Left front brake locked up!
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Novice
Joined: Jul 2010
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From: Port Hadlock Washington
Left front brake locked up!
I recently had my left front brake lock up while accelerating uphill shifting in to 6th gear at around 60 plus mph. I have a 2005 road king custom with dual front disc brakes,floating rotors and PM 4 piston brakes. I had the clutch pulled in to shift and out of nowhere the bike started to pull extremely hard and very fast to the left and come to a very quick stop. I am amazed i was not tossed on my face as I put all my weight to the right side as the bike stopped! It was nighttime and I could not see the rotor until the morning which is now very discolored. I rode home very nervous and slow. What would cause one brake to lock up without touching the brake lever? It seems odd that both brakes did not engage. There are no fluid leaks or air in the system I changed the fluid with synthetic last year, inspected the seals pads etc and commute year round and in 30 years of riding I have never had brakes lock on me.
Last edited by Bob D Solar1; Feb 5, 2013 at 08:59 PM. Reason: Typo errors!
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From: Ft. Worth, TX
Possibly water in the caliper that heated up and expanded?
The master cylinder feeds both brakes so that shouldn't have anything to do with it. You problem will be in that caliper. After it cooled off I assume the caliper released? Was your floating rotor installed correctly?
Just a few thoughts...
The master cylinder feeds both brakes so that shouldn't have anything to do with it. You problem will be in that caliper. After it cooled off I assume the caliper released? Was your floating rotor installed correctly?
Just a few thoughts...
Tourer
Joined: Sep 2004
Posts: 451
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From: Laurel,Ms USA
I'd be replaceing both the rotor and caliper. Your right that you were very lucky to have not gone down. Did you inspect it for a stray rock or something lodged in the caliper?
Last edited by rleggs; Feb 5, 2013 at 09:21 PM.
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From: Port Hadlock Washington
I am the third owner of the bike. The PM brakes and rotors were installed in 05 when new. I have been commuting on the bike for 1 1/2 years. No issues. i will be pulling the left brake caliper off this weekend and inspecting the seals shoes, rings etc.looking in to the master cylinder and inspecting everything. It very well could be moisture as riding in Washington State it rains a lot. I went to synthetic fluid to reduce moisture build up in brake fluid.
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Novice
Joined: Jul 2010
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From: Port Hadlock Washington
I contacted tech support at PM this morning they said to tear the system down and check the master cylinder for debris and look for restrictions in the small hole in the master cylinder that returns fluid and to inspect the calipers and seals/rings etc for evidence of moisture or corrosion. I would suspect moisture over air in the system as there was no sponge feeling or squeeling from air in the lines.
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Novice
Joined: Jul 2010
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From: Port Hadlock Washington
Pm brake front caliper/pistons locked up
After tearing my complete front brake system apart, ( master, cylinder, braided hoses, banjo bolts seals and calipers) I found moisture built up and water in the brake fluid. going deeper in to the system the left Pm 4 piston caliper had corrosion and flaking in one corner. the pistons were very corroded. I polished and ground down the corrosion and and replaced the seals, the pads and . flushed the complete system with synthetic dot 4. and took a ten mile test drive. The bike started to drag again. I pulled over and the heat coming from the left caliper was so hot I almost burnt my hand 2 feet away. I went to a friend of mine who took of his stock 4 piston calipers off his 05 Road King recently and installed PM 4 piston calipers on he front of his bike.
I removed both sides of the PM 4 piston calipers. Re bleed the system and they work fantastic. PM Brakes are overpriced and suck! I would not recommend them to anyone. I change my fluid every year and I work on hydrallic systems on boats for over 30 years and have never seen anything corrode so bad like this before. I have ridden Harleys and motorcycles for over 35 years, Raced Motocross, Speedway Flat Track and have owned 6 Harleys, Hondas, Bms's, Triumphs and never had a brake lock up on me before I am very happy to go back to the stock brakes. I am sad as the PM Brakes really looked nice and looked as they were designed well. I have used GMA and Brembo brakes in the past and they were also very good.
I removed both sides of the PM 4 piston calipers. Re bleed the system and they work fantastic. PM Brakes are overpriced and suck! I would not recommend them to anyone. I change my fluid every year and I work on hydrallic systems on boats for over 30 years and have never seen anything corrode so bad like this before. I have ridden Harleys and motorcycles for over 35 years, Raced Motocross, Speedway Flat Track and have owned 6 Harleys, Hondas, Bms's, Triumphs and never had a brake lock up on me before I am very happy to go back to the stock brakes. I am sad as the PM Brakes really looked nice and looked as they were designed well. I have used GMA and Brembo brakes in the past and they were also very good.
Last edited by Bob D Solar1; Mar 23, 2013 at 12:25 AM.
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From: Bedford UK
Also make sure your pucks can move freely in the caliper. One of my other bikes (different brand) suffers from a build-up of brake dust and makes cleaning the caliper a regular routine.
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From: anacoco, la
this i don't understand. how does only one caliper braking cause the bike to pull to the left? you've only got one front wheel. it would be akin to a softail pulling every time you applied your brakes. and what about all those guys going from dual to single rotors to show off more of their front wheel?
Last edited by skratch; Mar 23, 2013 at 09:47 AM.
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From: Near Myrtle Beach, SC
this i don't understand. how does only one caliper braking cause the bike to pull to the left? you've only got one front wheel. it would be akin to a softail pulling every time you applied your brakes. and what about all those guys going from dual to single rotors to show off more of their front wheel?