No resistance on front brakes

[cogsman]

Hi All,

I removed the right front brake caliper to rebuild it. Prior to this, I drained all brake fluid from the system.

Upon pulling the caliper, I found that the pistons were flush to the caliper chambers. Compressed air didn't work to move them, so I reconnected the caliper (minus the caliper bracket which i had already removed) and fed brake fluid back into the system.

I made sure there were no more air bubbles in the system, and did that for the left caliper as well.

With that done, and the master cylinder filled... I can't get any compression. No resistance when i pull the lever.

Can anyone venture a guess as to what I did/am doing wrong?

[Gryphon Rider]

How many times did you squeeze the lever?  It takes a few squeezes for pressure to build.  I usually rediscover this every time I back my bike out of the garage after doing stuff with the brakes. 

[WintrSol]

Just filling the reservoir doesn't get the fluid all the way into the calipers. Squeezing the lever does push a small amount of fluid down the line, while compressing the air in the system. If you have the time, squeeze the lever and hold it for about a count of 10; this will let some of the fluid pass into the caliper. Then, let the lever snap back, pulling some air into the master cylinder. Exercise the lever a little, to replace that air with fluid, then squeeze the lever fully, and hold again. Keep it up, until pressure builds. Or, you can push fluid through the bleeder and up into the reservoir, the reverse-bleed method, just make sure the reservoir doesn't overflow.

[Patrick]

If you drained all the fluid from the system it'll take quite a bit to get the air out of it and working again.
I use the system itself to remove the pistons. I use c-clamp vise grips to limit the travel of the pistons and use the hydraulic pressure to push them out.

[cogsman]

Reviving this thread after a long winter and half summer of maintenance :

I have replaced my front calipers.
I have connected all the hoses.
I have bled the brakes until there was no air in the lines.
I have checked and double checked everything.
There are no leaks.

I have no pressure at all. No matter how long I pump the lever. No pressure.

No drips no leaks. Any ideas? Do I need to rebuild the master cylinder?

One thing : while cleaning the grit out of the reservoir  I caught that tiny metal protector at the bottom. I didn't damage it but im not sure how it goes back in. The service manual just says don't lose it but nothing about what it does or how to place it.

Could that be the issue?

[vanagon40]

My suggestion would be to unhook the line where the front brake lines split. Make sure the line is filled with fluid from the master cylinder, then plug it. If you still cannot build up pressure, you likely have a master cylinder problem. If you do get pressure, reconnect and try the same thing with the banjo bolts at the calipers. Then connect one caliper at a time, etc.

Cannot help with the metal protector deal.

[Tfrank59]

yeah, based on what you've already done, and still can't get pressure, most likely the master needs rebuilt. 

[falconbrother]

On the big Harleys I have always had to reverse bleed to get them to work.  That is to force brake fluid into the caliper bleeder and up to the reservoir.  Bubbles prefer to go uphill.  On a Harley BT you can bleed for the rest of your life and never get it to work.  It always works the first time to reverse bleed.  I just have a cheep plastic bottle with a hose on it.  I put some brake fluid in it, make sure there are no bubbles when I flip it over and get busy squeezing.  Make sure the level in the reservoir is low.  Never tried it with a Valkyrie but, I feel certain that it would work.  Hydraulic brakes are all pretty much the same.  The principle is the same, bubbles like to go uphill. 

[Bighead]

Someone posted about a reverse bleed yesterday and said it worked great.
Never thought of doing this but will give it a shot next time

[indybobm]

I was thinking about using a big syringe, but why not use something like a ketchup squeeze bottle like you see in the diners?

[Bighead]

It was csj that posted that he had done it and he used a syringe on both sides and had someone watching the resivor so he wouldn't run it over.

[falconbrother]

I just have a small bottle that I probably bought at the dollar store and a section of hose that came free with a motorcycle battery.  I put brake fluid in it, connect the hose to the bleeder, hold it upside down, let all the bubbles run up into the bottle, open the valve and start forcing fluid into the bleed valve.  I do that for a short time and the close the valve with the bottle still connected and fluid sitting on top of the bleed valve so no air gets in.  Squeeze the lever and it's good every time.  Even a few tiny bubbles will cause a useless front brake lever.  I have a vacuum pump to bleed brakes but, I never use it anymore.  The reverse bleed works faster. 

[cogsman]

Bought a MityVac at Crappy Tire and bled the lines. I was impressed at the ease with which this worked. Thought I'd bled all the air. Not even close! Had this done in 10 minutes and the brakes work great!

Thank you all for the recommendations. After a long winter and spring, the beast is finally on the road!