Hi all. A question that has been asked several times, but searching the forum has not given me the answer. Can I ask what master cylinder I have on as OE. I am thinking that the seal inside the master cylinder might be weeping as I am getting a small amount of brake fluid leaking/spraying onto the reservoir and then mirror stem. But I cannot see the trail starting from the master cylinder lever/piston area?? If I ride in town there is no leak, but after a few miles of country road it appears. Braking is still strong although a little spongy, the fluid level in the reservoir is not noticeably changing I put on a new reservoir and problem yesterday thinking there could be a small crack etc but the leak persists. So it's not the reservoir. Trouble is I am supposed to be going to Ireland later on next week so I was thinking of getting a KTM master cylinder kit to fit my OE Brembo but not sure which kit i need. Can anyone point me in the right direction. Many thanks in advance. Best M
Check it’s not fluid spraying from the m/cylinder cap. It’s a common fault especially if it’s still original.
Hi It is not the original one, but I did wonder if it is coming out there as I cannot see where else it might originate from. It’s a metal cap on a brand new reservoir .
I don' think the reservoir should have a lot of in and out going on. Not enough to be squirting anyway.
Unfortunately tried that and also thought I might have overtightened the screws and caused a minor crack? So got a new reservoir and same thing happening.
I cured this problem by simply changing the original cap to a fancy one, did the same for the clutch reservoir for aesthetic reasons. Has been fine since.
I get the same on my 17 Enduro. I went with Bradders suggestion of putting a sweatband over it - you can see it has collected some outflow? Bit like brushing dirt under the carpet, but at least it stays off the paintwork?
Yes I have done the same, but I am worried that if fluid gets out then air gets in? And is it safe, might the brakes fail at any moment?
I changed mine to a fancy metal one about 5 years ago, have literally just put the OE one back on and will go for a ride to see if any better. Why does this happen??
Would love to have an alfa but I don’t dare! So is this weeping of brake fluid deemed normal and acceptable, if yes then I can blast off on holidays without worrying the brakes might fail at any given moment?
You can’t really say it’s normal but it often happens. I had it when heading off on my tour earlier this year. It’s often the cap. Over tightening is often the cause apparently. PTFE tape could sort it but I haven’t tried. I got one of my wife’s small elasticated hair bands and used that to hold some kitchen roll onto the pot. This then clearly told me if I had a leak or not and where it came from. I’ll see if I can find a pic.
With kitchen roll. Sounds daft but really helps trace where the leak is. Also good if you can’t get a sweatband in time. Check your hoses and hose connection. So long as the fluid is kept topped up enough there is no danger. BUT if you let it drop below the level then it could b e very very dangerous. Having said that the weep should be so slow that a capable fella like you should be able to monitor it and keep it topped up. Take a can of fluid with you. Don’t over tighten. If it’s not the pot ( new one) it must be the lack of seal from the cap. Or hose or hose connection. Most likely the seal. You’ve probably crushed it by over tightening or it’s gone brittle with age. If there’s time or you’re passing a Ducati dealer I’d buy one of those. I’d stick with your after market cap, I’ve heard of issues with the OE caps.
Many thanks. Just tried with the OE cap, and still leaking a little. Does not really require topping up, just very annoying. Hoses and joins all seem dry too. So now I have to travel with a can of oil and brake fluid , it’s becoming an old Brit bike.
Excellent. Why not put a bit of kitchen roll inside the sweat band so you can easily see if it’s leaking. I wonder if the black sweat band will stop it.
Despite there being a bit of fluid spray from the reservoir, you would need to lose a serious amount on a trip to warrant carrying spare fluid imo. All brembo reservoirs of this style do this (not just on Ducatis), its a shite design, and the only way I can stop it is to take the cap off, fully clean and dry the rubber diaphragm, don't overfill the fluid, refit it all without over-tightening the screws, and repeat at the first signs of fluid spots (usually another couple of 1000 miles)
