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Are there Glk front rotors that don’t warp? I have 50% pad life left, pads are MB. Rotors are Zimmerman and have warped. I had them turned 3000 miles ago and they just warped again. They are junk. MB rotors also warped.
I think the rotors are to lightweight. I heard of Cryogenically treated rotors but costs are much higher. Any better ideas?
That could be a build up unevenly on rotor , I went that route first and used a wire brush on a drill and retorqued everything. It helped for awhile . Then it got worse so I got a caliper to measure it . They were warped. I think the rotors are too light to take the heat once they wear down .
I don’t have the GLK any more so I can’t look on the rotors for the part number. After fixing them many times, I worked with the dealer to get the same diameter rotor from a different application that used ceramic pads. I think the front discs are 330mm and a number of MBs use them. That solved both the pulsing pedal and the excessive brake dust issues.
The dealer parts desk said that rotor material had to be matched to the friction material, so both rotor and pad part numbers changed. Calipers didn’t need to be changed.
Unless you're riding the brakes our GLKs are really not heavy enough (or fast enough) to warp rotors. Nobody likes to hear that, but it's the truth in 99% of cases we hear about online.
Most likely the brakes were not properly bedded in when installed, which leads to uneven deposits because of hot spots. These deposits will cause shaking every time you go touch the brakes.
Find an empty road and do about 10 stops from 60 to near zero, but never stopping completely. I mean hard braking that trips the ABS, one after another, speed up back to 60 and hard brakes again, repeat 10 times. Then just drive around for about 8-10 minutes without touching the brakes (probably get on a highway and go for a few miles). You will have cleaned both discs and pads, should have no shudder/shake after that.
I stop fast when needed in Chicago , but I put it in park or neutral so pads are not touching . I used a gauge , last year they were 2 and the other one 4 thousandths out, that is warped. I had them cut and in 3000 they are warped again! Zimmerman rotors. Mb pads. I know I need new rotors , but I still have 50% pads left so yes they warped too early . I now have new mb pads and just don’t know which rotors to get, maybe the cheapest from FCP is best
My commute is into/out of that hellhole known as Chiraq, so I'm very familiar with the excellent driving taking place around there... I survive a 200 mile roundtrip commute on the days I have to be in the office, no brakes warping here.
If you're going to buy new discs, FCP is a great place to get them and it's where I got my last set which has been completely trouble free for the last 12K miles. I would have recommended ceramic pads, but since you've already bought MB semi-metallics, they'll have to do.
Once installed, do the brake bed-in procedure I described above.
I stop fast when needed in Chicago , but I put it in park or neutral so pads are not touching . I used a gauge , last year they were 2 and the other one 4 thousandths out, that is warped. I had them cut and in 3000 they are warped again! Zimmerman rotors. Mb pads. I know I need new rotors , but I still have 50% pads left so yes they warped too early . I now have new mb pads and just don’t know which rotors to get, maybe the cheapest from FCP is best
If you believe the rotors warped because they're too light then it makes zero sense to have them "cut" as they will end up lighter. Why would you be surprised they warped again after making them lighter?
I replaced my rotors a few months back. I'm pretty sure they were factory original. No warping or pulsing; they failed because too much of the back side was rusted. Replaced them with Zimmerman rotors and Akebono pads. I've used this combo many times in the past with no issues (on other makes and models.)
I just looked at FCP , the rotors I saw were all 330 x 32mm thick. Did you purchase a larger size rotor than stock?
No. New discs fit with no mods to hub or calipers. I had a friend who is a MB trained mechanic do it in the unlikely case I was missing something (I’ve been doing brake jobs for 50+ years and 20 on Mercedes). All was okay from then until GLK was retired at 150k+. Ceramic pads lasted more than 2x as long, too.
I agree with andreigbs that the vast majority of times, a "warped rotor" isn't warped at all, but exhibiting the consequences of never having been properly bedded in (leading to uneven distribution of the brake pad material fused into the rotor, causing uneven friction around the rotor). If cleaning / wire brushing the rotor improves or fixes the pulsing brake, clearly the rotor didn't get straighter, but only cleaner.
With just a couple thousandths of an inch deviation, I wonder if it's more likely that the problem is caused by the (all too common) grunge on the back of the rotor / front of the hub. Often, there is rust and other crud on one or both surfaces, and that can easily cause the rotor to measure at least a few thousandths of an inch of deviation, and even a noticeable vibration if it's bad enough.
FWIW, I put on a set of Akebono pads on my front brakes, and bedded them in properly. They've been flawless so far, and produce essentially no visible dust at all. I've put probably 20,000 miles on the pads, and the inside "barrels" of my front wheels still look great.
So you think the rotor facing inside is cruded up? One rotor was 3 thousands out, won’t that make pulsing ? These rotors might have 20-25000 of city driving , I’m not sure .
I put Akebono pads on the front (2014 GLK Base) and bedded them in as required. They are ceramic and we've have had ZERO braking issues whatsoever. I just walked out to the garage and see 94,000 miles (rounded up) on the clock.
Some pad manufacturers actually produce pads with a dedicated "bedding layer". Many folks are clueless to the importance of bedding.
ALL original rotors on our GLK. Original pads still on rear. (only put Akebono's on the front two or three years ago).
On the 2001 Jeep, I've replaced the front rotors and pads (EDIT: oops, did calipers too, cause they froze), plus pads only on rear. It has 134,000 miles.
Be sure replacement pads are chamfered and have the center split. For a motorcycle, these features are important (ridden bikes 50 years now), so an advantage for 4 wheel vehicles.
Last edited by calder-cay; Aug 30, 2024 at 05:25 PM.
I think it's worth checking to see if you might have rust or crud between your hub and rotor faces. Then again, I suppose it's always possible that if you DO have 20,000 miles on the rotor, and it's been "not quite flat" the whole time, it could actually be slightly more worn at the "high spots" (where it would make contact before the rest of the rotor). But yeah, I'd check it.
If my (wild, unsubstantiated) theory is correct, I'd suspect you'd see that 2-3 thousandths runout in a nice, even distribution, with the low spot and high spot 180° apart, and a gradual "slope" between them on both sides of the rotor (that is, with the high spot at 12o'clock, and low spot at 6o'clock, 3 and 9o'clock positions should have about half as much runout.
Ok Thanks everyone, it gets confusing. I did clean the hub and inside of rotors with drill and nylon brush, then torqued it. It was better for a week, then I had them cut, now warped again. I think I’ll put new pads on bed them in properly. With new rotors. (I never did this ) I have a new set of MB pads siting around that I will use . Thanks all
I installed this combo on both of mine about 20,000 miles ago. I just checked and can see very little wear. No lip is evident on the disk edges and no rust at all. Of course, we don't get much rain here in Vegas but one of the trucks was washed yesterday and the disk face did not rust as I've seen some do. The main reason I installed these was to rid my wheels of that ugly black brake dust. Problem solved. Rear brakes are OEM and at nearly 50,000 miles have a wear lip on the disk but are still within limits.
I am not a spring chicken. I have worked on my own pad, and rotors, bleeding etc. I have worked on drum brakes but ages ago. I have never heard of bedding. I know that when you install pads, you have to make sure they are properly seated. I don’t think seating is what anyone is meaning by saying bedding. If bedding is important, can someone define it, and describe the process?
2006 Alfa Romeo Brera, 2010 GLK350, 2018 BMW 640i GT, 1997 Subaru SVX, 2012 Moto Guzzi Norge GT8V
Originally Posted by MB2timer
I am not a spring chicken. I have worked on my own pad, and rotors, bleeding etc. I have worked on drum brakes but ages ago. I have never heard of bedding. I know that when you install pads, you have to make sure they are properly seated. I don’t think seating is what anyone is meaning by saying bedding. If bedding is important, can someone define it, and describe the process?
2014 GLK350 base model (active) ; 2001 E320 base (retired); 2001 Wrangler soft-top
Originally Posted by MB2timer
I am not a spring chicken. I have worked on my own pad, and rotors, bleeding etc. I have worked on drum brakes but ages ago. I have never heard of bedding. I know that when you install pads, you have to make sure they are properly seated. I don’t think seating is what anyone is meaning by saying bedding. If bedding is important, can someone define it, and describe the process?
Still surprised folks don't know about it.
If you own a motorcycle, it's VERY important.
But yea, also very important for four wheel vehicles.
And guess what, knowledgeable bicyclists who have disc brakes, understand the importance.
A Google search will reveal tens upon tens+ and way more posts for bicycles, cars, and motorcycles. A start:
I am aware of a process of warming up carbon fiber brakes.
Full carbon fiber brakes have a property of grinding when cold.
So if you ride carbon fiber brakes, when cold, the pads and the rotors will grind in a manner that causes very excessive wear.
The process that is intended to be used, is a process similar to the process described in post 6.
This warms the brakes to the point wear now you can ride them to prevent acceleration.
Also, carbon fiber brakes are like sponges to water. Warming them up to boiling point exhausts all the water out that the brakes have absorbed.
All the above primarily relates to aircraft carbon fiber brakes, so maybe it’s the same for automotive.
Are there Glk front rotors that don’t warp? I have 50% pad life left, pads are MB. Rotors are Zimmerman and have warped. I had them turned 3000 miles ago and they just warped again. They are junk. MB rotors also warped.
I think the rotors are to lightweight. I heard of Cryogenically treated rotors but costs are much higher. Any better ideas?
I had something similar happen changed front rotors twice and they started warping within a thousand kilometers. I ended up figuring out that it was a seized caliper. Swapped out the caliper. Now I've been driving almost 10,000 km. No issues on Zimmerman rotors
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