The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: 79beem on September 17, 2011, 07:04:26 AM

Title: Clippety clack calipers and a leaky resovoir
Post by: 79beem on September 17, 2011, 07:04:26 AM

Been a busy day with the old girl.

Topic says it all really.

Stripped and cleaned calipers and pistons, nothing terrible to report. Put it all back together. Bled it.
Still the same sound when in motion, but no more clank! when braking on the center stand.

And then i hear another noise,  (bike in the shed) like an air leak/bubbling sound.
Bit of fiddling and searching reveals....... HURRAY! leaking reservoir.

When i pump the lever there's a pfht! sound, like air being forced through a small hole.

Loosened and re-tightened all related screws with no result. New
O-ring?

Could this leak/pressure drop be a factor in the horse impersonations going on up front?  

Title: Re: Clippety clack calipers and a leaky resovoir
Post by: montmil on September 17, 2011, 07:12:52 AM

Quote

... Could this leak/pressure drop be a factor in the horse impersonations going on up front?

Definitely a strong possibility. The hydraulic system must be air tight and secure to function properly. Your master cylinder could be contributing to the on again-off again barnyard noises you describe.

An occasional Moo is OK. ;)

Monte

Title: Re: Clippety clack calipers and a leaky resovoir
Post by: 79beem on September 17, 2011, 07:31:59 AM

Very funny Monte.

Replace O-ring under resovoir?

Its a 15mm square body with brembo calipers by the way.

Giddy up bulls eye, Moooooooooooooooo........

Title: Re: Clippety clack calipers and a leaky resovoir
Post by: montmil on September 17, 2011, 10:48:50 AM

Quote

Very funny Monte.
Replace O-ring under resovoir? Its a 15mm square body with brembo calipers by the way.
Giddy up bulls eye, Moooooooooooooooo........

Moo... Uh, I mean, yes.

There's an O-ring below the reservoir and, IIRC, another small one (two?) on the piston in the lower portion of the MC body. Check condition of the reservoir's upper gasket and also take a look at the rubber bellows inside the reservoir.

Monte [smiley=cowsleep.gif]

Title: Re: Clippety clack calipers and a leaky resovoir
Post by: Bob_Roller on September 17, 2011, 12:34:08 PM

When you release the brake lever, there is a small 'jet' of brake fluid that comes out of a very small hole next to the main intake for the brake piston, may or may not be what you're hearing  .

Have you checked your brake rotors for cracks, I had a severely worn set of rotors on my '82 LS, they were cracked in the bottom of the deep grooves in the rotor surface .

Title: Re: Clippety clack calipers and a leaky resovoir
Post by: 79beem on September 24, 2011, 02:12:15 AM

Rotors fine, turns out its the pins rattleing about. Opened up the spring a tad, problem solved. New pin set ordered.