[fencingdude101]

Hey all,

I rebuilt my front caliper today (i.e. new seals, cleaning and lubing) and after reinstallation, I cannot for the life of me bleed the brakes!
New brake fluid comes out of the bleeder valve, but no matter how much I bleed out, the brake lever pulls all the way in with absolutely no translation to brake force (With the valve closed, of course).
I don't know if I have air somewhere or what, but I really need help and have no idea what to do.

Thank you,
Grant

 

[Smash]

Sounds like you need to recheck everything you did. Something isn't seated correctly or tightened down right or you missed a seal somewhere or one of the pistons isn't smooth.

 

[fencingdude101]

I think it has to be an air problem. If a piston wasn't smooth, I don't think the lever would pull in with no resistance like it does. Also nothing's leaking, so I don't think I missed any seals.
My only idea right now it that maybe I didn't push the pistons all the way in? Not sure if it's possible to get air out from behind the pistons?

I ziptied the brake lever pulled open to see if any air would clear out, I'll check it in the morning. I may just have to take it apart again and recheck some things... Though the piston situation is my only idea.

 

[Smash]

Let us know what you find in the morning

 

[DaddyFlip]

Brake inspection today- not looking good

I rebuilt all three calipers on the ZR7. I had a big problem on the front with air. I ended up using a syringe and tubing to fill the whole system through the bleeder valve. This pushed all the air to the top. The main problem area was right at the master cylinder. If you have time to read this thread and look at the pics, I think you will find your answer. Be patient. My fight against air starts at post #60. Good luck.

 

[fencingdude101]

Brake inspection today- not looking good

I rebuilt all three calipers on the ZR7. I had a big problem on the front with air. I ended up using a syringe and tubing to fill the whole system through the bleeder valve. This pushed all the air to the top. The main problem area was right at the master cylinder. If you have time to read this thread and look at the pics, I think you will find your answer. Be patient. My fight against air starts at post #60. Good luck.

Thanks for the link, I'll look over that a bit if I have time at work or afterwards.
At this point, there's nothing else it could be other than a ton of air. Pumping the lever pushes fluid out of the bleeder valve, the caliper moves back and fourth along the pins easily, etc. I know I don't have stuck pistons, otherwise the handle wouldn't move at all. Here's what I'm going to do:

After work, I'm going to buy a better tube (The one I was using is a bit too big) and new banjo washers. I'll spend up to 30 minutes bleeding the brakes more, reusing brake fluid if I have to
If nothing comes of that, I'm going to remove the caliper again. I'll pump fluid through the line (from master cylinder, through brake line, out of banjo bolt that would connect to caliper) and get that all free of air, just in case. Then, since if it's air, there's nowhere else it would be than behind the pistons (At least to be problematic like this). I'll remove the pistons, inspect everything, push the pistons all the way back in (I'm worried I may not have done that the first time), and reinstall the caliper. I will then continue to bleed the brakes again, being much more cautios.
If THAT doesn't work, I'll try feeding the fluid through backwards or something, and past that I'll need to go to a mechanic.

So, the further up that list I find a solution, the better! And opinions, things I should add or change?
Thanks for the help so far!

 

[Easy Rider]

I rebuilt my front caliper today (i.e. new seals, cleaning and lubing) and after reinstallation, I cannot for the life of me bleed the brakes!

This is a common problem that often can be solved by using the banjo bolts as additional bleeder points.

The best way is to "reverse bleed" from the bottom but if you aren't equipped to do that, try cracking the banjo bolts just like it was a bleeder.
Start at the top one and work your way down to the real bleeder.

Notes:
You need to be real careful with this as brake fluid is an EXCELLENT paint remover....and it eats plastic too.
You almost need two people to do it right.

 

[fencingdude101]

This is a common problem that often can be solved by using the banjo bolts as additional bleeder points.

The best way is to "reverse bleed" from the bottom but if you aren't equipped to do that, try cracking the banjo bolts just like it was a bleeder.
Start at the top one and work your way down to the real bleeder.

I have no idea how to reverse bleed (Past the basic concept) so I will be doing what you said about the banjo bolts tomorrow.

Also, for a little update, I made a tiny bit of progress. At first I thought it was the caliper (With all the air in it for bad brake feel), but after some analyzing and such, even if there was all air in the caliper it would have bled out immediately as the bleeder valve is at the top. At this point, it has to be the master cylinder.

What I did so far- Bleed, ziptie the brake lever overnight, bleed more, remove the brake line from the caliper and bleed the line, bleed more. I have slightly better brake feel and the pads are actually grabbing now, but it still has too much air in it. I think the reason for the air is that some is stuck in the MC, but it doesn't push enough fluid to dislodge the last bit of air.
What I'm going to do- Perform Easy Rider's suggestion and bleed the air out of the MC (Through top banjo bolt), bleed the air out of the lines (Through the bottom banjo bolt again) then bleed any air out of the caliper. If that doesn't work, I'll shake the handlebars a bit and whatnot, then give up. Maybe try reverse bleeding, but I'm all out of ideas after that.

Wish me luck!

 

[DaddyFlip]

The large syringe to fill the system through the bleeder valve will solve your problem.

 

[fencingdude101]

The large syringe to fill the system through the bleeder valve will solve your problem.

Don't worry, I have read your entire thread (I was interested in more than just the bleeding). It sounds like you had the exact same problem as me, I'm just trying to find an easier way around in then going out to buy a syringe. I agree it is at the master cylinder, so that's why I want to try Easy Rider's suggestion first.

Just in case it doesn't work, however(I really hope it does): Where can I get a syringe like the one you used? How do I actually go across doing the reverse bleed?
I know I could do more research in another post somewhere, but I was wondering if you had any tips from when you did it.

 

[fencingdude101]

Guys...

I'm really starting to get scared here.
I tried Easy Rider's method- Using each banjo bolt as a bleeder valve. Pump a few times, hold down, loosen, tighten, let go of lever. I did that about 5 times for each banjo bolt, and more bleeding from the bleeder valve.
It felt better, brakes kinda apply, and it actually holds steady right before the lever hits the handlebar. But still...

Basically nothing.

But dude, try reverse bleeding!

Haha okay, okay, I hear yah! I'm wasting my time doing anything else. Agreed.
I try to figure out where to get a syphon, and the best places I can think of around here are CVS and RiteAid. CVS has one, but it really sucks and is designed for babies. Over at RiteAid, the pharmacy gives me one for free that has a nice seal, though it's a bit on the small side- 5mL. Oh well. It fits the tube perfectly.
I get home and start reverse bleeding, pulling fluid out of the reservoir then pushing it back through the bleeder valve. After about 10 times of doing that, I try for the brake, and--- Nothing.

Okay, so slowly doesn't work like I've been told. I go another 15 times or so as fast as I can (With the cover on, of course). Nothing.
I even try to pump fluid out of the little hole from the reservoir that feeds the master cylinder. Nothing.

What the heck do I do? I said before this was my last idea, and now I got nothing. I don't think the master cylinder seal is bad, because the brakes felt good right before the handlebar at one point. Is there are anywhere else?
What dos thou brakith gods hath to sayith upon me!

 

[fencingdude101]

Welp I think it is the master cylinder, but nothing to do with air being trapped in it.
I took it off and apart, and while everything looked fine (Seals, bore, etc) I then put it back together and tried running some fluid through with it off the bike. Barely any fluid came out (Where the brake line and banjo bolt would be) when pumping it, so I just went ahead and bought a rebuild kit off ebay. I'll update when that comes in and it's installed / tested.

Quick question though, how soft is that bore (The area in the master cylinder that everything sits in- seals, piston, spring, etc)? Should I be worried about something at one point getting in there- like dirt- and scratching it so it doesn't seal properly?

 

[DaddyFlip]

I worked on my brakes for two months. You have not yet suffered unto brake fluid.

Stop. Take a deep breath. Hammer time. Drain the whole thing and get ready to start over. Like open up the banjos and bleeder and let it all drip out. Disconnect banjos at MC also and leave cover off. I used the 60mL syringe from my fork oil leveling kit. You can get one for injecting turkeys with sauce, maybe at wal mart. Fill with brake fluid and hook up to bleeder valve on one side, making sure bleeder valve on other side is closed. Connect all banjos. Slowly, slowly push syringe to fill one side until MC is half full. With syringe still connected, close bleeder valve. Use your small syringe to remove brake fluid from MC, leaving enough to cover the two small ports. Move syringe to bleeder on other side. Slowly, slowly fill until MC is full. Close bleeder. Wipe off any excess. Put MC cap on. Bleed will not be necessary. Assumes your MC components, especially the primary and secondary rubber caps, are good.

The bore is aluminum; just don't gouge it. Actually, you won't get much fluid to come out. Tiny holes; braking system works on fluid hydraulic pressure, not volume. If the two rubber pieces are intact and haven't shrunk, they are good. Rebuild never hurts if you do it properly.

 

[fencingdude101]

I worked on my brakes for two months. You have not yet suffered unto brake fluid.

Stop. Take a deep breath. Hammer time. Drain the whole thing and get ready to start over. Like open up the banjos and bleeder and let it all drip out. Disconnect banjos at MC also and leave cover off. I used the 60mL syringe from my fork oil leveling kit. You can get one for injecting turkeys with sauce, maybe at wal mart. Fill with brake fluid and hook up to bleeder valve on one side, making sure bleeder valve on other side is closed. Connect all banjos. Slowly, slowly push syringe to fill one side until MC is half full. With syringe still connected, close bleeder valve. Use your small syringe to remove brake fluid from MC, leaving enough to cover the two small ports. Move syringe to bleeder on other side. Slowly, slowly fill until MC is full. Close bleeder. Wipe off any excess. Put MC cap on. Bleed will not be necessary. Assumes your MC components, especially the primary and secondary rubber caps, are good.

The bore is aluminum; just don't gouge it. Actually, you won't get much fluid to come out. Tiny holes; braking system works on fluid hydraulic pressure, not volume. If the two rubber pieces are intact and haven't shrunk, they are good. Rebuild never hurts if you do it properly.

I think I have a little while to catch up to you! :sweat:

The master cylinder kit will take a few days to get here- hopefully by the weekend. I'll use that time to get my mind off it, then when it comes in, I'll do the rebuild, install, quick bleed and see how it turns out. If it works, great! If it doesn't work, my dad worked out a deal that he will cover the cost of the kit if it doesn't- he was absolutely sure it would work, so what did I have to lose?
If it doesn't work, I'll go through what you said and do a complete refill with a (much needed) bigger syringe. Luckily I only have one rotor/caliper, so I don't have to worry about draining and filling two. And if that doesn't work, then I'll bash my head into a wall! :smashfrea
One question on the refill: do I need to drain the caliper? Take it off the bike and get all the fluid out, or is it okay if there's still fluid in there? Thanks for all the help, I appreciate it.

 

[DaddyFlip]

Leave it. Don't have to take it off again. Yes; walk away. I did several times. You have to get the brakes right or the rest won't matter.

 

[fencingdude101]

Leave it. Don't have to take it off again. Yes; walk away. I did several times. You have to get the brakes right or the rest won't matter.

I hear you, the most important system of the bike, with the suspension afterwards.

I think this break is helping my mind relax, and it's nice it's been raining all week and I'm not missing any good weather. Just for future reference, why don't you need to drain the caliper? Couldn't there be air stuck in there still?

 

[fencingdude101]

Update:

I got everything in for the master cylinder rebuild and the uber reverse bleeding attempt!

The syringe is 100ml, so I think it'll work just fine. As for when I'm doing the work, I've been crazy busy at work today, so we'll see how things go.
Tomorrow (hopefully), I will rebuild the master cylinder, making certain that it is not the problem I'm having right now (Assuming the bore isn't deeply scratched, which I couldn't see). Then, I'm using the syringe to reverse fill the MC with fluid. Hopefully, that's all I need to do, and after a quick normal bleed or whatnot, my brakes will be back to normal.
If not, I'm going to drain everything again, buy another new bottle of brake fluid, then refill by reverse bleeding. That gets rid of any possibility of air bubbles causing the bad feel.

We'll see how things go, I'll send out an update tomorrow night!

Edit:
For those who need to buy a syringe, this is where I got mine: http://www.amazon.com/EcoPlus-740610-Syringe-100CC-ML/dp/B002JLJDQ0
100mL/cc, ~$6.50, fits a 3/8" ID tube tightly (Can fit a 1/4" with a clamp), qualifies for Amazon Prime, and seems like it will work great!

 

[DaddyFlip]

I hear you, the most important system of the bike, with the suspension afterwards.

I think this break is helping my mind relax, and it's nice it's been raining all week and I'm not missing any good weather. Just for future reference, why don't you need to drain the caliper? Couldn't there be air stuck in there still?

Based on the orientation of the caliper when it is mounted to the bike, the highest point on the caliper is the bleeder valve. That's why it's the bleeder valve! So any air that might be in the caliper itself will rise to the bleeder valve or the banjo bolt and go back up the brake line. Brake fluid remaining in the caliper will pool at the bottom and not contain any air. My opinion is it's best to leave the caliper mounted to perform this work.

Looking good on the kit and syringe. I think you're headed in the right direction. IMO, you will love the reverse fill and will never try it differently again.

 

[fencingdude101]

Man, what a day...
One problem sorta fixed, another sorta showing up. Let's run through today...

I rebuilt the master cylinder and reverse bled the brakes with the large syringe: No go. What the heck?! I thought about it for a little; It can't be the master cylinder, it can't be air, so it has to be the caliper. After a few minutes of thinking- I knew that the caliper itself wouldn't be the problem, as any issues with it would only lead to lack of brakes/lockups/leaks- I realized it must be the things I changed: pads and a rotor. A little careful inspection brought me to the realization that half the large pad (The pad not being pushed by the pistons) wasn't on the rotor! Every time I would pull in the lever, an edge of the pad would push against the rotor, and most of the pad would then tilt a little bit and barely make contact with the rotor! This was my problem.

I took off the caliper, kinda fiddled with the pads a little, then stuck it back on- the brakes felt better. Useable better. After about an hour of engine-not-running diagnostics (No idea why, but it worked after draining the float bowls, fuel line, filling up the oil, and spending a bunch of time on and off the starter), I finally got to take it around the neighborhood slowly- the brake sucked! It worked though, and I would kinda stop, which I guess is good. I took it around the block for a minute or two to make sure it wasn't a quick bed-in thing, which sadly it was not.

So, all along my pads weren't aligned properly, which caused the horrible brake feel. They're still bad, and I think I need to spend a bit more time on them, but I at least have a new, known problem now. Thanks for all the help everyone!

On a side-note: Any ideas on what to do for the pads? I'm going to make a new thread for this, but do you think I installed them wrong? Looking for opinions on what to try out.

 

[fencingdude101]

As an update to this thread:

I figured out the problem with the pads- it was the caliper pistons. When I first installed them upon the caliper rebuild, they were very tight fitting, and I had to use a vice to get them in the rest of the way. With some help at the ninjette forum, a few members pointed out that the pistons should go in easily, so I took them out and re cleaned/re lubed everything again. After that, bleeding, and a ton of pumping, everything feels good and usable now! I need to tune it a bit more, but they work very well for new pads and rotors.

For the full story: https://www.ninjette.org/forums/show...760#post882760