bleeding master cylinder

[ldhthept]

rebuilt my master cylinder on my bike thinking that would cure my pulsating front brakes, didnt help but at that time i found some info on how to bleed the master cylinder only. i have since rebuilt both front calipers and need to bleed the entire system but i cant find the info on how to properly bleed the master cylinder...any help would be appreciated

[cactusjack]

If you bleed the calipers (I use a Mighty Vac), wouldn't that bleed the master cylinder as well? The purpose of bleeding is to evacuate air from the hydraulic system.

A pulsating brake lever (or pedal) is usually the sign of a warped rotor. I used to do automotive/truck brakes for a living.

[Blueraven]

Ditto with cactusjack

[classic1]

I had a Honda Magna that I had to bleed the clutch master cylinder on. The way I was told to do it is:
- take the brake line off at the master cyl.
- put your thumb over the hole and slowly squeeze the lever and this forces the air out passed your thumb.
- press your thumb against the hole while you release the lever.
- check fluid level and repeat.

This is a little messy and what ever you do, don't get the fluid on your paint.
I can't remember if I had to keep putting the master cyl cap on each time. Your not trying to build pressure, just getting the air out.

Good luck.

[ldhthept]

rotors are fine, the pistons where not putting equal pressure on the pads since they were compressing at different times due to the worn out seals and the crud on the pistons themselves. thanks for help.

[cactusjack]

Originally Posted by ldhthept

rotors are fine, the pistons where not putting equal pressure on the pads since they were compressing at different times due to the worn out seals and the crud on the pistons themselves. thanks for help.

My bad. From your original post I thought the pulsating lever was after you rebuilt the calipers.

[ringadingh]

Originally Posted by ldhthept

rebuilt my master cylinder on my bike thinking that would cure my pulsating front brakes, didnt help but at that time i found some info on how to bleed the master cylinder only. i have since rebuilt both front calipers and need to bleed the entire system but i cant find the info on how to properly bleed the master cylinder...any help would be appreciated

Gadgets Fixit site has an how to on brakes.

[crapper]

my 02 pulses a bit when the front brake is applied...keep thinking its not the rotors but i know it probably is.
can these things be machined like car rotors or will i have to buy new ones...................

[macmac]

Crapper, If you can find a shop that will take a light cut and all the rotors need to clean up is that light cut, you might band aid the rotors a bit, but heated and warped rotors tend to take a set and come back to warped pretty quick when they are thin to start with and Nomad rotors are thin to start with.

What the Hell kinda name is that? ldhthept, I can't even begin to say that word . It sticks my tongue in my teeth and then it just gets stuck. Who do you think you are some Greek God ? 'D

Anyway I hope you don't really mean ON the bike, as that is no place to over haul a master, since brake fluid (BF) eats paint!

I hope you mean 'bench bleed, which is pretty easy, and was stated you can pump the lever and use your thumb.

To do that would be a little extreme on such a small master in the first place. Gravity will bleed it pretty well, with a few light flicks of the lever when all the lines are hooked.

When I bleed bike brakes I don't use anything but a bleeder wrench, and a little clear tubbing into a jar. I allow for some gravity, and work the lever slow. I tap on any line fittings here and there to let air move UP to the master, where flicking the lever shows air bubbles passing into the rez.

Flicking the lever isn't even full throw movment, just little flicks to move the piston and make it draw back.

What ever you do, DO NOT get BF on that paint.

[ldhthept]

nope, not Greek.

[kpmhspirit]

Originally Posted by ldhthept

rebuilt my master cylinder on my bike thinking that would cure my pulsating front brakes, didnt help but at that time i found some info on how to bleed the master cylinder only. i have since rebuilt both front calipers and need to bleed the entire system but i cant find the info on how to properly bleed the master cylinder...any help would be appreciated

Russel Speed Bleeder are the way to go IMHO

http://www.russellperformance.com/mc...domestic.shtml

Pete

[macmac]

Originally Posted by ldhthept

nope, not Greek.

I typoed which is a pretty regular thing for me even if I can spell a given word.. After that greek God bit I typoed and the 'D should have been a

For that I am sorry, and had no intent to insult you over your handle, but man that word does stick tight on my lips and I will never be able able to say it even if I meet you face to face.

[ldhthept]

no harm no foul macmac. im a physical therapist, so it is ldhthept. for some reason these brakes are outsmarting me. the system was almost completey dry so it is taking forever to get all the air out. i will prevail.

[macmac]

Open the cap, slip on snug fitting clear tubing, into a jar, then open the bleeder 1 turn from closed. Graviety should flow into the jar. If it does not take a 13 mm short wrench and tap from the bottom up all the lines and fittings in the way.

Any fittings tend to gag air bubbles. Every once in a while flick the lever. Watch as you do this for air bubbles entering the rez.

Use so many blankets as you can muster to cover paint! before you do anything at all!

The reason I don't use trick tools for this is that the tubings always seem to get away from me and fling BF on paint!

'IF' you have been pulling the lever real fast and a lot, you are compressing air into BF and making it foam. Once you have created foams, they take a long time to gas out of the BF.

As they gas out they again tend to cling to any angles not smooth.

The wrench is just a little hammer in this case. It need not be 13mm exactly.

[ There isn't any chance you installed the rubber cups bassakwards is there?]

[ringadingh]

Many times just letting it sit overnight helps a lot in getting rid of air bubbles.