Malibu Maxx front-end vibration while braking

vibration
chevrolet
malibumaxx

#1

For a few years, I have noticed an undesirable vibration in my car’s front end. It started as a slight problem but continues to occur and is getting more noticeable. The vibration occurs when braking on a slight downhill before making a right turn. I looked for similar issues, but did not see anything similar after a brief search.

Last fall, I took the vehicle to a mechanic (Dealership service dept.) in a land far away. I left the car for a weekend and returned to retrieve it the following Monday. Initially the mechanic did not find anything after looking at tires, struts, joints, maybe… They wanted to bill me for 1/2 hour of time because they had to pay him to look at my car. I was not amused. I insisted that they find a problem and charge me more :slight_smile:

I hallucinated that I could persuade the sales person of a problem and that they would be able to describe it better than I to a mechanic. So I insisted that someone drive with me to ‘feel’ the vibration. I succeeded in that I was able to re-create the vibration, but only slightly. The vibration was not easy to localize where in the car it was originating. Sales person gave his testimony to the mechanic. The mechanic spent another hour of holistic examination and concluded that a grease job was in order on a ??? maybe it was a spline shaft in line with the steering column. I bought the grease job, but that shop has earned an anti-customer.

This evening, I just returned from a week of traveling for work, which involved lots of driving. I can re-create the problem by braking. Starting at highway speed, 55 - 70 mph, braking feels like a bumping on the brake pedal and steering column around 1-time per wheel revolution. Saying that another way, the vibration is faster at highway speed, but reduces in frequency (slower bumping/vibration) as the car slows. The vibration peaks while decelerating from 40 mph to 30 mph, then goes away. I should also mention that I typically brake in a straight line, then apply slight power while turning.

What is the group’s recommendations for next steps?


#2

Year and mileage?
Are these the original brakes? Original tires?
Have you checked for unusual tire wear?


#3

2006, 84k
believe that the brakes are original; tires have been changed at least once.
no unusual tire wire indicated, mechanical did verify that at least.


#4

@Klim

The mechanic did a really lousy inspection, but for only 1/2 hour labor, you can’t expect much

The mechanic should have driven the car on the freeway himself, and applied the brakes at that speed

FWIW . . . it sounds like your front rotors might be warped. Measuring runout will confirm this.

If I’m correct, the front rotors will have to be machined or even replaced, depending on how warped they are and how thick they are. And, of course, you’ll also need pads at the same time.

Anyways, if you need a brake job, I highly recommend installing genuine AC Delco parts. I’ve had very bad experience with some aftermarket brakes. The problem is usually noise. However, I’ve even run into aftermarket pads that don’t even fit correctly. The easy way to avoid this problem is to insist on using factory brake parts. AC Delco Durastop. Don’t get AC Delco advantage. Advantage is the “budget” line.

BTW . . . you don’t necessarily have go to a Chevy dealer to get AC Delco brakes installed

Does the steering wheel shake at freeway speeds if you’re NOT stepping on the brake pedal?


#5

I’d find a reputable owner-operated shop and have hem look at it. Dealerships for some reason aren’t usually interested in a car this age. They don’t seem to want to make an effort to actually diagnose and repair it. They’ll typically take a bunch of your money and do nothing useful.

Since the brakes are original, you’re probably due for a brake job. And that’ll include discs.

When the shop does the brakes, they should visually (and by feeling) check the tires for abnormal wear. If you have any, they should check out the chassis and also suggest an alignment.


#6

There are a variety of possibilities from a brake to suspension to a wheel issue to loose front bearings though warpped or scored brake rotors seem the best idea to me. Dealer service, especially if they are large can be good if they consult or useless if you get a trainee who can barely rotate tires. That’s where an independent excells when you can get the same two or three experienced people. If there are any brake and front end speciast in the area, I would go there first. Otherwise, we could be worse without your car on a lift or being able to drive it.


#7

This car has a seriously crappy brake system. I worked for the parts company (Delphi) that designed and made the system. It only feels and sounds good with brand new brake pads and rotors… for a while. You can choose pulsation (what you have now), or a grinding sound or a squealing sound. Sometimes you get 2 of the 3. The problem will develop over time and always before the parts are worn out. The only solution is to prematurely replace parts once it occurs. Or sell the car. Sorry.


#8

Thanks for the recommendations. The car now has an appointment with my local mechanic. At least the next owner will have a good brake system.


#9

@Klim

Are you getting rid of the car after the brake job?


#10

This works most of the time, find a lonely road, then at around 60 mph, apply the brakes hard, but not to lock up, just short of that, When you are down to about 5 mph, accelerate back to 60 and repeat. After the second application of the brakes, you are likely to find that the problem goes away, for awhile at least. If so, the problem was a build up of residues from the brake pads onto the rotor, the hard braking cooks the residues off.

It costs almost nothing to try this so if it doesn’t work, what have you lost but a little time, but most of the time it works. It almost always works if you are just experiencing a pulsing in the brake pedal. If the steering wheel shakes back and forth violently, then the rotors are warped and this won’t work so good.