Caliper Rebuild--how much brake fluid will spill out?

[Hotwatermusic]

How much brake fluid should I expect to come out when I remove the brake line from the caliper for a rebuild? Is there a trick or tip to removing the brake line with as little mess as possible? Thanks!

[DRACO A5OG]

Find a peice of 2X4 about 24" long.

Place it on the brake pedal and with a piece of clotch place the other end of the front part of the seat and move it forward so the pedal is depressed about 2".

Before you remove, place caliper on and press further down without lifting the pedal to insure fluid goes in and out of the bleeder valve.

A helper comes in real handy here.

Main idea don't let the pedal up when the line is disconnected

That's it brother!

[john walker's workshop]

you can also stick a small pointed awl type tool in the end of the hose. if the fluid is old, you should just flush the system.

[Eagledriver]

Pretty much no fluid if you depress the pedal as described above

[aldente295]

+1. works a treat

[sancho]

you would probably want to flush the system anyway if you haven't for a while.

[djbrand1]

Yup, just did this using a piece of wood with a old t-shirt bundled up on the end to protect the seat fabric. Disconnected the calipers, got a few drops but that's it. Most of the fluid came out of the caliper itself.

[hcoles]

+1 on don't pass up flushing if it hasn't been done for awhile

[Hotwatermusic]

Originally Posted by hcoles

+1 on don't pass up flushing if it hasn't been done for awhile

Flushing is definitely part of the project. I just needed to know how much fluid to be prepared for, as far as it spilling all over my garage floor, getting on stuff, etc. I have some ATE Blue brake fluid waiting to go in, but what was going to be a simple brake fluid flush has turned into caliper rebuilds and possibly brake line replacement. Ugh.

[DRACO A5OG]

Might also want to look into swapping out the bleeder valves to the one way speed valves, this way you can insure no air ever goes into the system when you flush.

[rnln]

Draco,
I don't get this part. Why depressing 2"? Why not just leave it untouched? Also, do you depress it 2" while bleeding the fluid too?

Originally Posted by DRACO A5OG

Find a peice of 2X4 about 24" long.

Place it on the brake pedal and with a piece of clotch place the other end of the front part of the seat and move it forward so the pedal is depressed about 2".

Before you remove, place caliper on and press further down without lifting the pedal to insure fluid goes in and out of the bleeder valve.

A helper comes in real handy here.

Main idea don't let the pedal up when the line is disconnected

That's it brother!

[DRACO A5OG]

Originally Posted by rnln

Draco,
I don't get this part. Why depressing 2"? Why not just leave it untouched? Also, do you depress it 2" while bleeding the fluid too?

Rnln,

2" is the sweet spot to just give enough pressure to the system so it will keep air from coming into the opened line.

Untouched, air will go up the line.

While bleeding, no because when you let your feet off, the bleeder valve is supposed to be closed, right?

When you pump, only then you open the valve and close before the helper release the pedal.

[Jesse16]

Because the Bentley manual specifically says so, thats why. I think Bentley says 1" by the way. Assume it has something to do with the position of the master cylinder plunger and isolating the reservoir from the line so its a sealed line at the top. At rest, the reservoir top is open to the open end of the brake line. Just put new rotors on the rear of my car. As was said above, mostly had to deal with fluid from the caliper as I pushed the pads in so could re-install over .070" thicker rotor. I just caught it in a short stack of paper towels, maybe 4 or 5 tablespoons came out of each side.

[dave 911]

Originally Posted by Hotwatermusic

.... but what was going to be a simple brake fluid flush has turned into caliper rebuilds and possibly brake line replacement. Ugh.

Yep, that's how mine started out. Actually, mine started as an even easier project - new tires, when I pulled the fronts off I noticed I had a sticky caliper. If you're doing the caliper rebuilds, might as well do the brake lines also while you are in there!

It was actually a pretty fun project though, just make sure you use flare end wrenches on the brake lines - you don't want to bugger them up!

[rnln]

Thanks.