So I have a 03 crf450 r put a new tire on and wen I put my rear breaks back on ....nothing . Rebuilt my caliper new piston & seal. And rebuilt my master cylinder . Filled with dot4 Tried to bleed and the piston won't even move ... I'm at a loss have no clue have messed wit these brakes for days. Any input please ?
breaks r breakn me
- Thread starter jpdidit91
- Start date
Air in the line. It compresses when you try to pump fluid, and when you relax the fluid pressure, the air expands, which counteracts the piston's movement.
The answer? More bleeding. Bleed it until the fluid is new, and then some. Sometimes it can take quite a few bleeding sessions. I like to tap the master cylinder when letting off the lever repeatedly. This will release the tiny bubbles, which is also bleeding your system. -BIG DAN
EDIT: Do not allow the master cylinder to go empty while bleeding... if it sucks ANY air in from the top, you might as well start over completely.
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So I like the constant flow method.
This requires a quart container and clear hose.
-Attach the hose to the bleeder and put the other end in the container.
-Fill the container with brake fluid until it is more than covering the tip of the hose. There should be no chance of the hose coming out of the fluid level.
-Next, pump the lever 3-4 times, hold the lever down, and crack the bleeder. Then shut the bleeder and repeat. This should slowly but surely, move the air out of the hose and into the container. Continue bleeding until the fluid pushes the air out of the hose completely.
-Once the hose is completely filled with fluid, you can just pump the lever continuously, with the bleeder open, and it will not let any air back in the system. You will see more air escaping while pumping.
REMEMBER to always top off the master cylinder. Don't let it get near empty, as this style of bleeding actually will start siphoning the fluid through the system without you pumping. If you let the master cylinder go empty, you have to start over.
-BIG DAN
This requires a quart container and clear hose.
-Attach the hose to the bleeder and put the other end in the container.
-Fill the container with brake fluid until it is more than covering the tip of the hose. There should be no chance of the hose coming out of the fluid level.
-Next, pump the lever 3-4 times, hold the lever down, and crack the bleeder. Then shut the bleeder and repeat. This should slowly but surely, move the air out of the hose and into the container. Continue bleeding until the fluid pushes the air out of the hose completely.
-Once the hose is completely filled with fluid, you can just pump the lever continuously, with the bleeder open, and it will not let any air back in the system. You will see more air escaping while pumping.
REMEMBER to always top off the master cylinder. Don't let it get near empty, as this style of bleeding actually will start siphoning the fluid through the system without you pumping. If you let the master cylinder go empty, you have to start over.
-BIG DAN
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Sorry for taking this a different direction however, I think Mihylo needs to chime in on this one..........
