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Rear brake lines

+1 to @Rod_Knox, I would plug at the master cylinder also. Easy enough to trace the lines. I am a weekend mechanic and could figure that out. No clue why the clutch and brake lines/fluid are tied together. But if this is a backyard hack job for demolition derby, who knows…, the car only has to run for about half an hour.

@volvo_v70 - I’m approaching from behind the veil of ignorance here – my test being, whether I, knowing nothing, came into this thread seeking guidance how to alter brake lines for nefarious purpose, would be able to do so. I can say with utter certainty after reading this, the answer is no. :upside_down: I’m inclined to leave it alone and second any safety caveats given.

You’re not going to be able to cap off lines from the master cylinder to the rear brakes. Half of the master cylinder operates the left front and right rear brakes, and half operates the right front and left rear. You’re going to have to pinch off the tubes at the rear of the car. Easy.

The 2.5 has 4 wheel disc brakes if I recall. Just put some line clamps on the rear brake hoses.

Must not have encountered many vehicles. This is quite common (and sensible) across a wide range of domestic, Asian, and Euro vehicles.

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I think the OP is confused by a hydraulic clutch and thinks it is connected to the brakes.
Any one who can’t figure out how to plug the rear brake lines has no business calling themselves a mechanic.
I am not comfortable telling someone how to do this.

I recall Morris/Austin used a combination clutch/brake master cylinder 50 years ago but in the years since the only connection I have ever seen between the brake and clutch master cylinders was a common fluid reservoir.

Good decision Carolyn.
It turned out that the OP wasn’t hoping to do anything dangerous (on the road at least) but in those cases where an OP does seek advice to do something dangerous, I’d much rather have him/her openly questioned (and chastised if need be) than to have his/her discussion closed. I believe it’s better to try to convince such an OP otherwise, and that can only be done with the thread open.

You mean like taping up a leaky brake line with duct tape? Who was that guy anyway?

He posted under at least two different screen names, and one of those names was ‘Indy’…something or other.
He claimed to be unable to prevent his elderly father from driving a Plymouth/Dodge Neon whose leaky brake lines had been…repaired…with duct tape, but that problem later resolved itself when his father finally had to give up on driving.

I don’t recall his more recent screen name, but I do recall his cars–sort of…
Originally, he was driving a Kia Sedona minivan, and later he bought a Chevy Impala–IIRC.
I expect that he will be back as soon as the weather turns colder and he again begins to experience problems with whatever heap he is driving nowadays. However, he is sure to be posting under yet another screen name at that point.

Do you plan on running for political office Carolyn? Or would you be interested in working in an advisory capacity for a well known political candidate who has a difficult time keeping his foot out of his mouth? Your reply here was so very uncritical of anyone. Bravo.

hmm … I guess if I didn’t have the service data on how the brakes were configured, and all I had was the car in front of me, with two lines coming out of the MC … I’d probably remove one of the output lines from the MC, plug that port (using an appropriate sized and threaded brass screw in plug) then open the bleeder screw on one of the rear wheel cylinders. Then press on the brake pedal. If brake fluid spurts out as I press on the brake pedal, the line remaining connected at the MC must feed that wheel cylinder. This method may not work w/ABS configured cars though.

I’ve heard of MC’s that have one fluid compartment for the brakes, and another for the clutch. More common in commercial/farm equipment I think.

This guy needs to watch his language


Umm, how will blocking off the fluid flow at the rear brakes cause the line to break?

And how will losing brake fluid ( if that happens) at the rear brakes affect the clutch? Is the brake master cylinder going to magically suck fluid up and out of the clutch master cylinder? Look at the reservoir, there’s no way loss of brakes is going to make the clutch lose pressure. Once the fluid drops below the feed line to the clutch they become 2 separate systems.

Or else what? Im not gunna be told im an idiot bc im trying to alter break
lines for a good reason. But w.e. if its that big of a problem get my
account taken idgaf. Bye no need for help from u guys cuz u obviously arent
mechanics if u dont swear.

The clutch is ran of of the main brake fluid resivour. Go look at a 2002
cougar 5 speed and come talk to me like an idiot after then till then dont
come at me like in stupid. Like,i said ill figure it out myself quit
commenting,in it,u guys are no helo at all.

I’ve seen more of those cars than you can imagine.

You obviously don’t understand how the fluid flows from the brake reservoir into the clutch master or how much fluid a clutch uses. Once the fluid is in the clutch there’s no way for it to get out of there, so loss of fluid from the brake system will not affect the hydraulic clutch. Unless the car is driven upside down.

You’re making this far more complicated than it needs to be.

I assume when the rear end gets all bashed up, the brake line will rupture I guess. Interestingly one of the best demo cars I saw was an old 60’s fairlane. There was nothing left of it but it just kept on going. Seemed like the larger cars never made it very long at all. That little Fairlane then the wagons seemed to do pretty good too. Its a young person’s sport. Seen a few women drivers.

What are you getting mad at me for

You’re complaining we’re giving you bad advice

If you’ll go back and read the replies, you’ll notice I didn’t give you any advice at all

But I did say you need to watch your language

I don’t care how you talk to your wife and kids . . . but that type of language is literally not tolerated here

I myself have been lectured a few times, but I don’t think you really care at this point

And since we all know what “idgaf” really means, why don’t you just spell it out

You won’t care, anyways, if our moderator kicks you out


I’m going to give you the best answer I can give you. You can do this one of two ways. The easy way, follow the lines from the master cylinder to the brake proportioning valve (block). Both lines go to the same place.

The brake proportioning valve is a flat block of metal with six lines to it. Two of those lines came from the master cylinder, the other 4 go to each wheel. It should be easy to trace the two lines from the from wheels, either go to each front wheel and trace the brake line back to the block or trace each line from the block to find the two that go to the front wheels.

The other two go to the back.

You could put the front end up on jack stands and trace the lines coming off the block and going to the rear of the vehicle. For this application, it does not matter which is right rear (RR) ad which is left rear (LR) as you will block both.

Now remove those lines from the block, cut off one of the fittings and go to a hardware store and get two plugs that match the threads of the fitting you cut off and use them to plug the holes in the block.

This is the only safe way to block off the rear brakes. If you try to block off the lines at the rear, you could easily break one of them during the derby and then loose all braking, so it has to be done at the block.

Okay then why is the line hooked up to it? Explain that to me