Author Topic: brake fluid leaking from hard pipe nut  (Read 583 times)

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Offline evanphi

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brake fluid leaking from hard pipe nut
« on: May 30, 2014, 06:56:10 AM »
I have finally figured out what might be my problem with mileage... the hard pipe to the caliper was bent funny to the rubber holder on the fender, and I think it was acting like a spring and holding the pad to the rotor. Derp.

Now that I have the holder bent out of the way so the top of the pipe sits freely, whenever I hold the brake lever, I see fluid seeping out around the pipe at the connection to the caliper. Not coming through the threads, but in the middle of the nut around the pipe. The nut is nice and tight.

I figure it is probably a crack in the pipe flare that is allowing the fluid to seep out. I'm not riding the bike until I get it diagnosed.

Anyone else have a similar issue/solution?
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline flybox1

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Re: brake fluid leaking from hard pipe nut
« Reply #1 on: May 30, 2014, 07:11:21 AM »
If it wont torque down properly and seal, get a new one.  They are cheap and available.
If you have long brake lines, run it directly to the caliper with a splicer(two male ends)
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline calj737

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Re: brake fluid leaking from hard pipe nut
« Reply #2 on: May 30, 2014, 07:26:10 AM »
Whatever is the cause, fix it! Very dangerous despite the mileage impact. And while you're at it, evaluate your pads since this constant rubbing may have worn them prematurely.
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Offline evanphi

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Re: brake fluid leaking from hard pipe nut
« Reply #3 on: May 30, 2014, 07:50:59 AM »
They are new pads as of last year. No significant wear on them.

I am going to order a new pipe from slingshot cycles. Previous good experience in the past!
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive