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Discussion Starter · #1 ·
First off, I have a 84 CJ7 with a I-258. I receintly bought this Jeep used and the vacuum hoses have mostly been cut out. The thing starts fine and runs well but when I touch the brake the idle starts to deteriorate and sometimes dies. What I have found is that there is a hose from the brake booster that goes to the Carburetor or just below the Carb. I am not sure where the carb ends and what the carb sits on top of, anyways this then goes to an open ended hose. When started this hose sucks wind like crazy. So I took a screw and plugged the hose. Now it idles a lot better but I need a long time to stop. Hinders stopping performance. I have looked through my Haynes manual and can not find any information about this. If anyone has a similar experience or could provide some help, I would appreciate it.

 
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Discussion Starter · #2 ·
The hose your refering to is the vacuum source for your Power Breaks. All vehicles with power breaks use engine vacuum as the power source. In a nut shell, the vacuum booster has a leak. The only solution is to replace it. A rebuilt unit is usually around $40-50. Its about a 20 min task.

John......southern CA
84CJ7,3"lift,32"BFG,4.11's,ARB,Solid Axle's
 
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Discussion Starter · #3 ·
So should I leave this hose open? Plug it with something? Or is it suppose to go somewhere? If so where?

 

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It sounds as if the vacumm line may not be connected correctly. You stated that the brakes work fine while connected but are bad when not. This is how they work. You also stated that the engine dies when at idle and the brakes are applied. Well the carb is sucking in all that extra air and the fuel/air ratio is leaning out too much and killing the engine.Don't go buying a booster just yet. Plug the hole and then get ahold of a vaccumm scematic and do the vaccumm lines correctly.

 

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DDawg16,

Where are you getting that price on a rebuitl? I paid that for a used one because I couldn't get a rebuilt
one at any price in less than two weeks and then the price was about $130. I've got a core, who rebuilds
for that price?


 

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I'll venture an educated guess. The brake vaccum line is connected to manifold vacuum. Not sure this is a universal thing but that is where it is on my XJ. Good Luck!!
 
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Discussion Starter · #8 ·
Does anyone else have a Jeep like the one that the problem is with ('84 CJ7 with the 258)?

If you do, and have a digital camera, perhaps you could take some strategic pictures of the engine bay in the area of the brake booseter and the associated vacuum lines. Might this help you out, JEEP_WV?

Marc
Contagious Racing
ICQ: 20889115
 
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