Front BMW brakes locking front wheels all the time, why...please guys can i have your advice? |
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Front BMW brakes locking front wheels all the time, why...please guys can i have your advice? |
budman5201 |
Nov 13 2008, 09:07 PM
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#41
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Senior Member Group: Members Posts: 595 Joined: 1-April 07 From: tempe, az Member No.: 7,635 |
I recently bought new rear calipers, redid the front BMW brakes up front and installed HAWK race pads up front. The braking has significantly improved! YES! but now i have one dilema......The front brakes lock up EASILY and the rears never at all..........I wish i could make all them lock up in emergency situations or at least more Braking in the rear.
Did i just significantly make the front brakes better by installing new race pads and BMW brakes? Can i adjust anything with the stock rear system to get more pressure to the back so i dont lock up the front VERY EASILY??? thanks guys i appreciate your help..... Stock 1.7 liter GOING SUBARU 2.5 200 hp N/A soon!! Trying to make everything else PERFECT before i get my third Subaru done.....The braking was lacking on my last conversion...... thanks! Attached image(s) |
Eric_Shea |
Nov 14 2008, 11:13 AM
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#42
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PMB Performance Group: Admin Posts: 19,278 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains |
Kyle,
Do you have a firm pedal issue? If so I would look to the shut-off valve and measures to make sure air is out of it. Regarding the locking - Dave Sprinkle had this same problem and his pads weren't bedded in yet. For his street car I recommended the Ceramic pads which he eventually thought were "good" (once they bedded) but not great. He ended up not liking them because they were very dusty. I have the same situation on my wife's Mercedes wagon. I "really" liked the ceramics but they are dusty. I think they're the best in-expensive pad solution at around $35.00 Back on target, you should have great pads, I would be concerned that they've yet to bed in as R4-S's are one of the best pads out there. The only other person I heard of with a similar problem was Dave and he reported back as mentioned above. Regarding the bench bleed and the pedal. You mention bleeding so I mention pedal. I don't think the master cylinder would be an issue. I have a theory on 914 brake bleeding that I want to look into this weekend. If I'm correct and I can come up with a solution this could solve the spongey pedal thing. It involves the shut-off valve. Work on getting the rears bled and bed in the pads and you should be good to go. |
davesprinkle |
Nov 14 2008, 11:59 AM
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#43
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Senior Member Group: Members Posts: 720 Joined: 13-October 04 From: Berkeley, CA Member No.: 2,943 Region Association: None |
Kyle, Do you have a firm pedal issue? If so I would look to the shut-off valve and measures to make sure air is out of it. Regarding the locking - Dave Sprinkle had this same problem and his pads weren't bedded in yet. For his street car I recommended the Ceramic pads which he eventually thought were "good" (once they bedded) but not great. He ended up not liking them because they were very dusty. I have the same situation on my wife's Mercedes wagon. I "really" liked the ceramics but they are dusty. I think they're the best in-expensive pad solution at around $35.00 Back on target, you should have great pads, I would be concerned that they've yet to bed in as P4S's are one of the best pads out there. The only other person I heard of with a similar problem was Dave and he reported back as mentioned above. Regarding the bench bleed and the pedal. You mention bleeding so I mention pedal. I don't think the master cylinder would be an issue. I have a theory on 914 brake bleeding that I want to look into this weekend. If I'm correct and I can come up with a solution this could solve the spongey pedal thing. It involves the shut-off valve. Work on getting the rears bled and bed in the pads and you should be good to go. I'm gonna weigh in here with my brake experience. I recently went through my entire braking system -- rebuilt all 4 calipers, new 19mm master cylinder, new lines, new rotors, new pads. Post-rebuild, the braking sucked -- soft pedal and poor decceleration. I'll spare you the interminable details, but the end result was this: A : You must ensure that all the air is out of your system. This will be less a problem when you are simply replacing the fluid, but if you've evacuated the system of hydraulic fluid (as would be the case if you've rebuilt the caliper, or replaced the mc), you're going to struggle to get all the air out. Conventional wisdom is that the air predominantly gets hung up in the proportioning valve. This may be true, but you shouldn't disregard your front calipers. I recently rebled my system and got air out of the FRONT, not the rear. Bleed, bleed, bleed. Use the McMark long-tube method so you can keep your wife out of the garage and save your marriage. Drive, bleed, drive, bleed. PITA. B : You must ensure that your new pads are bedded into the rotors. This has a big impact on braking effectiveness and the bedding might not happen readily if you're just cruising around town. Find an empty straight road. Get up to highway speed and then stop as aggressively as you can without locking the wheels. Do this over and over. At the end of this exercise, I could smell my brake pads, but damn they worked better. C : Pad choice is a big deal. Refer to Eric's recommendations. I'm currently running the PBR organics. I'm pleased. Low dust, good stopping performance. |
budman5201 |
Nov 14 2008, 03:18 PM
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#44
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Senior Member Group: Members Posts: 595 Joined: 1-April 07 From: tempe, az Member No.: 7,635 |
OKay guys I will ring back into here next week when my rear pads are in and i put 100 miles on them......Proportioning valve is STAYING due to safety....catch u guys later THANKYOU FOR YOUR HELP!!....
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