Worn thrust arms - Dangerous?

[David D]

My 2005 4.4i Sport has developed a clunk when braking at low (5 mph) speed, and a shudder at highway speed when braking. I'm taking it in to have it repaired asap, but a buddy of mine that works for a Mercedes dealership said he thinks it's dangerous to drive.

Anybody have any insight?

[Joshdub]

Well it depends on how worn they are. If they have completely disintegrated then yeah I'd say they are dangerous.

[4.8isX5]

If they are very worn/cracked, or the bushing is half missing it can be. The wheel has alot of slack front to back or 9/3 oclock positions if your standing facing the wheel.

[David D]

I don't know how much slack it has, but there is a definite "clunk" when applying the brakes with any force at 5 mph, or say when hitting a bumpy driveway entrance.

Thanks for the replies. I'm calling today to take it in...

[OptimusPriM5]

My philosophy is you could be ok but its not worth the crap shoot. Dangerous probably not but I wouldnt say its safe especially in a critical situation. The engineers designed the cars for specific tolerances no one knows specifically what could happen which is why your doing the right thing to have it checked out.

[Ricky Bobby]

Its extremely annoying to drive with worn thrust bushings, the whole friggin car shakes when you are braking off the highway - Just get it fixed and get any other worn suspension items replaced in the front at the same time and align it -

[David D]

Well, it's at the dealer getting fixed up. Chalk up another plus for buying the warranty!

[THE VEIN]

Originally Posted by Ricky Bobby

Its extremely annoying to drive with worn thrust bushings, the whole friggin car shakes when you are braking off the highway - Just get it fixed and get any other worn suspension items replaced in the front at the same time and align it -

i changed both thrust arm bushings about 25k ago and i just recently had my front brake pads changed. now i have bad vibrations while braking at highway speeds. the mechanic told me the new pads warped my rotors but after reading this, im thinking its my thrust arms again

[upallnight]

Originally Posted by THE VEIN

i changed both thrust arm bushings about 25k ago and i just recently had my front brake pads changed. now i have bad vibrations while braking at highway speeds. the mechanic told me the new pads warped my rotors but after reading this, im thinking its my thrust arms again

You can get a dial indicator to check out the rotors' lateral runout to see if they are warped.

[StephenVA]

There is a lot of basic brake info up on this site and on the internet that will help you determine the shuttering problem. If new pads were installed on old rotors with out "truing" the rotors first that alone could be your issue. A best practice is to replace rotors and pads at the same time as the costs are cheap. Quite a few owners have lots of success running two to three sets of pads per one pair of rotors. The rule of thumb is to measure the rotor thickness, replace as necessary and break in the pads correctly. If you try re -bedding the pads, your shuttering may go away as the pad material has not transferred to the rotor evenly.
An out of spec rotor is one that is not parallel on both sides or too thin. The thickness is stamped or cast into the face. As mentioned above a simple test using a dial indicator while the rotors are on the vehicle with the wheels removed. Takes 30 mins to confirm the status. Old saying in car repair world, Test, don't guess.