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Hydraulic brake bleed woes

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Hydraulic brake bleed woes

Old 08-25-20, 05:16 PM
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headwind15
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Hydraulic brake bleed woes

My bike's Shimano hydraulic brake hose/line was too short. I have replaced it with a longer one with new needle valves and olive washers. It seems like everythings hooked up right. I substituted the rear wheel and brake pads with an 8 mm allen key to take the place of the wheel & pads in case there is a leak. I am using the plastic Shimano funnel to put the fluid into the reservoir, I have the lever in a flat position and have pumped all of the air out. (It took hundreds of pumps to get the bubbles out) There is no leaking at the ends of the hose/ line. There is no grabbing force with the brake/ Pistons are not moving. Any ideas??
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Old 08-25-20, 05:28 PM
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If everything mechanical works, you have air in the lines. I am sure that someone can fill with fluid like that and pump the bubbles out, but I would get a syringe kit and bleed the brakes from the bottom up. Keeping the cylinders blocked, I remove the calipers and get them as low and as straight from the reservoirs as possible.
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Old 08-25-20, 05:34 PM
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Syringe kit?, I thought that was for Advid/ SRAM brakes. And, Isn't there only one reservior?
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Old 08-25-20, 05:39 PM
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Originally Posted by headwind15
Syringe kit?, I thought that was for Advid/ SRAM brakes. And, Isn't there only one reservior?
Not so far as I know, I have used my syringe kit on a few Shimano set ups.

And I mean there is one reservoir per lever.
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Old 08-25-20, 05:46 PM
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My bike's Shimano hydraulic brake hose/line was too short. I have replaced it with a longer one with new needle valves and olive washers. It seems like everythings hooked up right. I substituted the rear wheel and brake pads with an 8 mm allen key to take the place of the wheel & pads in case there is a leak. I am using the plastic Shimano funnel to put the fluid into the reservoir, I have the lever in a flat position and have pumped all of the air out. (It took hundreds of pumps to get the bubbles out) There is no leaking at the ends of the hose/ line. There is no grabbing force with the brake/ Pistons are not moving. Any ideas??
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Old 08-25-20, 05:48 PM
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Sorry to re-post... I have done this before with success, using this method.
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Old 08-25-20, 06:10 PM
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I just took both ends off. On one, the olive is pushed up to the end of the needle valve and the other one is not, could that be giving me a non sufficient seal? Also where the olive is pushed down, there was a little fragment of black exterior casing pertruding I sanded it off. , I just wonder if that was compromising the seal??
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Old 08-25-20, 11:41 PM
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Standard Shimano bleed procedure is to push mineral oil from the caliper into the funnel. On more recent models, they then instruct you to close the caliper and pump the lever to get any last air out of the reservoir, but on some older ones you're also supposed to close the bleed port with a tube attached, pressurize the system, then open up the bleed port, then close it before releasing the lever, and doing this until you see no air, and then proceeding with closing the caliper and getting air out of the reservoir.
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Old 08-26-20, 08:37 AM
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'Olives' are supposed to be squeezed. their edges biting into the hose,,

(I have Magura not Shimano brakes)
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