So I've been searching for some help and can't seem to figure this out. I cannot get fluid out of my rear caliper when bleeding. It only gets about 2" in the hose then won't move, only to start going back into the caliper. I lost my back brake completely when the hd shop put new tires on. After pumping I got some back but nothing I could use. Now it's back to no brake and I've been trying to bleed this bastard for some time. Is my master cylinder shot? Or am I doing something wrong? Is it reasonable to remove the reservoir and check for a clog? The front brake was so easy even with a new line, this rear has me completely stumped. Thanks for any advice

 

It sounds like you may have a rear MC seal problem. It's not unusual for an 8yo bike. The rebuilt kits for the MC are fairly inexpensive and it's a relatively easy job.

I had the same symptoms with mine about 1.5 years ago.

 

My advice is to contact the hd shop, why are you dealing with it?

You didn't, like, take a short drive after getting it to see if all was kosher? Seems like making sure both brakes function after a tire change is kind of important?

I think that's part of any pre-ride check.

John

 

I just went through this when changing rear pads. take the hose off the caliper, take off the little bracket holding it to the swingarm. Hold the hose end up higher then the rest of the system and have a helper push the pedal while you hold both sides of the banjo fitting with your fiingers. let off the fitting enough to get fluid out and watch for bubbles. Seal it up again with your finger and thumb before they let the pedal up. Do it again and again until you don't get anymore bubbles. Then hold it sealed and lower it to the caliper and bolt it up. Use a mityvac to finish sucking the air out of the caliper. You may have to seal the bleeder threads with teflon tape to get vacuum.

The problem is the layout of the line as it runs up and over the reservoir, there's not enough stroke in the master cylinder to get the air bubble up and over the hump.

ps: watch the fluid level in the reservoir as you do this you will lose some but I'm sure you already know that part

 

Another way to flush it is to push the new fluid from the caliper forward.

Get one of these
I found one at my local hardware store, the extension tube fits perfectly on the bleeder nipple and these are cheaper than bleeder kits.

Use the syringe to suck out all the fluid in the reservoir.
get your wrench on the bleeder screw.
Stick the syringe in your brake fluid bottle and suck some up until the syringe is full.
Stick the syringe over the bleeder screw.
Crack open the screw.
Depress the plunger and force the brake fluid into the caliper.
Stop when either the syringe runs out or the reservoir is about to overflow.
Close the bleeder screw.
Refill the syringe, do it again and watch the reservoir. you can stop when you don't see air bubbles coming up any more.
Close the bleeder, you're done.


Though like cHarley said, you may need a rebuild, mine did in the front at 9 years old.

 

This seems to be the classic primary cup failure in the master cylinder.

 

well old school trick..
get a piece of clear tubing at least two foot.

place it over your rear caliper bleed valve.
open the valve slightly, suck on the tube ( could use a baster) drawing the fluid from master cyl.
watch the level , keep it over the feed hole.

when you see clear fluid coming in the tube, close the valve.

(hint !! stop sucking on tube before it reach's your lips, " had to say that")

 

Well guys its been some time now since I last post and figured Id give an update. I rebuilt the master cylinder, put new pads on and flushed the system. Also have a mityvac for bleeding too.

But my nightmare hasn't ended yet. I still have no rear brake. I have good piston movement and it seems to push the outside pad full contact. I have no leaks. Myself and my dad have gone through the system and can only seem to point a finger at the caliper. But were baffled. Today everything is going back together again and its gonna get bled again.

Thanks guys for the tips. Trying to go at the bleeding in as many ways as I can.
John I did notice it right away and I had a fight with the shop, they refused to do anything without payment because on a tire swap "they don't touch the brakes"

 

Bleeding brakes can be a bl33ding nightmare - then the next time you do it you wonder why it took so much effort last time! There are tips in the Stickies in the Tech Brakes section that may help.

My first Harley was my first bike with hydraulic brakes and the way I bled the rear caliper on that was to unbolt the caliper and lay it on the ground, so it was the lowest part of the system. I haven't had any problems with my Sporty, so haven't looked to see if that would be easy to do.

 

Boy, it's never their fault, is it?

John