R3 2016 front brake resevouir leaking

[azmerlin]

Hi all,

I bought my R3 a few months ago and due to lockdown and rain I have not used it much.
However, I seem to have a leak from the front brake res from the narrow end closer to the clocks.
I tried fitting a new seal (rubber and plastic, but that does not seem to resolve the issue.
Any ideas would be great.

 

[atomsplitter]

Could you point out where the leak is? On the banjo fitting? Or has the reservoir sprung a leaK?

 

[azmerlin]

Could you point out where the leak is? On the banjo fitting? Or has the reservoir sprung a leaK?

It seems to be coming from around where the screw is between the cover and the res.

 

[atomsplitter]

So is the leak is through the rubber diaphram seal? Pull the cap off and check the inner seal isn't cracked or broken. Have you replaced the front brake pads recently? If you over pressurize the reservoir pushing the pistons back you could burp some fluid, however that seems unlikely. The cap isn't air tight and isn't meant to be, the diaphram is airtight. To allow the fluid displacement into the system as the pad wears the cap has to allow some air in, which expands the diaphram into the reservoir under negative pressure. If there's brake fluid on the outside of the diaphram the diaphram needs replaced. Without a good seal the fluid will absorb water (from the atmosphere) and munge up your brake calipers.

You can double check me but the part number for the diaphram is: T2026017

 

[azmerlin]

So is the leak is through the rubber diaphram seal? Pull the cap off and check the inner seal isn't cracked or broken. Have you replaced the front brake pads recently? If you over pressurize the reservoir pushing the pistons back you could burp some fluid, however that seems unlikely. The cap isn't air tight and isn't meant to be, the diaphram is airtight. To allow the fluid displacement into the system as the pad wears the cap has to allow some air in, which expands the diaphram into the reservoir under negative pressure. If there's brake fluid on the outside of the diaphram the diaphram needs replaced. Without a good seal the fluid will absorb water (from the atmosphere) and munge up your brake calipers.

You can double check me but the part number for the diaphram is: T2026017

Hi,
I hav e not replaced the pads, only the diaphragm (plastic and rubber kit. The leak has nothing to do with pressure, I close the cap turn the wheel so that the leaking area is lowest and it starts to leak, no need to do anything. By the way, I got the diaphragm from my local Triumph dealer today,

 

[atomsplitter]

Hi,
I hav e not replaced the pads, only the diaphragm (plastic and rubber kit. The leak has nothing to do with pressure, I close the cap turn the wheel so that the leaking area is lowest and it starts to leak, no need to do anything. By the way, I got the diaphragm from my local Triumph dealer today,

Are you saying the leak occurs when the bars are at lock to the left? Sounds like the new diaphram (item 10 in the diagram) is the wrong part if it's not sealing the reservoir.. Take the cover off and see if the diaphragm plastic goes to the edge of the reservoir cup all way round. That is supposed to be sandwiched between the cup and the cap. Make sure it isn't upside down while you're there.

 

[Wdugan9080]

It seems to be coming from around where the screw is between the cover and the res.

Are you sure you're tightening down both screw's evenly and a little at a time, low torque to higher torque. I don't use a torque wrench for it cause you really can't over tighten a Phillips head screw, worst you can do is strip out the head, don't do that. The rear cup is plastic so you can strip that out easily, just snug that one up easily if it leaks you can go a little bit more, make sure all the mating surfaces are flat and has no foreign material on or in it, like deep scratches. I just changed my fluid and had no problem, is the threads on the bolts and cylinder good? do they turn easily? I can't believe they suggest changing every 2 years, I've never done my car's/truck's. But GL

 

[azmerlin]

Update;
Seems to be solved, I went to my local dealer and they suggested that may be an idea to give all a good clean and dry, thin layer of grease and not over tighten as it may warp the seal and thus leak, seems to work, so far so good.