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Old 09-21-2010, 08:26 PM
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85 DSEL 85 DSEL is offline
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Join Date: Oct 2006
Location: Dayton, Ohio
Posts: 1,037
My recent brake story

After my pad wear indicator light started glowing I immediately ordered new pads, sensors, rotors, and MB grease from Phil and put them on the front of the wagon here about 4 - 6 weeks ago. The braking had a little 'warpage' pulse before I replaced them - couldn't really tell from which end it was, but thought I'd go ahead and replace the rotors as I figured they were possibly original equipment.

After reading many posts from this great site, I decided that I would use the Zimmerman brand rotors as there wasn't much 'bad' stuff about them. After doing the job I was careful to break-in the new parts as prescribed from the many posts I read. IF my 56 year old brain cell is firing on all 4 cylinders, I recall that I was to make a couple "firm" stops from ~40 mph to "seat" or "set" (ahh, there it goes, can't remember!) the pads and rotors. This I did and from then on for the next couple hundred miles used caution when hitting the brakes so as not to 'jam' on the brakes.

Over the past couple weeks the car has been getting progressively worse with regard to the pulsating rotors - almost vibrating when brakes are applied - can not feel anything in the steering wheel so that seems to indicate that it is coming from the rear rotors.

An unrelated issue that has needed attention is wheel/tire balancing. One of my pet-peeves is unbalanced wheels/tires BUT I don't think about it until I am on a 'road trip'! Well I remembered it this week and called a local European Indy shop (I actually met this tech several years ago before I ever owned a Mercedes through selling him a dump truck I used to have and we have just kept in touch over time!) that I thought I'd take it to and have them balance the tires and do a quick look-see under the front end, etc. After a little while I received a call from him and he stated that I had several issues going on:
  • Right front tire has a broken belt (Continentals)
  • Warped rotors
  • Sway bar bushings could stand to be replaced
  • Shock/strut mount bushings have settled and could be replaced (not essential but will "definitely improve ride")
When he told me about the rotors I asked him which rotors? He stated "all of them, especially the rears". When I told him that I had just replaced the front brakes he went on to explain that MB's and BMW's don't do well by replacing only front or rear brakes, they should be done at all four corners. Why, I asked. His theory is that when fronts are new (pads and rotors) that there is the break-in period and during that time the braking force is not what it should/will be when completely seated, thus it puts more strain on the rears to get the car stopped causing them (rear) to heat up more than normal and causing them to warp. It seems to make sense - any thoughts?

My close second pet-peeve is pulsating brakes. I don't like 'em! He suggested that the fronts may be "ok" after replacing the rears but that I will need to use extreme caution during break-in since the fronts would then be the primary stopping force while the new rear hardware is seating in. The fronts apparently are only warped "slightly". Oh yeah, another theory of his that makes a lot of sense is when one comes down off the interstate from highway speeds and the brakes are hot, one shouldn't sit with their foot firm on the brake pedal at a traffic signal but rather let the car 'creep' forward slightly so the pads don't press against the rotors in one spot allowing heat to transfer to THAT one spot only - potentially causing the rotors to warp. Thoughts or comments?

1995 E320 Wagon 185K [SOLD]
1988 260e Sedan 165K
2007 F-150 XLT 188K [SOLD]
2003 Harley Davidson FLTRI Anniversary 26K
2006 BMW 330Ci 110K - [SOLD]
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