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post #1 of (permalink) Old 08-17-2012, 06:26 PM Thread Starter
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Power brake question

Hi to the group:

A few weeks ago a co-worker was going to take his partially disassembled 1985 Laredo to the metal recyclers. I was talking to my wife about buying a few parts and she says, "why don't you buy the whole thing and just give him what the scrap guy would have given him".
Wow, I was shocked. Anyway, here I am with a rusty project in the garage, (the last inspection sticker is from 1995). It's been outside in an open carport since then, so you get the idea.
Right now I'm listing the areas to attack and prioritizing them.

Anyway, strangely enough the jeep has non-power front disc brakes. Being a driver since the early 70's Ive owned and driven a lot of cars with manual drum brakes, but only one with manual disc brakes. I thought it was hard to stop and I didn't have as precise a feel as I had with manual drum brakes.

My neighbor has a power booster from a CJ-5 that I'm thinking of retrofitting. my question is, if I do go to power brakes, do I need to change out the proportioning valve?

I know I'll have to make new lines to fit the new placement, but will the proportioning valve for the manual brakes work with a power booster?
Is there anything that else that may need to be changed?


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post #2 of (permalink) Old 08-19-2012, 02:18 PM
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That valve is properly called the multi-purpose valve, and has three functions; it sets an upper limit to the pressure going to the back brakes so that they can't be locked up on dry pavement, and if pressure is lost on either circuit it blocks the flow of fluid to that circuit and turns on the failure light. None of those functions should be affected by a booster, which just puts the same pressure into the lines with less leg effort.

But before you do anything drastic, try the Jeep out with out boosted brakes. They were an option on my '78, which I didn't want, and have never seen the need for. It does take more leg effort for a given stop, but IMO it's not excessive, just different. And also, IMO, the un-boosted brakes are more sensitive than boosted, not less.

EVERYTHING's easy for the guy who doesn't have to do it.
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post #3 of (permalink) Old 08-28-2012, 07:44 PM
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Leave the valve and see how she reacts. If you are paying for your neighbors booster, it may be wiser to search for a YJ booster. A better option in my opinion. You'll also need a YJ master and the lines will come off the passenger side, but the little bit of extra line tweaking will be worth it.

Is this the only hammer you've got?
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post #4 of (permalink) Old 08-29-2012, 09:23 AM
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i ditched my booster... i run just a corvetter master with 4 wheel disks.. and no valve.. works like a champ.. mucho better than before.. and simpler.. but mine is an OHV only..

I wouldn't sweat the booster.. its just there to make it easier to push... a manual isn't that much harder to push.. i prefer manual for better feel and control when in the rocks..

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