Front Brake doesn't work

I was bleeding my front brake yesterday which was mushy and it went from bad to worse. I used Castrol synthetic brake fluid. At first when I pulled the lever fluid would expell from the brake assy bleed valve. But after this happened about six times it stopped passing fulid. During the process I noticed that the master cylinder fluid level never decreased. I ended up taking the line and master cylinder off, and used compressed air to clear what I was hoping was a clog. The air moved through. There are no leaks anywhere in the system. I put the system back together and still no fuild depleation in the master cylinder as I pumped:banghead the lever and no pressure build up despite pumping the lever 100 times and nothing comes out the brake bleed valve. Any ideas? As I write this I was suppose to be riding. Not a great way to start the holiday weekend.

I was bleeding my front brake yesterday which was mushy and it went from bad to worse. I used Castrol synthetic brake fluid. At first when I pulled the lever fluid would expell from the brake assy bleed valve. But after this happened about six times it stopped passing fulid. During the process I noticed that the master cylinder fluid level never decreased. I ended up taking the line and master cylinder off, and used compressed air to clear what I was hoping was a clog. The air moved through. There are no leaks anywhere in the system. I put the system back together and still no fuild depleation in the master cylinder as I pumped:banghead the lever and no pressure build up despite pumping the lever 100 times and nothing comes out the brake bleed valve. Any ideas? As I write this I was suppose to be riding. Not a great way to start the holiday weekend.

You will need to pump WAY more than 100 times if your brake line is empty. It will take days!

You can use the siphon method to re-fill the line, or use a pump. Pump is better/faster.

You need a hand pump like that sold at harbor freight. Make sure it is brake fluid compatible.

-Take the Master Cylinder cover off.

-Remove the rubber insert

-Pull in the brake lever until you can see the valve/hole in the bottom of the reservoir open up

- Clamp/ziptie the lever in place to hold the valve open

- fill reservoir

- insert pump on bleed release valve, and open valve. Leave it open.

- start pumping

- NEVER LET RESERVOIR GET EMPTY while pumping or you will start all over again

- Eventually, you will see solid oil without bubbles.

- close valve

- Check brake lever feel.

- Reinstall rubber

- Test

I bought a brake vacum pump over the weekend and spent about an hour and a half trying to bleed my brakes. I filled the resivor, set up the vacum tool and pumped it per the tool mfg's instructions. When I had significant negative pressure I cracked the bleed valve on the brake and used the vacum pump to draw the fluid through the front bbrake bleed valve. I would get fluid but not a great deal. I filled the resivor about four times during the operation and never let it get empty. I still get some break fluid when I initially apply the vacum, but then as the pressure receeeds I get mostly air. After each vacum application I close the bleed valve. The Master's Resivor and rubber lid boot are off during the operation.

I still cannot get the slightest bit of pressure in the break line after all the time spent using the vacum tool when I pump the brake handle. Note, that I didn't have any fluid leaks. The project began because I had to use too much effort to lock the front wheel and believed that there was air in the line.

Any suggestions?

If you are sure the line has oil in it from top to bottom and you just have some bubbles. Leave the cap and rubber out. Tape the lever to the bars over night. Make sure the master cylinder is level and see if that helps.

It will take about 8 master cylinder fills to fill up the hydraulic line with oil.......

Do an advanced search for "front brake bleeding" in the CRF forum of your choice (try the 250-450R too). It's a popular topic and yields alot of good ideas.

Take off the brake line and fill the Master cylinder. You need to make sure your getting pressure from the master cylinder first Off. Put your thumb on it and pull the brake lever.

MC needs a rebuild most likely or something is clogging the hose. after all you say you have done these would be the only items i would check....

I did more bleeding using the vacum pump last night and still no pressure. I read the other forums. I think at the point that I have to rebuild the MC. I have the rebuild kit. Hopefully, I can get it working by Saturday AM.

Got it fixed. I rebuilt the MC, and used the heck out of the vacum pump. I probably filled the MC 10 times. It wasn't until my Brother-In Law who was filling the MC decided that he would pump the brake while I was using the vacum at the same time. When he did this we started getting pressure. After that it was all down hill. Still, the thing is that my nephew's 2002 KTM2300EXC front brakes are much faster to engage and with less effort. What are my options?

And thank you all very much for the suggestions. Without your help I would have been banging my head against the wall!

stainless lines and better pads

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