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Discussion Starter · #1 ·
Ok Folks,
I am retrofitting an IRS assembly into my restomod 1969 F100 (engine and tranny is 2019 Coyote).

I purchased lower control arms from a MKVIII, and new calipers. Brakes bled and all seems fine EXCEPT the rear brakes wont hold. I do NOT have the parking brake hooked up as I didn't have the intermediate cable and don't entirely know how to fab up a solution.

I am guessing, from trial and error, that with no parking brake cables connected, the calipers are not able to properly adjust to apply enough stopping power. Am I right? If I hold the parking brake lever on rotor part ways, pressing the brake pedal does indeed stop the wheel, but with the parking brake lever unattached, I can get no braking force from rear axle.

Looking for confirmation, and perhaps a solution! I intend to leverage the parking brake pedal in the truck, but apparently am missing an all too important intermediate cable with a spring-thingy...

BTW, no post is allowed without a pic I assume!!!

43569
 

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1994 Cougar XR7 DOHC/5-Speed
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The calipers should work perfectly normal without the parking brake system installed, so something else is wrong, either with the calipers the master(depending on the line arrangement) the lines or proportioning valves). Did you have to compress the pistons at all when you installed them? They're supposed to be screwed with a special tool to compress them inward, using a C clamp like one normally would on the fronts can actually severely damage the rear calipers
 

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Discussion Starter · #4 ·
The calipers should work perfectly normal without the parking brake system installed, so something else is wrong, either with the calipers the master(depending on the line arrangement) the lines or proportioning valves). Did you have to compress the pistons at all when you installed them? They're supposed to be screwed with a special tool to compress them inward, using a C clamp like one normally would on the fronts can actually severely damage the rear calipers
The calipers were new, so no compression needed.

Any reason why the calipers wouldn't self adjust?
 

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1995 Thunderbird LX 4.6 red
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What master cylinder are you using? what is the front brake setup that you are using?
 

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The mechanism that incorporates the parking brake is what takes up the initial slack, and the pullback that lets the pressure off after braking.
You should be able to actuate it by hand to take up the slack. it should work normally after that.

It's also what breaks after someone uses a c clamp to push in the pistons. I ended up replacing a caliper due to inadequate selectivity on my part on who l let work on my car. :)
 

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Discussion Starter · #7 ·
Meh, ok, I can make brakes work if I hold the parking brake lever about 1/4 of the way, but short of that they do not have enough clamping power to hold the car idling in reverse. Only I move the parking brake lever a bit the pedal supplies plenty of force. Poop. Maybe I did try to c-clamp em... meh. Ordering replacements now, luckily they are cheap.

Chris
 

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Discussion Starter · #8 ·
OK, Replacemts installed.

Same result. With no parking brake input they clamp enough to slow an idling truck in reverse, but not enough to stop it. If I apply a slight input to parking brake lever THEN pump the brakes they will stop the rotor completely and easily. I tried actuating the parking brake levers a few times if that is needed to adjust the calipers. no change.

What am I missing folks? New calipers didn't need to be turned back in, I installed them straight out of the box. Pads are brand new. Rotor brand new and 2mm larger than min spec of rotor....

Do I need to install a parking brake cable to make these brakes work? joy...

Chris
 
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