TiggersHHR

Greetings to all ,

I took the family on a 1500 mile round trip to Murfreesboro, Arkansas to dig for diamonds. During the trip back I noticed a shimmy in the front end when I would apply the brakes. Feels like the passenger side rotor has warped again. Had it in the shop this last February for this issue and they supposedly resurfaced the rotors.

I am looking at getting a set of EBC 3GD Series Sport Rotors (Model - GD7266) they are slotted and dimpled. Is that a good choice or not? Are there any other ones I should look at? Any benifit to cross drilled rotors?

Thanks for taking a look at my post

843de

Cross drilled rotors do have some benefits in high performance applications, think Corvettes or Porsches to name the first two that come to mind. In street applications drilled/slotted/dimpled rotors are primarily for looks with maybe a slight advantage in applications where frequent and heavy brake applications are the norm.

I'm sure the EBC rotors are just fine, but they may be overkill in your situation. I have no hesitation in recommending NAPA Premium rotors and pads. I'm running them on two of the HHR's in my...umm...fleet with no complaints or return of the infamous HHR brake judder after a total of 40,000 miles between the two.

hyperv6

Don't waste you money as drilled and dimpled rotors are no better than the standard solid OE rotors. In fact non drilled are better as they have more metal to absorb heat.

The key is to transfer heat out of the pasts to the rotors or just get them heat out the pads all together.

Just buy a good set of Bendix rotors and EBC Red pads. They are best for heat and dust.


Warp is often mistaken issue with many brakes and that is why so many continue to have the same issue over and over while many others never have the issue.

Often the judder is from pad material sticking to the rotor. Often this is due to lower quality pads and the fact the brakes were never seated in after install. Most shops do not seat them nor do the factory on new cars. By seating them in it lays a even layer of material on the rotor and it prevents the matieral from sticking to the rotor after a hard hot stop like on a off ramp.

The other issue is Roto thickness variation or RTV. GM even has a TSB on this one. This is where the hub bearing has more than .002 of play and it lets the rotor wobble hitting the pads as you travel on a trip It wears the rotors in a uneven thickness and creates a judder. Trips like yours can do this. A light cut on the rotor will clean it up. Many mistake this for warp and that is not the case and often it comes back again and again till the bearing gets replaced.

The fancey rotors today are only for looks . In the past they were needed to out gas pads but were more to cust unsprung weight on many race cars.

Ironic as it may be the owner of EBC taught me the truth of dilled and dimpled rotors. He said they have no performance advantage at all. He did not want to sell them till his staff showed him how much money there was to be made on them. He did point out sloted rotors have a use in cleaning the rotor under braking. Often on tracks rubber can build on rotors and it cleans them off. On the street they really have little effect but they can be of some limited help.

The real key it to learn how to seat brakes in or follow the install instructions as most quality brakes will state how they want the pads seated. Note too EBC has a bedding material on the pads that help seat them in under normal driving.

The key to solve the issue are thes points.

Check the Hub bearing for play. No more than .002

Use a good quality stock rotor Bendix etc

Use a good quality ceramic pad. EBC, NAPA, HAWK etc.

Then seat or bed them in after install. If not the issues will return everytime.

Trust me I used to have issues too but no longer buy following these points.

TiggersHHR

Thanks for the info. The shimmy was there before the trip and has just gotten worse. The passenger hub bearing assembly was replaced quite a while back. The rotor was resurfaced at that time due to what they called "hot spots". I may take it back in and have them look at it once to see if the hub is not right and/or rotors are warped. Then I just might just have to visit my local NAPA store. I refuse to have the same junk rotor put back on – even if GM is willing to put new ones on.

hyperv6

More than not it may be the pad material embedded on the rotor surface. Some call this hot spot too.

Just have them clean the rotors with a light cut and put on some good pads. Then seat and bed them in. That should solve your issue.

Again I would forget the warp deal as this will not solve the problems. Most times if a rotor is out like that someone wailed on it with a impact gun. Generally heat even over heated rotors will not warp to the degree many want to claim.

Rotors generally deal with a lot of heat pretty well.

When you hear a uneven cut on the lathe when the rotors are cut that often is uneven thickness wear not warp.

Also calipers float and if you stand on the pedal the judder will go away as the rotor will float with it after the initial clamping force.

With pad material on the rotor the judder will remain no matter how hard you stand on it.

The bottom line is the problems are not with the rotors and changing them will not solve your issues. I run nothing but OE rotors anymore and with proper seating and good pads I no longer have had brake issues for years.

Save the money on the rotors and put it into the pads.

2manyvans

Do you think that different pads [ceramic, metalic,semi-metalic,etc.] leave the resins at different rates? This HHR is the first vehicle that I've ever had problems with and I never bedded brakes before. John

Doctuh

So far, two of four hub bearings have been replaced under the power train warranty (hub bearings are covered for 2007 through 2009 vehicles only). Simply replacing the hub bearings improved the marked brake shimmy that I had, but it didn't fully resolve. I take it that I have some rotor thickness variation. My pads are down to 20%, so a light cut on the rotors when the pads are due to be replaced should get rid of the remaining shimmy, assuming the other hub bearing is OK (one has been replaced in front and one in rear, so far).

Can I expect a hub bearing or two to fail every few years as long as I own this vehicle (I'm at 80K miles and 4 1/2 years, so the power train warranty won't be there to hold my hand soon).

hyperv6

I find that cheaper the pad the cheaper the filler material of the pad. In other worlds the cheap stuff tends to stick more. But even with these proper bedding or seating of the pads will help prevent this.

How it effects you depends on your driving. Often hard stops on off ramps and sitting at the light with the pad clamped down will help the pads stick to the hot rotors.

Brake balance also effects some cars to do it more.

The fact is it is something that if you go to many web sites owner of nearly all makes complain of this judder.

I truley think it is due to the cheaper pads and the fact they need bedded in more than the semi metalics of the past. Remember oftem the MFG used the lowest bidder as the supplier. Save $10 per car pays a lot of UAW pensions.

hyperv6

Todays bearing are ball bearing vs the roller taper like we used to use. They are better for rolling but pay the price in durability. I am not sure if it is the bad roads, bad luck or the driver but some people have more issues than others. MOst new cars today can see a hub go anywhere from 60,000-200,000 miles.

This is common on most new cars even RWD that now use these ball bearing hubs.

I would say you just had bad luck. I live with a lot of bad roads but really have been lucky to not have any real issues with the hubs.

Note too the judder and RTV show up more under highway conditions vs city driving. The wobble at highway speed does more damage.

thegodfather

I also found that I have a 'shimmy' when applying the brakes on the driver's side front. I know the rotor should be resurfaced, but If I read correctly above, the calipers 'float', and was wondering if THAT could cause the ratteling sound I hear when I am NOT braking, BUT DEFINETLY DOES 'SHIMMY/RATTLE' WHEN BRAKING! I tried to 'move' (for lack of better descriptions) the caliper while the vehicle was parked, but couldn't seem to 'move' it. I HAVE noticed that temperature DOES seem to play a part in the 'ratteling' sound when going over bumps when NOT braking, BUT DEFINITELY DOES SHIMMY/RATTLE WHILE BRAKING. I am not mechanically inclined, & only had my HHR since February, so I DON'T have much 'on-hands' experience doing anytype of 'work' on it. I DON'T know what else to do or try EXCEPT ask you guys for information on what I could do, or what my problem is. I would appreciate some input on what would solve the issue BESIDES resurfacing the rotor since I Know That Is A Culprit Of The 'Shimmy', such as a possible caliper issue with the 'rattle' noise since it IS on the driver's front. THANKS GUYS!!!