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Dengura Problem


SCOTTY___

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Hey,

I bought a dengura some time ago now and ive barely used it, first thing i did was bleed it with water as it was full with air.

The bike has been sat for afew months at a time as i dont ride to much anymore, but with old friends starting up again im getting back into it. But im always finding my brake needs 2 be bled!

But now im finidng myself having to bleed it every 3/4 days as its losing fluid.. ive searched every leakable place, tightened all borts/grub screws and cant find the source!!

any help would be appriciated!

thanks in advance !

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Send it back to where you got it from and have it replaced. These brakes are a pile of shit unfortunately, I'm on my 2nd leaking set and both brakes I used started leaking a few minutes after the first ride.

edit:

Simpsonman: you mean the piston in the lever? Just put a Magura one in?

Edited by Inur
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Send it back to where you got it from and have it replaced. These brakes are a pile of shit unfortunately, I'm on my 2nd leaking set and both brakes I used started leaking a few minutes after the first ride.

edit:

Simpsonman: you mean the piston in the lever? Just put a Magura one in?

That possible? Cos i have a spare Magura lever ;D

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Simpsonman: you mean the piston in the lever? Just put a Magura one in?

Yea but its not called a piston is it? seal? something like that, yea my brake worked well for a while But after a hard hit on the cycliner it started leaking so i bodged it onto some magura cyclinder is was never the same. I thoguht it was just the cyclinders being gay and sourced a RB lever so sold the Dengura lever to ... urm..... EricChristoff on here, just chris! he had the same trouble with air keep getting in. Told me he replaced the seal and its been working well ever since :)

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lol, ericchristoff? funny man :)

Anywho, get a '04 maggie, take the piston and spring out of it, as the spring is bigger in a maggie, put them in, make sure it is all intact, then bleed it. Mine lasted ages without needing a bleed, but now its just gone back to how it was. :(

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That's quite interesting. I've got a similar problem now, with the first brake the fluid just came rushing out of a slave. Now it's mysteriously disappearing even when the bike isn't being ridden. I love the feel of this brake, it's just such a pain in the arse to use, reminds me of riding back in 2001 when one had to bleed brakes a few times a day on a long ride...

edit: this might be of use to you guys, i've found a neat way of bleeding the dengura which takes no more than a minute to do. All you need is a syringe without the plunger and with the appropriate M5 fitting. Undo the bolt in the lever, screw the syringe in, pour some water inside and pump the lever a few times. Done, it's fully bled :)

Edited by Inur
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With a water bleed you might be getting outgassing from the water. Any water that's been left stand for a while will have a certain level of dissolved gas in it. Putting water containing dissolved gas into a brake will lead to gas bubbles forming in the brake fluid with changes in temperature/atmospheric pressure (Not to mind the pressure changes in the fluid as the brake is used). I'm guessing this is why a lot of people using water bleeds spend loads of time rebleeding their brakes and I've had to rebleed my Maguras a grand total of never in the last few years. There's a good reason Magura chose hydraulic oil as their recommended brake fluid...

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Someone raises a point like this everytime.... but water bleeds are fine. I know this from experience as water bleeds have lasted me years with no problems I don't see how gas could form in a closed system, i would understand if it had a air resevior. Even if the problems you raised could happen in theory, they dont nessicarily in real life. Water bleeds are fine is you get all the oil out the system as you can, blowing all the individual bits through an rinsing them can help

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There's a good reason Magura chose hydraulic oil as their recommended brake fluid...

And theres a good reason why EVERY rider runs water bleeds.... i think you will rarely find a seasoned rider who still used magura fluid, don't pick 1 rider and try to rip me for it. Most people do... for good reason, it works and feels better and is no more prone to leaking

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As far as I can gather the main reason people seem to use water bleeds is because it's easier to do than buy the bleed kit. I have no fault to find with the standard oil bleed, so I'll continue using it. The outgassing occurs because the water is in a closed system - the water put into the brake will have a certain level of dissolved gas in it. The capacity of water to absorb dissolved gas changes with temperature and pressure, so depending on atmospheric conditions (while the brake fluid is segregated from the atmosphere, atmospheric pressure still acts on it through the master piston) air bubbles will form or be reabsorbed. I have yet to try a water bleed on a properly set up set of brakes, anyone I know who's used a water bleed tends to be a serial bike bodger, so trying to separate the dodgy setup on the brakes from the fluid the brakes are using is pretty difficult.

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Yes i understand your point, but i ran a maggie with a water bleed and i had 0 problems, no air bubbles whatsoever. I put a dengura lever on and i have nothing but trouble. I dont understand how air bubbles can come from the water in one lever but not the other :S

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As far as I can gather the main reason people seem to use water bleeds is because it's easier to do than buy the bleed kit.

No.... people genrally tend to bleed brakes using a bleed kit with water... its because of the viscosity of the water and the lever responsivness

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everyone ive know that has bled a dengura with water has had issue with seals and leaking. if its not designed to work with water its for a reason. just because water may feel better doesnt mean its working with the internals as well. it wont lube the seals or pistons like mineral oil for one.

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aye hearing alot about water leaking.. but theres no signs what so ever, no residue or anything.. its like its just evaporating !

Can anyone recoment something other than magura oil that works? Or an olternate bodge?

Someone above said 04 magura piston/seals in the lever body works, what about 05, will they also?

thanks

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No, its safe to say if deng sorted it out, it would kick the living poo out of a maggie :)

aye hearing alot about water leaking.. but theres no signs what so ever, no residue or anything.. its like its just evaporating !

Can anyone recoment something other than magura oil that works? Or an olternate bodge?

Someone above said 04 magura piston/seals in the lever body works, what about 05, will they also?

thanks

i havent tried a '05 seal, try it and tell us how it works.

Them main one is using the spring from a maggie, makes it feel alot nicer.

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will do when i get it, better ask the father where hes but the bugger !

if my memory serves, leave lever grub screw in, remove lever blade and push water through with sringe till it goes PoP and fires across room? and then take time 2 find the spring? ;p

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Can anyone recoment something other than magura oil that works? Or an olternate bodge?

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!

babyoil.jpg

:giggle: Not sure if it would feel nice or lubricate atall? But i might give it a try soon.

EDIT: pic wouldn't come up.

Edited by cai
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I've had 3 denguras.

The first one leaked on the first ride, was unusable afterward.

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.

On the third one, I didn't want to run it, so I gave it to my brother and bought a maggie :P No problems with the maggie, quicker rebound, no spongyness, and the cylinders seem to move more, so it has better lever feel as well.

I'd never buy another dengura. Too much hastle. They need to start using olives with them as well, makes shortening the hose a fack load easier.

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