Help...brake problems

[Bm1997]

My car is down so I need my bike for transportation right now. I was changing my front brake hose and I spent hours trying to bleed it and get it working again but no matter what I do I can't get any pressure on my brake lever. What am I possibly doing wrong? Could I have some how messed up the MC? 

[ClutchinChrisG]

They are just a pain to get started manually. You can get the flow started in a pinch by following this process:

Crack bleeder, pull lever, close bleeder, release lever, repeat.

But I would expect at least 15 mins if you're fast at this. Now if you can pick up or borrow a vacuum bleeder you'll be done in a couple minutes.

[Rhinoracer]

After pumping the lever for about an hour, I had to leave the MC positioned so the  holes in the reservoir were the highest point with no curves in the hose. I left it overnight.

 

[ClutchinChrisG]

If you're problem is no fluid to the caliper. Interesting idea, might help remive the caliper and hold it higher than the MC while doing a pumping bleed. This would keep the fluid from swapping places with the air in the lines so the MC could stay primed. Never tried this, just a thought.

[Bm1997]

1 hour ago, ClutchinChrisG said:

They are just a pain to get started manually. You can get the flow started in a pinch by following this process:

Crack bleeder, pull lever, close bleeder, release lever, repeat.

But I would expect at least 15 mins if you're fast at this. Now if you can pick up or borrow a vacuum bleeder you'll be done in a couple minutes.

I will get a vacuum bleeder tomorrow and hopefully that will work

[mtnpat]

Go to your local farm store and get a large syringe. Then go to your local hobby shop and get some standard size silicone model engine fuel tubing. Crack the bleeder valve on the caliper and use the syringe and hose to push the fluid into the system and up to the master cylinder being careful not to overflow the reservoir. Air bubbles naturally want to flow up and I have never not gotten a successful bleed this way. For the final step after finishing and closing bleeder, pull the brake lever and use a cable tie to keep it pulled, leave it like this overnight. It does hurt to also lightly tap on the brake line and master cylinder to get any stubborn bubbles moving.  Doing this last step let’s any bubbles in the system find there way out. 

[Bm1997]

23 minutes ago, mtnpat said:

Go to your local farm store and get a large syringe. Then go to your local hobby shop and get some standard size silicone model engine fuel tubing. Crack the bleeder valve on the caliper and use the syringe and hose to push the fluid into the system and up to the master cylinder being careful not to overflow the reservoir. Air bubbles naturally want to flow up and I have never not gotten a successful bleed this way. For the final step after finishing and closing bleeder, pull the brake lever and use a cable tie to keep it pulled, leave it like this overnight. It does hurt to also lightly tap on the brake line and master cylinder to get any stubborn bubbles moving.  Doing this last step let’s any bubbles in the system find there way out. 

How have I never thought of this method.... actually why hasn't anyone else on the internet? I looked all over today not understanding why I couldn't get it to work and I saw many many complicated methods. But this is so simple and brilliant. Thanks!

[mtnpat]

2 minutes ago, Bm1997 said:

How have I never thought of this method.... actually why hasn't anyone else on the internet? I looked all over today not understanding why I couldn't get it to work and I saw many many complicated methods. But this is so simple and brilliant. Thanks!

I think it’s a pretty common method for both motorcycle and mountain bike brakes. The trick is to not introduce too many new air bubbles into the system and to have a large enough volume syringe that you get a complete bleed without having to detach and reattach the syringe. The pulling the lever, opening the system and leaving it pulled trick really does work, for both hydraulic brakes and clutches. If necessary, but it usually isn’t, finish off with the more recognized method of bleeding by pumping the lever and holding it, then opening and closing the bleed screw (with a piece of hose directing the brake fluid into a bottle, you don’t want that stuff getting on your paint or anywhere else really), use clear hose so you can see if any air bubbles come out. 

[jjktmrider]

I started with the reverse bleeding a few years ago after getting tired of some of these mc's doing just as your describing . They get airlocked right at the little hole/valve at the bottom of the reservoir . One way I have had success with otherwise is to very , very rapid actuation, like the speed of a sawzall in/out ,just not full travel needed .Pressurizing the mc reservoir works ok as well if you have one of those systems. I've used the syringe tip and forced fluid directly into that little hole to get things started(bleeder screw on caliper cracked loose , then keep the res. topped off as it fills the line and caliper till it's running out the bleeder . If there isn't a big upward arc in the line you often don't need to much bleeding . Lots of ways to get it done .

Edited April 21, 2018 by jjktmrider

[mtnpat]

2 minutes ago, jjktmrider said:

I started with the reverse bleeding a few years ago after getting tired of some of these mc's doing just as your describing . They get airlocked right at the little hole/valve at the bottom of the reservoir . One way I have had success with otherwise is to very , very rapid actuation, like the speed of a sawzall in/out ,just not full travel needed .Pressurizing the mc reservoir works ok as well if you have one of those systems. 

The rapid actuation of the lever thing works great on Shimano MTB hydraulic brakes, it can get air bubbles out of the system without having to do a whole bleed with tools and fluid, etc. Good tip!

[Newjorciks]

Just yesterday I had the same problem. I would bleed it completely to the point that no bubbles at all are coming out the bleed valve, but still didn't have pressure. I have a front caliper with 4 pistons from a ZX6R. I took it off the bike, put a wood piece in place of the brake disc and while my dad was actuating the brake, I was turning the caliper all around and tapping it with a rubber mallet. After that, did a few bleeds again and some huge bubbles came out. Had good pressure after that.

So probably lightly tapping the caliper, even without removing, could help dislodge some of those pesky bubbles.

[1hp]

even with a vacuum bleeder i still had to use the zip tie method. it really works, just takes patience.