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yea it does,, its not losing pressure, it never had the proper pressure on the check valve since the brake line was replaced,,,
I can't believe none of you people know that!

Have you tried flushing the system.

Thanks

Ill ask him bout...

1 checking the calipers
2 flushing the system

Mr. Martian...
There is a check valve in there, but it has absolutely nothing to do with holding pressure in the lines. It's solely there so that you can push the cups back in without having to drain and re-bleed the whole system. Back bleeding is an effective way of completely bleeding brakes, but it has nothing to do with his problem, if that was the case he'd need them bled every time he went to use them.
Sincerely,
Mr. You need to go DIAF

Wrider? "its solely there so that you can push the cups back in without having to drain and re-bleed the whole system"? WHAT ARE YOU TALKING ABOUT? THAT MAKES NO SENCE!
did you just make that up?

The check valve is there to hold some presssure in the line so the brakes react more quickly
when you hit the brake lever it takes time for the pressure to build up inside the brake line before the pressure reacts to the caliper, so with a check valve it holds anywhere between 15 to 45 psi on the brake line at all times, even when the brakes are not applied, thats just enough pressure to hold the brake lines, but not to make a reaction to the piston in the caliper,,,, so when you hit the brake lever and you need brakes, the the piston in the caliper will react more quickly because the most of the pressure build up is already there, you don't have to wait untill the pressure builds up in the line before the caliper will react.

tell me?????? why do they always back bleed the brakes when the new motorcyle is assembled at the factory,,, why can't they just pour brake fluid in the master cyl and just pump the brakes like you do?

I understand that just a motorcycle rider like you doesn't understand an elementry concept of a hyd brake system and what a check valve is, but whats really pathetic is when a trainned motorcycle mechanic doesn't know that,,,,, I mean thats scarry, if he would work on my brakes causing my brakes not to work, causing me to wreck.
I am worried about some of you people that have no idea what you are doing repairing your brake system,,,, and when you trust some mechanic that's dangerous and wants to kill you, I say you have a serious problem,,,,,,,so go ahead and make fun of me

I think its funny how some of you people could be so proud and bull-headed that you wouldn't even try to back bleed your brakes, ha ha ha ! I guess the design engineers that over-see the assembly of the motorcycle at the factory are just a bunch of dunder heads because they want to back bleed it, ha ha ha ha ha ! ohhhh yea,,, you guys are sooo more intelligent than the engineer that designed the system,,,, you know better! ha ha ha ha ha ha ,,,, Joe the mechanic down at the local bike shop does it the old fashioned way, he bleeds brakes by pumping the lever and all that brake fluid squirts out all over the chrome on your bike and all over the floor and your tire runs over that oil and makes tracks all over the floor,,,ha ha ha ha ha ha
you know something? I am tired of everybody bringing their bike to me with problems right after they picked it up from a motorcycle shop with a $700 repair bill with the same exact problems and I find a simple problem that takes 3 mins to fix and they never offer me any money or a simple thank you!
sooo I no longer care what dunder-head works on your bike anymore, I try to give good avice cause I have been there, I have experienced that problem in the past and I learned and understand how it works,,,,, you see? you must understand how something works before you can repair it!

just like the Harley guys that tear down their engine cause they feel it wasn't running right, then it runs worse after they repaired it,,,, ha ha ha ha ha ha then they can't figure out whats wrong,,, ha ha ha

you guys are the same way!

You really need to stop spouting misinformation.
Some basics.
Brakes work off of hydraulic pressure.
Pressure at the lever pushes the cups at the caliper out, causing the pads to push against the rotor, causing friction to slow down the rotational speed of the wheel.
Any extra pressure in the system would cause the brakes to drag.
Check valve is there to make sure any extra pressure is bled off, not keep it in there.

Wrider wrote:You really need to stop spouting misinformation.
Some basics.
Brakes work off of hydraulic pressure.
Pressure at the lever pushes the cups at the caliper out, causing the pads to push against the rotor, causing friction to slow down the rotational speed of the wheel.
Any extra pressure in the system would cause the brakes to drag.
Check valve is there to make sure any extra pressure is bled off, not keep it in there.

The way you explain that makes no sence to me? Why would it need a check valve in the first place to bleed off or to release the pressure in the first place? I thought there's a piston inside the master cyl thats spring loaded that always has released pressure when the end stroke of the piston is open to a port inside the master cyl with no spring pressure is applied???/
I explained how a check valve works as simple as possible and i gave the reason why its in there!
If you can't get that then I just give up!
I never work on anything unless i totally understands how it works,,, all I know years ago i had the same problem when I had a brake fluid leak on one of my older bike,,, yes, i made that mistake of bleeding it the old fashioned way and I couldn't understand why I could never bleed it right then i found out by firguring it out that there's a check valve in there thats constanly holding pressure and the only way to defeat it was to back bleed it, It worked!
maybe you should be ashamed to give out wrong advice about an important saftey system such as brakes!

tell me this??? what would it hurt or harm if you would back bleed it?
is back bleeding sooooo horrible?
would it harm your brake system if you would back bleed it?
what would it hurt to try it?

yea,,, I know, it would hurt your feelings to know i was right and you was wrong,,,, huh?
its not a pissing match, I just want to help the guy with his problem

Check my post from April 6th at 5:01 PM.
"Back bleeding is an effective way of completely bleeding brakes, but it has nothing to do with his problem, if that was the case he'd need them bled every time he went to use them."

The check valve holds fluid in the system, but bleeds off pressure as soon as the brake lever is released. You cannot have constant pressure in a motorcycle brake system or you will have constantly dragging brakes. Not sure how else to explain a simple concept like that.