Front brake locked up after installing braided stainless steel brake line


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liv4spd

New Member
I have a 2012 Yamaha FZ6R. Its brakes were working perfectly fine before. Over the past weekend, I went ahead to replace the front brake lines with Galfer Braided stainless steel brake lines and also installed new ebay clutch and brake levers.

At the end of my test ride (about 4 miles) a couple of days ago, the front brake seized up completely. I had to use a 8mm wrench to open up the bleeder nipper and release some brake fluid in order for it to work. After that, it worked perfectly ok again. I thought the cause was because I put too much brake fluid in the reservoir (on the handle bar).

Then, I experienced the same issue again today, even though the brake fluid is no longer overfilled. Now I am confused What is the problem here? What did I do wrong when I replaced the brake lines?

Many thanks!
 
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liv4spd

New Member
It turns out the cause is the new brake levers!!!

If the new brake lever has a flawed design (too shallow of a dimple hole) and does not allow the plunger to release ALL of the way, your brake fluid will not bleed back into the reservoir when you release your lever.

In a nutshell, as you pull on the lever it moves the piston. But before the piston moves, the master cylinder uses the reservoir to load the chamber with brake fluid through a small feeder port. For the brakes to build and apply pressure, the piston movement down the bore seals the feed port from the reservoir so pressure can build in the brake line to the caliper.

IF the piston is partially depressed it closes that port! BUT - the brakes still appear to work fine as they apply pressure and release pressure. But - with the port blocked, the expanding fluid can not return to the master cylinder as heat builds. The next place it can go is to force the caliper pistons outward and apply the brakes as it did in your case.
 
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Bloo

New Member
in order to be helpful why not post what brand of levers you purchased so fellow owners can know what to avoid.
 
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Scott_Thomas

Insert title Here
Elite Member
Most aftermarket knock offs end up having to be filed down a Lil bit. I bought my red cnc shorty levers a few years ago and knee this was a potential problem so I fixed it during installation.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 

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bobjohnson

New Member
Yep I just got a set of these and the pivot cup was about 3 or 4 mm too shallow. As soon as I put it on I saw the problem, the brake master switch was pushed in slightly once the lever was tightened down. Took a little grinding bit and ground it out, works fine now.

You might also want to look at your clutch lever, I noticed on mine where the cable end sits theres a really sharp lip, you should also probably grind that down or the clutch cable will eventually snap at the pivot point.

Will say that even after having to grind it out, its still a better buy at 22 dollars versus 180+ for pazzo levers.
 
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