Author Topic: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.  (Read 12498 times)

0 Members and 1 Guest are viewing this topic.

Offline 428Bird

  • Jr. Member
  • *
  • Posts: 4
  • Referrals: 0
I know in this day and age most people are converting their drum brakes to either factory disk, or doing expensive conversions to aftermarket disk. For those who wish to keep their original drum equipment, this write-up is for you.  It is by no means the definitive method of installing this equipment, but for me seems to the easiest. I accomplished this yesterday with my dad teaching me how to do it, over the phone, while I was doing it - step by step. So I guess you could say it's his method.

Disclaimer: Wear your PPE. That includes gloves, and safety glasses. Wear a suitable respirator if you are cleaning away brake dust, or using cleaning solvents, or painting. This guide assumes that your brakes have been taken apart and that everything is clean. It assumes that all of your components are either new, or in used but servicable condition. It assumes you have a basic grasp of how to use hand tools. It is not a guarantee that your attempt will be a success, but I think it will make your attempt easier. It is not a guarantee that your brakes will work at all. If you are not confident in your abilities, take your car to a certified professional.

Helpful hints: They make tools specific for this job that would make it a tad bit easier. I managed with one screwdriver and a pair of channel locks. Do this job ONE SIDE AT A TIME if you can. Some parts are side specific and can be mixed up.

A little background: My car is currently dissembled to the last bolt. I took the rear apart to clean, paint, install new axle seals and brake cylinders. The springs and shoes you see in the picture are a little over a year old.

Okay, having got all of that out of the way, On with the show. This guide covers installing the brakes on the LEFT, or DRIVERS side.

1. Lay out and identify your parts.




This is the adjuster wheel. It is internally threaded on the left of the "star" wheel, and has a rotating "cup" on the right. The star wheel is always installed towards the rear.


This is the rotating cup end. Notice the stamped 'L'. That means that this adjuster wheel is for the LEFT, or DRIVERS side of the car.


Lubricate the threads and cup with anti-seize, do so SPARINGLY. You do not want any lubricant to get flung around and land on your drums or shoes. Excess also attracts dust. You don't need much is what I'm saying.


Grab your shoes and look at them. Each pair of shoes has a "long" shoe and a "short" shoe which is describing the length of "pad" on each shoe frame. When installing shoes, the "long" shoe goes towards the front, while the "short" shoe goes to the rear.


"short" shoe to the rear.


"Long" shoe to the front.


Lay out your shoes in the correct orientation. Place the adjuster wheel as shown.


This is the spring that will hold the bottom of the shoes together and will provide tension for the adjuster screw. Notice how the spring is orientated. It will install in FOUR different ways, but will only operate if you install it like this. Notice how the long end of the spring is formed to clear the star wheel.


Instead of trying to pull the spring, overlap the tops of the shoes to bring the spring holes closer together. Install the spring.


Extend the shoes as shown. You can lock the top of the shoes together to keep the spring extended if you need to set it down for some reason (as shown here). Look at your work, remember: long shoe to the front, short shoe to the rear. Star wheel to the rear. Spring properly clears star wheel. Everything correct? Move on.


Is your Parking brake cable installed? If not, install it now. You will hate yourself if you continue on without doing so.


This is the parking brake arm. It attaches to the cable and will install behind the rear shoe. Most times you can do a brake job without taking the cable off of this arm. If you did, separate the spring from the cable end and slide the cable into the slot at the end of the arm.


Just like that.


And this. This is how the arm will be orientated behind the rear shoe.


Let the parking brake arm hang from the cable. Take your shoes and separate them slightly so you can hang the assembly on the studs. Maintain proper orientation ( don't flip the shoes around! )


This for me was the hardest part of the whole thing. The parking brake arm like I said mounts to the inside of the rear shoe. See the triangular shaped hole at the top of the rear shoe? The little tang on the parking brake arm fits into that hole. The way to do it is to pull the parking brake arm forward so that the tang is engaging the hole at an angle. You then rock it in. I really can't describe it any better than that.


Parking brake arm installed.


Separate the shoes again just enough to get over the axle flange. Notice the half moon cutouts at the tops of the shoes, that is where the install on the mounting pin at the top of the backing plate. The brake cylinder plungers install in the slots provided for them. Try to keep things aligned as much as possible. It'll be easier for you because you won't be trying to photograph it at the same time.


This is a retaining pin. There should be a "2" stamped on the end meaning that the pin is to be used for F-Body's. If there is no number, or a different number, get the correct pins.


We will be installing the retaining spring and pin for the front shoe first. Thread the pin through the back side of the plate as shown.


Thread the pin through the front shoe.


This is the front retaining spring. Note the cone shape of the spring. It's also the longer of the two.


The retainer is a basic 90 degree lock. The retainer plate has a horizontal slot that will accept the head of the retaining pin. Press the spring/plate down over the pin, rotate 90 degrees, release.


This is the adjuster arm. Notice that it is an assembly. I didn't feel the need to take this apart. It will install over the rear shoe.


It mounts here and will be held in place by the rear pin/spring retainer.


It will pivot on this little spring cup.


Like this.


Insert your other pin from the rear. You may run into interference from the parking brake lever. Move things around as necessary.


Install your remaining spring retainer.


This is the parking brake strut in its installed orientation. Notice that the rear side has a wider gap than the front side, and that the front side has an oval spring. Also notice that the strut is offset and must be installed in this fashion.


The rear gap is wider because it must fit over both the shoe, and the parking brake lever (look close, you can see it behind the shoe)


Strut correctly installed.


This is the shoe retainer. Push the shoes towards the rear of the plate and install the retainer. There is a machined shoulder that this rides on. Make sure it's as far back as it will go.


This little rod installs next. Note the orientation.


Hook the little end into the top of the adjuster arm.


Pull foward with pliers and install over the pin as shown.


This is the front shoe return spring. The front spring is longer. Please note the orientation.


Hook the short end of the spring in the provided hole as shown.


Rotate the spring up and to the rear.


Pull spring with tool or pliers up and over the pin. If you don't have enough room on the pin, make sure that your shoe retainer is as far back as it will go, and that it is riding on its shoulder.


This is the rear shoe return spring, which is shorter. Note the orientation.


Hook the short end of the spring in the provided hole in the rear shoe.


Rotate the spring up and to the front.


Use tool or pliers to loop spring on the little rod we installed earlier. As shown.


This is the adjuster arm return spring. It installs between the arm and the inside diameter of the rear shoe. See the little tang?


Just like that.


Installed.


Make sure the star wheel engages the pawl of the adjuster arm correctly. You should be able to turn the wheel one way, but not the other.


Press both shoes inwards and make extra sure that everything is square and straight. Make sure the cylinder plungers aren't crooked. Make sure all springs are seated in the pin at the top. Make sure that the brakes shoes look "round".


Top view.


Rear view.


Front view.


Lastly, a note on primary adjustment. If you turn the little adjuster star wheel towards you (causing it to click against the adjuster arm pawl) The threaded portion will cause the adjuster length to widen, causing the shoes to move out at the bottom. You want to adjust these shoes so that when you go to place your drum, it just fits. If you adjust too far you won't be able to put the drum on, lift the pawl and turn the star wheel back the other way.

You don't want a tight fit on your drums, but you also don't want a mile of clearance either.


I hope this helps someone. Please let me know if you have any questions.

Britt
« Last Edit: March 28, 2013, 07:09:22 PM by 428Bird »

Offline oldskoolubr

  • Adv. Member
  • ****
  • Posts: 1950
  • Referrals: 0
Re: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.
« Reply #1 on: March 28, 2013, 06:01:40 PM »
Great Writup!  Wish I had seen this prior to rebuilding mine, then switching to Disc!  ::)

Offline pancho400cid

  • Sr. Member
  • ***
  • Posts: 669
  • Viva los PONCHOS!!
  • Referrals: 0
Re: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.
« Reply #2 on: March 28, 2013, 06:29:43 PM »
Magnificent write up!

This will probably start a deluge of controversy, but the "short" shoes go toward the front, and the "long" shoes go toward the rear.
1978 Trans Am - Brown - Current Project
1978 Trans Am - Silver - Future Uncertain

Offline 428Bird

  • Jr. Member
  • *
  • Posts: 4
  • Referrals: 0
Re: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.
« Reply #3 on: March 28, 2013, 07:11:47 PM »
Magnificent write up!

This will probably start a deluge of controversy, but the "short" shoes go toward the front, and the "long" shoes go toward the rear.

CRAP, You're right. That means I have to re-do my brakes, and re-do this write up.

Thanks,

Britt

Offline Matuna

  • Member
  • **
  • Posts: 116
  • Referrals: 0
Re: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.
« Reply #4 on: March 28, 2013, 09:50:08 PM »
Wow, wonderful post and instructional. Great pics, the whole 9 yards! Thank you!
-1975 Trans Am in Restoration Process-

Offline Greenbird76

  • Sr. Member
  • ***
  • Posts: 763
  • The way Grandma wishes she could of ordered it!!
  • Referrals: 0
Re: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.
« Reply #5 on: March 29, 2013, 10:00:22 AM »
I applause you on the awesome write up.  This will help many enthusiasts abroad.  One thing to add is all of the hardware is still made by companies like raysbestos and others.  About 10-15 dollars a side including the adjuster.

Offline lethal_inject1on

  • Member
  • **
  • Posts: 167
  • Referrals: 0
Re: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.
« Reply #6 on: April 15, 2013, 01:21:53 PM »
Very nice write up.

You mentioned that many people these days are converting from drum to disc brakes. 
Is that a difficult things to do ?

Offline oldskoolubr

  • Adv. Member
  • ****
  • Posts: 1950
  • Referrals: 0
Re: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.
« Reply #7 on: April 15, 2013, 02:54:20 PM »
If anyone needs some particular Parts IE: Springs clips etc. I have some left over and they are free just pay the couple bucks for shipping.  I can send a pic I know I have those 2 rubber elongated plug things along with a lever,  spring, retainer etc.

Offline goaltenda

  • Jr. Member
  • *
  • Posts: 19
  • Referrals: 0
Great Write up!

The one thing I like to do is take a couple pictures before I take the brakes apart. It's helped me out tremendously during reassembly. Just a tip.
If you're not first, you're last.

Offline ponchonutty

  • Adv. Member
  • ****
  • Posts: 1747
  • Referrals: 0
This should be a sticky some of us that have gotten use to disc sort of forget the little stuff.  BTW, I usually buy a whole new hardware kit like mentioned before.  All new springs and wear parts for about $20.  Only thing I would have done in this case was coat the inside and small parts with POR15 since heat brings moisture.  That's why these brakes rust so easily especially here in the Midwest.
Rich enough to own a TA, too poor to keep'm all ;)
1980 TA (1st car)
1989 Formula
1976 400 4sp
1976 400 auto
1978 WS6/W72 4sp
1970 455 4sp Formula clone
1980 Indy Pace TA

Offline TurdPolisher

  • Member
  • **
  • Posts: 160
  • Bucket List # 3 under way
  • Referrals: 0
Re: Assembling your GM Drum Brakes, 2nd Gen. F-Body, Rear, Picture Heavy.
« Reply #10 on: June 10, 2013, 03:09:06 AM »
Very good write up.  I could have used this when I had all of the parts thrown in a box.........sure would have saved me some time.
If you are going to do it wrong........you might as well do it RIGHT!