Author Topic: Odd Master Cylinder Weep  (Read 888 times)

Offline paulbaker1954

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Odd Master Cylinder Weep
« on: February 19, 2017, 04:36:31 PM »
Help

I seem to have a small amount of brake fluid leaking from around the top hose joint to the master cylinder.

I have replaced both banjo washer with new copper ones and replaced the bolt. There is no fluid on the hose it would seem is fine.

If I wipe it all clean and leave for a day or so I find fluid around the top of the rubber boot.

Given that fluid can't climb up from the joint into the boot this now mystifying me

Anyone got any bright ideas
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Offline peterengland

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Re: Odd Master Cylinder Weep
« Reply #1 on: February 24, 2017, 10:36:03 AM »
Mine does the same but causes no problems at all, in fact I have not even had to top it up in 3 years!
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Offline Green1

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Re: Odd Master Cylinder Weep
« Reply #2 on: February 24, 2017, 08:19:06 PM »
My Master cylinder was weeping under pressure and weeping around the cap.
I think the wind was blowing the fluid around the threaded part of the master cylinder when on the move and when parked up it was running down the side and gathering under the boot.
After changing the rubber diaphragm it stopped 
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Offline paulbaker1954

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Re: Odd Master Cylinder Weep
« Reply #3 on: February 25, 2017, 04:55:11 PM »
Thanks
I had come to the conclusion it was the cap

Ordered new one so fingers crossed
If you think there's light at the end of the tunnel it's usually another train !!

2016 Yamaha MT09 Tracer
1971 Honda CB500 Four K0

Offline florence

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Re: Odd Master Cylinder Weep
« Reply #4 on: February 28, 2017, 09:51:32 AM »
I replaced the rubber seal in the cap of my master cylinder and was rather annoyed to find it leaked a very small amout of fluid.  However, after a week or two of checking and re-tightening the leak mysteriously stopped all by itself and has been fine ever since.  I guess it must have needed to bed in.

Offline paulbaker1954

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Re: Odd Master Cylinder Weep
« Reply #5 on: March 04, 2017, 07:16:29 AM »
All fine now _ yes ''twas the diaphragm rubber
If you think there's light at the end of the tunnel it's usually another train !!

2016 Yamaha MT09 Tracer
1971 Honda CB500 Four K0

Offline Green1

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Re: Odd Master Cylinder Weep
« Reply #6 on: March 04, 2017, 04:37:14 PM »
That's good I don't always come out with mindless crap then.  ;)
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Honda CB750k1 Valley Green Metallic
Honda CB750k1 Candy Gold
Honda CB550k Candy Jade Green
Honda CG125
Aprilia Pegaso 650
Moto guzzi 1200 sport
Kawasaki EX650R (Mine until dave pays for it)
Kawasaki ZXR400 J

 

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