Brake bleeding

[slip]

I rebuilt the calipers and reinstalled them. Now how do I get the brakes to pump back up??? I filled the resorvoir up with DOT 4, but they won't pump up!

[hampshirehog]

Couple of things to check / do.

Sometimes you have to bleed these brakes in sections. Undo the banjo on the MC and squeez the lever (care - cover all your paintwork up as the fluid could spray in any direction). If you get fluid being pumped then undo the banjos lower down and pump your fluid through - carry on sequentially until you're bleeding normally via the bleed nipples.

If you can't get any fluid to pump through at all have a look at the bottom of the (inside) MC. 2 holes - one small hole you can see and one much smaller that I can't see but you might be able to (it's tiny and I need a magnifying glass now). The smallest hole can easily get bunged up with gunge which you would have to clean out.

[slip]

Couple of things to check / do.

Sometimes you have to bleed these brakes in sections. Undo the banjo on the MC and squeez the lever (care - cover all your paintwork up as the fluid could spray in any direction). If you get fluid being pumped then undo the banjos lower down and pump your fluid through - carry on sequentially until you're bleeding normally via the bleed nipples.

If you can't get any fluid to pump through at all have a look at the bottom of the (inside) MC. 2 holes - one small hole you can see and one much smaller that I can't see but you might be able to (it's tiny and I need a magnifying glass now). The smallest hole can easily get bunged up with gunge which you would have to clean out.

Thanks I'll check that.

[Nessism]

First thing to do is prime the master. One trick is to draw a vacuum on one of the caliper bleed nipples. Once you get some fluid through the master it should start pumping.

[jwhelan65]

Having a hell of time bleeding my brakes, they seemed very spongy the first time I did it. Any suggestions would be much appreciated...

[doctorgonzo]

Mine were just totally torn down and new lines installed. I had to bleed at every point in the system. Bleed where the line from master meets the juntion, bleed where each line meets the caliper, then bleed each caliper back and forth a LOT of times, probably an hour total, but finally got all the air out.

[almarconi]

Having a hell of time bleeding my brakes, they seemed very spongy the first time I did it. Any suggestions would be much appreciated...

It's really quite easy if you have a mity vac or phoenix injector. If not a large 60cc syringe would work.

Here is how I do it. Fill the master cylinder and open the bleed valve on one of the calipers (put a piece of clear tubing onto the bleed valve and place in a waste container). Assuming your system is completely dry the only thing I want to do is get brake fluid to come out the calipers. Not trying to bleed the air out at this point. Pump the brake lever in and out until the fluid flows. Once I've got fluid in the system, now I go ahead and bleed it.

Tie a cord around the brake lever so its depressed half way. This will keep the fluid from returning to the MC. You need to inject brake fluid into caliper one, the fluid will flow out of caliper two. Put a piece of tubing on the bleeder on caliper 2 and put the end in a waste container. Start injecting fluid into caliper one using the syringe, what you are doing is bleeding caliper one, the splitter and caliper two. When no more air is coming out of the tubing on caliper 2, close the bleeder on caliper 2.
Remove the cord from the MC and keep injecting fluid into caliper one. You will notice that fluid is now flowing into the MC. Continue until the MC is full. Install the cover on your MC and squeeze the brake lever. The lever should feel firm. If it is a bit spongy, pull the lever in as much as you can and bind it with the cord to the grip. Let it sit overnight. When you remove the cord, the lever should be nice and hard. I have used this technique on many bikes and it always results in a nice firm lever.

Hope this helps.

[jwhelan65]

It's really quite easy if you have a mity vac or phoenix injector. If not a large 60cc syringe would work.

Here is how I do it. Fill the master cylinder and open the bleed valve on one of the calipers (put a piece of clear tubing onto the bleed valve and place in a waste container). Assuming your system is completely dry the only thing I want to do is get brake fluid to come out the calipers. Not trying to bleed the air out at this point. Pump the brake lever in and out until the fluid flows. Once I've got fluid in the system, now I go ahead and bleed it.

Tie a cord around the brake lever so its depressed half way. This will keep the fluid from returning to the MC. You need to inject brake fluid into caliper one, the fluid will flow out of caliper two. Put a piece of tubing on the bleeder on caliper 2 and put the end in a waste container. Start injecting fluid into caliper one using the syringe, what you are doing is bleeding caliper one, the splitter and caliper two. When no more air is coming out of the tubing on caliper 2, close the bleeder on caliper 2.
Remove the cord from the MC and keep injecting fluid into caliper one. You will notice that fluid is now flowing into the MC. Continue until the MC is full. Install the cover on your MC and squeeze the brake lever. The lever should feel firm. If it is a bit spongy, pull the lever in as much as you can and bind it with the cord to the grip. Let it sit overnight. When you remove the cord, the lever should be nice and hard. I have used this technique on many bikes and it always results in a nice firm lever.

Hope this helps.

Thanks a bunch I'll try it

[almarconi]

Thanks a bunch I'll try it

Let me know how you make out.

[chef1366]

First I bleed the M/C by unhooking the line from the M/C going into the junction and dunking it in the resevoir and using a phillip screwdriver without the lever installed push in the piston until all the bubbles are gone.
Reinstall the junction. Get a squeeze bottle with a hose on the end. Crack open the banjo at the M/C and squeeze fluid the system through the farthest bleeder from the M/C. When you see fluid at the M/C tighten the banjo and bleed out the rest of the air. Do this without the brake lever installed but with a phillips screwdriver or something similar. The lever does not compress the brake piston all the way.

[Nessism]

The mity-vac is a miracle tool. Well worth the purchase - mine is about 20 years old.

[wilmas2cool]

Good advice and info. Especially the ALMARCONI technique. Can't wait to try it on our old Goldwing. Just wish I could come up with a great idea once in a while ! 83 GS1100E still stopping great.

[jwhelan65]

Alright, I have bleed at both calipers and at the anti-dive valves, still no lever? what's up?

[Macguyver]

Hmm, The previous should have fixed it, unless it is a slow leak at one of the joints. Did you replace all of the crush washers? Were they clean when reassembled? Are they tightened enough?

When I put stainless lines on my 650 I had to bleed it for an hour, only to realize the pneumatic brake light switch had a used washer between it and the M/C. Replaced it, built a brake vacuum, bled the lines, and all was good.

$2 Brake Vacuum (in case you haven't been able to find a mighty vac)

http://www.thegsresources.com/_forum/showthread.php?t=148769

Hope this helps,

P.S. If you build a vacuum, grab one with a round spout so you can put the hose on it and pump fluid UP the lines.

[jwhelan65]

They are better but not as hard as I would like, still a little spongy. I did have a small leak at the junction, I think its going to take solid hour of bleeding to get them clear.