Lots of travel before bite Hope brakes

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  • Lots of travel before bite Hope brakes
  • thresher
    Member

    I’ve got some old old hope brakes (M4 and Mini) on the Mini levers but there’s not a lot of power in them and the bite is quite far into the lever travel; is there a way to make them more “bite-y”? Even the Tektros on my mum’s hybrid feel more solid so I’m sure I’m doing something wrong but what?

    I rebuilt the levers yesterday, have bled them myself and by a shop, advanced the pads overnight, pumped the levers, changed pads, changed the M4 to the front on a bigger rotor, changed the reach adjuster, and filled them up as much as I can with fluid to very little change. I know they aren’t going to feel like anything current but would changing either the master cylinder/calliper to a newer model help? Or braided hoses? I don’t have money for all three at the moment so one or the other really.

    tjagain
    Member

    They are not working properly. Not centralised properly and / or sticky pistons would be my bet. I run mono minis still and easy one finger lockups. a long lever travel that is not spongy points to these two things

    Are you using cheap pads? I only use hope sintered

    Premier Icon tomhoward
    Subscriber

    Send them to hope for a service.

    thresher
    Member

    Do you reckon a calliper rebuild would help any? I’ve spent a while getting them centred with shims on the IS tabs so they should be fine there but I’ll have another look thanks for the advice. Pads are sintered but not sure what brand, maybe Disco brake or something from eBay? My main gripe currently is the lever travel and feel so I’ll get to better pads and what have you later.

    How much do Hope usually charge for a service do you know? Don’t mind putting the time in myself but don’t want to be paying massive amounts for old brakes.

    tjagain
    Member

    Hope service is good value

    You have centered the calipers – have you then centered the pistons? – video on the hope site showing you how to do this. I bet thats all you need to resolve the long lever travel but it could be a sticky piston. Power – ditch the cheap pads and get some hope ones. You also might have contaminated discs.

    Premier Icon molgrips
    Subscriber

    New caliper seals.

    I often wondered how the self-adjusting feature works until I found out. The seal between the piston and the caliper is designed to flex under normal operation, as the piston moves in and out. If the pads have worn and the seal flexes past a certain point, the piston will slip through the seal a little bit and take up the slack and when you let go the seal returns and the piston is in a new position.

    I think that if the seals get old or haven’t moved for a long time they stick to the seal so this doesn’t happen, or it takes more flex for it to happen, the result of which is that the bite point gets closer to the bars. Given that your brakes are old this is probably it I reckon.

    New seals will render the brakes good as new. The flexing seal is basically the only moving part in these – so if you replace it you’ll be good to go.

    thresher
    Member

    Great advice thanks! I’ll get some new seals and pads and then rebuild and set the callipers up properly even if it is just needing centred better to have everything new and give the rotors a blast with brake cleaner. I cable tied the brake lever flat against the bars overnight to ‘advance’ the pads but it’s not helped so probably a sure sign the seals don’t flex any more.

    tjagain
    Member

    No need to replace the seal in that scenario – ( which you desribe well). What you need to do is to free them up and lubricate them and then centralise using the hope 2 stage process

    vmgscot
    Member

    Last time I had a rebuild done by Hope it was around £60 inc shipping costs, etc per end.
    You can rebuild yourself for much less but you will need the bore cap tool for the caliper (not that expensive).

    thresher
    Member

    I’ll have a look now at the calliper but would rather clean them out and replace everything just to make it new and right as I’ve done the levers now. The callipers aren’t the ones with external bore caps they’re the split ones like this.

    Hope M4 Calliper Exploded View

    I paid £70 for front and rear so I probably won’t send them to hope just isn’t worth it for me and I like doing them myself.

    tjagain
    Member

    Those are easy to service and replace seals – I have done it. However before you get into that try lubing the seals and working the pistons in and out. Its normally enough

    I have a couple of those callipers sitting in my spares box BTW so it you need them PM me

    thresher
    Member

    I’ll open them up this weekend and see what’s up and let you know about the spares! Although if I can’t get them working I’ll get some Shimano instead.

    Premier Icon molgrips
    Subscriber

    No need to replace the seal in that scenario – ( which you desribe well). What you need to do is to free them up and lubricate them

    Yeah maybe but I’d suggest new seals anyway since I’d have a bit more confidence. There’s a chance they’d get damaged or something having been stuck and freed up. Plus they are old so might be a good idea anyway.

    thresher
    Member

    That’s what I’m thinking, if I take them out I’ll likely damage them in some way even on a minute level or get bits of dirt on them somehow so new seals on the cards for sure.

    Little bit of silicone lube and working the pistons in and out a few times should sort it.

    I had to do this with brand new brakes.

    thresher
    Member

    Don’t know if it’s the same problem, got replacement seals/pistons and tried to pump the pistons out but only 1 has come out. Disconnected now thinking I could pry them out but they won’t move more than a couple mm

    tjagain
    Member

    Thats the sticky piston causing the issue. You need to put the one thats out back in, hold the three that move and pump the brake until the sticky one moves. don’t try to pry them out. an airline can also be used You can also do this after splitting the caliper halves if you use an airline bu blocking off the transfer port YOU have to get all 4 pistons moving and hold in any that move more quickly when you pump them out.

    pedlad
    Member

    Worth noting the hope service includes new pads so v good value imho

    Premier Icon molgrips
    Subscriber

    Don’t know if it’s the same problem

    It is. If that one was stuck it would not be sliding through the seal to take up pad wear which would cause the symptoms you saw.

    Premier Icon jamesoz
    Subscriber

    Are you using the correct lever with those callipers? I may be wrong but I thought there was some differences in the amount of fluid pushed by different Hope levers.

    thresher
    Member

    They’re the right levers according to the Hope website but I can’t move the pistons at all with any source of pressure so can’t pump them in and out to get the moving. I can’t see how they were moving at all on the bike which explains the lack of power.

    Either way just going to get some Shimano/Magura to replace them, too much fannying about when others are so cheap in comparison.

    Premier Icon ogri
    Subscriber

    Thresher,before you lash out on more brakes have a look on the Pinkbike buy and sell page.Look on the brake sub section and you should find a little service kit that makes it easy to service four piston calipers.It has a brake block with a removable part that uncovers one piston at a time for easy cleaning and lubing.Additionally,the kit contains a spray bottle of alcohol for cleaning and an applicator for putting a thin bead of silicon lube around the piston outer diameter.
    Makes what was a real chore using a tiny G clamp a much happier experience.I bought the kit after experiencing the exact same symptoms as yours with a brand new set of hopes.

    Premier Icon ogri
    Subscriber

    Bollox! Should have checked before posting.Just checked the 19 pages and not listed on there.Sorry.

    thresher
    Member

    No worries bought the new brakes anyway I just want to ride the bike but thanks for the suggestion! I can always fix them later if I really want.

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