Stopping brake fluid flow without damaging hose

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JHZR2

JHZR2

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Some know I'm going to try to rebuild my 37yo brake caliper, and some know I have very little free time with work and kids. So it could take a bit of time...

So, what to do regarding brake hoses? I'd like to remove the caliper, so a rebuild, but not empty the reservoir and MC. I've thought about clamping the hose, but is that acceptable? Will it damage it? My hoses were replaced.

Or is there another way to cap the hose?

I'm concerned that over a week or more, even if the reservoir cap is tight, gravity will take its toll.
 
On my BMW (I don't know about the other cars) if you hold the brake pedal half way down it will prevent the brake fluid from leaking out. I have a brake pedal depressor and it worked well for that when I replaced all the lines on that car.

You still have to bleed things of course, but it prevented the ABS from draining out and having to be commanded open.
 
Banjo end or straight end?

If it is a banjo, get the appropriate sized non-serrated flange bolt and flange nut. Wrap the bolt threads with Teflon tape, put the bolt through with the correct brass washers, and then put the nut on the other side with another brass washer. Sealed.

If it's a straight fitting, take one of your old brake lines to a good hydraulic hose shop and they'll sell you a cap.

Been there, done that.
 
It is actually VERY simple to keep brake fluid in the lines, and master cylinder. You just take a prop-rod, or even a stick and depress the brake pedal partway down. Then the MC piston covers up the ports in the bore and traps fluid in the lines, and reservoir. It could sit for days and not leak out. It is just like dipping drinking straw in a glass of water and cover the top hole with your finger.
I've been doing it that way for over 30 years whenever I work on brakes, and makes bleeding much easier too when it doesn't all leak out.
 
Last edited:
Originally Posted by Traction
It is actually VERY simple to keep brake fluid in the lines, and master cylinder. You just take a prop-rod, or even a stick and depress the brake pedal partway down. Then the MC piston covers up the ports in the bore and traps fluid in the lines, and reservoir. It could sit for days and not leak out. It is just like dipping drinking straw in a glass of water and cover the top hole with your finger.
I've been doing it that way for over 25 years whenever I work on brakes.


I think this is the solution I'm looking for.


Originally Posted by Astro14
Gravity will take its toll, and no, I wouldn't clamp a brake hose, that's asking for trouble in the future.

But, you don't have ABS, so bleeding after caliper replacement isn't a big deal.

One of these would serve you well, no "helper" required.

https://www.amazon.com/dp/B0002KM5L0/ref=psdc_15707321_t1_B00O6FZJFG



Yup, one of the first tools I bought long ago.


Originally Posted by JLTD
It's a fitting with threads, get the right acorn nut and you're golden.


Yeah, that was my first thought. But without a free hose, it's tough to know what I need. It is a straight end, not a banjo.
 
On a banjo I took two cutoff pieces of bicycle tube and a small wood clamp to stopper it up.
 
Originally Posted by Traction
It is actually VERY simple to keep brake fluid in the lines, and master cylinder. You just take a prop-rod, or even a stick and depress the brake pedal partway down. Then the MC piston covers up the ports in the bore and traps fluid in the lines, and reservoir. It could sit for days and not leak out. It is just like dipping drinking straw in a glass of water and cover the top hole with your finger.
I've been doing it that way for over 30 years whenever I work on brakes, and makes bleeding much easier too when it doesn't all leak out.


thumbsup2.gif
 
I usually force a piece of hose or tubing through the hole of the banjo fitting. But it has to be tight!

Push & twist like screwing it in. And hang the hydraulic brake line upward. This will stop the flow of fluid. However, keep an eye on fluid level & drips and keep the reservoir topped off daily if the job will be taking you this long.

Good luck,

CB
 
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I have used Vise grips to pinch the cable.Before I knew better. When I worked on 528e brakes , I jacked the car up enough so I could tie the line up above the height of the MC. That 1/2 way position of the MC is definitely worth remembering Thank you Traction
grin2.gif
 
I shove a golf tee in the hose.

For banjo bolts I do the same as others mentioned above. I use the OD of a plastic plug. I keep a stash of plugs in a box that come in handy for many things.

It still drips, but at least the master cylinder doesn't drain.
 
JHRZ, I demount the caliper and use a board to take up the slack to use the pedal to extend the piston out enough to grab easily. Then I spin it off the hose. Due to sitting, stuck calipers were common. does the 300D use ATE calipers?
 
Last edited:
Originally Posted by JHZR2
Yeah, that was my first thought. But without a free hose, it's tough to know what I need. It is a straight end, not a banjo.

Then grab a golf tee and tape it on.
smile.gif
 
Originally Posted by Traction
It is actually VERY simple to keep brake fluid in the lines, and master cylinder. You just take a prop-rod, or even a stick and depress the brake pedal partway down. Then the MC piston covers up the ports in the bore and traps fluid in the lines, and reservoir. It could sit for days and not leak out. It is just like dipping drinking straw in a glass of water and cover the top hole with your finger.
I've been doing it that way for over 30 years whenever I work on brakes, and makes bleeding much easier too when it doesn't all leak out.

I can't believe how many people blew right past my suggestion. I didn't think of it, but I read it somewhere so many years ago. It works so well, and is so simple stupid, I could never forget the idea.
 
Last edited:
Originally Posted by JHZR2
Originally Posted by JLTD
It's a fitting with threads, get the right acorn nut and you're golden.


Yeah, that was my first thought. But without a free hose, it's tough to know what I need. It is a straight end, not a banjo.

If you look up a replacement hose on a parts store website, it'll probably tell you which thread size the hose has at each end. If you can't find a threaded plug in the correct thread size, disconnect the hard line from the hose and plug it there instead.
 
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