First waaay too much brake, now no brakes

I worked on my brakes tonight, and obviously have done something wrong.

So my front calipers were sticking closed, holding the front wheel. You couldn't even free-wheel the front when it was on a stand, it was that bad. Since in the many years of ownership I've never re-built the calipers, I decided to do so tonight.

I drained the fluid through the bleeders, removed the banjo bolts, took the calipers off the bike, stripped the calipers down to nothing, ran them through a parts washer (they were waaay crudded up (is "crudded" a word?), so too were the pistons), and put it all back together with new seals and new pistons, liberally lubed with new DOT 4.

After re-assembling on the bike (two new washers on each banjo fitting) and safety wiring everything, the last step was to re-fill with brake fluid & bleed the system. I filled the left caliper up from the bottom with a syringe & rubber hose via the bleeder screw until the master over-flowed. I tried the same thing w/ the right caliper, but fluid was going everywhere from the M/C so I didn't get too far with that.

Now I have next to no pressure at the lever, it comes all the way back to the grip and the pads haven't moved in the caliper at all. On a scale of 1-10, the pressure on the brake lever is maybe a 1. I bled the left caliper, and no air bubbles came out, only fluid. I did the one on the right, and same deal, a little air, but almost all fluid. Finally, I bled the screw at the top of the brake lines next to the master. A lot of air came out at first, but then it tapered off to nothing and now it's all fluid, too, no more air. But still no pressure at the lever.

What did I do wrong? I have dual steel-braided lines coming off a Nissan master if that means anything, and there are no obvious leaks anywhere along the lines.

 

You still have air trapped in the system, most likely the master.

 

If this was one line from the bottom up, it would be fine. Turn this letter "Y" upside down. At the "V" part, call these; the lines from the calipers. Call this "l" in the y; the one line to the master.

As you fill, can you see the oil drop over the V to the other empty line? Didn't you fill one line pretty good, but now you have a bubble trapped on the other line to the caliper? Dave Moss of OTT did a how-to with the reverse oil up the line. He used some pump tool he was pushing. Then he had to bleed the lines for 20 minutes after > Just to get the air out? :wow: :tut:

So you shoot liquid up the caliper. The air bubble meets the other line in the middle. That sends the oil up the master. You now have a long sorta bubble in the one line [semi-filled], pushing fluid up that master's line. Get it?

Breaking the master's banjo is the same action as opening and closing a caliper nipple so that is one trick to try. And that banjo bolt has to be horizontal with the master's bleeder, not the line coming up under the master, meaning, two different travels, one will trap air as in parallel in design over the other being banjo'd under the master.

Knowing the built-in bleeder at the master is so you do not have to break the seal at the banjo bolt. But in your case, there is still the dual banjo/master nipple tag teaming; if the bleeder did not successfully remove the air out of the system.

Next trick is to open both caliper nipples. Pump the master a few times so the flow goes on it's own. If not, then pump and fill the master as you pump away. You will hear the air out of one line eventually; if you could not find bubbles at the master's nipple/banjo, that is.

You just press the master lever down and close the one caliper. Just keep pumping fresh oil out once you release that lever. That one lever release [on the close] is not going send the oil far up the other line. You just keep pumping it as you go around on the other side so as to close the nipple on the other caliper. You should then feel a lever.
_____________________________________________________
Is this where you were real careful on the cleaning? All that grunge can look gone, but a white shadow is left. Once you air dry the caliper all gutted that is, use brake clean, you can see what remains in a white powder from. I'm after that groove in the caliper to be spotless, no gouges!

That new seal has to sit square in that groove. If not cleaned well, well, it will not retract the piston is how it returns to "memory!" That groove has to be picked at with a dentist tool, we are talking cleaning back down to exposing aluminum without tearing it up; removing the white stuff. No shit... Call the dentist for an appointment if you did not perform a thorough groove cleaning.

See that glass smooth finish in the caliper? Take 100% cotton to wipe out and clean that original finish. Anything else, you expanded the area. I love hearing the sandpaper or scotch-brite attacked on that finish, was not too bright, if you think about it.

 

1. pump brake lever several times
2. hold brake lever
3. open bleed screw
4. close bleed screw
5. repeat as necessary

You'll eventually get the air removed and start feeling pressure right before you give up thinking you're doing something wrong.

 

This works every time for me.

Get a plastic fluid bottle (brake, oil, ect..) A glass mayo or pasta sauce jar works also
Weight it w/ a couple of bolts ect..
put about 2" of brake fluid in it.

Now, drill the cap to accept a length of hose whose I.D> will fit snugly on your bleeder fittings. I prefere clear hose.
Drill a smaller hole to act as a vent.
Put hose through hole in cap, make sure end of hose is submerged in fluid.

Open your bleeder valve.
Remove cap from resevoir
Pump brake. If you've made the bleeder tool properly and the end of the hose is submerged, fluid will exit your brake system

Do small pumps at first, you'll notice if you have air, the fluid will try to suck back in. In this case, hold the brake lever to the bar for a sec and do micro pumps to try and work the air down. Also, tap the brake lines with a screwdriver handle to try and work any air up the lines.

I usually bleed the M/C before the calipers. Air travels up, and if you've got all the air out of the pump itself, the rest is easier to bleed.

I've used this method for about 15 years on cars and bikes and the only time it hasn't worked is when a component is bad (i.e. seals in M/C, bleeder valves not sealing around threads, ect...) To bleed a cycle w/ new brake lines should take no more than 15 minutes.

To close, make sure you loop the hose.. I use a chip clip to hold the hose to itself. If you don't, fluid will seep out of it

Hope this helps!

 

also bleed the banjo bolts...

 

I did this as well. I talked to onr of my guys and he said you can out the seals in baackwards. Like I did the first time. If you look at them really close they and the edges aren't flat that are angled. Just something to think about I couldn't get any lever pressure either then I took them apart flipped a few rubber rings and it was like magic. I am not 100% sure all brake calipers are like that but mine were on my 06 gsxr 600.

 

How does a person bleed banjo bolts?

I left the bike in the garage with the M/C bleeder open - hopefully the air in the system will find its way up to the top and out. But I honestly can't remember right now if the cap is on the resevoir or not. It was about 1:30 this AM when I quit working on it.

I hope the seals are not directional. I didn't see any difference in their shape/build, and the book didn't mention that they were directional.

If I can't fix this tonight I'm pretty much screwed and probably won't go to RRR this weekend. I can't take a bike down with me and not know if it'll run right or not.

I'm going to try to put a Mity Vac on the top-most bleeder this evening and see if that'll help. If not, I'll re-evaluate tonight.

Thanks.

 

It sounds like when you tried to reverse bleed the right side you trapped an air pocket in that line. If the left caliper and line was full (to over-lowing the reservoir), then adding fluid to the right caliper from the bottom pushed air from the caliper to the master. Do it the old fashioned way on both sides, as you probably have air in both lines. Push the pistons all of the way into the caliper (reduces volume of fluid in system) and bleed down. If you use a miti-vac you will witness bubbles coming from around the bleed screw. Just give it an old school bleed and your problem should go away. Expect it to take a while on the right side, but the left should be good.

To bleed banjo bolts just put some pressure on the lever and crack the bolt. Catch the fluid with a rag and watch for bubbles.

 

Like pscook said, compress the pistons and try again. I had the same thing happin last time I rebuilt my calipers. I must have somehow gotten some air trapped in the bore. I couldn't get it out no matter how much I blead until I recompressed the pistons.

 

On the 2006/2007 GSXR, as well as on the 2002 GSXR, and possibly many in between, the seals are NOT directional. They may look that way in the manual, and in the fiche, but those seals are NOT directional. It is the bevel of the machined grooves that the seals go into that is tapered, not the seals themselves.

Don't drive yourself crazy trying to figure out the direction of the seals like I did. One side of the seals is gray, and the other is black. I kept looking and looking at the stupid things imagining that I was seeing a subtle taper of some kind. But there was none. It does not matter which way they face on the GSXR, for what it's worth.

I don't even know if your bike is a GSXR, but I thought I'd let everyone know for future reference that the seals are not directional those models.

 

Tap calipers and master with a small hammer, you have air trapped somewhere, and it doesnt take a lot either. Try moving the bars lock to lock, anything that may dislodge an air bubble.

 

The pistons have not emerged from the calipers at all. There's no pressure to force them out (yet). I guess I should have mentioned that earlier. The more I think about it, the nervous-er I get. I suppose I should just hope the vacuum bleeder helps/fixes the issue.

In general, in tracking an issue like this down, is it best to bleed from the top down (M/C bleeder then right caliper then left caliper) or the bottom up (left caliper then right caliper then M/C bleeder)?

I like the idea of forcing fluid into that right caliper again. The more I think about it, it may have been forcing fluid into that caliper that pushed the air in the caliper/line up and elevated the fluid in the line above it up and out through the M/C.

 

bleed the banjos the same way u bleed the bleed screws, except cover then with a paper towel, squeeze lever, crack open banjo bolt and close banjo bolt.

also squeeze the mc reservoir tube.

 

You are right. The fluid from below pushed the air up, forcing the existing fluid to boil out of the reservoir. Do you have a bleeder nipple at the master? Use it when forcing fluid up the line. Or just use the master cylinder to push the fluid down to the right caliper.

 

You have air in the lines....thats all.

 

No shit, Capt. Obvious.

976, try this.

http://forums.13x.com/showpost.php?p=2449515&postcount=3

Same principle as Slowstad is talking about, just a easier execution. One thing I've found over the years of fighting with break systems is that on some systems Mighty Vac simply won't work. When it doesn't, I've learned to use this method and have seen it work first hand.

 

Well, nothing's working. The jar method: I improvised two water bottles w/ clear tubing. Brake fluid (barely-) comes out, but no air, well, a few grains of sand worth of air bubbles, but nothing appreciable. The brake lever still just flops around, no real resistance to speak of at all.

In the meantime I tried just "regular" bleeding. I managed to pump about 8-10 reservoirs worth of brake fluid through the system down to the calipers and out the M/C bleeder, but it's just clean fluid goes in the reservoir and comes out the bleeder.

With all the bleeders closed, I can see the pistons move out and in about .5 - 1mm when I squeeze the lever, but they haven't emerged to the point that they're contacting the rotor at all. They've got 3-5mm more to go before that happens.

I thought the Mityvac was doing a great job, tons of air bubbles in the line. I guess it was just sneaking past the seal on the outside of the bleeder and getting in the tube.

I'm screwed and have no time to try anything else and no idea what I would try anyway. Thanks for the input/help ('cept you, SpeedyE).

 

Take the trip, someone in the pits should be able to help you.

 

I'll try to bring my brake bleeding set up with me. If you show up, we can mess with it down there.