74 CJ5 Proportioning valve and brake line questions. - JeepForum.com
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post #1 of 5 Old 10-02-2013, 07:43 PM Thread Starter
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1974 CJ5 
Join Date: Sep 2013
Location: Lynnwood
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74 CJ5 Proportioning valve and brake line questions.

I am going through my 74 CJ5 I just picked up. The master cylinder was leaking all over the place so I just pulled it. Question 1 is, one of the lines broke at the fitting so I need to replace it. It was a weird coiled line, like a universal line. Are there factory replacements or do I need to buy a universal kit? 2nd Question, the Haynes manual says to open the proportioning valve during the bleeding process. The valve that's in this jeep is not one of the options available for this year. I think Ive ID'd it to a 97-02 TJ. I don't see any point where I can open it up like the D and W versions that were supposed to be in it? Does anyone know if this is an ok fit for this jeep (four wheel drum) or should I find a stock valve and put it back? It stopped fine, except pulled to the left. once I get the master cylinder in I plan on bleeding and seeing how everything works, then replacing the wheel cylinders if needed.

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post #2 of 5 Old 10-02-2013, 07:51 PM
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1985 CJ7 
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Location: The Mojave Desert - Palmdale, Ca. U.S.A.
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Save the fittings.
You may have to 'bend' the line yourownself.
Good luck,

Have'n you along, is like loose'n 2 good men
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post #3 of 5 Old 10-02-2013, 08:00 PM
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1974 CJ5 
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I did this about 6 months ago. You need to just get the standard replacement lines, bending them isn't hard if you have a bender, not sure how much they are, but if you try and do it without one you'll probably end up kinking it.

As for the proportioning valve I didn't even bother opening it up or anything and it worked fine. And it sounds like (no expect) that the valve you currently have in there will work. I would think the pulling to the left would be an adjustment problem with the adjustment screw in-between the pad in your actual brake setup.

So if you replace the lines and then bleed you should be all good to go.

good luck,
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post #4 of 5 Old 10-02-2013, 08:08 PM
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1981 CJ7 
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The coil in the brake line is to absorb movement, hence reducing the risk of fracturing of the line either from movement in the vehicle or when removing and refitting the brake master cylinder. It is good practice.

These are not "factory" parts per se, the brake pipe is bent into that shape by the fitter. All you need is a length of brake pipe, the fittings for the ends, a flaring tool and a round object to carefully bend the brake pipe around. Care is needed to avoid colalpsing the pipe and there are pipe bending tools out there which will do the job properly, though with some care and slow deliberate steps you can do it without. Don't use pliers, they will cause the pipe to bend over.

The "proportioning valve" is the Combination Valve. It has several functions but is a pressure differential and rear brake proportioning valve, and it sounds like you have one intended for front discs which require relatively less fluid than a drum. This MAY fool the valve into thinking you have a leak on the front. To be safe I would replace it with one intended for drum brakes. If you want to keep it there is a button on the right hand side that you need to have held in during bleeding, there is a tool but a helper with a large screwdriver could hold it there. Often during bleeding the flap valve is not activated by the bleeding process so often it does not need to be held, though I am not sure this is good news.

The pulling may be a wheel cylinder issue but more likely is adjustment. I will NEVER have front drum brakes through choice, they are a PITA.

You will have to bench bleed the master cylinder, are you aware of the procedure?

BagusJeep lives in Bali.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
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post #5 of 5 Old 10-02-2013, 09:22 PM Thread Starter
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1974 CJ5 
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Location: Lynnwood
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Thanks Bagus for the explanation. I kind of figured I was going to have to get line and bend it. I was trying to figure out the purpose of the "coil" in the line. Both lines had it. I am finding so many rigged things in this Jeep I figured the PO had extra line and was to lazy to cut it to fit so he wrapped it up. I was going to run a pretty straight line but now I know why not to.
I am heading to a Jeep ranch tomorrow for some other miscellaneous parts. I think proportional valve is now on there to. I have bench bled a couple master cylinders. Thanks for all the help. This thing is kind of turning into a monster. Every time I open something up I find something else rigged together.
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