Vibration when braking

[Gen-Eric]

Hi

I have a 2018 G80 Ultimate V6 AWD with only about 180 miles. Since I took delivery of the car I noticed a front end vibration (but not a steering wheel shake) whenever I brake from about 35 mph and higher. The vibration seems to be coming from the front in general but more so form the left front. The dealer said it was likely rust on the rotors and I should give the situation a little time to correct itself. I did not have a similar problem with my 2012 or 2015 Genesis sedans. Has/is anyone else experiencing this problem? Does the dealer's explanation make sense? Any ideas on how long I should let this situation go on before I bring the car in for a check-up? Otherwise the car is running just fine and stops with no problem.

Thanks

Eric

 

[dougmcp]

IMO rust on the rotors should not cause this problem. If it's only under braking you likely have a warped rotor or the wheels are put on too tight. With electric steering, feedback as in wheel shake is somewhat damped.
I would have the dealer rotate the tires and check the torque on the wheels which I believe is only about 70 lbs not a 100 like most dealers like to do.

 

[Gen-Eric]

IMO rust on the rotors should not cause this problem. If it's only under braking you likely have a warped rotor or the wheels are put on too tight. With electric steering, feedback as in wheel shake is somewhat damped.
I would have the dealer rotate the tires and check the torque on the wheels which I believe is only about 70 lbs not a 100 like most dealers like to do.

Thanks for the reply. I contacted the dealer this morning and they have arranged to pick the car up tomorrow morning to evaluate the situation. According to the sale's manager and service (independently), there appears to be known vibration problem which may be what I'm dealing with. Additionally, Genesis is staring a "service campaign" with regards to a vibration issue that has popped onto their radar. I will update once I have more information.

 

[Mark_888]

Thanks for the reply. I contacted the dealer this morning and they have arranged to pick the car up tomorrow morning to evaluate the situation. According to the sale's manager and service (independently), there appears to be known vibration problem which may be what I'm dealing with. Additionally, Genesis is staring a "service campaign" with regards to a vibration issue that has popped onto their radar. I will update once I have more information.

There have been at least two vibration problems.

One is vibration of the engine during idle (car not moving).

The other is vibration during braking that you have. But usually a vibration during braking is a sign of problems with warped disc rotors as explained above. Rotors can be exhibit this problem if the wheel is mounted too tightly, causing the rotors to warp slightly. Sometimes the problem can go away if the wheel is re-tightened to the proper torque spec, and other times the rotor is permanently warped. This is less likely to happen at the factory, but can easily happen at port of entry or at a dealer, especially if someone put on wheel locks.

I have also heard of some problems with vibration at high speeds which is attributable to out of balance wheels, having nothing to do with the Genesis per se, and usually easily fixed with a good road force balance.

 

[lobsenza]

The key to reducing the liklyhood of warped rotors is to torque all lug nuts on a wheel to exactly the same torque with a torque wrench. The exact torque value is not as important as making sure all the lug nuts are torqued to the same value.

 

[Gen-Eric]

Update 1: Genesis service picked up the car this morning and there is no doubt that I have a bad set of rotors. New rotors were ordered and will supposedly be shipped overnight so I hope the repairs are completed by tomorrow.

 

[1FstYota]

I guess I could see it, the car is heavy and probably a decently aggressive compound on the brake pads, so generates enough heat where you come to a stop and hold the brakes while rotors are hot then it could happen.

 

[kn5owa]

I had the same problem on a new ford taurus

The car had been sitting on the lot so long before the sale that the rotors were heavily rusted.

They machined the rotors - better practice nowdays to just replace them.

Machining fixed the prob. which was most definitely heavy rust build -up not the type you get overnite after a shower

 

[Seejay]

I had the same problem with my 2015 Signature. The rust could be a problem, but the vibration may be caused by frictional differences between the rusted area and the area that was next to the pads (just guessing here). In time, the pad materials work their way into the rotor pretty far, necessitating cutting them deeper than one would expect. I complained and they replaced them.

 

[1FstYota]

The surface rust doesn't change the structural of the rotor, the rust wipes away as soon as you apply the brakes. When its warped the rotor literally is not flat and the heat has cause it o warp which causes the vibration, at this point a replacement is necessary, turning the rotor won't solve this.

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[Mark_888]

The surface rust doesn't change the structural of the rotor, the rust wipes away as soon as you apply the brakes. When its warped the rotor literally is not flat and the heat has cause it o warp which causes the vibration, at this point a replacement is necessary, turning the rotor won't solve this.

Agreed. However, there are other things besides over-heating that cause warped rotors, specifically improper mounting and torqueing of the wheels. This has been reported in the past on this forum for brand new Genesis models, which presumably had wheel locks improperly installed at port of entry or at dealer.

 

[Gen-Eric]

Agreed. However, there are other things besides over-heating that cause warped rotors, specifically improper mounting and torqueing of the wheels. This has been reported in the past on this forum for brand new Genesis models, which presumably had wheel locks improperly installed at port of entry or at dealer.

No wheel locks were installed. So I'm guessing either just a bad set of rotors or improper mounting. Waiting to hear back from service as to the status of the fix.

 

[Mark_888]

No wheel locks were installed. So I'm guessing either just a bad set of rotors or improper mounting. Waiting to hear back from service as to the status of the fix.

Could be improper mounting and torqueing of the wheel at any time. Hard to believe it was improperly torqued at the factory, but that is possible.

 

[Gen-Eric]

Update 2: Just heard back from service. They changed the front rotors but the car is still vibrating when braking at above 40 mph. They have ordered new rotors for the rear and will replace the brake pads all around. Loosely quoting Hans Solo "I'm getting a bad feeling about this". The service manager also stated that there is "recall" for this problem.

 

[1FstYota]

Wheel lug torque is far fetched as far as warping rotors, either its a bad batch of rotors or something happening with the calipers that causes uneven pressure. I'm gonna go with most likely a bad batch of rotors, that came out the mold wrong.

 

[Mark_888]

Wheel lug torque is far fetched as far as warping rotors, either its a bad batch of rotors or something happening with the calipers that causes uneven pressure. I'm gonna go with most likely a bad batch of rotors, that came out the mold wrong.

The issue with wheel lug torque is not how much torque is applied, but whether they lugs are tightened in a cross-pattern (correct) versus just sequentially round the wheel (incorrect). Doing it incorrectly, can definitely cause warping. For example, you want to tighten the lugs in order of something like 1-3-5-2-4 and not 1-2-3-4-5 (doesn't matter which is number 1).

Brand new brake rotors are machined (turned) after the casting (mold), so I would doubt the that the mold is the cause. An initial casting is not expected to be particular accurate. It could be they were initially machined (turned) incorrectly after the casting. I had a severe problem with pulsating rotors right after a brake job years ago, because the technician who turned the rotors did it horribly wrong, and they ended up having to buy me new rotors.

 

[Gen-Eric]

Update 3: Genesis service returned the car to my residence yesterday afternoon. They replaced all four rotors and new brake pads all around. I took the car out this morning and its perfect!!! Hard to believe that all four rotors could be bad but I guess anything is possible. Thanks to all who replied to this thread with info and insights.

 

[Mark_888]

Update 3: Genesis service returned the car to my residence yesterday afternoon. They replaced all four rotors and new brake pads all around. I took the car out this morning and its perfect!!! Hard to believe that all four rotors could be bad but I guess anything is possible. Thanks to all who replied to this thread with info and insights.

If the same idiot installed all 4 wheels with an air power wrench, and did not torque them in the proper order and/or to proper torque specs, it is not surprising at all that all 4 needed to be replaced.

 

[Seejay]

If the same idiot installed all 4 wheels with an air power wrench, and did not torque them in the proper order and/or to proper torque specs, it is not surprising at all that all 4 needed to be replaced.

I had to replace the front rotors at 200 miles, and when it was time to replace the tires, I had to have a stud drilled out of the RF hub because those clowns severely over-torqued the locking lug.

 

[GV70GUY]

If the same idiot installed all 4 wheels with an air power wrench, and did not torque them in the proper order and/or to proper torque specs, it is not surprising at all that all 4 needed to be replaced.

Good point, Gen-Eric you might want to re-torque them yourself to make sure, otherwise.......