Bleeding front break! Help please!

[Optik]

My dad and I were trying to bleed my front break because it had to be pulled in quite far until it grabbed.

Now when I pull the break in it moves right up to the grip without any resistance, its not grabbing at all! I think the problem is a lot of air in the line or something. What should I do?

 

[Durt Cycler]

Take the cap off and keep the resevior filled with brake fluid. Then get a 8mm wrench for the bleeder on the caliper. Pump the lever about 20 times (make sure there is play in the lever bolt and resevior piston so the air can release) and hold the lever all the way in to the grip. Then have somebody break open the caliper bleeder (he must unscrew it and retighten it real fast aslong as fluid comes out). You might have to do this 5-20 times before you restore pressure.

 

[Optik]

Thanks!

Ill give that a try tomorrow.

 

[Lutz]

Yeah, keep the resevoir filled completely at all times. If you run the master cylinder out of fluid, you suck air into the lines. Also, when the bleeder is opened, you need to keep holding pressure on the lever until the bleeder is closed. When the lever drops to the bar after the bleeder is opened, just hold it there until the bleeder is closed. Then pump it until you get pressure and repeat the process. Not holding the lever down is the most common mistake I see people make when bleeding brakes; if the lever is released with the bleeder open, air will be pulled into the system.

Good luck,
Lutz

 

[levert]

Also,
If you got lots of little bubbles, take the caliper of the front fork leg and hang it from the ceiling above the master cylinder. Leave it over night, yes its tough to bleed up there but all the bubbles will now float up right by the bleed screw, usually only 4 or 5 squezes and its done.

 

[Wallis]

Keep at it. I went through this last night after not holding the lever down while the bleeder was open. It took me quite a while to get all the air out of the system but eventually you start feeling pressure in the lever.

 

[canyncarvr]

Durt said: take off cap, fill reservoir.

Yes. And although implied, but not explicit, KEEP the cap off during the process. If you take the cap off, fill it, put the cap back on, go through the bleeding process...you may find yourself not getting the job done at all.

Use the correct fluid!! Don't mix 4 and 5..AT ALL! Use what it says on the res. cap if you have any questions. Preferably from a NEW bottle..NOT something that's been sitting in your (damp) garage for the past six years.

You know that brake fluid ruins stuff? When it gets ON stuff it's not supposed to? Keep it OFF of stuff as much as possible.

 

[shr]

A tip for cleaning break fluid that spills or gets on things.

The best way to clean up break fluid is water. You can wipe it up with a wet rags or even better, if the situation allows is hosing it off with a garden hose.

 

[splatt]

If all else fails get a vacuum pump from your local auto parts store. I had the same problem you are having used a vacuum pump on it and was done in a couple of minutes.

 

[Optik]

Okay, tried a few of those suggestions but none worked. To me it seems like the pump isnt primed at all. We keep pulling it but nothing happens. With the bleed screw open pulling the lever wont even pump the fluid out, it just slowly drains out itself.

 

[Hogwylde]

OK....here's how to bleed front brakes. SPLATT has the best "costly" way, but there are easy and cheap ways to do it too.

Now, what you have to remember is that air bubbles RISE in a liquid medium. When you are pumping and pumping your master cylinder, you try to force the air DOWN the hose into the caliper. For the little bit of fluid you get per bleeding operation, this takes forever IF IT WORKS AT ALL...which seems to be OPTIK's problem.

So, wadda ya do????? Couple things can work. First, try removing the master cylinder from the handlebars and laying it on the floor. Make sure that the caliper is the HIGHEST point in the system. THEN try the pump, bleed, pump, bleed procedure. You will probably have some success that way.
What I like to do is this....I went to Tractor Supply and bought a veterinary shringe (60cc), and some plastic tubing that fit over the end. This happens to fit over the end of the bleed nipple too. Fill the shringe with brake fluid (plastic tube also...NO air bubbles), then attach to the nipple. Open the bleeder and force the fluid (and any trapped air) into the caliper and back UP to the master cylinder. This will completely eliminate any air in the system and almost guarentee a good brake feeling on the first squeeze.

Just remember to catch the fluid as it fills the master cylinder and overflows.

 

[Wallis]

Keep going. I had to fan and hold the brake lever then open the bleeder valve several (5-10) before I started to see bubbles. Be sure to only open the bleeder for 1-2 seconds and close it quickly, you don't want to allow even more air into the system. Slowly you will start feeling pressure in the system. As others have said - be sure to keep the cap off the resevoir and watch the fluid level.

Persistance will pay off.

 

[Optik]

Thanks guys

I tried a few more of those methods and none have worked so far... I asked the mechanic and he said the best way was with a pump. I can bring my bike in and he said he'd do it in a 1/2 hour so it wont cost too much. I think I'll try the syringe method first though.

 

[jdbrusch]

Optic , try the reverse method as Hogwylde posted,I find on my friends KTM's this is the only way to bleed the clutches it works great on front brakes also, you can sometimes sit there for hours doing it the regular way and get nowhere.the small amount of movement in the master cyl. does not create enough flow to force the air out the same way as in a car system. you can also try to suck the fluid through the system with a syringe from the bleeder nipple this may work also.

 

[shr]

Optik, if your having this many problems, maybe your master cylinder needs to be rebuilt. Also there are little port holes that feed the piston that can get plugged from old fluid and sludge.

Question; Is the plunger (piston) returning all the way back? The lever should have only a small clearance to the plunger in the relaxed position. About a 1/4" play at the end of the lever.

 

[flyinfish]

I've tried all of the aforementioned ways, but the only way my bike will firm up is to take the caliper off of the forks and the lid off the master cylinder. With a screw driver or a c-clamp compress the pistons on the caliper all the way and watch the air bubles come up and out of the master cylinder. Leave the caliper down low when using this method. Now pump the brake handle with long full stroke pumps until the pistons come back out and do it again. This may take a while at first with the lack of pressure but I did notice it's faster if you let the brake handle return fully before pumping again. You may even want to let the adjustment screw out a little. Did it last night took about 5-6 cycles with 50 to 100 pumps of the brake handle in between. I use a mighty vac to get it primed but I have never got it to firm up using only the pump. Good luck!

T.J.

 

[Durt Cycler]

Originally posted by canyncarvr
Durt said: take off cap, fill reservoir.

Yes. And although implied, but not explicit, KEEP the cap off during the process. If you take the cap off, fill it, put the cap back on, go through the bleeding process...you may find yourself not getting the job done at all.

I never said to put the cap back on. :debil: