R4S vs Stock brake pads.
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C63 AMG (W204)
R4S vs Stock brake pads.
Today I changed my brake pads both front and rear from stock to Porterfield R4S. I also resurfaced the rotors.
The pedal feel is much softer, and the bite and stopping power seems much weaker.
Is it because it's the first day? Or do others also feel weakened stopping power when changed to R4S from stock pads.(Non p30)
The pedal feel is much softer, and the bite and stopping power seems much weaker.
Is it because it's the first day? Or do others also feel weakened stopping power when changed to R4S from stock pads.(Non p30)
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2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
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'20 GLE450; '06 CL65
I have an E63, but just changed to R4S' about 700 miles or so ago. I also changed rotors at the time as well, so YMMV. However, I bled the system in proper sequence with a Motiv bleeder and bedded the brakes and have noticed no real difference from OEM's I had on it before. Initial bite is about the same, but then Porterfield's aren't known for their spectacular initial bite. Pedal feel and stopping time/power for me is similar to OEM's if not a little better when you really get into them. The OEM brakes are pretty good, though, so I wasn't expecting a huge improvement in some of these areas. Dusting is certainly better than OEM's, but they are in no way dust-free.
There is a sequence to bleeding as I noted above; which bleeder valve to start with and which to move to next. It is by most accounts important to follow that pathway. Starting there and then bedding properly as members above noted should yield similar results to that noted above.
NOTE: The brakes on the P30 cars on the E63 are the same as the base E63's. Also, my note above on bleeding sequence is from my experience on the E. I assume it would be similar on the C, but you should investigate first.
There is a sequence to bleeding as I noted above; which bleeder valve to start with and which to move to next. It is by most accounts important to follow that pathway. Starting there and then bedding properly as members above noted should yield similar results to that noted above.
NOTE: The brakes on the P30 cars on the E63 are the same as the base E63's. Also, my note above on bleeding sequence is from my experience on the E. I assume it would be similar on the C, but you should investigate first.
Last edited by Skizz; May 24, 2016 at 11:59 AM.
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Changing pads and rotors doesn't normally require bleeding the brakes. I'd try bedding first. Links from BLKROKT are the best explanation I've seen of the why and the how of brake bedding.
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'20 GLE450; '06 CL65
Caveat: I changed my lines and pulled the calipers for painting, hence the bleeding on my part. I probably would have done it anyways while I was in there.
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2010 C63 AMG sedan
There is a high probability that you'll never get your pads to bed in now that you've glazed them if you don't.
If your brake pedal feels spongey/soft....it could be the process you went through to install the new pads. If you didn't crack the bleeder screw at the caliper when you compressed the caliper piston, then you forced fluid backwards up through the system....pushing moisture and debris/contaminants backwards up into the ABS valves and master cylinder. This can damage both the ABS and the seals in the master cylinder, causing a spongey feel to the pedal if not full on ABS failure. If you did crack the bleeder screw when compressing the caliper pistons, then you could have let air into the system and I'd recommend doing a brake fluid flush.
While it's not a requirement to do a brake fluid flush when replacing pads, keep in mind that brake fluid does need to be changed from time to time and there really isn't a better time than when you have the car up in the air with all the wheels off while servicing the brakes. Just sayin....
Just my $.02.....been a professional mechanic for the majority of my life.
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If you didn't crack the bleeder screw at the caliper when you compressed the caliper piston, then you forced fluid backwards up through the system....pushing moisture and debris/contaminants backwards up into the ABS valves and master cylinder. This can damage both the ABS and the seals in the master cylinder, causing a spongey feel to the pedal if not full on ABS failure.
Just my $.02.....been a professional mechanic for the majority of my life.
Just my $.02.....been a professional mechanic for the majority of my life.
Just my $.02.....been a clumsy amateur mechanic for the majority of my life.
