I have a 83 d150 slant six 4 speed single cab short bed an the parking brake doesn't work. When it's pushed all the way in. I'm out of town at the moment so I won't be able to put hands on it, but would like to know how to fix it an if I'd need parts for it so I can order them online. Drums in the back disk in the front. When it's at an incline I put the parling brake on an it still goes back. Also is the parking brake on all 4 brakes or only the rear or front? Thank you.

Parking brake is a purely mechanical system that operates the rear brakes only. In your case, your floor-mounted pedal pulls on a cable, that most likely splits into two cables under the vehicle. You could have a stretched or broken cable. You could also have a stretched front cable that has disconnected from the equalizer. You'll have to get under the truck for a visual inspection.

Good luck.....Roger

So only rear brakes got it. Looking at the cable inspection understood anything that I could look inside the rear drums? Do I have to adjust some how?

There are star-wheel adjusters back there that can be used to expand the rear shoes, should they need it. You could also access the adjusters from the rear, through a small, oval-shaped hole that's supposed to have a rubber plug in it, located low on the backing plate. However, those aren't supposed to be used for park brake adjustment, but normal service brake adjustment. If you really need to get into the brakes that far, I might suggest pulling off the rear drums and finding out how much they're rusted up. Adjusters are known to have a habit of rusting enough to freeze up.
Google can provide you with a reference pic or drawing of rear drum brakes with parking brakes. Most of them are quite similar.

Word to the wise......DO NOT disassemble both sides of your rear brakes. One side at a time.....that way you can use the other side for reference.

Roger

There is an adjuster on the E brake cable itself. About right underneath you when you are sitting in the car. That is where you adjust the brakes tighter, not at the drums. The adjusters on the wheels are self adjusting as long as they are working properly.

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12.70 @ 104.6

Your truck should have an equalizer and adjustment threads near the driver's side frame / gas tank area.

Check for broken cables or rotted broken stamped parts on the pivot or equalizer mechanism.

If all of that checks out then tighten the adjuster on the cable. Usually these can get rusty so get your 1/2" box wrench or ratchet wrench some kroil and a small torch if needed to break it loose to allow the threaded adjuster nut to turn.

Aim the heat away from the fuel tank if you choose to use the "fire wrench".

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