Greetings Posted February 6, 2008 Report Share Posted February 6, 2008 The second one worked well, then I broke a hose, and rebled it with water. Huge mistake. It leaked all the time, I'd have to rebleed the brake every second day. It also became very spongy and slow acting with the water inside...not designed to be used with water as far as I can see.Has anybody else had similar experience? Is that really the reason (can't see any logic behind it) or just a coincidence?The sponginess and poor responsiveness was probably due to it not being bled properly. A Dengura on a water bleed has a very similar feel do a disc brake lever, you can hardly feel any resistance. Quote Link to comment Share on other sites More sharing options...
baladi Posted February 6, 2008 Report Share Posted February 6, 2008 [...] becaus eit is thicker than water it doesnt leek out where the water would .leoni dont think that what you say applyes, the main reasons for using oil is first: proper lubricating the rubber seals, and second: buy their mineral oil Quote Link to comment Share on other sites More sharing options...
*Tom* Posted February 6, 2008 Report Share Posted February 6, 2008 I've had my dengura on water for about two months with no problems Quote Link to comment Share on other sites More sharing options...
Waynio Posted February 6, 2008 Report Share Posted February 6, 2008 my rear brake is fine, i got one to try and am just getting annoyed with the black bits on the pistons :@ as on HS33's the black rings are so much easier to adjust.i do think that from the factory they arent bled that "great" but if you just fill the resevoir (a bit of a top up) then im sure it would work fine.the "waterbleed" thing will always be an arguement, just like "chris king Vs hope pro2 trials" youve just got to live with it each to their own opinion.Iv been happy with trying dengura's i feel that if your willing NOT to use what is supposed to be in the brake then whats the point buying them in the 1st place but thats only my opinion.Like shimano and magura disc brakes use mineral and Hope use dot4???? why do people not use the oil vice versa in those brakes???? because dot4 F**Ks seals in mineral brakes and mineral fluid knacks dot4 seals. its the same kind of thing. notice how water bleeds you feel you can "pull the lever harder" well thats probably because the water is thinner and you can compress it even further than oil???? hence why you use oil. Wayne. Quote Link to comment Share on other sites More sharing options...
Ash-Kennard Posted February 6, 2008 Report Share Posted February 6, 2008 isn't alot of the reason water works because of hydrogen bonding? the oxygen is clearly not going to separate from the hyrdogen, hence no problems...the reason the leak with denguras is that it rots the seal as there is no lubricant, so either change the seal (old maggie?), bleed it every few days or run oil Quote Link to comment Share on other sites More sharing options...
psycholist Posted February 6, 2008 Report Share Posted February 6, 2008 Hydrogen bonding is caused by Hydrogen and Oxygen having electronegativities that are different enough that even though the bond between them is nominally covalent, there is a charge difference created across the molecule. These charges attract oppositely charged parts of other water molecules, holding the water together as a liquid up to far higher temperatures than other compounds of comparable molecular weight. The oxygen that bonds with hydrogen to make water is not where the dissolved gas I mentioned earlier is coming from. When I said gas dissolves into water that's literally what's happening, the water is not chemically changed in any way, it just holds some unbonded oxygen/nitrogen/CO2 etc. molecules within it. Quote Link to comment Share on other sites More sharing options...
Greetings Posted February 6, 2008 Report Share Posted February 6, 2008 notice how water bleeds you feel you can "pull the lever harder" well thats probably because the water is thinner and you can compress it even further than oil???? hence why you use oil.Water is one of the most incompressible fluids around, what are you talking about Quote Link to comment Share on other sites More sharing options...
SCOTTY___ Posted February 6, 2008 Author Report Share Posted February 6, 2008 05 Magura seal / piston [ Whatever people wont to call it. ] + Spring = mega. ;D rode today no change. But only time will tell.. Quote Link to comment Share on other sites More sharing options...
El Cristoff Posted February 6, 2008 Report Share Posted February 6, 2008 Springs tiny in a dengura isnt it, recoiling a bit better? Quote Link to comment Share on other sites More sharing options...
SCOTTY___ Posted February 6, 2008 Author Report Share Posted February 6, 2008 Spring is exactly the same size of the 05 maggy. Just fort it would be better to have 05 Maggy Piston+Spring than 05 Piston and dengura lever ! Quote Link to comment Share on other sites More sharing options...
Greetings Posted February 6, 2008 Report Share Posted February 6, 2008 This is a new brake. No wonder it leaks! Quote Link to comment Share on other sites More sharing options...
baladi Posted February 6, 2008 Report Share Posted February 6, 2008 (edited) I've had my dengura on water for about two months with no problems i have my HS33 bought brand new in 2001 and they weren’t bled 'till now, no leaks, the pistons in the back are perfectly dry, not even lubrified. I vote Maggy F T WWater is one of the most incompressible fluids around, what are you talking about Yes, as i leaned in college: water is "incompressible"(as in: you dont care about compression, only in big industrial devices) Edited February 6, 2008 by baladi Quote Link to comment Share on other sites More sharing options...
Ash-Kennard Posted February 6, 2008 Report Share Posted February 6, 2008 Hydrogen bonding is caused by Hydrogen and Oxygen having electronegativities that are different enough that even though the bond between them is nominally covalent, there is a charge difference created across the molecule. These charges attract oppositely charged parts of other water molecules, holding the water together as a liquid up to far higher temperatures than other compounds of comparable molecular weight. The oxygen that bonds with hydrogen to make water is not where the dissolved gas I mentioned earlier is coming from. When I said gas dissolves into water that's literally what's happening, the water is not chemically changed in any way, it just holds some unbonded oxygen/nitrogen/CO2 etc. molecules within it.your on about dipoles aren't you? as in hydrogen will be slightly positive and oxygen slightly negative, but has two lone pairs, and attracts charged hydrogens. and some shite about intermolecular forces keeping them attracted. Quote Link to comment Share on other sites More sharing options...
Tomy P Posted March 3, 2008 Report Share Posted March 3, 2008 Here's a tip from Heatsinkbikes.com: Sidestep extortionately priced rebranded mineral oil sold by the manufacturers, and try some clear mineral oil available cheaply in any high street. For example why not put some Baby Oil in your brakes! Not sure if it would feel nice or lubricate atall? But i might give it a try soon.EDIT: pic wouldn't come up.I always use baby oil and rarely ever bleed my brakes, magura on rear, dengura on front. Works well for me. Quote Link to comment Share on other sites More sharing options...
Simpson Posted March 3, 2008 Report Share Posted March 3, 2008 your on about dipoles aren't you? as in hydrogen will be slightly positive and oxygen slightly negative, but has two lone pairs, and attracts charged hydrogens. and some shite about intermolecular forces keeping them attracted.I do chemisty. So as much as this is interestingWater is virtually incompressible, when only using it for a simple hydraulic functionAnd if theres a gap in the system water will get out, anything will leak, if it has hydrogen bonding or w.e.Baby oils alright to bleed with, just goes all over your hands and leaves your pistons greasy and gamm if they snap, stick to water.... Quote Link to comment Share on other sites More sharing options...
psycholist Posted March 3, 2008 Report Share Posted March 3, 2008 (edited) your on about dipoles aren't you? as in hydrogen will be slightly positive and oxygen slightly negative, but has two lone pairs, and attracts charged hydrogens. and some shite about intermolecular forces keeping them attracted.That's about right - even though nominally Hydrogen and Oxygen share electrons (Covalent bond), the electronegativity of Oxygen (3.44) is a lot higher than Hydrogen (2.2), leaving the covalently bonded molecule with a slight negative charge on the Oxygen and a slight positive on each Hydrogen. These charges allow adjacent H2O molecules to bond weakly to each other, making it harder for the water to vapourise (It takes more energy as it's a more tightly bonded liquid).All I've ever used in Maguras is Citroen LHM Fluid (It's for the hydraulic suspension systems and is probably chemically identical to Magura Blood). The compressibility of water is 2.3GPa - what this means can be found here: http://en.wikipedia.org/wiki/Bulk_modulus - what it effectively means is that you're not going to notice the fluid being compressed compared to the other sources of sponginess in a brake system. Edited March 3, 2008 by psycholist Quote Link to comment Share on other sites More sharing options...
NileBrown™ Posted March 3, 2008 Report Share Posted March 3, 2008 I do chemisty. So as much as this is interestingWater is virtually incompressible, when only using it for a simple hydraulic functionAnd if theres a gap in the system water will get out, anything will leak, if it has hydrogen bonding or w.e.Baby oils alright to bleed with, just goes all over your hands and leaves your pistons greasy and gamm if they snap, stick to water....Erm, Not questioning is this is right or wrong but didn't you fail your chemistry course hahaha I love you mike Quote Link to comment Share on other sites More sharing options...
Ducko Posted March 3, 2008 Report Share Posted March 3, 2008 id happily say that the magura manufacturing quality is alot higher than that of a dengura, sounds like the seals are crap, or that the piston bores are made oversize.stick with a good ol' hs33 happy days;) Quote Link to comment Share on other sites More sharing options...
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