Pad/Disk Contact @ 0 Pressure

daves79x
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Location: Knox, PA
Location: Knox, PA

Re: Pad/Disk Contact @ 0 Pressure

Post by daves79x »

Yes, they are square profile and there's no 'correct way'. The seal groove is tapered and this gives the seal it's 'taper' when everything is installed, and this taper gives you the piston pull-back when you release the lever/pedal.

Dave

Larry Zimmer
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Re: Pad/Disk Contact @ 0 Pressure

Post by Larry Zimmer »

Just a supplement note for brake work: When you are rebuilding calipers or m/c, put them into a pot of boiling water for 15-20 minutes first. (After removing all seals, etc.) Might clean any outside grease/oil first. Then, let them dry. This won't take long. It will significantly loosen all the crud and corrosion that has gathered from brake fluid. And, residue brake fluid. After that, they will clean much easier. What remains is just light crunchy debris that cleans very easily from all the grooves, etc. Also, it helps clean passage ways.
Not certain this works if you have been using Dot 5. Probably not.
Larry Zimmer
cbxlarry@sbcglobal.net

Brian G
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Re: Pad/Disk Contact @ 0 Pressure

Post by Brian G »

:oops:
I think I've got it. Took her for a 32km run at highway speeds this afternoon and even after using the brake a couple of times, the disk temp was only 10 deg. above ambient.

I'd taken the caliper apart - for the 3rd time - to check the groove for crud etc., found virtually nothing, flipped the seal for good measure and put it back on the bike. I tightened the caliper bolts hand-tight to connect the brake line and bleed the system then spun the wheel to check that the brake applied and released nicely when I pressed the pedal by hand. It did, so I tightened the caliper bolts to book value (11-15 ft.lb.) and gave the wheel a final spin. Except it didn't want to turn - considerably more resistance. This was a bit of a puzzle - the sliding pins should be drawn out when tightening the bolts, not the caliper pulled in - right?

I had cleaned and greased the sliding pins earlier, but used only a smear of brake grease applied with a fingertip. I'm guessing they need more than a smear, so I poked a bit more into the hole, tightened the bolts until I felt resistance, and went for the aforementioned test ride. I'll have to check the pins more thoroughly, as it started raining and the bolts aren't yet torqued to book value but as long as the brake works and doesn't overheat, a little blue loctite should do the trick.

Thanks so much to everyone who offered advice and tips. Hopefully my blockheadedness and this forum thread may help someone else in the coming years.
1969 BSA Rocket 3
1976 Kawasaki KH400
1977 Yamaha XS650D Cafe
1978 Honda CB550K
1979 Honda CBX

Rick Pope
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Re: Pad/Disk Contact @ 0 Pressure

Post by Rick Pope »

Good to hear you've got it figured out. Now go enjoy that beautiful scenery. PEI has to be one of the prettiest places on the planet, especially to an old retired farmer. And after being there, I don't even slow down in Maine for lobster.
Rick Pope
Either garage is too small or we have too many bikes. Or Momma's car needs to go outside.

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