I’m going to replace a brake line on my 2000 xterra, my question is: how do you keep the mc from running out of fluid? Or is it ok if I just refill it after I’m done?
Brake line replacement??
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Replacing all the hardlines or just the rubber hoses?
When replacing hardlines, I'll cut the ones coming out of the MC and bend them up, so the MC can't drain out. Then, when you've got everything in place, you can swap the new lines in place of the old ones still attached to the MC. Minimal fluid loss this way.
If just hoses, I pinch the old ones shut with some vise grips, then do the swap quick enough to where I don't lose that much fluid.
When replacing hardlines, I'll cut the ones coming out of the MC and bend them up, so the MC can't drain out. Then, when you've got everything in place, you can swap the new lines in place of the old ones still attached to the MC. Minimal fluid loss this way.
If just hoses, I pinch the old ones shut with some vise grips, then do the swap quick enough to where I don't lose that much fluid.
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If I can, I will plug the line or use a pair of vise-grips to pinch the hose.
But I see it as a slow way to bleed the lines and if I open up any part of a brake hydraulic system I will bleed it out with fresh fluid.
But I see it as a slow way to bleed the lines and if I open up any part of a brake hydraulic system I will bleed it out with fresh fluid.
You are certainly going to loose brake fluid in the process. You could have someone put their thumb over the brake line going to the MC that will be dripping brake fluid by gravity. Until you get things all set. If its steel brake line I suggest nickel-copper rather than steel. If its a flex line soak the connector the night before with PB-Blaster along with the bleeder screw. Be prepared for any fitting to snap the line. Its been corroding shut for 17 years.
Flare wrenches for brake connectors. 6 pt box end or socket for bleeder screw.
Flare wrenches for brake connectors. 6 pt box end or socket for bleeder screw.
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
I’ll try wit the pedal half way, maybe it works,,,, I’m definitely replacing all the fluid,,, I just want to keep air from entering the MC and abs unit
Originally Posted By: koffy
I’ll try wit the pedal half way, maybe it works,,,, I’m definitely replacing all the fluid,,, I just want to keep air from entering the MC and abs unit
Right, I went ahead and bled the system when I got done with my repairs but it was nice it didn't keep spilling out all the time. Plus my ABS requires you to short out some pins on the system to open it up for bleeding if you let it run dry.
I’ll try wit the pedal half way, maybe it works,,,, I’m definitely replacing all the fluid,,, I just want to keep air from entering the MC and abs unit
Right, I went ahead and bled the system when I got done with my repairs but it was nice it didn't keep spilling out all the time. Plus my ABS requires you to short out some pins on the system to open it up for bleeding if you let it run dry.
Originally Posted By: kschachn
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
As far as I know all automotive MCs function in the same way. I've never heard of this before on any car, but there should be a position that blocks the passages in the MC and stops the fluid from leaking out. Different MCs might have passages in different locations but it seems theoretically possible that it could work on other vehicles.
Thanks for the info!
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
As far as I know all automotive MCs function in the same way. I've never heard of this before on any car, but there should be a position that blocks the passages in the MC and stops the fluid from leaking out. Different MCs might have passages in different locations but it seems theoretically possible that it could work on other vehicles.
Thanks for the info!
Originally Posted By: kschachn
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
I replaced hard lines on my 2000 Mazda MPV earlier this year. Yes, either find a way to depress pedal half way, or I used rubber plug over new nut that threads back into the port (distributor valve). I also recommend copper-nickel lines. No matter what you do, do not let MC and ABS pump run dry. Otherwise, you'd need to activate ABS pump for purge air either thru scan tools (if you have them) or by dealers ($$$). Lay the new line, and put in place, before doing the re-connection, so you only have a short window for fluid loss.
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
I replaced hard lines on my 2000 Mazda MPV earlier this year. Yes, either find a way to depress pedal half way, or I used rubber plug over new nut that threads back into the port (distributor valve). I also recommend copper-nickel lines. No matter what you do, do not let MC and ABS pump run dry. Otherwise, you'd need to activate ABS pump for purge air either thru scan tools (if you have them) or by dealers ($$$). Lay the new line, and put in place, before doing the re-connection, so you only have a short window for fluid loss.
Originally Posted By: kschachn
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
If you do this you'll have an air space immediately below the MC. Hold a glass of water upside down. It glugs out. Your fluid will glug out, albeit very slowly.
Fill the reservoir to the peak and leave everything alone. You might lose 1/4 inch in an hour with it dribbling normally.
The slit in the MC that lets fluid in from the reservoir is extremely tiny and won't let much flow.
As for pre-job planning, I would run the new line parallel to the old one and make the fluid connection the last one. Will you be flaring the existing line halfway somewhere? Do you know what sort of flares you'll encounter when you take it apart? Having to run to the parts store for adapters halfway through the job is no fun and the system's open a long time.
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
If you do this you'll have an air space immediately below the MC. Hold a glass of water upside down. It glugs out. Your fluid will glug out, albeit very slowly.
Fill the reservoir to the peak and leave everything alone. You might lose 1/4 inch in an hour with it dribbling normally.
The slit in the MC that lets fluid in from the reservoir is extremely tiny and won't let much flow.
As for pre-job planning, I would run the new line parallel to the old one and make the fluid connection the last one. Will you be flaring the existing line halfway somewhere? Do you know what sort of flares you'll encounter when you take it apart? Having to run to the parts store for adapters halfway through the job is no fun and the system's open a long time.
Originally Posted By: maxdustington
Originally Posted By: kschachn
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
As far as I know all automotive MCs function in the same way. I've never heard of this before on any car, but there should be a position that blocks the passages in the MC and stops the fluid from leaking out. Different MCs might have passages in different locations but it seems theoretically possible that it could work on other vehicles.
Thanks for the info!
I have seen that recommended in some of Chrysler's service procedures.
Originally Posted By: kschachn
I don't know if this is true for most cars, but on my BMW if you depress the brake pedal about half-way (and hold it there by some means) it will block the brake fluid from draining out of the reservoir.
As far as I know all automotive MCs function in the same way. I've never heard of this before on any car, but there should be a position that blocks the passages in the MC and stops the fluid from leaking out. Different MCs might have passages in different locations but it seems theoretically possible that it could work on other vehicles.
Thanks for the info!
I have seen that recommended in some of Chrysler's service procedures.
In my brake line R+Rs, I always started by a stop to get at least a qt of brake fluid and some fittings. I use plugs and other things to keep the MC and ABS units full. As I connect stuff up I make sure the line drips before I cap it off. On the Rat, by the time I had replaced all the lines and all but one of the hoses, I was into a 2nd bottle. My BIL, had a 25' roll of steel tubing. I've graduated to making my own flares. You would never confuse my work for factory, but it doesn't leak. My take on the copper nickel tubing is that it should put in at the factory. What is the sense of putting it on a car that is about 15 yrs old before it blows a steel line? 3/16 steel line is easy to work by hand, use your thumbs.
Originally Posted By: koffy
I’m going to replace a brake line on my 2000 xterra, my question is: how do you keep the mc from running out of fluid? Or is it ok if I just refill it after I’m done?
I have always let it run out as you will be bleeding the system anyway and the fluid will flow out of the abs unit anyway.
I’m going to replace a brake line on my 2000 xterra, my question is: how do you keep the mc from running out of fluid? Or is it ok if I just refill it after I’m done?
I have always let it run out as you will be bleeding the system anyway and the fluid will flow out of the abs unit anyway.
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Disconnect the line somewhere upstream and thread in a plug:
You can buy plugs at an auto parts store that are the same thread size as the brake line fitting.
If you need a plug with female threads, buy a male threaded plug like the one pictured above and thread it onto a brake line union:
Then you have yourself a female threaded plug.
You can buy plugs at an auto parts store that are the same thread size as the brake line fitting.
If you need a plug with female threads, buy a male threaded plug like the one pictured above and thread it onto a brake line union:
Then you have yourself a female threaded plug.
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