Front Brake Calibers

[diesel freak]

I rebuilt my front brake calibars with new rubber lines, should I try to load it up with brake fluid before I mount them or just try to flush with the brake pedle. I am afraid of all the air in the new calibars and lines.

[82vdub]

You should be able to bleed the rubber lines and calipers once the components are installed. Once installed, I would recommend just opening the bleeder screws and let the fluid run out by gravity for 10-15 minutes and then close the bleeder screw. You have to keep an eye on the fluid in the resivoir, but other than that, you shouldn't need to use the pedel to bleed the brakes. Just make sure you don't let the resivoir run dry when you swap over the components. I've actually done it by letting the lines leak fluid, while assembling the new components. Of course, I'd install as much as I could before I open the lines. This allows you to not have to bleed the master cylinder, which will take a bit to get the air out of it.

[Quantum-man]

If your front brake lies slope upwards all the way to the reservoir [they do on the Quantum, then they almost completely self bleed any how ].

However to bleed the brakes generally; best to use the tube and ball valve, if on your own, or with an assistant merely a length of tube and a jam/jello jar. Remember to hold pedal down until bleed valve tightened slightly with the latter method.

I cannot see how slow draining will shift stuck bubbles downwards.
Only 'rapid' flow will shift downwards. Someone please explain otherwise.

[82vdub]

I've gravity bled brake systems several times. On my old 60's Ford, 80's Chevy truck and on my VW's. If the system will flow fluid by itself (gravity) and you haven't let the resivoir run dry to let air in, allowing the fluid to flow will move the air out the bleed valve. I've changed the master cylinder on my 60's Ford, bench bled the master and installed it on the car when all the lines were new. Just kept the resivoir with fluid and after 30-45 minutes, the brakes were bled. I've changed the main rear brake line on my truck by doing the same thing. Brake fluid has low viscosity that it will flow a bubble, at least in the systems that will gravity bleed.

[Quantum-man]

I've gravity bled brake systems several times. On my old 60's Ford, 80's Chevy truck and on my VW's. If the system will flow fluid by itself (gravity) and you haven't let the resivoir run dry to let air in, allowing the fluid to flow will move the air out the bleed valve. I've changed the master cylinder on my 60's Ford, bench bled the master and installed it on the car when all the lines were new. Just kept the resivoir with fluid and after 30-45 minutes, the brakes were bled. I've changed the main rear brake line on my truck by doing the same thing. Brake fluid has low viscosity that it will flow a bubble, at least in the systems that will gravity bleed.

So do you think the bubble climbs up to the reservoir, or gets pushed down? I think you are saying the latter. Surely low viscosity coupled with greater density than air will allow the bubble to rise, unless the flow rate out of the bleed valve is fast enough? The 'old' holding the foot to the ground was to stop air going into the bleed screw and travelling back up the line wasn't it? That was what Gunsen's "Eazy Bleed" helped with to make the job one-man

I can't remember having much problem with my 1960's stuff, but when I've messed with the Quantums for the last 20 years, I always found that the front lines needed minimal bleeding, especially useful when the bleed screws had snapped off, and the only way to bleed is to slacken the actual brake line

[82vdub]

The air comes out with the fluid. It flows at a decent rate. Remember, I'm not talking about bleeding the air from a brake system where there's air in the master cylinder. The brake lines are small enough where it will flow a bubble or more. Just try changing a hose or caliper or replace a piece of line with the remainder of the system having brake fluid coming out of it. It gets messy. I've bled brakes by gravity, by two people pushing the pedal and releasing the bleed screw, and by a mighty-vac bleeder. Using the last two methods is faster than gravity bleeding, but it's easy to start cleaning up while the system is bleeding itself. You'll know if it worked or not when you think you're done and push on the pedal. If it's soft/mushy, there's still air in the system.

[Quantum-man]

They certainly do bleed a lot, especially when you are trying to be careful. Time for beer in between wheels I supose

[FriedRabbit]

I rebuilt my front brake calibars with new rubber lines, should I try to load it up with brake fluid before I mount them or just try to flush with the brake pedle. I am afraid of all the air in the new calibars and lines.

I am courious if you had trouble dis-connecting the rubber line from the hard line connection. I was planning on replacing my rubber lines this past week end and the hard line connections were so stuck I had to use vise grips to get them loose, even a tube end wrench would slip?

[joat]

sounds about right ... anything over 2 years and the units weld themselves together with rust. ( oh well, its best to replace the steel lines at the same time anyway)

[Fatmobile]

I hope you put some antisieze on them this time