Author Topic: Front Brake Trouble!  (Read 417 times)

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Offline Obohebev

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Front Brake Trouble!
« on: January 27, 2019, 05:28:27 PM »
Hello helpful people!

My 76' XS500 has been in the shop 3 time because the front brake is seized.  Each time, the mechanic says he has fixed it, taken it apart and cleaned everything, nothing looks wrong, etc.  I ride it home, am happy, everything is great.  Then without fail, a week or two later, the weather gets nice, I go to ride, and.... it is so seized I can't do anything.  Whacking with a rubber mallet helps a little, but not much. 

So, any suggestions? Should I just get a new front disk and caliper set and rebuild? Is there something obvious I am missing?

Thank you.

Attached are pics of Chewbikeah for reference, although none of closeups of the front brake.

Offline guylr

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Re: Front Brake Trouble!
« Reply #1 on: January 27, 2019, 10:29:42 PM »
I despise the pin slider calipers on the second generation XS500s and other Yamahas of the late 70s. They don't stop as well as the early iron calipers and have the problem you described. Over time mine did the same thing as yours so I finally gave up and changed to the solid mount dual piston calipers. The pin sliders want to lock up because the pistons don't retract like they should. I rebuilt mine with new seals and carefully lubed the pins but after a short time they acted up again.

Now I went to the extreme of building a custom set of forks based on some TX750 legs I bought on eBay  that used the early style calipers as on the 1973 to 1975 models. Then I bolted up a pair of TZ750D  alloy calipers and it really stops and doesn't lock up.

For a less involved fix I'd buy a good modern four piston fixed caliper and have an adapter made to mount it to your fork. I like the late 90s R6 and R1 caliper that show up on eBay a lot. Not sure if anyone makes an adapter for our old bikes, probably not so you'll have to go custom.

Guy
« Last Edit: January 27, 2019, 10:32:16 PM by guylr »
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"