SteveUK

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.

In 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.

Hello, I'm Steve and I don't ride trials. I'm into mountain bikes - trail and DH type stuff - and have been for about five years or so. I really only signed up so that I could add some information to a thread which contains links to my maintenance blog, but some of the topics in the Chit-Chat forum have caught my eye, too. Anyway, nice site you guys have going on here; from what I've seen so far it has a good vibe to it. Maybe I should start riding trials!!