5th gen Braided Brake Line Options - Advice and Opinions Wanted

Discussion in 'Mechanics Garage' started by RllwJoe, Jun 30, 2024.

  1. RllwJoe

    RllwJoe Insider

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    Can anyone confirm that the master cylinder bleed/ return hole is a straight shot down into the area that the spring occupies? No turns or anything that may block a wire from clearing the hole from the resevoir?

    Mello dude's suggestion to rebuild the master may be the real issue as I think about it. It may be that the push rod/ seals assembly is not fully returning and the speedbleeders when opened do not "bleed" because the hydralic pressure is very light at that point but enough to make the brakes drag.
     
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  2. Terry Smith

    Terry Smith Member

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    I recently put an old but lightly used front wheel and new pads in my VFR and was astounded at the drag. So I disassembled all the parts and reassembled and checked everything was smoothly moving, and I still had a lot of drag. In the end I concluded the dics had been sitting long enough to form a reasonable layer of corrosion, and just went riding. After a few miles the drag was gone...
     
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  3. mello dude

    mello dude Administrator

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    You could test your speedbleeder idea by going back to stock and rebleeding using this MotionPro bleeder.
    It's essentially the same thing as a Speedbleeder but now inline external to the caliper..
    https://photos.smugmug.com/photos/i...xvPXc5FqKVZtRdkpWw2vCmwPPzr/M/i-Shb8QC7-M.jpg
    I have quit buying Speedbleeders and use this thing, works great.

    The check the each side thing....what I meant was test each side individually, with the other disconnected off the circuit....
    YRMV.....yeah it is a big PIA bleeding exercise....just an idea...
     
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  4. RllwJoe

    RllwJoe Insider

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    You may be on to someting that makes sense Terry.

    The discs are a used set that I purcased from a facebook listing. They are not yet to the minimum thickness specification, and are not warped. Before installing them on the rim I cleaned them with brake cleaner, and scrubbed them with a 3M Scotch-Brite pad. I have, however, not changed out the pads. I wonder if my used pads (which have plenty of pad left yet) are worn at an angle, and may be forcing the pistons to bind when enough pressure is applied.
     
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  5. RllwJoe

    RllwJoe Insider

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    The synapsis that are happening in my brain are forcing me to conclude that the master cylinder is not the problem.

    Mello's suggestion of checking each caliper indiivdually turned my thoughts back to the multiple times that I forced the calipers apart to see if one or the other was dragging more. Every time that I did that, the other caliper continued to drag. In other words, I would pump the brake lever multiple times giving it full brake pressure. After releasing the lever, I would attempt to spin the tire and wheel. Grasping the tire and spinning it as hard as I could would only result in a quarter of a turn of the tire after my hand let go of it. This has not changed after a few hundred miles, and the new lines. Following the spin test I have pressed one of the calipers to release the pad from the disk. No matter which one was release the other was still dragging.

    Thinking through the above "test", wouldn't both of the calipers release when forcing one of them to release if the problem was residual fluid pressure? Both calipers share the same pressure, so when one of them is pressed apart, the shared pressure would be released. Therefore the dragging of the caliper is not a result of trapped or unreleased brake fluid presssure, and the issue must be in the caliper/ pad/ disc area.
     
    Last edited: Aug 3, 2024
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