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FFCobra Fanatic
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Discussion Starter · #1 ·
OK, my head hurts with this brake pedal/box modification stuff! Someone tell me what to do...I've got: 84 Jeep M/c (no power), I'm running discs-front, drums-rear. I've cut the brake pedal 1 1/2", and made the Jeep M/C pushrod adjustable. So, whats next? I've read sooo many different configurations, ...just tell me what has worked for you, with a similar setup. and..THANK YOU... :mad:
 

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That sounds good. Leave it like that and see if you like it. Use nice screws to put on the top of the footbox instead of ribits and remodify it yearly until you run out of money.
 

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What Matt said. And after all the manual set-ups have been tried and rejected, put it all back stock and mount a power booster and discover what real sports-car brakes should feel like.

Just kidding. But I did go through three manual set-ups and was never satisfied with the brakes until I converted to power.

David
 

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As long as this brake thread is started I'd like to add a question. I 've seen guy's add the booster by just cutting the section of 1" square tubing and welding another piece just to the outside. Well I figured I could just mount a smaller diameter booster and not have to do the cutting. I think the stock booster is about 9" in diameter isn't it? I found one from a Subaru thats only 6 1/2" in diameter and it won't even come close to fitting. Has the 1" square tubing changed location with the mark II frame?
 

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I could never find one that was small enough to fit without cutting the frame, which is almost impossible to do with a finished body on. So I went with the Buick GN.

David
 

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The regular, run-of-the-mill Fox booster is 7" (roughly) in diameter, and allegedly fits with cutting one 3/4" bar and enlarging the center hole. I bought a Geo Metro Booster/MC which was only 6" and it still wouldn't fit without cutting. I too went with the Buick. Oldsnake...here's the scoop for you: With a non-boosted setup, you need to cut 1.5" out of the pedal between the pushrod pivot and the top pivot. That increases your mechanical advantage. In order to get the pedal back down to the same plane as the clutch, and to get your MC pushrod halfway near straight, you need to utilize the other hole Ford thoughtfully provided in the footbox. Look at the box and you'll see another hole about 1" lower in the box where you can relocate the upper pivot. Here's a picture from one of Dave Borden's excellent articles:



Happy motoring

[ August 20, 2002, 11:30 PM: Message edited by: oldguy668 ]
 

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Discussion Starter · #7 ·
OldGuy, Great Minds, and all that. I did exactly that, after seeing the pushrod was at a very dis-advantageous angle. It appears that the pushrod needs to be significantly shorter than stock, also. Thanks folks, I appreciate the help... :D
 

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OLDGUY
The picture was worth 1000 words. I went with the Jeep M/C also. I left the pivot bolt in the upper hole and put a scribe in the lower hole to find the arc on the brake pedal. Then I drilled the brake pedal arm a little above center on the arc and made a copy of the spacers above and welded them to the arm. This will allow you to use both pivot points (1) for Boost (2) Lower for Manual brakes. Buy changing the pivot point you get almost 100% incress in brake system pressure for the same foot pressure .Very simple and nothing to cut up.
 

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I'm with David on this one. I've got discs all around so went with the GN and had a friend turn down the Rod from the donor.



I had to bend a bracket out of some 3/4" steel. Had to drill 2 mounting holes in the lower 3/4" fram rail. Got the pedal hooked up last night and works great. Blew the plug right out of its' hole.

Ben
 

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Kostiuk
I would love to post pictures but I still run Netcape and its the pits . Looking at your brake pedal the pivot point is at the top off your arm and your M/C pushrod pivot is 3 3/4" below it.Now if you put your arm in the second hole you brake pedal is now 1 1/2" longer than your clutch pedal. Like I wrote just drill hole that the upper pivot bushing will go through and make two spacer like above. What you did was lower the upper pivot point and increasing force applied to the M/C.By going this route you don,t have to cut your arm off and reweld.This is like the 4 cyl. arm.This is a KISS fix. Give me a call Don 713-943-1233
 

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Here's another way...

1) Use the lower hole in pedal box.
2) On the pedal, cut off the old mount for the rod and drill a new hole about 1 1/2" higher.
3) Run a bolt through it to mount a heim joint.
4) Replace the mastercylider rod with a threaded rod running into the heim joint.
5) You will need to cut off the bottom 1 1/2" of the pedal and move/replace the pad with the AC pedals but hey they look cool anyway.

No welding (which I like)



[ August 22, 2002, 09:57 AM: Message edited by: rlogan ]
 
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