Alex Dark Posted September 1, 2009 Report Share Posted September 1, 2009 Basically, got a try-all hope mono trial. Pistons are extremely sticky and covered in gunk. When this brake was last working, the performance was temperamental to say the least. Soooo.... should i strip the whole brake down and put new seals in it? or would just a good clean be in order?is there any way of getting the bore cap off other than the tool?if not...does anyone have one that i could possibly borrow?Thanks, any advice welcome Quote Link to comment Share on other sites More sharing options...
Muel Posted September 1, 2009 Report Share Posted September 1, 2009 I've got another Hope to give the Muel treatment this week, so I'll make a video or a wiki with pics.But for now:should i strip the whole brake down and put new seals in it? Yes, unless the old seals arn't leaking, and even then I'd do it anyway so it's done.or would just a good clean be in order? See above.is there any way of getting the bore cap off other than the tool? Yes, get a piece of stell, file it down with the two edges rounded until it will fit across the bore cap, put this piece of steel in a vice, mount the caliper to a fork or a piece of steel with a caliper mount cut out of it, thenwith one hand press the caliper down hard, and with the other gently undo the bore cap.if not...does anyone have one that i could possibly borrow? Nope, sorry. But making your own is piss easy. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted September 1, 2009 Author Report Share Posted September 1, 2009 I've got another Hope to give the Muel treatment this week, so I'll make a video or a wiki with pics.But for now:should i strip the whole brake down and put new seals in it? Yes, unless the old seals arn't leaking, and even then I'd do it anyway so it's done. Ah right, full rebuild kit or just caliper?or would just a good clean be in order? See above.is there any way of getting the bore cap off other than the tool? Yes, get a piece of stell, file it down with the two edges rounded until it will fit across the bore cap, put this piece of steel in a vice, mount the caliper to a fork or a piece of steel with a caliper mount cut out of it, thenwith one hand press the caliper down hard, and with the other gently undo the bore cap. Exactly what i was planning to do...just with an extremely thick spoonif not...does anyone have one that i could possibly borrow? Nope, sorry. But making your own is piss easy. ideal...cheeeeers muel, thought you'd come to my aid Is it worth polishing the pistons as well? Quote Link to comment Share on other sites More sharing options...
Muel Posted September 1, 2009 Report Share Posted September 1, 2009 Yes, definately. You need to remove the corrosion from the pistons otherwise it'll just rip the new seals apart. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted September 1, 2009 Author Report Share Posted September 1, 2009 Yes, definately. You need to remove the corrosion from the pistons otherwise it'll just rip the new seals apart.ah right nice one Muel. I'm gonna get a seal kit ordered up tonight i thinks . Quote Link to comment Share on other sites More sharing options...
trialsmax04 Posted September 1, 2009 Report Share Posted September 1, 2009 Im going to stick my eggs in here as im in the same situation as alex. Taking the outside piston must be okay because of the removable bore, but what about the other side? And when rebuilding is Dot4 okay? Quote Link to comment Share on other sites More sharing options...
Katkin Posted September 1, 2009 Report Share Posted September 1, 2009 (edited) Im going to stick my eggs in here as im in the same situation as alex. Taking the outside piston must be okay because of the removable bore, but what about the other side? And when rebuilding is Dot4 okay?Removing the other side is ok too, as long as it is not too stuck.Pump yer pistons in and out before taking the bore cap off, pushing them back carefully with a screwdriver.Take out old pads.Pump yer pistons right out.Squirt oil everwhere.Remove bore cap.Remove first piston.Remove second piston.Or Watch Muels video for much better advice than the useless babble I just typed.- MattEdit: Arrrgggg for f**k sake woman sign ouuuuuuuuuuutttttttttttttttttttttttttttttt! Edited September 1, 2009 by Katkin Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted September 1, 2009 Author Report Share Posted September 1, 2009 (edited) Im going to stick my eggs in here as im in the same situation as alex. Taking the outside piston must be okay because of the removable bore, but what about the other side? And when rebuilding is Dot4 okay?yeh dot4's fine check out this link i found earlier hope strip-downEDIT: This lever strip-down guide might be of some use as well: lever strip-downTo Trialsmax04....if you need a hand servicing yours, PM me...im sure ill have figured it out by the time ive finished doing mine Edited September 1, 2009 by Alex Dark Quote Link to comment Share on other sites More sharing options...
Muel Posted September 1, 2009 Report Share Posted September 1, 2009 MattEdit: Arrrgggg for f**k sake woman sign ouuuuuuuuuuutttttttttttttttttttttttttttttt!Matt just make seperate users for f**ks sake! Yeh Dot 4 should be fine, Never used it though I as always use 5.1 because it's supposed to be slightly better. Quote Link to comment Share on other sites More sharing options...
trialsmax04 Posted September 1, 2009 Report Share Posted September 1, 2009 The reason i ask is that I have always thought dot 5.1 is something waaaaayyyyyyyyyy differnt to other dot fluids? Quote Link to comment Share on other sites More sharing options...
DannyBazz (: Posted September 1, 2009 Report Share Posted September 1, 2009 The reason i ask is that I have always thought dot 5.1 is something waaaaayyyyyyyyyy differnt to other dot fluids?dot 5.1 replaced dot 4 because its better in every way Quote Link to comment Share on other sites More sharing options...
SteveUK Posted September 6, 2009 Report Share Posted September 6, 2009 dot 5.1 replaced dot 4 because its better in every wayIn very simple terms, DOT ratings are given to reflect a fluid's boiling points (wet and dry) Here's a link to an article on the subject for those who may be interested. Typically, a DOT 4 fluid will have a lower BP than a DOT 5.1. It is possible, however, to find a high performance DOT 4 (like Motul) which would be "better" than a low performace DOT 5.1.Hope brakes are filled with DOT 5.1 at the factory, so, although it's perfectly safe to top-up or bleed with DOT 4, the resulting fluid mix is only going to be as good as the lesser performing fluid. Not a huge issue for trials as riders won't be generating the kind of heat that might affect the brakes of, for example, a DH bike, which sometimes have to make long descents with prolonged braking.As a side note, silicone-based DOT 5 fluid is not in the same group as glycol-based DOT 3, 4 & 5.1 and is completely unsuitable for use in bicycle brakes. It will cause seals to swell and render them useless quite quickly. Shimano/Magura mineral oils are also unsuitable.In regards to caliper overhauls - I'm the author of the guides linked by Alex, by the way - don't use a screwdriver, or indeed any metal object, especially sharp ones, to push pistons in/out of the caliper. Phenolic pistons are relatively fragile and can be chipped or cracked by metal tools. Even a small chip in the side face can affect the piston's movement past the seal. Worse-case scenario is that fluid will be allowed to pass and the brake will lose pressure very quickly. A plastic tyre lever is ideal for moving pistons - just pay attention to keep any pressure to the center of the piston to prevent it twisting in the caliper bore.Unless you are very handy with tool fabrication, I'd probably advise against improvisation for getting bore caps out. Bear in mind that if you round-out the tool interface you will NOT get the bore cap out without having to destroy it completely (by using a Dremel to make a slot for a heavy screwdriver, for example). The tool is cheap and somewhere like Chain Reaction will get it out to you next-day. OK, I'll shut up now. Please don't hesitate to give me a shout if you need any advice on overhauling your Hopes. Quote Link to comment Share on other sites More sharing options...
Muel Posted September 6, 2009 Report Share Posted September 6, 2009 Making the tool is a piece of piss, and you don't need to give it a lot of stick to get the bore cap in or out, you have to have used a file before but it's really not hard. Quote Link to comment Share on other sites More sharing options...
SteveUK Posted September 6, 2009 Report Share Posted September 6, 2009 (edited) Making the tool is a piece of piss, and you don't need to give it a lot of stick to get the bore cap in or out, you have to have used a file before but it's really not hard.OK, so you found it easy - I don't doubt it; however, regardless of that, there are pitfalls that folk need to consider. I've had Mono series calipers in for service/repair which have had their caps ruined by people using filed down sockets, screwdrivers (to hammer them out) and other "smart" ideas. Yes, people have gotten the caps out with improvised tools, but people have also brought themselves a load of grief, including not being able to get them back in again properly. My opinion, as I've said, is that unless you're genuinely handy with tool fabrication it makes sense to just pick up the proper tool. My experience has been that the caps don't always come off easily, especially on brakes which haven't been touched for years. Edited September 6, 2009 by SteveUK Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted September 6, 2009 Author Report Share Posted September 6, 2009 OK, I'll shut up now. Please don't hesitate to give me a shout if you need any advice on overhauling your Hopes.Ideal, thanks very much Im ordering seal kit tonight, so I'll update tomorrow if ive got any problems Quote Link to comment Share on other sites More sharing options...
Muel Posted September 6, 2009 Report Share Posted September 6, 2009 I got some pics yesterday when rebuilding my mates Mono Trial, all being well I'll make a wiki article tommorrow. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.