Viewing 14 posts - 1 through 14 (of 14 total)
  • Hope Mini biting point question
  • Dorset_Knob
    Free Member

    Old style Minis – the sort from about 10 years ago.

    After a bleed and refurbish, the biting point is about 2 mm away from the handlebars, whereupon the braking action is all nor nothing, with no modulation.

    What do I need to do to get the bite point back where it used to be (10 years ago), almost as soon as the lever starts moving, with plenty of lovely modulation?

    Re-bleed? Is there a chance the bike shop used the wrong dot during refurbishment?

    kcal
    Full Member

    is it the reach, or the bite point (or both) that’s controlled by the tiny, long, allen bolt accessed from the side? Can’t recall the name of it, and you need to slacken the lever pivot bolt, but that might help wind the lever?

    Onzadog
    Free Member

    Very unlikely to be the wrong fluid. Hope have been in this game longer than anyone else. I’d be very surprised if a bike shop made a mistake like that. If they did use mineral oil rather than brake fluid, you’ll know soon enough as seals swell and you get nothing at all from the brakes.

    Unlikely a bleed will do anything if you get the brakes working, just later in the stroke.

    When I’ve had this in the past, it was cured by a change of seal. It could either be that the caliper seals are letting the pistons slip all the way back or the first seal on the master piston has failed and it’s the second seal doing the work.

    Is it both levers or just one?

    kcal, that fixing only adjusts the lever reach although it could be that the levers are just wound in too far. Wind it all the way out and see how things work.

    Dorset_Knob
    Free Member

    Nah, it’s not the reach adjustment.

    Both levers affected, but the one for the back is much worse than the front.

    I’ve been away from the bike for a while so I’ve forgotten all the maintenance routines but I seem to remember needing to set the callipers in a certain position when you do a bleed – I wondered if that’s what went wrong during the refurb.

    But a seal failure certainly seems plausible given the age and lack of recent usage.

    Aristotle
    Free Member

    One thing that I’ve found having bled many different brakes on various bikes and motorbikes is the importance of getting as much air as possible out of the master cylinder(squeezing the lever quickly and repeatedly, but only far enough to produce a stream of tiny bubbles. When this stops the air has hopefully left the cylinder). The lines can be air free, but an air pocket can sit in the master cylinder which requires compressing before the pistons move.

    Push the pistons fully back to squeeze any air out from behind them and rotate the calipers around to dislodge/move any pockets of air.

    Check for sticking pistons.

    bwaarp
    Free Member

    1) Ask Hope, they are great and will help out.

    2) Have you tried the rubber band method?

    3) Sounds like a seal issue or a dodgy bleed.

    BigJohn
    Full Member

    I run original Minis. I changed the pistons and caliper seals last year (or maybe 2 years ago) and the seals seem to have perished. Only ever used 5.1 As a result the pistons wouldn’t withdraw to get new pads in. Easy enough to replace. I used the old ones, which were in my spares box and they seem fine.

    If the bite point is too near the bars try adjusting the lever though.

    Dorset_Knob
    Free Member

    What’s the rubber band method, bwaarp?

    I’ll do another bleed myself, I think, and check carefully for air bubbles. Then check the seals, before bothering Hope.

    First time I’ve used a bike shop for years, now I remember why it’s best to do your own maintenance 🙂

    If the bite point is too near the bars try adjusting the lever though.

    I’ve fiddled with the reach – I have big hands so the levers were already set to max. reach. And the bite point is not just close to the bars, the lever is practically touching the bar before I get any bite. On a long descent, on a hot day, I know I will have no back brake at all.

    TandemJeremy
    Free Member

    Sounds to me like it could be one of several issues or a combination.,

    Poor bleed leaving air int eh brake
    sticky pistons
    Callipers not centralised properly

    Hope have useful videos on their site.

    I would rebleed – its very simple, I would check all pistons movinfg properly and lube them with dot fluid

    However – given a shop did this perhpas you should take the brakes back to them and get them to do it correctly? I do wonder if they have used an innapropriate lube on the pistons and damaged the seals

    I would centralise as in the hope video

    Dorset_Knob
    Free Member

    Poor bleed leaving air int eh brake
    sticky pistons
    Callipers not centralised properly
    I do wonder if they have used an innapropriate lube on the pistons and damaged the seals

    All of this bothers me too – just feels like a sloppy job. I’ve had a chat with the mechanic, he wants to take a look. But did they not check it before it left the shop? (Yeah, I noticed as soon as I wheeled it out the door, and I should have said, but I was in a hurry so just rolled my eyes and thought ‘last time I ask someone else to fiddle with my bits for money’).

    I’m more of an own-bits self-fiddler, TBH.

    Dorset_Knob
    Free Member

    … I suspect a poorly rolled diaphragm. Seems like the easiest thing to accidentally not take care over if it’s not your bike and your tea’s going cold.

    boxelder
    Full Member

    Elastic band to hold lever on tight overnight. Drives air to cylinder. Top up cylinder.

    bwaarp
    Free Member

    What’s the rubber band method, bwaarp

    This

    Elastic band to hold lever on tight overnight. Drives air to cylinder. Top up cylinder.

    Also, you should open the master cylinder top cap with the elastic band still pulling the lever back. Taking it off before removing the top cap is a common mistake. Then remove band and top up fluid. The band has to hold the lever REALLY tight, full braking braking force.

    Made a difference for me.

    boxelder
    Full Member

    band has to hold the lever REALLY tight, full braking braking force

    which is why I use a zip tie

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