GenVibe - Community for Pontiac Vibe Enthusiasts

Okay, I am no youngster. But I need some real experience here. I am very mechanically inclined and do all my own work having $3000 in tools. So please read and give your best ideas. 1st-For quite a while I have had verying degrees of steering shake while braking. I have 2 sets of wheels/tires. Happens on both sets. Both sets show no signs of unusual wear. So alignment is not the issue. Shake happens now above 60 mph or when going down a steep down hill above 45. And gets worse as the rotors heat up. Dial indicator says-ALL items are within spec, rotor runout .001", hub runout-good, wheel bearing play-good, etc. The caliper slides have been greased using the proper grease. I even removed the rotor(s) and bought a new rotor to confirm the runout was not awarp issue. Meaning a runout of .001 was in the same spot new or old. Thus my car has an assembly variation. POINT being, I suppose I need a runout of .000" to eliminate this shake? ALSO the Toyata dealer said he cannot promise ZERO runout after he cuts the rotors using an on car lathe. And basically said,"just get cheap rotors and pads, bye". But using a new one as stated, I confirmed that will not fix it. DEALER = jerk. PS- I tried getting this looked at under warranty and got a run-around.Car is out of warranty. NOW Rotors measure .975" thick...almost like new and pads have more than 5mm @ 40k+. As heat seems to make this worse. Would slotted rotors help keep the heat out? Any genius ideas would be appreciated...

when you say wheel shake your strickly talking the front wheels? Steering wheel?Being your an awd when was your last awd fluid change? could be cvjoint, could be an axle going bad. Any noises? Squeaks? leaks?try looking at other possible issues, as it seems you have deff ruled out brakes being the issue.

I have changed all the fluids.Steering shake only happens w/brakes applied. I can do 90 mph...no shimmy. But hit the brakes and hang on. It gets worse the hotter the brakes get. SO, It's not a CV joint. It has been there since almost new. BUT Pontiac service sucks..."we don't feel it".. AND I must fix this myself. It has gotten worse to where it is now. These are not Cadillacs with big tires. As these little cars have the wheels rotating faster than most other cars. Thus the slight non-perfect runouts shows up. I suspect the hub(s) were improperly machined or improperly installed. Another one that got out from Nummi that shouldn't have. I may be replacing or removing the hubs unless someone else has an idea?

Well a hub has no rotational motion... a rotor would not vibrate the car.since your awd... maybe the rear drive shaft is out of balance?

I also have a 2005 AWD Platinum and did have the same issue.I also thought rotors might be bad, since I had the wheels balanced during rotation at 30k.Double check the torque of the lug nuts. (You are using a decent torque wrench, right?) They should be at 76 ft. lbs. and not an in. lb. higher. Over-tightening of the lug nuts is common and can cause the rotor to warp.When you changed the rotors, did you change the pads too? Do a search on the forum for the proper bedding procedure, as this could also cause an issue.After every wheel service, I check the torque and it is always wrong.I also performed some hard stops from highway speeds (off-ramps work) and forced the steering wheel straight by holding it tightly while braking hard as a "pseudo-bedding" on the off chance the pads were not properly bedded.My brake shake has noticbly improved to the point of not noticible.Good luck!

Mavrik, If the drive shaft was out of balance, it would cause the whole car to shake....it would NOT cause JUST the steering wheel to shake side to side when only braking. I did not say it was the whole car. The front axle "HUB" is as described in the Matrix manual with pictures is "where the rotor sits".Ehoff, I torque all the nuts(craftsman torque wrench) properly, do my own rotations and have 2 complete sets of wheel/tires and nuts. ALL 8 wheels have had the balanced checked. I will say my snows give a better ride than the junk GoodYears. You say you have a brake shake as well. BUT I find this shake unacceptable and scarey to my wife. NO car should have steering shake when you hit the brakes. Something is wrong. I have not changed the rotors yet. As stated above I used one NEW rotor as a check of if the issue had a common spot on the hub. Result = yes, same spot. I believe it is the simple runout due to the hubs. Just have to find a way to fix it. Problem, it is due to NUMMI parts & assembly. Must be the hubs the rotors sit on. Ehoff, I see you are in Fairfield. I suggest you go on the Merrit pkwy. I remember there is a steep hill or 2 there. Try hitting the brakes hard at 65 on one of those DOWN hills. I suspect you may feel what I am refering to. Down hill causes more load on the front brakes. And repeated braking on hills makes it show up. In the cooler weather we have been having...it may take a bit more braking to make it obvious. OR try it at 80mph going straight and flat. Oh yes, straight and fast makes it obvious. Turning and braking clearly lessens the effect. Side loads and damping effect of the tires. I am wondering how many have noticed the same as me? Lastly, it is nearly impossible to warp/bend a rotor from torquing a nut a bit too much. That is something mechanics use to scare you. As torquing the nut is creating a clamping force to the hub. And the wheel itself speads this clamping force. And the rotors once set on the hub for a while are ON the hub. Unless not OEM,they are not floating on the hub. Thus no play between the 2 surfaces. It would likely take enough torque to brake the stud(s) to damage/bend the rotor or damage the hub. ONLY I HAVE removed or mounted the wheels on this car. Having 2 sets(alloy and steel), I get one balanced while the other is on the car. If you have not guessed...I do everything myself. PS- I do appreciate all the ideas thus far.

you mentioned you swap tires and rims. Do both sets of rims have hub centric rings?if your rim is slightly larger than your hub this could possibly be causing your issue?Just another thought

BOTH sets are OEM Pontiac..steelies and alloys. We all know they say Toyota on the back.

Does this problem show itself even under light braking - or only under hard braking? Also if the hubs and rotors are within spec....I think you need to look elsewhere........0.001 runout should not be a problem and I don't believe 0.000 is a possibility on a production line. I have had rotors that have been problematic and feel warped when driving but measure fine. There must be some kind of built in stresses that manifest themselves with temperature. I think my next step would be to remove the rotors and have a real light cut put on them and install a new set of pads. Chances are they will work fine for a while and then the problem will return - so new rotors that you actually install and use may be the only solution. It may also be appropriate to get a good set of rotors....maybe something better than OEM. There was a fellow here at our office that had Dodge pickup and the front rotors would act just like you describe. He had them turned and the problem came back, the dealer put on new OEM rotors and the problem came back. The weird part was that he could drive around town and never have a problem, and the first time he would drive the truck on a trip where he would drive for several hours non-stop the pulsing would show up again. He gave up on the dealer and I installed some good quality slotted rotors - and problem never showed up again. I can't really say that the slots helped - it could very well have been just having a good quality rotor.The last step I would consider would be aligment even though the tire wear is not unusual. Too much toe out will not cause unusual tire wear - but will cause squirrely handling. Under hard breaking the front wheels could be toeing out excessively and causing the car to "trammel" or follow paving irregularies. If the shaking is directly related to the wheel rotation and slows down in relation to the wheel speed......then this probably is not the problem.....however if the car is just moving around and is hard to keep straight under hard braking....it could be alignment. I have not yet figure out how hotter brakes will have any affect on alighment?

I have absolutely no unusual tire wear...as stated earlier. TOE OUT causes lane changing on the highway to be sudden like following a rail all of a sudden. I do not have any handling or wear issues. Sorry you do not believe .000 runout is possible. Which is required on smaller wheels. But this seems to be the thought these days that poor quality is to be expected form US manufacturing. I can say that from the 9 cars prior to this(4 FWD, 1 AWD, 4 RWD) I have owned or driven for my company(each over 60k). ALL 9 have had .000 runout. Thus Toyota or Nummi quality is lacking. The slotted rotor idea is a thought I contemplating. I will say these rotors are thicker on the outside because Toyota acknowledges the outside pads rub even after the brake is released. My runout is not due to the rotor because as stated before a new rotor gives me the high spot exactly as the old....As marked on my studs. So it's the hub the rotor sits on was not machined proper or something. I have some ideas on correcting this. AND when I do, you all will know. Yes, I will be getting new rotors. As the Toy dealer says his are $120 ea.I will look elsewhere.

So I guess the next step would be to find out why the hub with runout is "defective". Either the bearing has some runout or the hub has runout. If you measure the hub runout on the vehicle by taking off the brake disc and using a dial guage it will have significantly less runout than the disc as the radius is much smaller - the disc has a much larger radius and the runout will be much bigger at the extreme outside edge. If you find that there is runout you would have to remove the hub from the bearing and mount it in a lathe and see if the face has any runout. The studs could be pushed out and the face lightly machined to even up the face (I am not sure if they are too hard to cut on a lathe) - or you could get a replacement. If the hub does not have any runout then it could be the bearing.As you stated earlier - you could also have the disc machined on the vehicle with the disc mounted to the hub - and this could correct the runout if the machining is done well.I know it is easy to misinterpret email postings.....but I somehow felt you were a bit irritated by my alignment comment. It is obvious that you do know about toe out, trammeling and the feeling you get from having a car that is not in alignment - however tire wear is not always evident with minor alignment problems. If the feeling you get only occurs during braking and is a "pulsing" then it probably is related to the brake discs and hubs and not to alignment. If it is not a pulsing during breaking and it is just erratic steering during braking - it could be a suspension problem that only occurs during braking - if a ball joint, strut or bushing is worn or loose it could allow the alignment to change under hard braking.

Yes, one option is to remove the hub. Question is...is the hub not machined or made properly? I have been going over some ideas. 1st there is a possibility of what is called play/twist. That when the 30mm nut on the hub was tightend it cause the hub to tilt just that slight bit on the splines of the axle shaft. This can be due to 2 things. 1st was the hub painted prior to assembly? If painted where the hub contacts the bearing. There are special paints. ...But this could be bad because the painted suface MUST be evenly compressed. Also how much play is there between the axle shaft splines and hub? Again the twist/tilt/play theory. It is surely the hub. Yes it's within spec. And after looking at the book .002 they state is too much for a rotor and should be "adjusted" on the rotor. SO half that is still not good. No one will promise a better than .001 when cuttiing the rotor w/ on car lathe. Yet they want over $200 to do it. I will be getting an adaptor to check the runout again on the hub for exact numbers. And double check that the caliper pistons are surely working properly. If piston sticks, rotors overheat and warp. Main worry problem is, I remember others posting similar "downhill issues". They had their rotorcut. But that did not fix it. Likely because it was not done on the car by a proficiant mechanic. I am sorry, but my 20 year garden tractor is built better than this. I am old enough to have driven or owned almost every type of car out there. Every one put over 60k on them. One I put 200k, 2 with 120k on them. Only shakes were from rotors not being true zero runout due to just stuck calipers causing overheating or mechanics not cutting the rotor properly. So for this to be an issue from almost new and not to have GM support the vehicle has me upset. Again, brake shake is not normal on any car, new or near new. I don't have a garage and do very little hiway driving. That is why it won't be cured till spring. If anyone else has this issue and under warranty...time to be a pain. Thanks for letting me vent...

First off, where in Western CT are you since I am in Milford and work in Norwalk. I drive an AWD Trix.I had a wheel shake but for me it was due to the snow. You get some of that stuck in the wheels and getting yourself up to 60 you will feel the shake. Then above that it gets ridiculous. I had to drive 55-57 for a few days on the highway till it melted off.Could be several items too. You could have a bent rim as well which would cause the disruption. The lugs could be loose on one wheel allowing it to wobble. Your tire could have a flat spot or bulge in it. You could even have an issue with a control arm on one of the A bars underneath the front end.

Since the issue is most obvious when the brakes are warm. It has nothing to do with snow. I know what it feels like to have the snow/ice throw the wheel out of balance.It is most obvious in the summer. Brakes heat up faster. Also as I stated at the beginning. I have 2 sets of Pontiac/toyota wheels all balanced. A balance issue gets worse with speed. This is not a balance issue. I can do rather "unsafe" speeds and no problem till the brakes are applied. Loose lug nut...no way on any of my vehicles. I am quite a perfectionist with the torque wrench. REMEMBER- this is not a totally new issue. All my measurements point to one issue that should have not made it off the line from NUMMI. I read something about cars coming off the line that should have never got out...due to defects. Now, I know what my defect is on mine. Which I will fix. I hope NUMMI closes or they fire the people letting these examples out. And they reopen the Canada plant. PS..Whelan..I'm way north of you.