Front Brake Leak '86 R65

[Red_Hen]

Ron - your brake lines looked original to me when I saw your bike.

I suggest ordering Stainless lines from Spiegler Performance - you'll get a better brake feel at the lever and they will serve you well, considering you're brake strength is up front.  The drums brakes work but the stopping power is up front.

While you're at this maintenance area, I suggest you investing in new brake lines! While you're at it, inspect the pads - Spiegler also sells Carbone Lorraine pads - on my R65LS, my front rotors were so beat up that I sent them in for a rotor conversion - expensive but well worth it - the rotors are now floating (they flex when stopping) and they are smooth and solid as butter.  

For me, turns out to be very addictive fixing up these old bikes but very rewarding!

[montmil]

... they are smooth and solid as butter.

Frozen or room temperature?

[Ron_S.]

Thanks again, Ken.  I've already ordered a stainless line and will look at the pads again.  

[Ron_S.]

OH, and yes, I'm somewhat alarmed at how addictive this is becoming.  

[Red_Hen]

... they are smooth and solid as butter.

Frozen or room temperature?

How about smooth LIKE butter  

[montmil]

... they are smooth and solid as butter.

Frozen or room temperature?

How about smooth LIKE butter  

That I can understand.

[raymr]

Ron, what is the master cylinder size on your R65? For some reason mine had a 15mm installed, which is wrong for a single disc Brembo. I got a new 13mm and braking is much nicer.

[tvrla]

I'm coming to this one a bit late, but my guess is the reservoir o-ring is leaking, and it might just be some corrosion where it seats.

If the brakes work fine, a rebuild isn't necessary and I wouldn't touch the rest of the master cylinder. Well, they're so easy to get into, I tend to take a look and clean up what ever I find, then put it all back together. Save the rebuild kit for when it's needed.

As for honing the master... don't! At least not with stones! The aluminum is too soft and too much will be removed. The best method uses a wooden dowel with some wet/dry sand paper, and twirl low speed. check often. Doesn't take long.

[Ron_S.]

Ron, what is the master cylinder size on your R65? For some reason mine had a 15mm installed, which is wrong for a single disc Brembo. I got a new 13mm and braking is much nicer.

Mine is a 13 mm.  That's what I have coming.  

[Ron_S.]

I'm coming to this one a bit late, but my guess is the reservoir o-ring is leaking, and it might just be some corrosion where it seats.

If the brakes work fine, a rebuild isn't necessary and I wouldn't touch the rest of the master cylinder. Well, they're so easy to get into, I tend to take a look and clean up what ever I find, then put it all back together. Save the rebuild kit for when it's needed.

As for honing the master... don't! At least not with stones! The aluminum is too soft and too much will be removed. The best method uses a wooden dowel with some wet/dry sand paper, and twirl low speed. check often. Doesn't take long.

I just got back from "vacation" to Massechusetts.  Been off-line for a bit.  Thanks for the info before I screwed it up.  =)

[Ron_S.]

I certainly have some braking power now!  When I pulled the master cylinder I encountered some corrosion-quite a lot of it.  Took some very fine emery cloth, a wooden dowel, some duct tape, and some patience, but it cleaned up nicely.  Put in the new piston, bled the system, brake is firm and no leaks.  
I had no idea my bike would stop like that.  Thanks to all, but especially Ken Tuvman for pointing out the problem.  

[Red_Hen]

Good job, Ron!