[Pagman]

My front brake oil looked like French pressed coffee so I decided to bleed it in order to replace it with new brake fluid. I've never done this before but I have seen others do it. I thought I knew what I was doing and my front brake lever is now soft. I started by opening the nipple on the caliper. I then pressed the brake lever to release some brake fluid. A squirt of oil shot out of the nipple. While keeping the lever closed in, I then closed the nipple. I pumped the brake lever a few times and then repeated the process. I had fresh brake fluid readily available and tried to avoid letting the reservoir being exposed to air, but I believe I did.

I attempted to pump the brake a few times while the nipple was closed and then opening the nipple while the brake lever was held in. Only a sad stream of oil falls out as opposed to a straight squirt. I tried this a couple of times and still cannot get the lever to firm up with pressure. Also, I do not see the air bubble floating up in the reservoir as I pump the lever although the new brake oil has been flowing through the nipple. Nothing appears to happen to the oil when I apply the brake. What am I doing wrong??

 

[GFISH]

I attached a 1/4 in clear tube to the nipple. took the cover off the reservoir. I opened the nipple and started pumping the brake and kept filling the reservoir until clear fluid and no bubbles came out then I locked down the nipple. I did the same to all the nipples. Brakes stop on a dime. I did buy the large bottle of fluid to make sure I had enough to put clean fluid in all the lines.

 

[Ndr]

a brake bleeding vacuum pump IMOP is the best way to go to bleed brakes.

Something like this: http://www.harborfreight.com/automo.../brake-bleeder-and-vacuum-pump-kit-69328.html

1. Attache the line to the bleeder valve (nipple) and the vacuum pump with the cup/reservoir in the middle.
2. Open the Master Cylinder cover, remove any old fluid from the reservoir.
3. Pour in new fluid
4. With the pump attached to the closed bleeder valve, pump a few times to build up vacuum pressure. now open the bleeder valve. This will start to suck the old fluid and any air out of the line.
5. Close the bleeder valve before the vacuum presser completely drops (watch the gauge)
6. Top off the fluid in the MC reservoir. Be sure while sucking fluid through the line that the reservoir does not empty or you will need to start over.

7. Repeat pumping and topping off until all old fluid and air is removed from the system.

 

[Kawi Rick]

I've had the best luck with a miti-vac pump as well. I don't know why, but sometimes these brake systems can be very difficult to purge air from. Keep trying and you'll eventually get it.

 

[Dan66]

Like with cars, it is almost always easier to bleed brakes with two people. One pumping the lever/pedal and one handling the bleeder.

Vacuum pumps are notoriously leaky themselves let alone maintaining a seal on the bleeder.

 

[davidr]

Bike brakes are a pain it the azz to bleed. I have been a professional auto tech for 27yrs, so I know how to bleed brakes and the same thing happened to me, so don't feel too bad.

Now that you have all the old fluid replaced, there are a few things you can do.

1. The Mityvac suggestion is a good one and they do come in handy for other things. This is not a cure all, however. I own an air operated vacuum pump for bleeding brakes and still had issues.

2. Remove the caliper from the mount and raise it above the lever (w/ the lid on) to allow all the air to escape more easily. (This makes it a two person job)

3. Depress and tie the brake lever to the handlebar over night. I have used this method after replacing the master cylinder with a new one and just couldn't get the lever to firm up. This worked and was the simplest.

Good luck, you'll get it.

 

[Dean]

I have seen in other posts that there might be a blockage in the baffle or valve in the reservoir. Use a toothpick and very carefully wiggle it gently through the valve using only the very tip of the toothpick.

 

[sfair]

1. Remove the top of the master cylinder.
2. Peer down inside and at the bottom, you will see two very small holes.
3. Run a fine copper wire through them to make sure they are clear.

 

[vivadude]

I just did mine and used the "gravity method" on the front and the "crack open, pump, crack shut on the rear. Used my left hand on the bleeder and right on the brake pedal. 1/4 tubing was not tight enough for me. Needed 3/16" ID. Thankfully no problems.

 

[SpinDog]

I used this one recently: Hydraulic Brake Bleeder with good results. I found that orienting the check valve vertically and above the caliper worked best in that any air bubbles naturally rose straight up and away from the caliper. The instructions show the check valve dangling down from the caliper; that orentation didn't work as well.

I too mistakenly ran the reservoir dry at one point and it was just a matter of filling the reservoir with fluid and pumping the fluid through again. It took quite a few pumps to get the fluid flowing again. The piston only moves a small amount of fluid per stroke so it takes some patience if you’ve run it dry.

 

[pcarrell]

I have worked on cars since I could hold a wrench, and I have plenty of grey hair now. I've bled hydraulic lines more times then I care to think about. I learned how to bleed using the pumping method, but that takes two people on a car. I then learned about gravity bleeding and was in heaven for many years. Thing is, it takes time and uses a good amount of fluid. When it came to bikes, I would gravity bleed, but because Dot4 is more expensive, it got costly. I then came across this ( http://www.gadgetjq.com/hydraulic_bleed.htm ) and ran down to my local Tractor Supply store (they're on line too) and bought me a syringe and some clear tubing, and all is good in the world again!

 

[colemantle]

a brake bleeding vacuum pump IMOP is the best way to go to bleed brakes.

Something like this: http://www.harborfreight.com/automo.../brake-bleeder-and-vacuum-pump-kit-69328.html

1. Attache the line to the bleeder valve (nipple) and the vacuum pump with the cup/reservoir in the middle.
2. Open the Master Cylinder cover, remove any old fluid from the reservoir.
3. Pour in new fluid
4. With the pump attached to the closed bleeder valve, pump a few times to build up vacuum pressure. now open the bleeder valve. This will start to suck the old fluid and any air out of the line.
5. Close the bleeder valve before the vacuum presser completely drops (watch the gauge)
6. Top off the fluid in the MC reservoir. Be sure while sucking fluid through the line that the reservoir does not empty or you will need to start over.

7. Repeat pumping and topping off until all old fluid and air is removed from the system.

I've got the brake bleeding blues too. I finally gave up and ordered a vacuum pump kit. Should be here Tuesday. If I'm reading this right does the vacuum kit replace the fluid while bleeding the lines at the same time?

 

[ktek01]

One nice thing with the vac pump, suck most of the dirty fluid out of the master before bleeding and refill with clean. Keeps you from having to pump all that dirty fluid through your system.

 

[davidr]

Colemantle, No. You have to manually pour in new fluid. And like ktek01 said, suck the fluid out of the master first.

 

[colemantle]

No. You have to manually pour in new fluid.

Ok right. I didn't say that quite right. The vacuum pump allows you to change the fluid and bleed the lines simultaneously? While you manually put fluid in the reservoir. Is that correct?

I couldn't get the air out of the rear lines yesterday. I was trying to do it according to the shop manual.

 

[Izzy's08V2KCLT]

I used this one recently: Hydraulic Brake Bleeder with good results. I found that orienting the check valve vertically and above the caliper worked best in that any air bubbles naturally rose straight up and away from the caliper. The instructions show the check valve dangling down from the caliper; that orentation didn't work as well.

I too mistakenly ran the reservoir dry at one point and it was just a matter of filling the reservoir with fluid and pumping the fluid through again. It took quite a few pumps to get the fluid flowing again. The piston only moves a small amount of fluid per stroke so it takes some patience if you’ve run it dry.

Used the same bleeder as SpinDog and had good luck with it. $15.00 from Amazon. Get the optional 4 ft length of tubing because there isn't enough included with the bleeder. If you use a syringe and put fluid in the tubing attached to the bleed valve and then hook up the check valve, you won't get any air in the caliper. Always bleed the farthest from the brake cylinder first and work your way back. PITA but it works. Bob

 

[Phil Manwarren]

a brake bleeding vacuum pump IMOP is the best way to go to bleed brakes.

Something like this: Harbor Freight Tools – Quality Tools at Discount Prices Since 1977

1. Attache the line to the bleeder valve (nipple) and the vacuum pump with the cup/reservoir in the middle.
2. Open the Master Cylinder cover, remove any old fluid from the reservoir.
3. Pour in new fluid
4. With the pump attached to the closed bleeder valve, pump a few times to build up vacuum pressure. now open the bleeder valve. This will start to suck the old fluid and any air out of the line.
5. Close the bleeder valve before the vacuum presser completely drops (watch the gauge)
6. Top off the fluid in the MC reservoir. Be sure while sucking fluid through the line that the reservoir does not empty or you will need to start over.

7. Repeat pumping and topping off until all old fluid and air is removed from the system.

can you fix the web sight thanks

 

[CRU]

can you fix the web site thanks

Search the HF site for brake bleeder. You find a few options.

Harbor Freight Tools – Quality Tools at Discount Prices Since 1977

 

[Sabre-t]

can you fix the web sight thanks

Like CRU said, search HF. The post you are asking about is 8 years old.

 

[JohnnyV]

Oops.