The disassembly procedure for both Chevy 10- and 12-bolt rear differentials is virtually the same. You do not need to be concerned with getting it out of alignment. As long as you take the proper steps to ensure that the shims go back in the correct location, the entire unit can be disassembled, cleaned, and inspected, with the exception of the pinion gear.
This Tech Tip is From the Full Book, CHEVY DIFFERENTIALS: HOW TO REBUILD THE 10- AND 12-BOLT. For a comprehensive guide on this entire subject you can visit this link:
SHARE THIS ARTICLE: Please feel free to share this article on Facebook, in Forums, or with any Clubs you participate in. You can copy and paste this link to share: http://www.chevydiy.com/how-to-disassemble-chevy-and-gm-differentials-step-by-step/
In both units the pinion gear uses a crush sleeve to set the preload on the bearings and removing it requires the installation of a new crush sleeve. So, consider this fair warning.
Although other components do not have to be aligned, you need to keep the inner pinion bearing properly aligned. This bearing is pressed on and removing the bearing instantly changes alignment. Don’t remove the bearing unless you are replacing it.
You can work with the axle assembly in the vehicle or on the bench. It really doesn’t matter which. There are drawbacks and advantages to both, especially in the set-up phase. Most applications require removing only a few extra bolts to the get the housing out of the vehicle. If you are performing a complete overhaul, taking the housing out of the chassis allows you to clean and paint the housing. However, it’s your decision whether or not to unbolt the axle from the chassis. Here are some of the pros and cons you must consider.
If you have the use of a lift, you can more easily remove the entire housing because you aren’t on your back under the car to complete the procedure. If you do not have a lift, you need to jack up the car and place it on jackstands. Removal is a bit more difficult. However, removing the housing is often the best way to go because it’s much easier to work on the entire housing on a bench or stand rather than still installed in the car.
Limited-Slip or Open Differential?
You need to determine which differential is in your vehicle. One of the most common questions when looking at an axle assembly is, “Do I have a Posi-Traction (limited-slip) or an open carrier?” There are several ways to answer this question. Most gearheads use the common burnout method: Do a burnout, and if you get two black stripes, you have a working Posi-Traction carrier. This doesn’t always work, however. Posi-Traction is a limited-slip design, and over time, the clutches wear out and function essentially as an open carrier.
Another simple test is to jack up the back of the vehicle with the wheels off the ground and the trans-mission in neutral. Spin the tire and watch which direction the other wheel turns. If it spins in the same direction, it is a Posi. If it spins in the opposite direction, it is an open carrier. Without a load on the clutches, even a worn Posi carrier should function in this manner.
To conclusively determine the type of differential, you can always open the housing and look at the carrier itself. In certain situations, this is the only way to know for sure. Open carriers have four spider gears and a crossbolt. GM Posi units usually have four spider gears, a crossbolt, and a pair of S-shaped springs with a set of four coil springs between two plates in the center of the carrier.
Most axle assembly issues make noise when in operation. Howling, clunking, or banging indicates different issues inside the axle housing. Many signs can tell you that the differential is worn out and may be close to failing. The following is a brief list of signs and their general cause.
A small pool of gear oil on the ground by the rear tires or a greasy wheel/tire is a sure sign of a bad axle seal. Often, worn axle bearings cause this condition. You can tell it is gear oil by the color and smell. Gear oil is always dark and it smells horrible. There is nothing else like it.
Don’t just replace the seals, you should go ahead and replace the bearings too. If you ignore this sign, the bearing could lock up, which will also lock up that wheel, destroy the tire, break or bend the axle, and possibly wreck the vehicle.
Groaning or Howling
Two things typically cause these sounds: worn bearings or gears out of mesh. Gears usually howl when they have not been set up correctly. In most cases, this is a result of too little or too much backlash as well as not correctly setting the preload on the pinion bearings. Unfortunately, an incorrectly set up differential will damage the ring-and-pinion gears within a hundred miles or so, and correctly resetting the backlash does not eliminate the howling. If the howling appears after many years of use, a worn or damaged bearing is most likely creating the noise.
Six bearings are installed in GM 10- and 12-bolt rear axle assemblies. Two bearings are in the axle ends, two are in the differential carrier bearings, and two are in the pinion bearings.
Knocking or Banging
Worn bearings or improper gear adjustments most often create these noises. Keep in mind that worn-out U-joints in the driveline can also cause clunking sounds; inspect those first to eliminate that possibility. Does the noise happen when shifting, under a load, or when letting off the gas? The following tests can help you localize the issue. It is best to per-form these tests on a clear stretch of road without other vehicles around.
Cruising Speed: When driving the vehicle, accelerate up to a speed over 30 mph and maintain that speed. Listen closely for any kind of noises coming from areas of the vehicle other than the axle assembly. Axle assembly noise is usually not heard at a constant speed, unlike engine, suspension, and transmission noises, which can be mistaken for axle assembly noise.
Varying Speed: Many axle issues become evident when you quickly accelerate and decelerate using the throttle. When you do this test, you are loading and unloading the gears and bearings. Clunking or banging is evidence of worn bearings or seriously worn gears.
Coasting: If you hear a howl or whine when the vehicle is coasting, you most likely have a worn-out pin-ion bearing.
With the car parked, jack up the axle assembly and support the vehicle on jack stands. Never get underneath a vehicle supported by just a floor jack. If it fails and you’re underneath the car, you can be crushed. Try to lift the wheels to determine if there is any movement in the axle. There should be very little. If the wheel moves up and down, the axle bearings are most likely worn or failing.
Also check the pinion yoke with the same test, after unbolting the U-joint. The pinion bearings could be excessively worn and need replacement if the yoke moves up and down.
The axle assembly must be rebuilt once you have determined that it is generating noise from worn gears or bearings, leaking a lot of fluid, or has completely failed. If you can completely remove the axle unit from the car, it will be far easier to rebuild on a bench. Different makes and models require different methods to remove the housing. Therefore, I can’t cover every removal procedure for specific cars and trucks. But I can explain the most common procedure for removing these axle assemblies.
The first step is to suspend the chassis and let the rear extend freely under the car. Use the properly rated floor jack to jack up the car and place the correct jackstands under the frame rails. Remove the lug nuts and take off the rear wheels. The shocks are fully extended and can be unbolted. Once the shocks have been removed, more of a load is placed on the leaf springs and the axle drops farther.
Brake Lines and Cables
Depending on the length of the brake lines, you may or may not have to remove them before you remove the shocks. You need to ensure the brake lines are correctly routed so they do not contact the exhaust or any moving parts.
It’s a good idea to take a photo at this stage of the project so you know how to route the brake lines when you re-install the axle assembly on the vehicle.
You need to remove the parking brake cable. Pull back the boot on the bracket and remove the retaining clip; then the fitting can be removed from the bracket. Use a wrench to remove the flexible brake line fitting on the top of the axle housing.
Driveshaft and Leaf Springs
Next, turn your attention to the driveshaft. First, you need to remove the four bolts that retain the U-joint. These hold the two straps on a GM strap-type driveshaft. Once the bolts have been removed, push the drive-shaft forward and the U-joint will separate from the pinion gear yoke.
Remove the leaf springs and then you can move the axle assembly to your workbench for rebuilding.
Corrosion and Rust
The axle assembly and rear suspension on street cars are exposed to corrosion, moisture, and all kinds of debris. As a consequence, they suffer corrosion and rust. If your axle assembly hasn’t been removed in years, the retaining bolts and nuts are most likely corroded and it’s not going to be an easy job. Here are the steps I use:
Soak the front and rear leaf-spring shackle bolts and nuts with penetrant lube. Use an impact wrench or a 1/2-inch ratchet to remove the front leaf springs nuts.
If the penetrant lube is not sufficient, you may need to use a propane torch or similar device to heat the nuts. Apply heat for at least one minute and if it does not do the trick, try it again.
Extend the floor jack so it is just under the pumpkin (center section) so that when the leaf springs are removed the axle assembly does not hit the floor.
Remove the nut from the front shackle of the leaf spring. Remove the nuts that secure the spring pack and remove the rear shackle bolts.
Once the leaf springs have been removed, you and a helper can roll the axle assembly out from under the car. At this point, you and your assistant can lift the axle assembly onto your workbench.
Make sure you have an oil pan or tray underneath the housing to catch the fluid. Use a socket and ratchet to spin off the center section. Use a screwdriver or scraper to gently pry the cover from the housing. A gasket and often silicone sealant hold the cover on, so expect some effort in splitting the cover. Let the fluid drain before moving to the next step.
Inspect the fluid as it drains and then examine it in the catch pan. Chunks of metal are obvious signs of a major gear or component failure. If the fluid is shimmering with silver streaks or flecks, you know you have metal wear on the inside of the unit. If you see this, do not ignore it, you need to replace all the bearings and races inside your housing.
When differential fluid is new, it is clear. Many miles of use causes the fluid’s color to gradually change as it absorbs heat and provides lubrication. Water and dirt contaminate the fluid and it quickly turns dark. At the end of its life cycle, the fluid is very dark. Moreover, any old oil residue from the old oil changes the color of new oil in short order. The primary things to look for are signs of metal wear and overheated oil, which smells burned, but even that can be tricky with gear oil.
You can check the mesh between the gears by holding the carrier with one hand and rotating the pinion yoke. It should move a little, but it should not be loose. If you want to determine the exact amount, mount a dial indicator and take the measurement. This is an unnecessary step if you are rebuilding the unit.
Pinion Yoke Removal
A large nut secures the pinion gear to the pinion yoke. Using an impact wrench is the easiest way to remove the nut. If you don’t have air tools, you can use a breaker bar and socket to remove it by hand. First, you need to lock the axles from spinning.
This can be done with a helper or by setting a box-end wrench on one lug of an axle and letting it rotate until it locks against the workbench or the shop floor. Once you break the tension on the pinion nut, you should be able to remove it easily.
Step 1: Remove Pinion Nut
A fair amount of torque is required for removing the pinion nut. If the axles have been removed, it’s difficult to prevent the pinion from moving when trying to remove the nut because the axles provide resistance. However, the axles can be held tight so that the pinion doesn’t spin. Impact tools do the job. Note the thick washer behind the pinion yoke nut.
Step 2: Remove Yoke
A few blows with a soft hammer usually gets the yoke free from the splines. Tap on one side and then the other so it slides off the spline. Make sure to use a soft hammer because you don’t want to damage the yoke. Once the axle has been rebuilt, the yoke can be reinstalled if it is not damaged.
Step 3: Remove Pinion Seal (Special Tool)
The pinion seal is positioned at the end of the tail section. A seal removal tool quickly and safely extracts the seal from the end of the housing. Or you can use a medium-size cold chisel to remove the seal. Run the tool around the lip of the seal to start the process. Tap on one side of the seal, then switch to the other side so it comes off evenly and does not become cocked in the housing end.
Axle Shaft Removal
Most GM 10- and 12-bolt axle assemblies have C-clips retaining the axles, but some Buick, Oldsmobile, and Pontiac 10-bolt housings have bolt-in axles. Remove the disc brakes or drum brakes before you proceed. You need to remove the drum brake cover and then remove the brackets that retain the brake shoes. At this step, you should be able to deter-mine the style of ring gear carrier in the axle: open, limited-slip, or locker.
Each of them can be removed using the following procedures.
On the carrier, a center pin runs through two of the four spider gears. A small bolt holds one end of this pin onto the carrier. This bolt is just to the side of the center of the carrier; remove it using a socket and a wrench. The end of the bolt has a long pin. With the bolt out, the center drift pin should slide out easily from the carrier. You may need to rotate the carrier to get the pin clear of the case. Now, the axles can be pushed into the housing from the outside.
If the assembly has C-clip axles, the clips are on the end of the axles. Pull them off and the axles will slide out of the carrier and can be removed from the housing.
If the axles are bolted in, there are no clips and you will not be able to push the axles into the housing. In this case, follow this procedure: Four nuts on the end of the axle tubes hold the drum brake backing plates to the housing and bolt-in axles. They also secure the axle retainers. Remove these nuts with a wrench or socket, and the axle and backing plates will separate from the housing.
You may want to remove the brake backing plates on bolt-in and C-clip housings if you plan to paint the case.
Step 1: Remove Center Pin
In the process of removing the pinion yoke, you need to remove the center pin. The center pin is in the middle of the carrier; it holds the yoke to the pinion gear.
Step 2: Remove Pin Bolt
The pin bolt retains the center pin; to remove the center pin you need to remove the bolt.
Step 3: Remove Pin Bolt (CONTINUED)
Use a ratchet, extension, and a 1/2-inch socket to turn out the pin bolt. An extension is required in order to clear the carrier bearing cap.
Step 4: Drive Down Center Pin
Use a large fl at punch and a hammer to drive out the pin. Be patient and take your time when tapping it out. Some-times it doesn’t require much effort so don’t use heavy blows; other times the center pin slides right out. If the pin is stuck or stubborn, use a soft brass punch to get it moving. But don’t drive it all the way out just yet.
Step 5: Move Carrier into Position
Roll back or rotate the carrier so the other side of the pin is exposed. Use pliers to pull it out. Try not to damage the pin’s surface; you may be able to reuse it.
Step 6: Properly Store Parts
Be sure to properly organize and store your parts. Have a box or tub handy to store all the hardware. At this stage, do not dispose of any parts; keep all of them. Some will be replaced, and some will be reused.
A pair of main caps fastens the carrier inside case, and these caps are designated for a particular position. An arrow on the main caps usually points towards the axle tubes, indicating the direction that the cap should face. Use a grease pencil, paint marker, or hammer stamp to mark both the cap and the housing for each cap so the caps are installed in the same place and correctly oriented. Remove the two bolts per cap and set them aside. The caps require some effort to remove them from the case because of the tight fit. A plastic mallet or hammer can be used to tap them out; alternatively, a screwdriver or pry tool can be used to ease them out. You want to work them from the top and bottom. Don’t just pry on one end because they sit in a deep relief and are easily cracked.
With the caps out, the carrier can be removed. There are shims on either side of the carrier bearing races. Most stock units use cast shims, but if the housing has been rebuilt before, there may be multiple shims. The stock rings are very fragile, and if they fall, they may shatter. Having a second set of hands to help catch them is very handy here. The carrier fits tight to the housing; you will need the pry tool to slowly wedge the carrier out of the housing. Label the shims to match the side they came from; if you get them backward, the alignment will never be right.
Step 1: Remove Axle Shafts
To remove the axles, the C-clips have to come out. The axle assembly should be positioned on jack stands or a bench. You can use your hands or a block of wood to push the axle shaft toward the center section. Push the axles in as far as they will go.
Step 2: Remove Axle Shafts (CONTINUED)
The axle shaft end extends into the center of the carrier and gives you the room needed to remove it. This C-clip (arrow) is just below the axle end flange.
Step 3: Remove Axle Shafts (Special Tool)
Several methods can be used to extract the C-clip from the carrier housing. You can use a pick, screw-driver, or wire hook. A magnet tool is the best method of removing the C-Clip.
Step 4: Remove Axle Shafts (CONTINUED)
Now you can slide the axle shafts out of the axle tubes. Grab hold of the hubs and pull the shafts out. If the bearings are damaged or seized, the axles may be difficult to remove. With enough effort you should be able to pull them out of the housing.
Step 5: Identify and Mark Axle Shafts
Axle shafts are the same length from side to side, but you should reinstall one in the same axle tube it was originally removed from, especially if you are not replacing bearings. Take this opportunity to mark each side.
Step 6: Find Main Bearing Caps
A pair of main caps holds the carrier in place. These are side- and top-bottom specific.
Step 7: Mark Main Bearing Caps
Use a number or letter stamp to mark the cap and its respective side. You can use a paint marker too.
Step 8: Remove Main Bearing Caps (Professional Mechanic Tip)
You can use a socket and a breaker bar to remove the main bearing caps. But I recommend using an impact gun to loosen the caps. Then you can remove them by hand.
Step 9: Remove Carrier and Ring Gear
With the main bearing caps removed, you can see the bearing race (top arrow) and a cast-iron shim (bottom arrow).
Step 10: Remove Carrier and Ring Gear (CONTINUED)
Pull straight back on the carrier to slide it out. A significant amount of force is required to get it moving, but once it does, the carrier slides right out.
Step 11: Remove Carrier Shims
Carefully remove, tag, and store the shims. If these fall to the garage floor, they will break. Use a Sharpie and some tape to mark each shim and designate its installation side.
At this point, the pinion gear is exposed. If you are not changing gear ratios or the pinion bearings, there is no need to go any further. However, when you disassemble the axle, you might as well replace it all.
Use a soft-blow hammer or mallet to tap the pinion out of the case from the front side; you need to hit the yoke side of the gear to remove the pinion. Remove the small-diameter bearing on the front side behind the seal along with a fl at washer. Keep the washer, as it will be reused. You can remove the seal before or after the gear; it really doesn’t matter.
The second pinion bearing is a large bearing pressed onto the gear, and it can only be removed with a press. There should also be a crush sleeve on the gear shaft.
Several races should be replaced because after extreme use or high mileage they are most often worn. Use a brass driver or a race driver/removal tool kit to tap each race out of the case. The races on the axle tubes for the axle bearings are difficult to remove because you need a long bar to reach them from the inside.
Here’s a handy tip to drive out the race: Place a large socket that matches the diameter of the bearing race inside the axle tube. Guide a piece of heavy tubing or bar through the opposite end of the axle tube until the socket rests up against the bearing race. Use a hammer to hit the bar and drive out the race. Repeat for the other side.
Step 1: Remove Pinion Gear
With the carrier and related parts removed from the center section you have room to drive the pinion gear out of the housing. Use a soft hammer to tap on the threaded end of the pinion gear and drive it into the axle housing. If the axle assembly has not been damaged, the pinion should come out with a few taps.
Step 2: Remove Pinion Gear (Important!)
If the pinion gear is stub-born and binds up, use a ballpeen hammer to drive it out. But you must protect the gear threads if you are going to reuse the pinion. If that is the case, thread the pinion nut back onto the pinion and use a bigger hammer. The pinion nut is always replaced so you don’t need to worry about damaging it.
Step 3: Remove Pinion Gear (CONTINUED)
If the pinion gear still does not slide out of the housing, you can put the pinion and housing in a press. You have to be careful here because too much pressure could break the housing. If you put it in a press and it doesn’t move with a couple tons of force, you need to stop. Another method is to apply heat to get the pinion gear to move.
Step 4: Remove Pinion Gear (CONTINUED)
This 12-bolt passenger car housing had been run low on gear oil, so it overheated and the front pinion bearing seized onto the pinion shaft. I used an oxyacetylene torch to heat up the pinion gear but I am careful not to apply too much heat in any one area.
Step 5: Remove Pinion Gear (CONTINUED)
This is a severe case and I hope you don’t have to take such extreme measures. Running this axle without fluid created some difficult problems in disassembly. In the end, I used a torch to cut the bearing and free the pinion.
Step 6: Inspect Pinion Gear (Critical Inspection)
Lack of lubrication in an axle assembly typically causes bad things to happen such as catastrophic failure. You can see the scarring on the pinion. With this kind of scoring, it cannot be reused. I will need a new pin-ion and ring when I reassemble this axle.
Cleaning the Housing
I usually pressure wash the entire housing and axle tubes. If you don’t have a pressure washer, you could take them to a self-serve, manual car wash. Or you can apply a lot of degreaser, such as brake cleaner, and use a lot of rags to strip the grease, oil, and other gunk out of the housing. You need to ensure that the entire axle assembly is thoroughly cleaned so the axle components don’t fail prematurely or underperform because of contaminants in the bearings, components, and oil. Cleanliness is very important for bearing health.
Do not leave the axle exposed to elements. Once you have cleaned it, coat the surfaces with WD-40 to prevent oxidation or rust. If you are looking for a deep clean on your housing, especially if you plan on painting the unit, you might want to look into one of the following cleaning methods.
Although some enthusiasts own media blasting equipment, many do not own the other cleaning equipment. You may need to call the shops in your area to see if they have suitable cleaning equipment for your project.
Media blasting is an excellent way to clean the housing and can be done at home with a portable unit or you can find a local blaster to do the job for you. To clean the case, you can use several types of media: walnut shells, baking soda, crushed glass. Remember that you need to protect several precision finishes in your housing, so I recommend that you avoid using sand.
Walnut shells and baking soda are the best blast media for a housing because they don’t damage any of the precision surfaces. In addition, walnut shells are not highly abrasive and therefore don’t generate much heat (no warping), and are environ-mentally friendly.
If you use baking soda, be sure to neutralize the soda residue with a vinegar and water mixture before painting.
However neither walnut shells nor baking soda can touch rust. If the housing is just a little rusty, you can clean it by hand, or you can use crushed glass. Crushed glass does not release free silica so it’s safe for the environment. And it’s less likely to damage precision surfaces as long as you have some experience.
A true hot tank uses an acid/water bath to strip away grease, grime, rust scale, and almost any-thing else on the surface of an axle assembly. Many shops no longer use this method because the acid is a hazardous substance and EPA permits are required.
If you can find a working hot tank, have your axle assembly cleaned in it because they do a better job than any other method. Just make sure you neutralize the acid before painting.
A wash tank is an environmentally safe equivalent to the hot tank. These are essentially large dishwasher-type units that use near-boiling water and detergent to clean the parts. If you can find one large enough to fit an axle assembly, it can do the job.
A pressure washer is one way to clean an axle assembly at home, and you won’t anger a car wash owner by leaving a large spot of grease on the car wash floor. Soak the housing with a degreaser (even oven cleaner works quite well), let it sit for the specified amount of time, and then spray away. If the axle assembly has never been rebuilt, it’s often very dirty; some of these housings are 40 years old. If that’s the case, the axle is likely to have loads of caked-on grime. You should expect that the axle is going to shed a lot of grease and grime so plan accordingly. It usually takes two to three washings to get it all clean.
Project: 12-Bolt Brake Conversion for a 1967 Chevy Truck
GM 12-bolt axle assemblies use C-clips to hold the axle shafts in the axle tubes. The C-shaped steel clip slides into a groove around the axle about 1/4 inch from the end. The clip pushes against the spider gear or limited-slip plate while a steel bar (held in place with a small pin bolt) keeps the axles from pushing toward the middle of the carrier.
Some GM 10-bolt housings and Ford 9-inch housing use bolt-in axles. Pressed-on bearings and a plate on the outer tubes retains the axles, and the backing plates bolt to this.
Once the axles are out and the backing plates are off, the rest is a simple bolt-in process. A kit from Classic Performance Parts was installed on my 1967 shop truck, and it uses Cadillac calipers and replacement parts for the brakes. The brackets are well designed and easy to install. The edges are quite sharp, so you should wear gloves when handling them. The Cadillac calipers feature integrated parking brakes, so there is a secondary parking brake similar to some other kits.
This kit also included new parking brake cables that connect to the factory cable under the frame, which is a nice touch.
One note about a rear disc brake swap: You have to replace the axles if you have six-lug axles and want to change to five-lugs. Many axle manufacturers offer these conversions from basic stock axles to high-performance units. The 12-bolt GM housing is quite stout, and many performance options are offered.
If you want to swap bolt pat-terns, now is the time. I chose to keep the six-bolt pattern. The previously installed front discs conversion retained the six-bolt pattern as well.
The entire process only took a few hours and the results were impressive, the truck stops better than before with just the front discs, and I retained the six-lug bolt pattern.
Step 1: Remove Wheels
Remove all the lug nuts and take off the wheels. This is a six-lug-axle truck, and this lug nut set from Classic Performance Parts (CPP) retains the wheels.
Step 2: Remove Brake Drum Cover
Many vehicles have old, rusty drums that can be difficult to remove. A subtle tap with a hammer knocks the brake shoes loose from the brake drum.
Step 3: Remove C-Clips
Use a ratchet and socket to remove all the bolts retaining the differential cover. Rotate the carrier into the proper position and remove the center pin. If the pin sticks, you can use a hammer and brass punch to drive out the center pin. Push the axles in to the center and pull out the C-clips. Then pull out the axles.
Step 4: Remove Drum Backing Plates
These bolts tend to be rusty so you may need to use penetrant lube and/or heat. Use a wrench or socket and ratchet to remove the four bolts retaining the plates to the axle tube ends. The brake shoe assemblies lift off once all the retaining bolts have been removed so there’s no need to disassemble the mechanisms.
Step 5: Remove Emergency Brake Cables
To fully remove the backing plates, the emergency brake cables must be removed as well. Use Vise-Grips to stretch the cable; then unhook the ball end from the bracket on the brake shoe. If you are replacing the brakes (as I am here), disconnect the parking brake cables at the trailing arms as they will be replaced.
Step 6: Install Emergency Brake Cable Links
The Classic Performance Parts emergency brake kit comes with new cables to link to the original cable. These attach to the original cable clips just as the originals did. The cable is not under tension because it is not connected to the caliper. Therefore you can simply push the ball through the clip and pull it into place in the narrow slot.
Step 7: Install Calipers on Axle Ends
Some brackets may require modification to fit a particular vehicle. In this case, the brackets fi t the Chevy 12-bolt axle housing and no additional modifications were necessary.
Step 8: Bolt Brackets to Axle Ends
The brackets bolt to the backside of the axle ends as did the original drum brake backing plates. Make sure the orientation matches that in the instructions. Properly align the bracket under the axle ends and torque down the bolts with a socket and ratchet. The bracket ends face forward toward the front of the car so you can mount the caliper to it.
Step 9: Install Axle Shafts
The axle shafts are fed through the axle tubes and extend into the center of the differential. Hand install the C-Clip over each axle shaft end and then use a socket and ratchet to install the differential center pin.
Step 10: Install Brake Rotors
This is a mechanically actuated Cadillac rear caliper with built-in emergency brakes. This eliminates the need for a second caliper.
Step 11: Mount Calipers to Brackets
Insert both brake pads into the caliper. Slide the caliper over the rotor, and then bolt it to the new brackets using the supplied hardware. Most calipers are torqued to between 20 and 30 ft-lbs but you must follow the torque specs included with the instructions.
Step 12: Install Cable Locks
The emergency-brake cable locks into the lever through the return spring. Be sure that the cable end is secure in the tab. You can add a zip-tie to keep it in place before the emergency brake is set.
Step 13: Bleed Brake System
Don’t forget to bleed the brake system! You can use a pressure or vacuum bleeder or the two-man system where one person pumps and holds pressure on the pedal while the second person opens the bleeder screw releasing air and fluid. Start at the farthest corner from the master cylinder and move toward the closest corner. Work each caliper until there is no more air coming out of the brakes.
Written by Jeferson Bryant and Posted with Permission of CarTechBooks