Front Brakes Wont Disengage

[RoyalRider05]

My brakes are rock hard and engaged up front (dragging). Time to replace master? Any help is appreciated!!

[CaseyJ955]

My brakes are rock hard and engaged up front (dragging). Time to replace master? Any help is appreciated!!

 

Old brake hoses can come apart from the inside out and the rubber can work like a check valve mimicking a frozen caliper. Not real common but it happens. Also a MC can do that as you mentioned. If you crack open the caliper bleeder screw/s and the caliper relaxes then you can start looking at master cyl and possibly a hose.

 

If you crack the caliper bleeder screw and it continues to drag than the caliper is probably seizing and should be removed for inspection. When this happens in my experience the caliper is often the culprit.

 

Old brake fluid is rough on master, slaves and calipers. I hope you get it sorted

 

If you find it a caliper then when you unbolt them they should sort of wiggle off the rotor and if one is seizing and holding on you will know when it doesnt wanna come off

Edited November 5, 2016 by CaseyJ955

[bongobobny]

If you empty your master cylinder and look on the bottom, you will find a little pin hole. This is a pressure relief orifice. Dollars to donuts that little orifice is clogged!

 

When is the last time you flushed the entire brake system out?? This is something that should be done every couple of years or so...

[RoyalRider05]

Just cleaned out master and clucth this summer. I just pulled apart one side of the caliper. WOW its nasty dirty. Found a set of used calipers im going to try! The hole in the master seems to be working. When i pull the lever it squirts! LOL Thanks for the responses. I think i have some rotted seals (just happen to not leak). It took me forever to pull out a piston.......my guess is if its hard to get out, its not going to go retract either!

[CaseyJ955]

It sounds like at some point the flushing was not done. Im with Bongo, 2 years tops between flushings.

Glad you got it nailed.

[bongobobny]

OK, with the wheel cylinders what happens a lot is when the brake pads are changed people tend to neglect cleaning the pistons when changing pads. A lot of the brake pad dust accumulates on the piston and gets trapped within the seals as well!! This is really what causes the pistons to seize up, crud trapped on the piston and in the seals!! Every time you change the pads you should spray brake cleaner all over the pistons to wash away brake dust!!! Do this BEFORE you force the pistons in to make room for the new pads...

[camos]

Every time you change the pads you should spray brake cleaner all over the pistons to wash away brake dust!!! Do this BEFORE you force the pistons in to make room for the new pads...

Following up on this. When cleaning the pistons, after pulling the caliper remove the pads, spray with brake cleaner then use that toothbrush you saved a long time ago. Then put the two pads between the pistons and use the lever to push the piston out. Pay attention to which ones move or don't move easily. Spray the pistons again and brush. Push the pistons all the way back in then spray and brush again. If all the pistons do not move at the same rate do it again.

 

I made a clamp out of 1/8" x 2" flat bar with two nuts and bolts that make it easy to do this job without scoring the caliper.

[RoyalRider05]

Thats extacly what happened!

 

OK, with the wheel cylinders what happens a lot is when the brake pads are changed people tend to neglect cleaning the pistons when changing pads. A lot of the brake pad dust accumulates on the piston and gets trapped within the seals as well!! This is really what causes the pistons to seize up, crud trapped on the piston and in the seals!! Every time you change the pads you should spray brake cleaner all over the pistons to wash away brake dust!!! Do this BEFORE you force the pistons in to make room for the new pads...

[RoyalRider05]

I ended up ordering some used 2009 calipers for 60 bucks from Pinwall! So ill have another set to sell when i clean em up!

 

Following up on this. When cleaning the pistons, after pulling the caliper remove the pads, spray with brake cleaner then use that toothbrush you saved a long time ago. Then put the two pads between the pistons and use the lever to push the piston out. Pay attention to which ones move or don't move easily. Spray the pistons again and brush. Push the pistons all the way back in then spray and brush again. If all the pistons do not move at the same rate do it again.

 

I made a clamp out of 1/8" x 2" flat bar with two nuts and bolts that make it easy to do this job without scoring the caliper.

[bongobobny]

Yup!! +1 on the toothbrush thing, they work GREAT!!!

[Rick Haywood]

I am surprised nobody suggested this but there is an adjustment screw on the brake handle itself that if you adjust ir to tight the same thing will happen. I adjusted mine because the cruise kept kicking off and I thought maybe the lever was to loose. I got it a little to tight and rode maybe 100 feet and the bike stopped and I couldn't get the front brake to release. I turned out the adjustment screw a half turn and bingo off I went.

[RoyalRider05]

I will take a look at that too! But i can tell ya, the pistons on the set on my bench right now are COVERED in black grime.....they were def sticking bad

 

I am surprised nobody suggested this but there is an adjustment screw on the brake handle itself that if you adjust ir to tight the same thing will happen. I adjusted mine because the cruise kept kicking off and I thought maybe the lever was to loose. I got it a little to tight and rode maybe 100 feet and the bike stopped and I couldn't get the front brake to release. I turned out the adjustment screw a half turn and bingo off I went.

[gggGary]

There are two ports in the MC, the big one, and the tiny little equalization port, that little one is the likely source of your problem. While sticky pistons will create drag and poor brake action they will NOT cause a rock hard lever. Please do a full R&R, it's time.

[Rafterd]

Had mine lockup at 70mph once. The little hole in the master cylinder was clogged. Completely cleaned and flushed the front brake system, but also opened the hole a little larger. No more problems.

[RoyalRider05]

They were seriously dirty. Probably need new seals. I ended getting a used set from pinwall for 60

[MikeWa]

All good points but here is another often overlooked item. When pushing the piston back to replace brake pads open the bleeder. This does two things First it keeps old dirty fluid from being forced back into the master cylinder which can cause problems. Second it verifies the bleeder is working.

 

Mike