I put a new front tire on, pumped the brake lever, no brakes.
Checked level, low, figured maybe I pumped some air in, topped up the master, bled brakes with brake lever.
Brakes pump up , but as soon as you try to move bike lever goes to the bars.
Ok tried vacuum bleed, brakes pump up, as soon as you move bike, levere goes to bars.
Ok reverse bled brakes, same thing.
Ok, rebuilt master, same thing.
Ok, installed new master, pumped master to remove air, vacuum bled, same thing.
I'm out of ideas.
Anyone have any thoughts or similar experience?

Bike is 97 flhtcui, with upgraded brakes to the 03-07 style.
Brakes have worked fine for years prior to this.
I've probably spent 8 or more hours on this so far, with no luck.
I've bled brakes many times before on bikes and cars, and rebuilt several bike masters as well, though now it's sporting a brand new from dealer zero miles master.

I've checked for leaks and cannot find one as well.
I also, with the rebuilt cylinder taped the handle all the way back overnight, no luck.
I've probably pumped a bottle and a half of fluid thru system by now.
I've also loosened banjo bolts at calpers and pumped fluid out there as well.

 

Try using a syringe and bleeding them from the caliper up into the MC, after that, zip tie the lever back to hold the brakes on and go to Hooters, or wherever you go to distract yourself from your bike not working, don't come back until late the next day and cut the zip tie, see how that goes for you.

Ultimately, you may need to rebuild the calipers.

You have checked that there is no play in the wheel bearings and all the spacers are correct?

 

Yes all the spacers are in place , and bearings seemed fine.
I did a reverse bleed as you mentioned, but will try again with the lever tied back after that .

Why would the caliper rebuild affect the problem?
As nothing else seems to be working I was starting to think about that.
Thanks.

 

Well if you fitted a new master cylinder already, calipers are all that are left to cause problems. Possibly when you pushed the pistons back in during wheel removal, it fubared the years-old seals and they are now letting air in.

 

Yes , but wouldn't that likely let fluid out at the same time?

 

One would think so...

 

They aren't hard to do and don't need all gadgets like vac pumps.

On the side stand, move the bars and the master cylinder till the hose front with fitting is at the highest point but level as much as possible.
Check fluid level.
Gently and SLOWLY work the handle a little, not a full pull, stop when the little bubble steam does.
Give it a few seconds and repeat this process till no more bubbles. This method creates is own suction pulling trapped air up through the lines, why SLOW is critical.
Keep the fluid topped through this whole process. Should have some level by now.
Go to the low side caliper, pull the level in, DON'T pump it and crack the bleeder, reseat. Let go the lever, give it a few seconds and repeat.
Do the other side if it's dual calipers.
Lever shouldn't bottom out. It does there are mechanical issues yet like pistons stuck, seals or the master isn't doing it's job. And yes, new doesn't mean good.

Yet to have this method not get the desired results on non ABS bikes. SLOW is the trick here, give the trapped air time to rise, most go after that level like they jacking it off.

 

Lets start with basics, and assembly 17, has to be all the way back, before it going to allow the fluid from the reservoir, to allow fluid to flow downwards/air back up..


Caliper wise, need to make sure that piston is not stuck in caliper channel, but more so, have to make dam sure that you do not use a petroleum grease on slip pins, or O ring 12, since will swell the O rings up, and cause the caliper to bind up as well. On these parts, you have to use a silicone based grease.

So best guess, if you don't have air in the lines, the calipers and brake pads are mounted correctly and not binding, then have a problem with the upper plunger not sealing off fast enough, or not spring all they back out to allow the system to pick up new fluid. If such is the case even with new lever assembly, then not hard to pull the plunger assembly to check the plunger U seal,spring, and channel, to make sure that that they are clean and good, and moving/sealing correctly in channel.

Myself, since will be using silcone brake fluid, like to lightly coat the plunger parts and channel with light coat of slilicone grease, then reassembly, with a few pushes, and rebounds on the plunger assembly to make sure it coming all the way back. Also, on U plunger seal, like to slightly bend it lips back as I coat it with silicone grease, to make sure it going to flair out correctly to seal as well. Once you have brake working and pressure on the lever, can gorilla grip the lever to flair the seal out more in the channel.

Note,with pistons pushed al the way in to install new pads and remounted, once you do have air out of the system, will need to gently pull the levers in, slowly release it all the way out and over and over a few times, to allow the piston to be pushed out far enough by the new fluid in the line from the reservoir , that the caliper can center on rotor with both pads making contact to start with, before your going to get brakes again at the lever. Same goes for rear brake as well.

Short of that, last person used wrong brake fluid, and lines are just toasted with either crystalized build up, or collapsed from same instead,

 

Nope, they keep the fluid in the caliper, it isn't the calipers leak but rather the distortion seals do weird stuff and can either cause the pistons not to retract, or to retract too far.

 

Ok thanks.