brake pedal feel change over time?
05-31-2018, 12:52 PM
#17
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A couple of additional questions that came to mind:
1. I've heard it's possible to get air into the abs module when pushing the caliper pistons back in during a brake job. How can I tell if that happened and how do I fix? Will a normal brake bleed fix that? Somebody mentioned a possible solution is opening the bleeder valve at the caliper while pushing the pistons in instead of the usual opening of the reservoir. Any truth to that?
2. How can I tell when calipers are done for and need to be rebuilt or replaced?
Sorry for the 1000 questions, but trying to learn
1. I've heard it's possible to get air into the abs module when pushing the caliper pistons back in during a brake job. How can I tell if that happened and how do I fix? Will a normal brake bleed fix that? Somebody mentioned a possible solution is opening the bleeder valve at the caliper while pushing the pistons in instead of the usual opening of the reservoir. Any truth to that?
2. How can I tell when calipers are done for and need to be rebuilt or replaced?
Sorry for the 1000 questions, but trying to learn
05-31-2018, 02:31 PM
#18
yes but that does not change the reaction of a thinning pad. I don't think any pad works without loss of efficiency until the backing plate. I could be wrong. Also bonding of pad with or without supplemental riveting or copper wear pinning may have more to do with pad material and cost control. I'm no engineer but if padgids use more ceramics than metalics in their formulas that can greatly effect bonding. Some ceramics are very difficult to bond to. Perhaps pinning overcomes that. Everything engineered has some kind of compromise.
05-31-2018, 04:00 PM
#19
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yes but that does not change the reaction of a thinning pad. I don't think any pad works without loss of efficiency until the backing plate. I could be wrong. Also bonding of pad with or without supplemental riveting or copper wear pinning may have more to do with pad material and cost control. I'm no engineer but if padgids use more ceramics than metalics in their formulas that can greatly effect bonding. Some ceramics are very difficult to bond to. Perhaps pinning overcomes that. Everything engineered has some kind of compromise.
I've found some pads are better throughout their wear than others. It had a lot to down the compounds, how they oxidize, temps the pads get exposed to, time, and more. The manufacturing and performance philosophy of the company also has a lot to do with how they design their pads.
05-31-2018, 04:31 PM
#20
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REQUEST MY bed-in process.. do not change pads back and forth, it creates more heat as the pad is wearing into the rotor, which can accelerate cracking. find a pad that you like at the track and has enough grip to run as a street pad when cool. most all racing pads to day can be used in this fashion, but bedding is critical for success. ive helped 20+ here on the list with the issues of noise and dual purpose use. send me a note and ill send the instructions. i use pagid RS14s and PFC--11s with no issue street and track. the reason , is the bed in methodology.
1. 8-10 medium-hard stops from 90Mph down to 50mph
2. let brakes cool for 5 min
3. 5 more medium-hard stops from 90Mph down to 50mph
05-31-2018, 05:39 PM
#21
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I had the identical problem as the OP recently. The problem did not go away with a 2nd round of bleeding the brakes and new fluid on my '11 Boxster S.
Then the actual cause was discovered: in one caliper the "dust cup" (is that what it's called?) had deformed and it was sticking out, above where it belonged. So when the brakes were applied there was some pedal travel required to push it back into place.
New dust cup installed and instantly brakes were 100% A-ok.
YMMV of course, but that was my issue.
Then the actual cause was discovered: in one caliper the "dust cup" (is that what it's called?) had deformed and it was sticking out, above where it belonged. So when the brakes were applied there was some pedal travel required to push it back into place.
New dust cup installed and instantly brakes were 100% A-ok.
YMMV of course, but that was my issue.
06-01-2018, 01:35 AM
#22
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I had the identical problem as the OP recently. The problem did not go away with a 2nd round of bleeding the brakes and new fluid on my '11 Boxster S.
Then the actual cause was discovered: in one caliper the "dust cup" (is that what it's called?) had deformed and it was sticking out, above where it belonged. So when the brakes were applied there was some pedal travel required to push it back into place.
New dust cup installed and instantly brakes were 100% A-ok.
YMMV of course, but that was my issue.
Then the actual cause was discovered: in one caliper the "dust cup" (is that what it's called?) had deformed and it was sticking out, above where it belonged. So when the brakes were applied there was some pedal travel required to push it back into place.
New dust cup installed and instantly brakes were 100% A-ok.
YMMV of course, but that was my issue.
06-01-2018, 06:25 AM
#23
Three Wheelin'
Still on stock pads. Severely tapered though. And now that pads come to the end of their life pedal travel definitely is longer and softer !
06-17-2018, 01:44 PM
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Quick update on this. I did a full brake job last night where I put in cup style caliper studs, swapped to Sebro slotted rotors, pagid RSL1s up front and pagid RSL29s in the rear, and then flushed out the ATE fluid I had and filled with Motul 600. Brakes grip like all hell now, and the pedal feels much more normal.
The old RS29 pads I took off the front of the car had some pitting and cracks throughout the pad, and the front rotors had cracks on almost every single cross drilled hole, with a handful of the cracks connecting 2 holes, so I'm going to pitch both rotors and pads up front. The rear rotors & pads looked like they should be okay to reuse, stored them away.
I had one really scary incident while doing the brake job, but after heavy testing every seems to be OK. While I was pushing in the front right pistons (there are 6 pistons in the caliper, my spreader tool only can press 4 at a time), I spread them too quickly/aggressively which caused a spill over from the top reservoir (should have pulled more out) but also blew out one of the bottom pistons, dumping fluid all over the floor! The piston looks like it's only held in by a rubber ring, so I just cleaned up the fluid and pressed the piston back in. It slid right in and the ring seemed to pop back into place. Cleaned up the mess, finished the brake job. Pressurized the system and bled/flushed and filled the system. No leaks from the piston. I then took it for a test drive and did a few "medium hard" stops. Pulled over and checked. No leaks. Went out and bedded the brakes fully (smelled like barbecue pad ) came back in and checked again, still no sign of leaks in piston and the fluid level looked the same. So I think it's fine, but curious if anyone has any thoughts on that?
The old RS29 pads I took off the front of the car had some pitting and cracks throughout the pad, and the front rotors had cracks on almost every single cross drilled hole, with a handful of the cracks connecting 2 holes, so I'm going to pitch both rotors and pads up front. The rear rotors & pads looked like they should be okay to reuse, stored them away.
I had one really scary incident while doing the brake job, but after heavy testing every seems to be OK. While I was pushing in the front right pistons (there are 6 pistons in the caliper, my spreader tool only can press 4 at a time), I spread them too quickly/aggressively which caused a spill over from the top reservoir (should have pulled more out) but also blew out one of the bottom pistons, dumping fluid all over the floor! The piston looks like it's only held in by a rubber ring, so I just cleaned up the fluid and pressed the piston back in. It slid right in and the ring seemed to pop back into place. Cleaned up the mess, finished the brake job. Pressurized the system and bled/flushed and filled the system. No leaks from the piston. I then took it for a test drive and did a few "medium hard" stops. Pulled over and checked. No leaks. Went out and bedded the brakes fully (smelled like barbecue pad
) came back in and checked again, still no sign of leaks in piston and the fluid level looked the same. So I think it's fine, but curious if anyone has any thoughts on that?
06-17-2018, 05:19 PM
#26
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Quick update on this. I did a full brake job last night where I put in cup style caliper studs, swapped to Sebro slotted rotors, pagid RSL1s up front and pagid RSL29s in the rear, and then flushed out the ATE fluid I had and filled with Motul 600. Brakes grip like all hell now, and the pedal feels much more normal.
The old RS29 pads I took off the front of the car had some pitting and cracks throughout the pad, and the front rotors had cracks on almost every single cross drilled hole, with a handful of the cracks connecting 2 holes, so I'm going to pitch both rotors and pads up front. The rear rotors & pads looked like they should be okay to reuse, stored them away.
I had one really scary incident while doing the brake job, but after heavy testing every seems to be OK. While I was pushing in the front right pistons (there are 6 pistons in the caliper, my spreader tool only can press 4 at a time), I spread them too quickly/aggressively which caused a spill over from the top reservoir (should have pulled more out) but also blew out one of the bottom pistons, dumping fluid all over the floor! The piston looks like it's only held in by a rubber ring, so I just cleaned up the fluid and pressed the piston back in. It slid right in and the ring seemed to pop back into place. Cleaned up the mess, finished the brake job. Pressurized the system and bled/flushed and filled the system. No leaks from the piston. I then took it for a test drive and did a few "medium hard" stops. Pulled over and checked. No leaks. Went out and bedded the brakes fully (smelled like barbecue pad ) came back in and checked again, still no sign of leaks in piston and the fluid level looked the same. So I think it's fine, but curious if anyone has any thoughts on that?
The old RS29 pads I took off the front of the car had some pitting and cracks throughout the pad, and the front rotors had cracks on almost every single cross drilled hole, with a handful of the cracks connecting 2 holes, so I'm going to pitch both rotors and pads up front. The rear rotors & pads looked like they should be okay to reuse, stored them away.
I had one really scary incident while doing the brake job, but after heavy testing every seems to be OK. While I was pushing in the front right pistons (there are 6 pistons in the caliper, my spreader tool only can press 4 at a time), I spread them too quickly/aggressively which caused a spill over from the top reservoir (should have pulled more out) but also blew out one of the bottom pistons, dumping fluid all over the floor! The piston looks like it's only held in by a rubber ring, so I just cleaned up the fluid and pressed the piston back in. It slid right in and the ring seemed to pop back into place. Cleaned up the mess, finished the brake job. Pressurized the system and bled/flushed and filled the system. No leaks from the piston. I then took it for a test drive and did a few "medium hard" stops. Pulled over and checked. No leaks. Went out and bedded the brakes fully (smelled like barbecue pad
) came back in and checked again, still no sign of leaks in piston and the fluid level looked the same. So I think it's fine, but curious if anyone has any thoughts on that?
06-17-2018, 09:54 PM
#28
Three Wheelin'
If you have the Durametric software, you might try recycling the brake fluids within the anti-lock brake reservoir. This will purge all the air out of that ABS fluid chamber if there is any. Bear in mind the fluid within the ABS chamber cannot be flushed without activating the ABS solenoids and the Durametric software will activate the solenoids for the pumping action. Other than air within the system, I can't think of any situation that will cause the brake pedal to sink. Oh yes, the adhesive dampening pads will give you a softer pedal feel, but nowhere close to sinking the pedals all the way down. I personally dislike the dampening pads and took them off and they do make a firmer brake feel. Some people claim that brake noise will be excessive without the dampening pads, but I never have that problem after removing it.
06-18-2018, 12:14 PM
#30
Three Wheelin'