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power brakes? steering box modifications possible?

Posted By: AMC400Mopar

power brakes? steering box modifications possible? - 02/28/13 12:36 AM

Another couple of my newbie questions. Keep in mind our '74 Javelin/Mopar engine car is for the strip only, never street use.

Question 1: It is my understanding the bore diameter of manual and power brake master cylinders is different, so simply removing the booster will result in very high brake pedal effort. So I wonder, could the leverage ratio of the brake pedal itself be changed somehow, maybe by moving the pivot point, to make a power brake master work acceptably without a booster?

Question 2: I have seen people remove the power steering pump and simply run a short loop of hydraulic line full of fluid between the input and output of the power steering gearbox. I understand steering effort at low speeds is very high with this setup, partially because of the power steering gearbox ratio but also because of the resistance from a hydraulic piston or restriction to fluid flow within the box? So I wonder (A) how does the power steering gearbox actually work, and (B) could someting internally be opened up or removed to reduce steering effort when not using a pump?

I ask this stuff not only because I'm cheap, but because I'm curious! Plus AMC manual steering boxes and brake master cylinders don't exactly grow on trees around here...

Thanks for your input!
Posted By: Mopar-Al

Re: power brakes? steering box modifications possible? - 02/28/13 01:33 AM

there is a guy in my town that has more than a dozen javelins in his collection. I am quite sure I could dig you up a box in time if you had to have one. A power steering box not beeing used under power, really really sucks and tends to have slack in the steering. Also, don't over think the master cylinder. The booster has the mechanism on it as well as under the dash. I do a lot of conversions as to what your questions are asking. It really is not as hard as you think it will be.
Posted By: Sixpak

Re: power brakes? steering box modifications possible? - 02/28/13 02:10 AM

There may be more to swapping to manual brakes than swapping out a master. Check to see if power setups use a different linkage for the pushrod - many mopars did add an additional lever setup not found on manual brake setups. And its not as simple as removing the extra lever - on an A body for instance you need a different pushrod thats designed to work without that extra lever - it bolts right to the pedal bracket.Best to check the FSM and see what the linage looks like between manual and power.
A power gear box has a piston in it and fluid is applied to either side of the piston . This piston adds the power assist to what is essentially a manual steering box.There's a valve mechanism usually where the hoses go into the box and just by turning the steering shaft a vale redirects the fluid coming from the pump to one side of the piston or the other, depending on which way you turn.
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