Brakes 1979-1986 Fox Parking Brake Adjustment

LiquidStangs

Well-Known Member
Dec 13, 2015
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Indianapolis metro area
If you've got a 1979-1986 Mustang (lovingly referred to as "four-eved Fox bodies"), and your parking brake doesn't work or barely works, then you're in the right place.

In 1987, Ford redesigned the parking brake lever for Mustangs to include a self-adjusting mechanism, powered by a spring. Most directions for adjusting Mustang parking brakes refer to this mechanism, and include references for welding the lever to disable the adjustment, locking the spring to tighten it, and other such steps. These directions aren't any help to those of us with older Mustangs, and are often the cause of confusion for people trying to use the Internet for directions on getting their parking brake working. I believe my own car was a victim of this; it had a brand new set of parking brake cables, but with no adjustment done, so they didn't work, and the owner expressed confusion as to why they didn't work when I bought the car.

These directions were performed on a 1985 Mustang GT with a manual transmission, rear drum brakes, and a swapped 8.8" differential with 4-lug axles. To my knowledge, the swapped diff shouldn't make any difference. The procedures should be the same for any car originally equipped with a 5.0 engine, and probably also apply to cars with 4 or 6 cylinders, or the 4.2 Windsor V8 that came with a few early-year Foxes. Factory SVO cars with rear disc brakes may be different than this; if you know about these, please follow up and let us know. If your car is a model year 1987 or later, or has aftermarket upgrades to the brakes, these directions probably won't apply to you. Please follow up if your experiences were different from mine, or if you see any inaccuracies.

So, without further ado...

FIRST STEP: Fix your rear brakes!

Many times, the parking brake doesn't work because the rear brakes don't work even with the normal brake pedal. So, step 1 is to make sure your brakes are in good shape. Are the shoes worn out? Drums toast? How's the slave cylinder? Any broken springs or other parts? Get those fixed first. It should go without saying that your brakes are more important to you when you're moving down the road, so make sure the rear brakes are doing their part.

One step often overlooked is the adjustment of the rear brakes. Generally, they should be self-adjusting using a mechanism that kicks in when you stop after reversing. Many people (myself included) have seen improvements by just going to a parking lot, going in reverse fairly quickly, and hitting the brakes hard. Of course, don't be unsafe doing this. This generally works if the brakes grab just a little when using the regular pedal.

If that doesn't get them adjusted right, then you may need to do a manual adjustment. I'll leave that for others to document, since I didn't have to do it, but it involves removing a rubber plug from the back side of the brake and turning the adjustment wheel with a screwdriver.

So the rear brakes work fine with the regular pedal, but the parking brakes still don't work? Time to adjust the parking brake mechanism.

TOOLS

I got by with a jack and jack stands, Philips screwdriver, 1/2" deep socket, extension, and ratchet. Something to prop up the center console will be helpful if you don't remove it all the way.

JACK IT UP

You'll need to test whether your rear wheels can turn freely or not, and you'll also want to make sure there are no problems with the cable system underneath the car. Thus, it's best to jack up the rear of the car.

Of course, use jack stands to actually hold the car up. Be safe, everyone! Keep in mind that, with the rear wheels in the air, your front wheels can still roll freely, so put a wheel chock or block of wood on either side of a front tire to ensure the car doesn't roll on you off the jack stands somehow.

If you've checked on the rear brakes as part of the First Step, above, then hopefully you've already got the rear wheels in the air safely.

CENTER CONSOLE

The center console makes it really difficult to get to the adjustment nut, so you'll need to get it out of the way.

There are instructions for fully removing the center console, but I'm not going to get into all that, because I was able to just loosen it up and prop it up in the back. To do this, open up your storage bin in the center console. Sitting right on the ledge opposite from the hinge are two screws; remove those. Then pull up on the parking brake lever a bit and pull the tray up in which the parking brake sits; with the two screws out, it should slide back a little bit to disengage the tabs at the front, and then lift out around the lever.

Now look inside the storage bin. In the bottom will be 4 screws holding it down; remove all of these.

Finally, after pulling out the tray right below the lever, there will be two screws holding the main center console against the carpet and transmission tunnel. Remove those. Make sure you note how they went in, as you'll have to find the holes in the carpet through which they go later.

I also removed the plastic cover around the transmission shift lever. Strictly speaking, I'm not sure if that was necessary, but it helped. Folks with automatic transmissions may need to do this too. I was able to pull up on the top edge of the cover (closest to the dash), then pull towards the dash to disengage the tabs holding it in.

From here, I used my screwdriver to prop the back of the center console up. There's enough slack in the console for it to lift up several inches. This was all I needed.

In theory, you should be able to make this adjustment with just the tray out, but I found the adjustment nut to be too hard to get a socket onto. I'd be interested to hear if anyone was able to get this to work.

DOING THE ADJUSTMENT

If you raised the parking brake lever before, put it down now, and look on the passenger side of the lever. You should see the end of a threaded rod with a nut on it. Here's a picture:
mustang-brakes-1.jpg

That nut is the adjustment nut. The threaded rod goes through a hole in the floorboard and ends in a hook, which holds a metal piece into which the two parking brake cables (one per side) are threaded. Tightening this nut shortens the hook, which pulls more on the cables, which pulls on the parking brake mechanism inside the brake, which applies the brake more. We want this to be long enough that the brake isn't applied at all when the lever is down, but short enough to fully engage the brake when the lever is pulled up.

It might be prudent at this point to go under the car and check out that hook and cable. See if everything is still hooked up, with the two cables coming off the metal piece and through two pulleys to opposite sides of the car. When I did this, the cables were taut, but not overly so; they'd move a little when I pulled on them. If they're really loose, or some part is missing, you've probably got more issues; see if the cables are broken somewhere, or not hooked to the brakes, or something.

The Haynes manual mentions the presence of a lock nut, which must be loosened before you can make the adjustment. My car didn't have a lock nut. I can imagine that my directions would be more difficult if there was a lock nut on there, so you might want to take the lock nut off if you have one. But beware: that looks like a difficult place to get the lock nut threaded back on. Judge for yourself whether to do that or resort to a 1/2" wrench; I tried the wrench, and found that to be way more difficult than the deep socket.

Now get your 1/2" deep socket, extension, and ratchet. Put the socket on, with extension, so it looks something like this:
mustang-brakes-2.jpg

Set your ratchet to tighten (clockwise), and ratchet away!

Stop every so often to spin the rear wheels. If they start getting hard to turn, you've gone too far; loosen up the nut until the wheels spin freely again. Also, pull out your ratchet every so often, and try pulling up on the lever to engage the parking brake and see if it holds the wheels in place.

Once you get the brake working to your satisfaction, put the locking nut back on and tighten it down if you have one. Then, reassemble the center console. "Assembly is the reverse of removal." (Don't you hate it when people say that?) The part that hung me up was the two screws that held the center console down in the middle of the console, where the tray goes, because you have to find those holes in the carpet to stick through.

Finally, test your newly fixed parking brake with the rear still up in the air. Does the parking brake work better now? Congrats! You've achieved parking brake nirvana, and can let go of your fears of hill parking and sloped driveways. If it doesn't, well, you probably should have tested a little better earlier; you get to start over.
 
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LX Dave

Active Member
Jul 2, 2017
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I'll add another thing that might help from pulling your hair out.
If the nut all of a sudden gets really hard to turn, STOP!! Pull the socket and make sure the D shaft isn't trying to spin inside of the mechanism. If it is, get another person to go under the car and hold the end to keep it from turning. I had to chase the threads on mine twice before I figured that out because when I would back the nut off, the shaft would spin back and look like nothing was wrong. Things wear, be cautious.