PDA

View Full Version : help bleeding front brakes


shotgun46
13th June 2007, 20:30
I just about had enough I have been tring to bleed the front brakes for 2.5 hours and have read the manual and read in here about bleeding and it aint working please help !

WinXP
13th June 2007, 21:02
The master cylinder needs to be horizontal an level as possible. Remove the top an slightly bump the lever with one finger repeatedly not mashing it in all the way, just in about 1/4 to 3/8 inch. Watch for the bubbles letting air escape from system. Do this for a few minutes the tap the line going to caliper. Start bumping the lever again an it will start showing bubbles in the resevior again. Took about 20 minutes to do mine when install a braided brake line.

http://xlforum.net/vbportal/forums/showpost.php?p=42311&postcount=10

http://www.xlforum.net/vbportal/forums/showpost.php?p=61198&postcount=1

87-1100
13th June 2007, 21:13
Vaccum bleeder. Well worth the $30 I paid.

CBAS5
13th June 2007, 21:25
Here is how I bled by front brake.

1) Put a piece of 2x4 under the kickstand to level the bike.
2) Take off the cover from the master cylinder.
3) Loosen the nut from the bleeder nipple, but not enough to let air inside.
3) Attach a piece of clear hose to the bleeder nipple.
4) Open the bleeder by loosening the nut and push down on the front brake hand lever at the same time. Before the hand lever reaches the end of it's travel you should close the bleeder.
5) Look at the plastic hose to see if you see bubbles. If you see bubbles, then you need to repeat step 4 until you see only fluid in the line.
6) Add fluid to the reservoir as necessary.

Step 4 is very important. The sequence you do stuff in matters. If you release the brake lever before closing the bleeder, then you will introduce air into the system. So you should open the bleeder as you are pushing on the front brake lever and make sure that you close the bleeder BEFORE letting go of the brake lever.

The last thing is that if you have no fluid in the system (such as if you just installed a SS braided cable), then it will take awhile for you to regain brake pressure.

You will know if you did it properly because the front brake lever will remain stiff 24 hours later.

whittlebeast
13th June 2007, 21:33
If the system is totally empty, It's a little more involved.

Get a large syringe from Walgreen’s. They are used to force feed very sick infants among other things.

Remove the front caliper and use an air chuck to blow air into the caliper to get it to expand the pucks until the pads clamp down on a 3/16 plate. Now remove the drain valve. Add fluid with the syringe till it appears to be full. Reinstall the bleed valve. Hookup the brake hose at the caliper and at the master cylinder. Carefully/slowly bump the pads apart until the caliper just barely slides on the disk. Mount the caliper.

Get some 1/4" id clear plastic tubing about 4' long. Hook one end to the brake bleed valve and wire tie the other end to the handlebars. Slowly fill the hose about 1/2 way with brake fluid. Turn the wheel if required to get the throttle as high as possible. At this point hook the syringe to the open end of the hose up by the handlebar. Open the bleeder valve about 1/4 turn. You are going to use the syringe to force the fluid back and forth SLOWLY until very few air bubbles end up at either end. At the master you will see extremely tiny bubbles coming out of bleed holes in the bottom of the master cylinder resevore. There will be microscopic bubbled all thru the system that will very slowly work their way to the top of the system. At this point I close the bottom bleeder and check for a reasonable lever feel. Every few once in a wile grab the brake lever and give it a SLOW squeeze. For the next few hours you will get a few more bubbles that show up as you start to pull the lever. Just leave the master cylinder so that the highest point in the system is that tiny bleed hole in the MC.

I figured this all out when I was bleeding the Dyna brakes being operated with a 1/2" MC. All normal methods were useless when the calipers have lots of pistons pushed with a tiny MC. This is the same method we use on the racecars.

AW

pquirk
13th June 2007, 21:43
When I put a new brake line on I just opened up all the stuff (bleeder & reservoir) and pushed fluid UP through the bleeder with a syringe. After that a few traditional open-pump-close sequences and it was good as new. Ten minutes total.

There are a few threads on this topic with many creative solutions, try a search and pick one you think sounds like fun :).

CBAS5
13th June 2007, 21:45
whittlebeast,
You don't need to do all that if there is no fluid in the system. I managed to regain brake pressure just by doing what I listed although there was no brake fluid after I installed the SS braided cable.

whittlebeast
13th June 2007, 22:01
I could never get the master to move enough fluid to overcome the hystresis in the 4 pistons. After a long afternoon we noticed the pads moving about .010" and then returning to the starting position. It was the O ring/seals around the brake pucks. We were just moving fluid and bubbles back and forth. That's when we regrouped and redesigned the method.

PS: I own 5 street cars, 2 home-built race cars, 3 motorcycles, a boat trailer with disk brakes, a ski boat, 3 jetskis (one with hydrilic brakes), a bicycle with hydrolic brakes and a very understanding wife. This sort of this comes up on occation. You can get creative when things don't go per the books

AW

shotgun46
14th June 2007, 05:51
yea that worked thanks!

pquirk
14th June 2007, 12:17
yea that worked thanks!Which procedure did you use? I'm always curious because there are so many different takes on this. :)

shotgun46
14th June 2007, 15:15
The master cylinder needs to be horizontal an level as possible. Remove the top an slightly bump the lever with one finger repeatedly not mashing it in all the way, just in about 1/4 to 3/8 inch. Watch for the bubbles letting air escape from system. Do this for a few minutes the tap the line going to caliper. Start bumping the lever again an it will start showing bubbles in the resevior again. Took about 20 minutes to do mine when install a braided brake line.
but it took 3 hours

whittlebeast
14th June 2007, 15:29
Thats the second half of my procedure. The part after you have a reasonable lever. It helps to have the the brake line in a constently upword path. It also may help to start the bike (assuming the cap is on the resevor) and let the vibration of the motor shake the bubbles loose. The jetski has clear brake lines and you can see the bubbles get traped in the lines.

AW

shotgun46
14th June 2007, 16:28
part of the bleeding hassel was the buck horns I could not get the resevor level BUT the wife is happy now with the bike set up buck horn bars dyna seat with a back rest & floor boards and a big honkin windshield

Moved On / My Own Choice
14th June 2007, 22:04
I'll say one thing about Andy, the man is F@#%@#ng THOROUGH!!!!

;)

whittlebeast
14th June 2007, 22:34
I'll say one thing about Andy, the man is F@#%@#ng THOROUGH!!!!;)


Kev

What's your point?
:doh :D

AW

shotgun46
14th June 2007, 22:52
hey thanks for your help thats pretty much the way I did it but because of the bars I could not get it level ! when I did mine it took like 10 minutes her just had to be difficult out there in the hot garage but its done now

Slipstrm
1st November 2007, 16:11
When I put a new brake line on I just opened up all the stuff (bleeder & reservoir) and pushed fluid UP through the bleeder with a syringe. After that a few traditional open-pump-close sequences and it was good as new. Ten minutes total.

There are a few threads on this topic with many creative solutions, try a search and pick one you think sounds like fun :).

This works great, pull the air out of the caliper and it'll float up the tubing to the top of the syringe, then pump fluid back in, do that until there is no more air and you'll be good to go.

Alf
15th January 2013, 14:03
The master cylinder needs to be horizontal an level as possible. Remove the top an slightly bump the lever with one finger repeatedly not mashing it in all the way, just in about 1/4 to 3/8 inch. Watch for the bubbles letting air escape from system. Do this for a few minutes the tap the line going to caliper. Start bumping the lever again an it will start showing bubbles in the resevior again. Took about 20 minutes to do mine when install a braided brake line.

http://xlforum.net/vbportal/forums/showpost.php?p=42311&postcount=10

http://www.xlforum.net/vbportal/forums/showpost.php?p=61198&postcount=1

I know this is (really) old but massive thanks for this - was trying to bleed brakes for over an hour, got nothing, never felt brakes so soft with fluid in. Thought I'd for sure got miss matched banjos or something. Tried this - 5 minutes later and they're hard as you like.

Best tip i've ever come across!

I did it so I was hitting the brake lever and then letting it go back its self making a lot of noise (sounded like I was hitting it with a hammer) tons of bubbles later and brakes are perfect. Didn't even need to touch bleed bolt.

shabalaihui
19th January 2013, 12:00
Use PVC tube connected with syringe, put tube on bleeder hole, you can suck oil out in 3 second.

motorend
19th January 2013, 13:02
An old turkey baster works too.

cootertwo
19th January 2013, 13:54
When I had buck horns on mine, and a longer line, I had the bleeding problems too. Finally took line off at master cylinder, covered hole with my finger, and bled the air out. Reconnected the line, then bled at caliper, no problem.

dpiacentijr
19th January 2013, 14:03
i filled the bleeder line with fluid connected it back to the bleeder valve and blew the fluid back through the caliper. worked perfect. 1 hour trying to do it the normal way 2 minutes once i thought of this. Odd yes but very easy