Spongy lever on disc brakes after travelling
Moderator: robbosmans
When I travel abroad I have a spongy brake lever and have to do a mini bleed to get lever feel back . I am sure I’m doing bleed correctly and there is no air left in system. Does the reservoir in the lever have a small amount of air in (to allow for pad wear) do others have this problem after travelling / inverting the bike , if not is there a bleed trick to alleviate this or should I Cable tie the levers down before travelling , many thanks in advance for any advice.
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to me, anytime you invert the bike you invite air bubbles to migrate from the reservoir into the master cyclinder. I always store disc bike level, or by hanging from the front wheel. I once hung a disc bike by the back wheel, and got a bubble in the rear line which required bleeding.
No experience with road hydraulics but I can't imagine they can be different to mtb. In the case I get spongy lever knowing that the system is bled correctly, I pump the levers for a while till I get desire response.
There is a rubber bladder to compensate for fluid expansion and pad wear. A good bleed will get all of the air out of a sealed system. Air does disolve in fluid though and you need to put a vacuum to get this disolved air out. Changes in pressure and temperature can release this air giving you a spungy lever. Also a bad bleed can leave air in the system. Air loves to hide in the nocks and crannies. Degassing is essential for a nice solid lever feel.
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Tie down the lever after arriving.PaulH wrote: ↑Fri Aug 02, 2019 4:58 pmWhen I travel abroad I have a spongy brake lever and have to do a mini bleed to get lever feel back . I am sure I’m doing bleed correctly and there is no air left in system. Does the reservoir in the lever have a small amount of air in (to allow for pad wear) do others have this problem after travelling / inverting the bike , if not is there a bleed trick to alleviate this or should I Cable tie the levers down before travelling , many thanks in advance for any advice.
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This is what I do and 9/10 times it's all I need.. that 10th time I bleed
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Even then, I just do the mini bleed procedure where I zip tie the lever for a couple hours, come back, use the bleed syringe or cup on the lever size with a small amount of fluid and just flick the lever a few times to shake the bubbles out. With a SRAM system and syringe you can do one better and push/pull on the syringe plunger to further pull the gas bubbles out.
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yeah sorry.. I dont do a full bleed either.. just get a few bubbles out of the lever with the cup deal and I'm done.. < sub 5min job and it only takes that long because the lever screw gets stripped super easy so I take my time.TobinHatesYou wrote: ↑Sat Aug 03, 2019 3:14 am
Even then, I just do the mini bleed procedure where I zip tie the lever for a couple hours, come back, use the bleed syringe or cup on the lever size with a small amount of fluid and just flick the lever a few times to shake the bubbles out. With a SRAM system and syringe you can do one better and push/pull on the syringe plunger to further pull the gas bubbles out.
2024 BMC TeamMachine R Building
2018 BMC TImeMachine Road
2002 Moots Compact-SL- getting aero look makeover
2019 Parlee Z0XD - "classified"
2023 Pivot E-Vault - completed project, full Xplr package
2018 BMC TImeMachine Road
2002 Moots Compact-SL- getting aero look makeover
2019 Parlee Z0XD - "classified"
2023 Pivot E-Vault - completed project, full Xplr package