View Poll Results: Pentosin Super DOT 4 VS Bosch DOT5
Pentosin DOT4
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100.00%
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0%
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Weak stopping power 2012 GLK350 4MATIC
Thread Starter
Junior Member
Joined: Dec 2016
Posts: 21
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2014 C300 4MATIC LUXURY & 2012 GLK 350 4MATIC
Weak stopping power 2012 GLK350 4MATIC
Hello,
So trying to resolve a weak breaking power on my 2012 GLK 350 with 40k miles. The breaking power is not that great comparing to my 14 C300 that can stop on a dime. Replaced front rotors with generic ones last year in summer and didn’t help solve the issue. So ordered Brembo front UV Coated rotors and Brembo ceramic pads. For rears I bought Bosh Quietcast UV Coated rotors and Bosch ceramic pads. Do you think this will help? Not sure what the issue might be pedal is fine lines are fine. I’ll try to suck up the old fluid thru reservoir since never been change and look dirty and greenish and put a either pentosin super DOT4 or have bosh DOT5. Anybody has similar issues and advices ? I appreciate thanks.
So trying to resolve a weak breaking power on my 2012 GLK 350 with 40k miles. The breaking power is not that great comparing to my 14 C300 that can stop on a dime. Replaced front rotors with generic ones last year in summer and didn’t help solve the issue. So ordered Brembo front UV Coated rotors and Brembo ceramic pads. For rears I bought Bosh Quietcast UV Coated rotors and Bosch ceramic pads. Do you think this will help? Not sure what the issue might be pedal is fine lines are fine. I’ll try to suck up the old fluid thru reservoir since never been change and look dirty and greenish and put a either pentosin super DOT4 or have bosh DOT5. Anybody has similar issues and advices ? I appreciate thanks.
Junior Member
Joined: Nov 2021
Posts: 56
Likes: 16
From: Quebec
GLK250
Bleeding your brake system will help for sure. Changing the oil from the reservoir won't fix anything. Simply put, the moisture resistance of your brake fluid will wear down over time and begin to absorb air. When you get air into your brake system, it’s going to make stepping on your brake pedal feel soft and spongy. Do some research for bleeding or changing brake fluid.
MBWorld Fanatic!
Joined: Jul 2012
Posts: 1,369
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From: WI
GLK 250
MB specs DOT4, so I'd stick with that. Nothing "silicone or synthetic," just fresh DOT4 fluid from a reputable brand. If you've never done it before, I'd pay a pro shop to do it.
For me it was worth the $103 with taxes
For me it was worth the $103 with taxes
Thread Starter
Junior Member
Joined: Dec 2016
Posts: 21
Likes: 0
2014 C300 4MATIC LUXURY & 2012 GLK 350 4MATIC
Bleeding your brake system will help for sure. Changing the oil from the reservoir won't fix anything. Simply put, the moisture resistance of your brake fluid will wear down over time and begin to absorb air. When you get air into your brake system, it’s going to make stepping on your brake pedal feel soft and spongy. Do some research for bleeding or changing brake fluid.
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Joined: Sep 2015
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2013 glk 350
Stock mb rotors have great grip , they were not designed for good wear or low dust, they are to stop you fast. They are better than harder aftermarket rotors, for stopping power. Many people change rotors because of the dust mb create, but that softer mb compound that wears fast is giving you the best grip. Stock pads are also made to stop you fast.
Change Brake fluid. Its supposed to be changed at around 40,000m . Your brakes which control antilock, stability and traction control should not be neglected. The brakes do so much more like control the AWD in snow and ice.
Once years ago on a Camry I hired a big chain shop to flush my brakes. My friend happened to have a lift and we were changing motor oil a month later . That’s when I noticed my bleeders were never touched. So deal with someone good , maybe even check to see the fluid is new , and a wrench was on the bleeders.
My 13, Glk , 70000m , has been flushed twice, with MB brakes and Michelins, it will throw someone into the window, the brakes are that good.
Old fluid could ruin a +10,000$ system, keep the fluid maintained- clean. Use Mb fluid or maybe Pentosin or other top German brand . I would not let someone - mechanic pick my fluid. FCP euro will ship you the correct fluid.
Change Brake fluid. Its supposed to be changed at around 40,000m . Your brakes which control antilock, stability and traction control should not be neglected. The brakes do so much more like control the AWD in snow and ice.
Once years ago on a Camry I hired a big chain shop to flush my brakes. My friend happened to have a lift and we were changing motor oil a month later . That’s when I noticed my bleeders were never touched. So deal with someone good , maybe even check to see the fluid is new , and a wrench was on the bleeders.
My 13, Glk , 70000m , has been flushed twice, with MB brakes and Michelins, it will throw someone into the window, the brakes are that good.
Old fluid could ruin a +10,000$ system, keep the fluid maintained- clean. Use Mb fluid or maybe Pentosin or other top German brand . I would not let someone - mechanic pick my fluid. FCP euro will ship you the correct fluid.
Last edited by Mmr1; Mar 23, 2022 at 02:15 PM.
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From: New Hampsha
'17 GLS450, '14 GLK250, Grandpa's Roadster
No help with the braking effect, but do not introduce even a drop of DOT 5 fluid into that system. DOT 5 is incompatible with any other fluid and requires a complete flush of the system to remove all traces of the original fluid. The usual recommendation is a complete overhaul of each and every component in the system.
With today's sophisticated ABS and automatic braking systems, it is best to stick with the fluid spec'd by the manufacturer.
With today's sophisticated ABS and automatic braking systems, it is best to stick with the fluid spec'd by the manufacturer.
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2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
DOT 5.1 is a glycol fluid compatible with DOT 3 & 4 fluids.
But changing hydraulic fluid type will not help brake performance unless the temperature limit of the existing fluid in the system is being exceeded. Brake performance is primarily determined by the characteristics of the friction materials. We had our 2015 GLK350 for over 155,000 miles and stopping was not a problem on Mercedes Benz pads, rotors, and fluid.
We also have a 2013 C-Class. Lower center of gravity, lighter. It probably out stopped the GLK. But it will take corners that would overturn the GLK, too.
If the brake performance is poor with OE parts, find the cause and fix it. There are certainly aftermarket parts that will improve the straight line brake performance over stock, but the GLK is still a tall square box.
But changing hydraulic fluid type will not help brake performance unless the temperature limit of the existing fluid in the system is being exceeded. Brake performance is primarily determined by the characteristics of the friction materials. We had our 2015 GLK350 for over 155,000 miles and stopping was not a problem on Mercedes Benz pads, rotors, and fluid.
We also have a 2013 C-Class. Lower center of gravity, lighter. It probably out stopped the GLK. But it will take corners that would overturn the GLK, too.
If the brake performance is poor with OE parts, find the cause and fix it. There are certainly aftermarket parts that will improve the straight line brake performance over stock, but the GLK is still a tall square box.
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From: New Hampsha
'17 GLS450, '14 GLK250, Grandpa's Roadster
That is true, but the OP specified DOT 5, not 5.1, and the poll says "silicone". Whoever decided to call a glycol fluid 5 dot anything should be banned from the mechanical world forever.
Last edited by John CC; Mar 24, 2022 at 01:14 PM.
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Joined: Jul 2012
Posts: 1,369
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From: WI
GLK 250
Also, I can attest that old fluid (likely original) vs new fluid of the same type makes a night-and-day difference. The pedal feel is so much better, the braking itself seems vastly improved and I'm well into a set of front brakes (probably 45k miles now).
Just get it done with the right stuff and you'll see a big difference. And when the time comes, I'd prefer to stick with ceramic pads based on great experience over the past 10 years.
Just get it done with the right stuff and you'll see a big difference. And when the time comes, I'd prefer to stick with ceramic pads based on great experience over the past 10 years.
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Joined: Jul 2012
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From: WI
GLK 250
MB and OEM pads are likely semi-metallic compound. They're designed to bite quick even cold and to stop you quickly. The drawbacks are they will glaze when hot and may fade sooner as a result. Think long, steep incline where you're riding the brakes (which you shouldn't when you can use engine braking...). They're also super dusty after just a day or two and they don't last very long.
Ceramic pads, in general, may take a bit to warm up before offering optimum stopping power. Once fully warm, they stop as well if not better than stock. They will resist heat and glazing far better, they produce minimal dusting and will generally last longer than stock pads. Combined with premium rotors (I prefer cross-drilled or slotted and cryogenic treated) they will outperform standard MB braking setup in every way.
Stock pads will be cheaper, but you'll replace them more often. You'll be cleaning your wheels more often and deal with squeaking likely after the middle of their lifespan. Ceramics are typically quiet always.
Different strokes for different folks. My point of reference is that before I replaced the brakes on our GLK, it had received 3 different front brake sets by the dealer in 49k miles due to warping and irregular wear. That last 3rd set was replaced by me at about 70k miles since I couldn't stand the vibration and lack of confidence, not to mention safety. I replaced the fronts with cryo-treated cross-drilled rotors and ceramic pads, and they're about halfway thru their service life now at 124k without one issue. I recently replaced the rear brake set, stayed OEM there.
Ceramic pads, in general, may take a bit to warm up before offering optimum stopping power. Once fully warm, they stop as well if not better than stock. They will resist heat and glazing far better, they produce minimal dusting and will generally last longer than stock pads. Combined with premium rotors (I prefer cross-drilled or slotted and cryogenic treated) they will outperform standard MB braking setup in every way.
Stock pads will be cheaper, but you'll replace them more often. You'll be cleaning your wheels more often and deal with squeaking likely after the middle of their lifespan. Ceramics are typically quiet always.
Different strokes for different folks. My point of reference is that before I replaced the brakes on our GLK, it had received 3 different front brake sets by the dealer in 49k miles due to warping and irregular wear. That last 3rd set was replaced by me at about 70k miles since I couldn't stand the vibration and lack of confidence, not to mention safety. I replaced the fronts with cryo-treated cross-drilled rotors and ceramic pads, and they're about halfway thru their service life now at 124k without one issue. I recently replaced the rear brake set, stayed OEM there.
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2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
Good point about the factory rotors on the GLK. They were awful. At about 50k miles our dealer recommended a change to different rotors which they stocked. I don’t have the details any more, but I think they were the same diameter and standard on a different vehicle. Those rotors were still on the GLK when it was retired at 155k miles. Still used the OE pads, but they lasted much longer on the new rotors. Brake performance didn’t seem to suffer. Lived with the wheel dust.
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From: Northern NJ
GLK 350 / Porsche 993
ATE 200 DOT4 is just fine. Flush every 2-3 years. It's cheap and easy. There is no need to go crazy. Like others said DOT 5 is a big NO!
Check your rotors/pads. Rotors can have build up and grooving on inside. Mercedes pads suck really bad they leave deposits on the rotors and ruin them.
Check your rotors/pads. Rotors can have build up and grooving on inside. Mercedes pads suck really bad they leave deposits on the rotors and ruin them.
