Xcrider220

Please help! I’ve been riding a set of Avid Juicy 3 hydraulic disc brakes for nearly 10 years. They have been flawless over the years, always well-maintained. About a month ago I noticed a faint ‘whine’ coming from the front brakes after about an hour of riding, but could make it go away temporarily with a flick of the lever. Today, after about an hour of riding, I noticed the front brake randomly sticking going down tight switchbacks. And then..suddenly (when I was on a bridge) they locked on without me touching the levers, and i did a beautiful Endo right off the bridge. Luckily everything was ok. What is going on with my brakes? Do I need to bleed.. is the fluid too old? Something else?
Any suggestions would be great.. I’m trying to avoid a trip to the bike shop, as I am a former bike mechanic and always built and serviced my own bikes.
Thanks in advance for any useful advice

hounslow

I would flush them through with fresh fluid (new bottle, DOT fluid absorbs water from the atmosphere so once opened it doesn't keep). If this doesn't help throw them in the bin as Juicy 3's were obsolete over 10 years ago and had an awful reputation for reliability. Modern brakes are leagues better.

andrewclaus

It sounds like a caliper problem to me. It may be time to remove and rebuild, or better to replace as noted above.

well biked

Throw them away and replace them.

cxwrench

I get to tell this story every now and then...it's funny and gets the message across very effectively.

While I was a Trek employee I went to a week long 'expert' mechanics class in Waterloo. One day was Trek product, one was Shimano, one Fox, one SRAM and one Bosch. The SRAM day covered 2 products as they accounted for far more attention than all the others. In the morning we went really deep w/ Reverb droppers, the afternoon was brakes. The guy that was presenting went to his white-board after lunch and started writing. He made it about 2 letters and stopped. He turned around and said "Before we get started I just want to apologize for the last 5-7 years of SRAM/Avid hydraulic brakes. We know they suck and we're working very hard to make them better."

Bigbus

I had that happen to me on a dirt bike when I was out patrolling one day. The front brake started grabbing and then suddenly just locked up. I pulled off the cover and the fluid overflowed. I bled the brake down just so I could ride it back to the shop. After flushing the entire reservoir and lines with fresh fluid to make sure there wasn't anything of the old left, I filled the reservoir back up and bled the brake until it was working normally again. I only had that bike in the fleet for another year before it got replaced, but it never gave me another problem. I would definitely give it a try with your bike if you haven't already and see what happens. Endos when planned can be a blast, unplanned, not so fun. I was fortunately cresting a hill at a relatively low speed when the brake locked up so there wasn't any harm to me or the bike, except for looking like a fool to a couple of guys sighting in their rifles. Good luck

Xcrider220

That’s awesome! Thanks for the story

masonv45

This is very common on motorcycles.

The cause is the fluid return hole on the master cylinder has become plugged. As the fluid heats up (like on a downhill), it expands. Since the fluid cannot return to the master cylinder, the only other outlet is pushing the brake pistons out.