Rear wheel locked up

Duck749

XS650 Enthusiast
Messages
52
Reaction score
27
Points
18
Location
CNY
Took my ‘78 special out for ride today, it left me stranded when I lost power going up hill. As I safely pulled over I had smell of burnt clutch/brakes. I could start the bike but it would not go forward, rear wheel was locked up (while in neutral). It was so bad a passerby and I couldnt even push it. I let the bike cool for 20 min and was Then able to move it and it acted normal.

This leads me to two paths, originally I suspected a clutch issue but more got thinking about this is could I have had rear brake lock up? Looking for tips on where to start digging first. Bike was running great, shifting great and even able to downshift no issues during the “power loss” event.
 
Blocked return port in the master cylinder a prime suspect. There are two ports a big one and tiny little one. That small one is the usual culprit Then look into rubber hose that has started collapsing on the inside where you can't see it. These hoses are 40 + years old. Take it as a sign you need to do a full monty brake rebuild with new stainless steel hose.
 
Great thanks! After building the bike it does have rebuilt caliper, SS line and cleaned MS. Cant remember if/what i replaced on MS other that new reservoir and line to cylinder. Appreciate quick feedback.
 
Exact same thing happened to me on a CB1100F, thought I was losing power also. LOL Coulda had a brat fry on that rear rotor.
 
With the rear wheel elevated, can you spin it easily or is there lots of brake drag? You might try a couple quick trips around the block then check the rotor to see if it's getting hot. If there's any water in the system, as it heats up that expands and starts applying the brake.
 
If a brake locks up because of hydraulic problems, relieving pressure will let the caliper release. Just back off the bleeder valve a bit until it stops passing fluid, then stay off that brake until you can baby the bike to safety.
 
Exact same thing happened to me a few weeks ago. The MC piston seized in the bore.
 
Assuming it's a disk brake, if you pry the pistons back into their bores it can clear a clogged return hole.
 
Back
Top