Purge Brake Lines of fluid, procedure?

[Frogmella]

As I cannot undo the brake pipe to brake hose unions on three corners of my car and I've already had an advisory about corroded pipes I am considering tackling the total replacement of all solid pipes. I have read several threads on the subject.



Presumably, as a first step, one needs to get all the fluid out of the old pipes.



What is the procedure for doing that? Is it just a case of opening the bleeders in turn and pushing the fluid through? I have a Gunson Easy Bleed kit (not tried using it yet).


Thanks in advance for any help as always.

[marinabrian]

Alex, if you are replacing the fixed pipework, and wish to do so without covering everything in brake fluid, take a piece of timber and a tea towel, open one of the bleed nipples, I use the NSR, but any will do for this operation.

Push the brake pedal to the floor, then wedge it there with the piece of wood against the seat cushion using the teatowel to protect the seat.

Once this is done, it will prevent the fluid siphoning out of the brake master cylinder, and make the job much more pleasant to carry out.


Brian

[bluebird]

You dont have to expel the fluid, just remove the pipes, all will be well.

[Frogmella]

Originally Posted by marinabrian

Alex, if you are replacing the fixed pipework, and wish to do so without covering everything in brake fluid, take a piece of timber and a tea towel, open one of the bleed nipples, I use the NSR, but any will do for this operation.

Push the brake pedal to the floor, then wedge it there with the piece of wood against the seat cushion using the teatowel to protect the seat.

Once this is done, it will prevent the fluid siphoning out of the brake master cylinder, and make the job much more pleasant to carry out.


Brian

Thanks Brian,


I was hoping to empty all (as much as possible anyway) of the old brake fluid neatly into a container before cutting off the old pipework, is that not the way?

[marinabrian]

Originally Posted by Frogmella

Thanks Brian,


I was hoping to empty all (as much as possible anyway) of the old brake fluid neatly into a container before cutting off the old pipework, is that not the way?

No, if you stop the siphoning action, it will prevent the possibility of damaging the seals in the master cylinder, and prevent lots of mess while the pipework is disconnected.

I do it this way, as apart from anything else, I hate cleaning up the mess on my driveway from spilled brake fluid.

Brian

[COLVERT]

As per post three for me. I just lay a plastic sheet under the car.

I try to have the whole system as pressure free as possible so as not to upset any other part of the braking system.


( Having read tales about the brakes anti-locking system )--

[Frogmella]

Looks like a combination of posts 2 and 3 then. Thanks guys, once again.


All I have to do now is to practice pipe flaring, all mine have come out a bit lop-sided so far.

[Rich in Vancouver]

Pipe flaring is an acquired skill.
On the rare occasions I have done it I tend to get one perfect flare followed by a total dud.
Good Luck!

There isn't a pipe kit available for the 75/ZT is there?

[RoverP480]

As previously stated, do not drain the system and don't let air into the ABS modulator , I have just changed all the front pipes from the ABS modulator to the wheels on my Rover 45 . Just kept the brake pedal pressed down with a block of wood and gradually replaced all the steel pipe and flexibles to each wheel . Opened the bleed screw and released the pedal and allowed the fluid to run through under gravity and then just one press of the pedal before tightening each bleed screw.

[Alan_M]

Quote:
Originally Posted by Rich in Vancouver View Post
Pipe flaring is an acquired skill.
On the rare occasions I have done it I tend to get one perfect flare followed by a total dud.
Good Luck!

There isn't a pipe kit available for the 75/ZT is there?
A lot depends on the quality of the tool you are using. I have never had a bad flare, even on steel pipes from my first flare and I’m no professional. Mines the old version of this - https://www.sykes-pickavant.com/prod...ring-tools/584

Just used it this week to make this repair section - bends made using the tool with the kit. You will often find only the sections near the wheel arches need replacing, and there’s no problem cutting back to where pipe is good and just replacing rusty section.
Also I would strongly recommend using kunifer (copper-nickel alloy) pipe rather than the plain copper. This does not work harden like the copper and does not fail by fracturing like copper will.