freeing that up, perhaps the vibration would be gone (i.e. perhaps the pistons were not seized but not working smoothly enough with all that crud around the seals). Well the vibration is still there. When I rotated the rotors by hand they looked like they were spinning quite nicely, no significant variation on the edge of the rotor. The tires are evenly worn and there is no vibration unless I am applying the brakes!

So I am thinking more and more that the problem is tied to the clunking noises, whatever that may be.

Be sure the front bushings in the lower control arms are ok. I have seen then wear to the point that the arm is resting on the frame. Also, check and be sure the two bolts on the front of both braces under the hood (the ones that go from the fenders to the upper core support) are tight. Even if they are a little loose, they will make a "pop" or a "clunk" type on noise on accel or deceleration.

Excellent ideas gmtech1. Thanks bud, I'll check those items later today and post the results.

Other things got in the way and I just got to check these items today.

All six bolts on the braces were all a little loose, front and back. I tightened them and there seems to be no more clunking, at least not on the driveway. I have not yet taken it further.

The bushings at the front of the control arms look good with quite good clearance between each control arm and frame parts. However, I did notice that the seal above the ball joint on the driver's side looked quite empty. I pressed on it with my finger but could not tell that there was any grease left! I saw no rust coming from it, but it's possible that this sealed joint has prematurely gone dry and is rusting inside! Could that cause the vibration when braking? I've replaced ball joints on other vehicles before but those vehicles did not vibrate like this one! The ball joint on the passenger side looked much better with the boot seal much fuller.

I doubt the ball joint is the vibration. Typically rear rotors will cause a vibration and the front rotors are more of the pulsation feel. Have you inspected the inside face of the rear rotors for bad spots?

I have run my fingers over the inside and outside surfaces of the rotors to feel for gouges, etc. but I have not taken off the rotors to have a really close look at the surfaces. Is that you mean (like pits, rust inclusions, etc.)? I didn't think that small imperfections would cause the whole vehicle including the steering wheel to shake when the brakes are applied hard!

At first I thought that one of the pads was a little more worn than the others at the back, but when I took them off to squeeze the caliper pistons, I had a good look at them and they are all the same thickness, all evenly worn.

The rotors on the vehicle now are the highest quality made by Raybestos and have only been there for one year!

I wish I could drive and feel this vibration...If there is no play in tie rods, ball joint, bushings, and the rotors are ok, it's tough to say. I can tell you this, typically when a vehicle comes in with a vibration when braking complaint, the first thing I'll recommend resurfacing the rotors. This eliminates the most common cause. Without feeling it first hand, it's tough to say.

I'm going to take the rotors off at the back to look really closely at them. I also initially suspected the rear rotors or calipers, but so far I haven't seen anything that would cause this vibration. I'll keep looking ...

Alright, I just finished taking all the brake parts apart on the back end, but still I see nothing about the brakes that would cause this vibration. The rotors are clean on both surfaces, save for the rust rim around the perimeter, they spin nearly perfect, the pads are wearing evenly, the sliding pins are operating smoothly, and the caliper pistons squeeze smoothly. I doubt that any very slight rotor rotation imperfection would cause this vibration! I've done all I know of.

I have only one mechanic I trust to work on my vehicles in my area where I go to do things I feel uncomfortable doing myself. I'm going to get a set of NGK Iridium IX spark plugs (my favorite) for him to replace the OEM ones with on this vehicle (since they are a nightmare to do) and I'll see if he can nip this vibration issue in the bud for me.

Your assistance was invaluable, gmtech1, as usual. I have read about owners taking their Uplanders to their local dealers, paying a fortune to have all sorts of things done to get rid of the clunking noises, including but not limited to replacement of ball joints, steering columns, tie rod ends, and other parts and still the clunking noises prevailed on their vehicles. Your suggestion was awesome and my clunking noises are gone. If they come back, I will put some loctite on the bolts and re-tighten them, or pull them and put lock washers underneath their heads to permanently avoid this nuisance.

The brake problem (vibration) turned out to be a front rotor that was pitted in an area on the inside wearing surface, but only in a quarter of the surface, so when I ran my hand over it, I had missed that part of the rotor and was unaware of this pitting until I took the rotor completely off the vehicle. I have replaced the rotors with the same kind, only coated. I have just finished speaking with Raybestos Representative local to my area about issuing a refund for the replacement pair of rotors, which sounds promising, but I'll have to go through the dealer. I have also been assured that Raybestos rotors don't normally do this, that this is a one-off case. Although my confidence in Raybestos rotors had been shaken somewhat, I hope this is not going to happen again.

My trusted mechanic did the plugs for me, and am I glad I had him do that, took him an hour and three quarters to complete the job! This was the most expensive spark plug replacement job I have ever done! The OEM plugs were starting to look quite corroded and carboned up. One even had a longitudinal small hole through the ceramic allowing the combustion to flow through it! Hopefully the new Iridium IX spark plugs will hold up better.

I hope this helps those on this forum facing similar problems.

Cheers

Glad to hear you got if fixed!