Bicycle Mechanics - Shimano 600 brake question

I'm stripping down an early 80's vintage Miyata 912 - all Shimano 600 equipment. I've looked in Sheldon Brown's website and done searches here, but it's still not clear how to remove the brake assembly. I've got a hex bolt head, washer, brake arm, washer, spring retainer, "funny looking bumpy spacer?", brake bridge. I really need to get front and rear brakes apart and don't want to break anything. Thanks!

Rear Brake: Look behind the brake bridge...there should be a 5mm allen head nut that you will loosen by turning counter-clockwise. Remove this nut and the brake caliper assembly should slide right off the frame. If it is not an allen head type fastener then it will most likely be a 9 or 10mm nut...regardless, the part you need to remove will be behind the brake bridge.

Front Brake: Same as rear brake...look on fork crown behind the brake caliper assembly for either an allen head fitting or nut.

If these directions don't help, take a couple of pictures and either post them or email them to me and I will make further suggestions.

-J

I'll take pictures tomorrow and post, but there is no nut behind the bridge. The bridge itself is threaded. I'm thinking that the funny looking "spacer" in front of the bridge, the one that looks like a cog, is actually a lock nut that has to be loosened before I can unscrew the allen bolt.

Are the brakes on or off the bike? If they are on the frame you take them off from the backside, either a recessed hex nut or a regular nut. If off the bike, and dependent on vintage, you can use a cone wrench or a box wrench (12-point?) on the back and whatever fits the front. On mine the the 12-point also looks to be a locknut. I've had them apart before but that was over 10 years ago. You might be able to just hold the caliper with your hands while you turn the 12-point nut.

I'll take pictures tomorrow and post, but there is no nut behind the bridge. The bridge itself is threaded. I'm thinking that the funny looking "spacer" in front of the bridge, the one that looks like a cog, is actually a lock nut that has to be loosened before I can unscrew the allen bolt.
No, that's just a lock washer to prevent the caliper from rotating out of alignment with the rim. Look closer; there will be an Allen head nut to loosen the bolt:

http://os2.dhs.org/~john/allenbolt.jpg

No, that's just a lock washer to prevent the caliper from rotating out of alignment with the rim. Look closer; there will be an Allen head nut to loosen the bolt:





JohnD Thompson is correct. That bumpy, cog-like looking spacer is a serrated washer, or generally called a 'star washer' and does as he describes. You'd be surprised how beneficial those little star washers are on single-pivot brakes, so dont lose 'em. :D

Got it. The hex nut was flush with the brake bridge and grungy (SP?). I need more light and more powerful reading glasses for really close work. Got the whole bike stripped down except for the BB and the lower headset bearing race, the latter looking like a job for my LBS.

Any tips on a cheap source for star washer wrenches?

What's a star washer wrench?

What's a star washer wrench?

Bike mechanic who gives sponge baths to celebrities.

Your initial post, not knowing how to remove the brakes from the bike, does not instill confidence in your ability to take the brakes apart. Are you doing this to overhaul the brake calipers? How much do they need it?

edit: here are a couple of pictures of early-mid 1980's Shimano 600 caliper brakes, from the original build (http://www.unc.edu/~cupery/pics/bikes/Centurion_Comp_TA/) of my Centurion Comp TA (http://www.unc.edu/~cupery/pics/bikes/Centurion_Comp_TA_repainted/).

What's a star washer wrench?

Aha, I thought the serrated washer pictured above was related to the serrated nut on my Shimano 600 headset...nevermind.

bike mechanic who gives sponge baths to celebrities.


+100!