Exactly!! And just when I'm convinced that the tires are out of round too, I chance upon what's probably the only smooth pavement left in the Metroplex, and the Panel felt like new (for 5 seconds). I just wish the defective part(s) would go ahead and FAIL so I could fix it. Only problem, I may be injured or killed when it occurs. I first thought I should be concerned about the other drivers out there, but I was mistaken.

 

I just replaced a replacement for a new rear hub. 2 defective new hubs! Anyway the new good one improved the braking by a huge factor (now I have 4 good hubs)! Most of us never even inspect the rear hubs, you might check them out, if they have ANY end play or if they seem to "scrape" or make any noise when turned with drum off or seem to offer a lot of resistance then they are bad.

 

Jacked it up again Sunday, looking at everything previously checked before. This time, I really worked at trying to induce movement in all wheel hubs. I've been able to find loose or worn hubs in other vehicles, but find none in mine. My buddy checked my results. Then I spun the rear wheels: only a light scrape sound from each, and they would spin twice around or more before stopping (the same set-up I looked for in my front drummed cars and trucks, old days). I placed straightedges on top and front of each to determine out-of-round (almost undetectable). Went to the front. Same hub check. OK. CV joint-play check. Normal (based on comparison with similar HHR with no problems). Checked for out-of-round, with same straightedges. Left tire ok, right slight amount of un-trueness. Replaced it with another Firestone, same amount of tread, from a vehicle with no history of front end shudders. Checked for out-of-round. Ran true. I drove it home 55 miles later that night, and it felt 90% better. Same this a.m., in my 60 mile trip to work. But this afternoon, from 4 p.m. to 5:30 p.m. (80 degree temps, stop and go), it felt as bad or worse than ever. Sometimes I feel the shudder start thru the seat of my pants, sometimes nothing until the wheel shakes at 30 mph, and nothing at all if a really hard braking event occurs. I've now used 8 different tires in checking this out (right tires always on right, left on left), and tried every work-around to avoid the shudder (late braking, slow braking, hand braking, combo braking). And I keep checking the rotors for warp, and find none, though the pedal never vibrates. The intermediate shaft rattles sometimes, and I am going to try to rig a damper like I did to fix my Silverado's I shaft wobble. Maybe that'll work.

 

OK, this is getting into the realm of "weird" for some reason, so I'm going to throw out ideas of a possible cause that I've ruled out until this time.

You might have a caliper "hanging" on you causing the brake to drag on one side, that would cause excessive brake heating and subsequent rotor warping....plus the attendant judder/shudder.

Or, and this would be odd for such a young vehicle, you might have a brake line that has deteriorated inside causing it to become a one way "valve" at times. Usually brake lines show the obvious signs of deterioration from the outside, like cracking and checking, but they can also fail internally. What happens is that a flake or section of the internal surface works loose, then when you use the brakes the fluid goes one way just fine, but as it tries to return the flake restricts the return flow....mimicking a "hung" caliper.

Do you have, or does your buddy have access to an infrared thermometer? With that you could see if one side was running hotter than the other after a drive.

You're probably still going to have to shell out for new rotors, even fresh out of the box, there isn't much meat on them to allow for resurfacing or cutting to correct for warping.

 

One of the things that can cause the annoying, but not fatal shudder is just the weight distribution on the HHR. With no load in the rear (and the panel, I think has bigger rear springs) darn near all of the weight is on the front. And, they did a real good job of distributing load so that when you do have a load the %'s stay pretty close until overload. I have hauled 600 Lb. and the rear did not show any sag.

What I am trying to say is the rear tends to "fly" upon medium to hard braking, causing something of a "judder". But, I would still go with "that's just an HHR" until you actually get a pulsation or stopping distance is affected.

 

843de-Possible, but hard to verify in daily driving. And there is no pull to either side on braking...just the shudder at 30mph. I can use his infrared sensor, and compare rotor temps (after pulling off the highway!!), but we simply haven't been able to duplicate the conditions of my afternoon commutes. I'm sure that this shudder is an amalgam of convergent smaller problems (old tires, old struts, incipient LS bushing problems, original-turned once-rotors, and an intermediate shaft going bad). The sudden onset and growing severity (at times) of the shudder made me want to find it fast, before sudden catastrophic failure occurs. But now, having nut-and-bolted everything, finding no broken parts, and driving another 2k miles with it this way, I guess it's not gonna launch me over a rail on a curve. It drives great at speed (more is better), so now I gotta plan my trips without any stops (ha). Money is real tight right now, so I can't justify throwing a bunch of new parts at it, if I can't pinpoint the main cause. I'll borrow the infrared this weekend, and report the results.

 

This is getting old...even to me, but a new defect has popped up. I had said that the steering was fine, except for a shudder on braking. Now there's a noticeable 2" side to side dead gap when going straight , no braking. And as usual, only sometimes. I guess this is another common defect... as quoted from SS Fan's post on Canadian steering parts recall thread. Is there any adjustment for the steering sector to minimize that dead spot, which I now think is a MAJOR cause of my shudder?!? ALSO: I 'm also going to upgrade/replace my rotors, even if I can't find anything wrong (yet) with them. Has anyone used the Bosch QuietCast Brake Rotors? The Bosch website states that they resist brake judder. But they are priced double the other rotors at O'Reilly Auto. Will they be worth it?

 

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