Hey Dave what do you mean about being air locked?
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There is air in the Master cylinder and it is preventing the flow of brake fluid through the small passages between the reservoir and the cylinder bore.
Brake fluid has a high surface tension, so bubbles can form easily and are strong. Most Master Cylinders have to be "bench bled" by connecting a tube from the outlet back into the reservoir and repeatedly pumping fluid through them until the fluid is free of bubbles. Then the line can be connected and the system bled.
Brake fluid has a high surface tension, so bubbles can form easily and are strong. Most Master Cylinders have to be "bench bled" by connecting a tube from the outlet back into the reservoir and repeatedly pumping fluid through them until the fluid is free of bubbles. Then the line can be connected and the system bled.
Thanks Dave for your explanation,I have bench bled many of master cylinders before but its been a very long time ago.If it comes down to me having to take it off I will do a bench bleed.
You can do it on the bike. Just be careful not to spill any brake fluid on anything painted. Have LOTS of rags around!
Took and drained all the fluid out of the master cylinder.I found a ton of crud at the bottom and tryed blowing 100lbs of air through it with the handle compressed which should open the valve correct?The air didnt blow through from either side.So I sprayed brake cleaner with brake line disconnected and kept squeezing the handle.I did notice air bubles and its sucking it in slowly.I hope this is a good thing and that this mean what ever crud is in the small hole is getting cleaned out.
When the lever is pulled, the master is closed. Otherwise it wouldn't be able to push the fluid to the caliper and move the piston...
Get the master torn down right away and clean all the seals before the brake cleaner destroys the seals! You will notice on the label of the brake cleaner can that it says NOT to use it on rubber parts. It attacks rubber.
Get the master torn down right away and clean all the seals before the brake cleaner destroys the seals! You will notice on the label of the brake cleaner can that it says NOT to use it on rubber parts. It attacks rubber.
Its flushed and and I pumped brake fluid through it.I have the manual downloaded I`ll get it taken off soon asap.All I can do tonight dam misquitos nare too hungry.
Also on bench bleeding the master cyclinder from our bike I put a fitting in he hole that the brake line attaches too with a clear peice of tubing so I can see the fluid being pumped through the master cyclinder correct?
Clear tubing is best, but what ever you can make work. I've even used steel automotive brake line before. Just be sure to keep the end of the tube submerged in the brake fluid so it can't suck any air back in.
Thats what I said in post 11, this made it to 50 posts. I think I went to youtube quicker, when i was doing it the first time. My last time, I jacked it up, by not paying attention to the disc pads. I took the tire off, and when I re-assembled the system, I did not look at the brake caliper. If I would have I would have noticed the one brake pad hanging there. then when I cranked up the pressure in the brake lines, I set the caliper cockeyed in there. boy did I figure I was screwwwed. I made it though just like you did. a little bit of air pressure to pop the piston, and alot of patience.
Well I should have just planned on rebuilding the MC when I started working on the front brakes.You can see 32 years of crud on the inside when its buried deep with in.
Crap I was working on bleeding the system for about 20 minutes.I have fluid and air along with the crud coming out my bleeder screw.Its just fricken muggy hot along with my sweating profusely I have continue this evening.
I think Im going to have to no other choice.Nothing is working that I have tryed.I took the MC ff the bars and filled with fluid where the line connects.I squeezed the handle and it will suck the fluid in.I hook it up and pump the handle and try to bleed little tiny amounts of fluid and air come out but still builds no pressure.
I was trying to figure out how to get the elctrical line off and Im kinda stumped.Looks like its just a rubber plug that holds the wires can I just pry it?
I was trying to figure out how to get the elctrical line off and Im kinda stumped.Looks like its just a rubber plug that holds the wires can I just pry it?
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Nevermind got it
Ok I need help taking this thing part,anyone got any tips or tricks on how to do this?
thanks
thanks
Whoo Hoo I fixed it.I got front brakes again
corruptmind
XS400 Addict
Congrats. Now dont forget how much power you have in your hands and overbrake. 
Oh I know all about it already I was thrown off the bike last year when they locked up because of over heating.
Under Dog
XS400 Addict
YES!!!! Glad to hear!!!
