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Discussion Starter #1
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I just purchased a new 2019 yamaha grizzly 700 LE and have ridden it 3 times. Each time taking it out about 10 minutes into the ride the rear brakes lock up solid without ever touching the brake lever. Only way to release the brakes to continue riding is to loosen the bolt holding the brake line onto the caliber and release the pressure.
I contacted the dealer and he said he's never heard of this issue. To me it seems like a line is close to a heat source thats expanding the fluid. Again never made a brake application for this to happen and once i relieve the pressure the brakes are fine for the rest of the ride, And again its happened 3 times on 3 rides all within 5-10 mins of the ride and when the brakes are locked up I cannot even budge the hand brake lever but once the pressure is released all is fine.
Any help would be GREATLY appreciated
 

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I had this issue on my 2014 after i had a hard crash. My rear brakes wouldn't release after an application. When i crashed my bars went forward and pinched the rubber brake line against my rox handle bar riser. It wasn't visible but the inner hose was pinched and wouldn't allow the fluid to return to the master cylinder. It might not be the same issue, but i thought i would share.
 

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Welcome from Colorado.
I doesn't matter if this is new to the dealer, take him for a 10 minute ride and let him see it happen, then fix it with new parts as required.
 

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Hey...jasonm...Welcome to GC from Wisconsin.

I've seen a problem similar to yours on a 2015 and a 2016 Griz. We found that the foot brake pedal was sticking on the pivot point causing the brakes to drag, overheating the brake fluid, locking up the brakes.
We used a file to ream out the pivot hole and the problem never came back.

It seems that the riders didn't knowingly step on the pedal. I was riding in the back and noticed their brake light was on
 

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When mine was new from the dealer I discovered that the throttle cables were routed incorrectly during dealer un-crating/assembly.
It was a bit more involved than just sliding the throttle off the handle bars.


I had to completely remove the handle bars to fix. I all ready had the "Yamaha Assembly Manual" P/N LIT-11666-22-42 from my previous 2010 Grizzly
for reference which helped in the discovery and remedy of the problem.
Otherwise I might have ridden it that way and found out the hard way.


If there is "air" in the line and it heats up enough "expands" maybe the cause. But the lines should have never been opened during dealer un-crating/assembly.
I can't imagine that the hydraulic/brake fluid can expand.


I would double check all handle bar cable/wiring routing. The line could be getting pinched after turning the handle bars a few times while riding.
To troubleshoot try not riding and just let it warm up with out handle bar movement, or just move the handle bars several times like your riding it with out warming it up.


Also when it's not locked up try applying/pumping the brake to see if if feels soft/squishy or normal. Also I would jack the wheels of the ground while performing these tests
to see if there is much drag.
 

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in normal operation, a brake system is open to the reservoir through the compensating port. its located at the first 1mm of piston travel, so when you touch the brake pedal, the piston slides past the port, and then builds pressure, when you take your foot off the port is exposed and fluid can return to the reservoir. if the port is blocked, by debris, by incorrect pedal free play, or by something like a pinched or blocked hose then pressure builds up in the system and the pads get applied harder and harder.

id guess that the pedal isnt returning all the way or something got bent
 

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Great Explanation!
I didn't know exactly how the system new how to hold pressure or not.
It's like a thermos, how does it know to keep cold thing cold, and hot things hot?
 

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in normal operation, a brake system is open to the reservoir through the compensating port. its located at the first 1mm of piston travel, so when you touch the brake pedal, the piston slides past the port, and then builds pressure, when you take your foot off the port is exposed and fluid can return to the reservoir. if the port is blocked, by debris, by incorrect pedal free play, or by something like a pinched or blocked hose then pressure builds up in the system and the pads get applied harder and harder.

id guess that the pedal isnt returning all the way or something got bent
Just a little clarification, the compensation port is in the master cylinder not the caliper.

I've only seen this on the rear brakes. As I said earlier the brake pedal was the cause.
 

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Discussion Starter #9
Good day
Thank you to everyone who put in the effort to give their 2 cents on the issue.
The machine was returned to the dealership as the issue was not just mine but I was the first person to buy the new 2019 grizzly from the dealership. A customer bought a new unit and as they were loading it up the service manager noticed the brake light was on.
Upon investigation they noticed the hand brake at the handlebars was installed wrong from the dealership which was causing a slight brake application which was causing friction at the caliper and causing heat which pressured up the line.
They inspected the rest of the units built and they were all the same. Once they got my unit they confirmed that was issue
 
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