Topic: What's the best way to disconnect brake line/master cylinder, etc...

[rusty_tank]

Howdy folks. I have a 78 CB550K. I'm doing my first tear down and rebuild. My question is concerning disconnecting the brake line/master cylinder. I just don't have any experience with it and I'd like to know the best way to avoid a big mess of brake fluid, or at least minimize it. I'd also just like to know the standard practice of how to do it, you know, if there's a step 1, 2 and 3. OR if there is one. OR, if anyone knows a thread that discusses/explains this please post it here.

Thanks!

[madmtnmotors]

If you are going to rebuild the caliper, then remove the caliper first and use the master cylinder to pump the piston out. Do this over a bucket, and continue to pump after the piston is out until the master cylinder is sucking air. This will contain most of the fluid. Clean the caliper, stuff a rag in the piston hole, and bolt the caliper back on to the bracket. This will help give you leverage to loosen the bleeder and to disconnect the brake line. Disconnect the brake line from the master cylinder before unbolting it from the bars, again for leverage. Use rags to catch fluid as you disconnect the lines.

EZPZ. 

[jeffg]

I use a long cheep clear plastic tube, over the bleeder valve. If your not familiar with break parts or names, I would highly recommend taking your time and do some reading before you begin.
I also use the same clear tube to complete the bleeding process.
make several loops with it to trap the air, it really helps and is lots less messy.
ALSO: if you don't want to get any fluid on the tank it is real simple to just remove the MC perch from the handle bars.
then take the cap off and tip it over in a drain can away from the bike.

[rusty_tank]

If you are going to rebuild the caliper, then remove the caliper first and use the master cylinder to pump the piston out. Do this over a bucket, and continue to pump after the piston is out until the master cylinder is sucking air. This will contain most of the fluid. Clean the caliper, stuff a rag in the piston hole, and bolt the caliper back on to the bracket. This will help give you leverage to loosen the bleeder and to disconnect the brake line. Disconnect the brake line from the master cylinder before unbolting it from the bars, again for leverage. Use rags to catch fluid as you disconnect the lines.

EZPZ. 

I don't know if I'm going to rebuild the caliper. I say that because I haven't had any issues with it so it wasn't on my radar. Thanks for the break down though madmtnmotors 

[rusty_tank]

I use a long cheep clear plastic tube, over the bleeder valve. If your not familiar with break parts or names, I would highly recommend taking your time and do some reading before you begin.
I also use the same clear tube to complete the bleeding process.
make several loops with it to trap the air, it really helps and is lots less messy.
ALSO: if you don't want to get any fluid on the tank it is real simple to just remove the MC perch from the handle bars.
then take the cap off and tip it over in a drain can away from the bike.

Thanks for the reading suggestion regarding language jeffg, great point. 

[robvangulik]

The total amount of fluid in your brake system comes to 100 cc at most so the aforementioned rags should be sufficient to deal with any spills.
It's easy (and wise) to put your tank out of harms way before engaging your master cylinder, and  should you by accident spill brakefluid in unwanted places, just rinse with a copious amount of water, it's highly hygroscopic and will be diluted instantly.

[RAFster122s]

A good tear down and cleaning of the piston and caliper and new seal is recommended as a good preventative measure. Once you have the piston and seal out you can inspect the caliper piston seal groove to ensure it is clean before reassembly.  A brass brush or brass wheel in a dremel will clean the square groove very well. The seal is $8-9 and keeping the brakes it top condition is a essential practice as your life is riding on the ability to stop sometimes.  Good tires are a close second.  All of which are complemented by good safety gear.

David

[madmtnmotors]

A good tear down and cleaning of the piston and caliper and new seal is recommended

That's what threw me... I took it for granted if you're going to break open the brake system why not replace the caliper seal as a preventative measure? Even from the dealer the caliper seal is only $7, Honda P/N 45108-300-003... 

The moisture and sludge tends to collect at the caliper since it is the lowest point.

[754]

Use a Flare-nut wrench on the caliper.

[70CB750]

Definitely full disassembly and clean up of the caliper with a new seal.  Never hurts to go the extra miles for your brakes.

[NobleHops]

If you are going to rebuild the caliper, then remove the caliper first and use the master cylinder to pump the piston out. Do this over a bucket, and continue to pump after the piston is out until the master cylinder is sucking air. This will contain most of the fluid. Clean the caliper, stuff a rag in the piston hole, and bolt the caliper back on to the bracket. This will help give you leverage to loosen the bleeder and to disconnect the brake line. Disconnect the brake line from the master cylinder before unbolting it from the bars, again for leverage. Use rags to catch fluid as you disconnect the lines.

EZPZ. 

Contributing nothing except to say this was awesome.

[madmtnmotors]

If you are going to rebuild the caliper, then remove the caliper first and use the master cylinder to pump the piston out. Do this over a bucket, and continue to pump after the piston is out until the master cylinder is sucking air. This will contain most of the fluid. Clean the caliper, stuff a rag in the piston hole, and bolt the caliper back on to the bracket. This will help give you leverage to loosen the bleeder and to disconnect the brake line. Disconnect the brake line from the master cylinder before unbolting it from the bars, again for leverage. Use rags to catch fluid as you disconnect the lines.

EZPZ. 

Contributing nothing except to say this was awesome.

LOL, thanks.

After having let mine set up for long periods, and having to deal with more stuck calipers than I can count, I managed to develop what I believe to be the least painless set of steps to cope with them. Of course, this only works if the master cylinder is still functional... 

[NobleHops]

If you are going to rebuild the caliper, then remove the caliper first and use the master cylinder to pump the piston out. Do this over a bucket, and continue to pump after the piston is out until the master cylinder is sucking air. This will contain most of the fluid. Clean the caliper, stuff a rag in the piston hole, and bolt the caliper back on to the bracket. This will help give you leverage to loosen the bleeder and to disconnect the brake line. Disconnect the brake line from the master cylinder before unbolting it from the bars, again for leverage. Use rags to catch fluid as you disconnect the lines.

EZPZ. 

Contributing nothing except to say this was awesome.

LOL, thanks.

After having let mine set up for long periods, and having to deal with more stuck calipers than I can count, I managed to develop what I believe to be the least painless set of steps to cope with them. Of course, this only works if the master cylinder is still functional... 

Ya, I have determined to scrounge a decent used MC and keep it on the shelf just for these extractions. The grease gun method is awesome, but a trifle messy.

[madmtnmotors]

Ya, I have determined to scrounge a decent used MC and keep it on the shelf just for these extractions.

I've done that! Had about four or five calipers needing attention so I bolted up a freshly rebuilt MC to the bars of a future "project" and pumped them all apart in short order.

The grease gun method is awesome, but a trifle messy.

Yep. I didn't much care for the volume of grease required nor for the level of cleanup required for this method, but will work in a pinch.

[rusty_tank]

Got it off with no problems guys. Thanks a bunch!