Good afternoon. Car is a 1989 560SEL, 175K miles. Car has been in the shop for the third time in 3 weeks. Problem is a strong vibration in the front end, experienced during braking from 45 - 50 mph. The entire front of the car shakes and wobbles, but only during braking. The upper ball joint assembly, including the bushings and lower ball joints were replaced, and the problem remains. All four rotors and pads all around were replaced 50 miles ago.

Mechanic now reports the drivers side brake rotor is blue, and he has changed the passenger side caliper with a "used but good" caliper he had in his shop.

I was wondering if this could be related to the anti lock brake system malfunctioning? Does anyone have any ideas?

I am out about $1,000 USD so far, and I am quickly losing confidence in my mechanic's ability to diagnose the problem.

Thanks for the help. I am at the end of my rope, and my checkbook.

MFG
John

__________________
1989 560SEL (172k)
1989 325IC (122K)
2004 Suzuki Volusia LE (3500 miles)
2005 Yamaha Road Star (20 K miles)

Does this vibration seem to come from one side of the vehicle?

Does the vehicle pull one way or the other when braking?

Does the vibration occur when you brake at 70 mph? Is it worse or better?

Does the vibration occur on light braking or on heavy braking or both?

Does the vibration go away if you do very heavy braking?

Is there any vibration at 70 mph without braking?

Vehicle does not pull to either side, and the vibration seems to come from the passenger side.

I will not drive 70mph when I have problems braking. 45-50 mph is even too fast.

Vibration is slight at lower speeds, and seems to be more pronounced during harder braking at higher speeds.

There is not any vibration without braking, at any speeds.

__________________
1989 560SEL (172k)
1989 325IC (122K)
2004 Suzuki Volusia LE (3500 miles)
2005 Yamaha Road Star (20 K miles)

Be very careful with the answer to this question:

Was the problem there before the pads were changed?

The problem existed before the rotors and pads were changed. No change in symptoms was experienced when the pads and rotors were changed, as with replacing the upper and lower ball joints.

__________________
1989 560SEL (172k)
1989 325IC (122K)
2004 Suzuki Volusia LE (3500 miles)
2005 Yamaha Road Star (20 K miles)

I definitely feel that these symptoms are brake/rotor related. The ball joints could never have caused the vibration that you are referring to on braking.

If any one of the suspension components, on one side, has failed, the vehicle would pull. So, I am leaning away from any of the suspension bushings.

Have the mechanic setup a dial indicator (he ought to have one) and measure the runout of the face of both brake rotors. To do this, remove the wheel, setup the indicator on the face of the rotor, and rotate the rotor.
The runout should be about .001 or less. You will probably see numbers at .005 or above for the symptoms you are describing, if this is the culprit.

Now, if you get a high value, it does NOT mean the rotor is bad. The mounting face for the rotor might be dirty or rusted and the mechanic simply slapped a brand new rotor in place. These vehicles are very sensitive to runout in the rotors, no matter how it occurs. Such a condition can also occur if the wheel bearing is damaged (unlikely, but possible).

The aforementioned test is very inexpensive and valuable.

Consider additional suggestions from others. However, do NOT spend any more money throwing parts at it. The problem that you are experiencing can be diagnosed with the proper knowledge and measuring equipment.