Author Topic: Hope disc brakes  (Read 4160 times)

Tigerrr

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Hope disc brakes
« on: March 01, 2012, 09:44:05 am »
A year or so ago I replaced the magura cable disc brakes with a set of hope hydraulic disc brakes - in fact had it done @ shop.

Replaced the pads a month ago but have been pjagued with constant rubbing ever since. Pistons very stiff I think - and when trying to sort it out last night I overbraked the piston so it pushed far out and and a bit of fluid leaked - result is now no braking action at all. Whats the form to sort this out? There is a funny nozzle thing by the brake piston block that looks like maybe a pump of special tool involved.
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Re: Hope disc brakes
« Reply #1 on: March 01, 2012, 09:51:05 am »
Bleed the brakes, at a guess. I could tell you how to do it on a car or motorcycle - never done it on a bicycle though. I can't imagine the procedure is hugely different.

There's 'specialist' kit out there for doing it to motors - in reality you don't actually need it. Again - it may be different for bicycles, but I suspect not....

Re: Hope disc brakes
« Reply #2 on: March 01, 2012, 10:07:06 am »
Yes, probably need bleeding, and maybe a fluid top-up.  Lots of tech support info for Hope brakes here: http://www.hopetech.com/page.aspx?itemID=SPG131

Re: Hope disc brakes
« Reply #3 on: March 01, 2012, 10:34:41 am »
If you have to push the piston back in, getting a ring-ended spanner in there as a lever (carefully !) does the trick, preferably not directly on the pistons. But take the pads out first and swap them for some old ones, otherwise you'll probably wreck the pad surface (DAMHIKT). Dribbling a bit of brake fluid around the edge of the piston and activating the brake several times might help free it up a bit too. I've had to do this on a few occasions with some old Hope minis after they've seized with winter salt on the roads.
If you just want to move each piston in turn, applying an open-ended spanner across the other piston<>caliper outer (mebbe with some packing to take any slack/prevent marking) helps stop t'other one moving.

PaulF

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Re: Hope disc brakes
« Reply #4 on: March 01, 2012, 10:57:25 am »
If you've had a fluid leak make sure that you haven't got any on the pads. If you have best to bin the pads

Re: Hope disc brakes
« Reply #5 on: March 01, 2012, 11:06:52 am »
I find with the 2 sets of Hopes we have -  used heavily off road - that the pistons get dirty and the only way to get them perfect again is to pop the pistons out as far as you dare and clean the piston with strong degreaser then isopropyl alcohol on a cotton bud. 

It sounds like you need to top up the brake fluid and bleed the brakes too - the Hope little bleeder kit makes this very quick ad easy, but it can be done without - Chris's link above is good or search youtube.

Mr Larrington

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Re: Hope disc brakes
« Reply #6 on: March 01, 2012, 12:47:40 pm »
If looking at the My Little Bleeder, make sure that the bit that attaches to the fluid reservoir is the right shape.  Hope changed the design of the fluid reservoir about five years ago, hence the older My Little Bleed wot I haz doesn't work with the brakeson my Speedmachine.
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Arellcat

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Re: Hope disc brakes
« Reply #7 on: March 02, 2012, 03:55:33 pm »
I've never tried My Little Bleeder, but instead I carried out the process much the same as you would with a car.  8mm ring spanner and then plastic tube over the bleed nipple, a jam jar, a syringe for adding fluid to the reservoir, and a bunch of old newspapers.  Loosen, brake, tighten, release, repeat, repeat, repeat, and indeed, rinse as required.

For pushing the (clean!) pistons back into the calipers, the best tool I've found is 90º internal circlip pliers.  The Hope Minis on my bike have been disassembled for cleaning several times and still leaked a bit onto the pads; the Minis I had on my previous bike were brilliant.

Tigerrr

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Re: Hope disc brakes
« Reply #8 on: March 06, 2012, 03:15:50 pm »
Well - it appears the issue is that one has to clean these brakes.  If they are not cleaned the pistons clog and get stiff.  What a rip off - you pay a fortune for these things and then you have to clean them. Nobody said anything about that when I bought them.

I think I am entitled to feel very let down by Hope.
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Re: Hope disc brakes
« Reply #9 on: March 06, 2012, 03:54:40 pm »
I dunno about their more recent offerings, but the original Minis I have, have the original ally (?) pistons - there are phenolic replacements available for 'em now which might be more crud/corrosion-tolerant. So I've been tempted to get those (plus seals) and strip 'em down..tho' I'm also tempted to simply replace the things with some BB7s and forego the periodic joy of having to bleed the damn things, and being careful not to get DOT everywhere.

Tigerrr

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Re: Hope disc brakes
« Reply #10 on: March 07, 2012, 01:47:48 pm »
Today has arrived from wiggle a box with a mini bleeder kit. the instructions are brill.  Put the bleeding fluid in the bleeding bottle and locate the bleeding nipple etc etc.
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Tigerrr

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Re: Hope disc brakes
« Reply #11 on: March 08, 2012, 12:19:01 pm »
Aaargh - who the hell has star-profile allen keys? I mean - why on earth are the units sealed with a tool as rare as a hens tooth when a simple allen key would do just as well?  Halfway through the job - bits all over the place - and I have to go and buy a tool that will only ever be used once for this job. Ye gods there must be a better way to do things.
No wonder its called Hopes little bleeder.
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Andrij

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Re: Hope disc brakes
« Reply #12 on: March 08, 2012, 12:22:14 pm »
My Avids take a star-profile allen key - which came with the brakes.  Did you not get one with your Hope?
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Biggsy

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Re: Hope disc brakes
« Reply #13 on: March 08, 2012, 12:25:43 pm »
Are we talking Torx here?

It's vastly superior to hex (in terms of slip resistance at least) and gradually getting more popular.  Even some multi-tools include a Torx AKA star bit, with disc brakes in mind.

http://en.wikipedia.org/wiki/Torx
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Tigerrr

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Re: Hope disc brakes
« Reply #14 on: March 08, 2012, 12:59:43 pm »
I expect the special tool is in the original box which the bike shop binned. Grrr.
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Mr Larrington

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Re: Hope disc brakes
« Reply #15 on: March 09, 2012, 09:36:35 am »
They used to be 2mm Allen bolts, but changed them to Torx when they redesigned the reservoir.  Tools not supplied in box either - I obtained a set of small Torx bits from Maplins for not very mcuh dosh.
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Tigerrr

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Re: Hope disc brakes
« Reply #16 on: March 09, 2012, 09:55:59 am »
I too went to maplins and spent £1 on the tool. Plus an hour to get there and back.
Armed with the new tool I have proceeded to follow the instructions in the box for bleeding the brakes.
You may imagine my delight to discover, having dismantled the brakes and carefully laid out the little things thjat go sproing on the floor in the basement workshop at the office, to discover a few lines down that I need to connect the whole shebang to a car tyre to pressurise it.  Not that it actually says - now find a handy car tyre or anything like that - it just says connect the valve to car tyre valve @ 25PSI. I spent a while looking in the box for the valve until I realised I was supposed to be doing this work surrounded by car tyres.
That really made my day.
I mean it should be obvious to anyone that you need a car tyre to service the brakes on a bicycle. I realise I should have forseen that and only a dimwit would think of working on a bike without a handy car within 3 ft.
So - not only have I had to buy the bleeding kit I have to buy a bleeding special spanner, and then buy a bleeding car in order to get some bleeding air from one of its bleeding tyres.
All in all these Hope Brakes have got some hidden costs haven't they.
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PaulF

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Re: Hope disc brakes
« Reply #17 on: March 09, 2012, 10:22:05 am »
Surely there's a car park near by? I'm sure J Random Stranger won't mind helping you out?

Re: Hope disc brakes
« Reply #18 on: March 09, 2012, 04:29:47 pm »
Well, disk brakes are still largely the preserve of MTBs and a good proportion of those (possibly a majority, but I'm not sure) will use schrader valves. So often, you'd just connect it to your own front wheel...

There does seem to be a widespread obsession with bleeding brakes.   ??? I've been using Hope hydraulic discs since, IIRC, 1999, and the only time I've felt the need to bleed them is when replacing the hoses, wholesale; ie. When the system needs completely refilling. On those rare occasions I just gravity bleed them*.

 I've never had to pop out pistons for cleaning. The most I've needed to do is remove the pads and work the pistons in-and-out a little to free them up.

Of course, mine get constantly flushed with liquid mud, which is a surprisingly good lubricant. Perhaps discs used in less extreme conditions build up a different consistency of muck...  :-\

*I generally don't even use a hose. Just remove pads, open the nipple, and let the fluid drip onto a strategically positioned rag, which goes in the bin. When complete, rinse the calliper off, replace pads and Robert's yer dad's brother.
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PaulF

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Re: Hope disc brakes
« Reply #19 on: March 09, 2012, 05:59:32 pm »
A more sensible solution that's cheaper than buying a car :)

Get an empty plastic fizzy drink bottle of about 1.5 litres and a Scrader valve from an old tube. Drill a hole in the lid and fit the Scrhrader valve to the lid. Fit the lid to the bottle and inflate.  Hey Presto a reservoir of air. Haven't tried it myself (yet) but the MTB folk use a similar solution for seating tubeless tyres and take them up to a claimed 60psi!

Tigerrr

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Re: Hope disc brakes
« Reply #20 on: March 30, 2012, 01:19:59 pm »
Since the bleeding incident I have been riding without a rear brake.  This has had absolutely no discernible effect at all on the braking effectiveness of the bike.  I am left wondering if in fact rear brakes serve any useful function at all. I may simply remove it and continue with the front brake which is very good.
Any thoughts?
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Kim

  • Timelord
Re: Hope disc brakes
« Reply #21 on: March 30, 2012, 01:25:39 pm »
Rear brakes fulfil a legal requirement, and provide a useful source of emergency stopping power and components with which to resurrect a broken front brake at the roadside.  They're also essential for Comedy Off-Roading on mildly inappropriate bikes.

I wouldn't be seen without one.
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