Replacing o-ring in front resevoir

[Gregory]

Swab the bore with a Qtip soaked in brake fluid...this helps the piston slide in and not grip against the dry bore walls.

oops. i used a bit of wd40 instead

[chuck hahn]

Just ever so slightly wiggle the lver and look into the resivoir...bunch of little bubbles will escape. easiest way to do it is a power bleeder. I have a Mighty Vac. Used it just today to do brakes on an 82 Honda CB900 Custom.

[chuck hahn]

That shouldnt contaminate the brake fluid that much.

[Big T]

oops. i used a bit of wd40 instead

Sorry, but you need to tear it all apart and clean it and start over

Any petroleum oil in the brake system is strickly forbidden. The brake system's going to lock up on you soon if there's oil in it.

Go to your auto parts store and get some silicone brake lube that is designed for O rings. They may sell it in a little $1.50 pack by the parts counter or check out, If not, the Permatex Ultra (google it) for about $6 will last you a lifetime

http://www.permatex.com/products/aut...ne_Formula.htm (also comes in a smaller tube)

Take the MC apart, including the Resevoir O ring you greased and clean it with brake clean.

Reassemble using the silicone grease, put it on the O ring, the cup and the piston and reinstall the parts

Ask me how I know this (experience)

[chuck hahn]

T...I was taught years ago doing cars that you always lube with what the part is gonna be handling..but in this case its not so critical. He can fill the resivoir and place his finger over the banjo bolt hole and pump it a bit to simply flush the master before installing the rest of the lines and stuff. Can also use compressed air to blow it all out real good. Not an OMG moment by any means..easily rectified.

[Gregory]

...and i dont thind wd40 is petroleum based...it is fish oil based isnt it

[SVSooke]

Here's a question for you.Do you want to risk having your brakes not work?Think Big T's recommendation would be the way I'd go.I never use anything but brake fluid to lubricate things in the brake system.

[chuck hahn]

Put the resivior on the bars, fill the cup, put your finger over the banjo bolt hole and pump till it primes and builds pressure. Continue to pump and let the fluid seep past your finger a bit onto a rag. do this till the fluid has been drained from the cup and ran thru the works..this will flush the master cyclinders bore sufficiently.

[Gregory]

Ok, I took it back off the bike. Mainly because I was concerned that I may have not put the circlip in the right groove.

This was due to the fact that even though there was some fluid that would come out the Banjo hole, it did not "squirt out". Also, when fully pulling the lever in I could only see very small bubbles in the resevoir. (before i did the rebuild, there was a large amount of fluid swishing back into the resevoir)

Now that it is off the bike again, I found that the circlip is correctly placed in the second channel. My next question is whether I have the piston rubber on in the right direction (see pic above).

Shouldn't the air or fluid SQUIRT out strongly? Right now I can hold my finger over the banjo hole and pull the lever and if i slightly let off of the hole I can hear air coming out.

Does this sound like it is working correctly?

[chuck hahn]

The "bowl" side of the cup faces the banjo bolt hole. In other words as the fluid builds up behind the cup the sides open up a bit and squeeze the fluid down the brake lines. Picture how air infltaes a parachute and holds the sides out round. There was squiting before because all the air was out of the bore. The little bubbles is the air seeping out from the return port. do this..fill the bajo bolt hole full of fluid and put your finger over it. keep it capped. Now fill the cup and pump the brake lever. you will feel it build pressure. The mighty vac will suck all the air out of the entire system and you will have solid brakes..but nothing will happen until all the air is out of all the system.

[chuck hahn]

When you feel it try to make pressure, allow it to slowly seep some fluid past your finger onto a rag..Each time you do that, more and more air will be purged from the bore till it is fully primed. Now you wont see bubbles and youll see the fluid squirt back thru the return port again. Go to Auto Zone or Murrys and ask them for their power bleeder for brakes. Pump the guage WAY up and crack the bleeder and watch the guage drop..stopping before the guage stops dropping. Repeat the process till a good amount of fluid collects in the collection bottle. Keep an eye on the master and dont let it run dry of fluid and suck air back into the system. Do each caliper and then pump up the brakes withn the lever and level off the fluid in the cup.

[Gregory]

Thanks a bunch.

I think thats the way I have it with the "wide" part of the "bowl" facing the banjo bolt. I will now go out and try it all again with fluid in it.

I apologize for being so helpless.

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[chuck hahn]

Be sure the banjo bolts are good and tight...but dont strip them. Use new crush washers that you can get from any parts store. Take an old one with you to match them up. Once all is tightened, then use the mighty vac to suck the air out and draw fluid thru the entire system like i described before. Youll be done and have solid brakes in just a few minutes.

[chuck hahn]

Have the tool rental guy give you one of these.. Basically you put the suction hose from the bottle on the bleeder nipple and suck a vacuum into the catch bottle..watching the guage go up on the pump. Crack the nipple and close it before the guage drops all the way. Repeat till theres good amount of fluid in the catch bottle. Repeat the process on the other caliper. Use the lever to pump up the pistons and seat the brake pads against the rotor. re fill the master to the proper level.

http://www.compacc.com/p/Mighty-Vac-Brake-Bleeder

[Gregory]

Thanks Chuck, will do, a friend of mine has one and bringing it over tomorrow. Will report back.