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Front brake locking up!!
- joshmickelson
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I ride a ’78 KZ650 with the dual front disc brakes. I was riding last night, and it started to feel funny, it was making a rhythmic squeak coming from the front wheel. Within 5 minutes of riding the front brake completely locked up. (I assume from overheating?) The lever was in the extended position (not pushed in) and wouldn’t go anywhere. The brakes were fully on and the bike wasn’t moving. I released the pressure valve, and it cleared everything up and worked perfectly after that.
The reason for the post is I am confused as to why this would happen in the first place? I just bought this bike on Monday. I am thinking I need to change the brake fluid, but is there anything else I should be looking into? Possibly one of the hydraulic pistons isn’t firing in line? Etc etc.
Thanks a ton in advance! Picture of my bike:
'78 KZ650
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- trianglelaguna
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- New and improved - extra strength
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the disk after braking......i would wait and see what guys here think ...and dont worry about posting probs thats what brings us together here and helps someone in the same boat later.....i think if you pull the calpers and let the fluid psi out that you can clean
with brake cleaner and a toothbrush
around the pushing side of each ones piston and also lube with grease the two "carrier" bolts that bolt the caliper together (not the mounting bolts)also tighten the mounts good with lock washers on install,i just almost died when i spaced it last week on a bolt:woohoo:
and slide em back in also sand some glaze off the pads while you got em off and when you reassemble
get a bleeder kit for 10 bucks from harbor freight or just use 2-14 inch vertical tubes and really feed some fluid out while bleeding tapping stuff and wiggleing lines ect.each time...some times the piston on a caliper cant go back from crudd....but wait and see what folks here think first...my way takes an hour at best...peace and welcome...craig
1976 KZ900
2003 ZX12R
2007 FZ1000
2004 ninja 250R for wife
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- mariozappa
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1977 KZ650C1
and the KZ650/KZ750 Conversion
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- joshmickelson
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'78 KZ650
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- The Garbone
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- User is Currently waiting for his bailout check..
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I have the same rig and just pulled apart the brakes recently. It seems the brake pad that seats on the caliper is really only held in loosely and if worn to thin might fall between the rotor and bracket causing a lockup. Or you pad might be separating from the backer and folding over causing the same thing..
Best bet would be to remove the caliper in question and have a look.. I found it easier to put the calipers back on the bike after fiddling with em if you take the top off your master cylinder and use a blunt object to push the piston in and allow more space for placement.
Good luck..
2007 Royal Enfield Iron
1979 KZ650 & Hack
1949 Ford 8n
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- Buda
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Tom
1982 KZ 1170 LTD
10.25 to 1 comp
K&N pods
GPZ cams
Vance&Hines pipe with comp baffle
dyna coils and wires
97 Valkyrie Standard
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- 650ed
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Never on a bike, but it happened to me on a '79 Caprice.
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- MFolks
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Take a toothpick and see if either of them are pluged(you might have to remove the small piston that is moved by the brake lever). I'd check the seals on the piston and the condition of the piston on the brake caliper(s).
Be careful as brake fluid makes a great paint stripper!!
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- Patton
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The larger hole feeds fluid into the bore.
The small hole, sometimes difficult to see, relieves pressure from the bore and line when brake handlebar lever is released.
The small hole might be blocked and thereby unable to relieve brake line pressure, resulting as if brake remains applied after releasing handlebar lever, so brakes over-heat and pads lock up against the disc.
I would check out the small hole.
Good Luck!
1973 Z1
KZ900 LTD
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- joshmickelson
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There are two holes between reservoir and bore.
The larger hole feeds fluid into the bore.
The small hole, sometimes difficult to see, relieves pressure from the bore and line when brake handlebar lever is released.
The small hole might be blocked and thereby unable to relieve brake line pressure, resulting as if brake remains applied after releasing handlebar lever, so brakes over-heat and pads lock up against the disc.
I would check out the small hole.
Good Luck!
wow this sounds a lot like the culprit. Thanks again everyone. I am going to delve into this issue over the weekend and I will report back!
'78 KZ650
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- mtkawboy
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78-KZ1000/1105, 80 KZ1000, 82 Kawasaki GPZ750, 95 Harley Fatboy, 80 Suzuki GS1100ET, 81 GS1100E parts bike, 83 GS1100SD Katana/1394,78 Yamaha XT500, 81 Yamaha XS650, 78 Yamaha XS650E, 48 Whizzer model J motorbike, 71 Honda CT70H, 71 Honda CT70, 81 IT 250 Yamaha,82 Honda XL100S owned
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- bountyhunter
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That was my guess. gas expands when it gets hot.You could have air in the line(s). Try bleeding your brakes.
1979 KZ-750 Twin
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