Mustangs – How to Disassmble the the Rear Axle and Rebuild Assembly

Rebuilding the Rear Axle Assembly

First-generation Mustangs came with one of three rear axle assemblies from the factory: 71⁄4-, 8-, or 9-inch. The axle size for a given car depended on a number of factors including engine size, trim level, and option choices. As a general guideline, the 71⁄4-inch axles were found in 6-cylinder cars, the 8-inch axle was found in most small-block V-8 cars, and the 9-inch was reserved for small- or bigblock high-performance vehicles. There are exceptions to the rule, such as with our 1968 GT. It came with a 9-inch rear axle even though it is only a 302 0-ci V-8 because it is also a GT version with a 4-bbl carburetor, and thus is considered a high-performance vehicle. There’s an easy way to identify the 9-inch rear end. If a socket won’t fit on the rear end’s two lower nuts, and an open end or box wrench must be used, then it’s a 9-inch.

---

This Tech Tip is From the Full Book, HOW TO RESTORE YOUR MUSTANG 1964 1/2-1973. For a comprehensive guide on this entire subject you can visit this link:

LEARN MORE ABOUT THIS BOOK HERE

 

SHARE THIS ARTICLE: Please feel free to share this post on Facebook / Twitter / Google+ or any automotive Forums or blogs you read. You can use the social sharing buttons to the left, or copy and paste the website link: https://www.diyford.com/mustangs-disassmble-rear-axle-rebuild-assembly/

---

 

I cannot show how to rebuild every possible iteration or combination of axle assembly and vehicle; rather, I focus on rebuilding the 9-inch that came with our 1968 and include information about other versions as we go; the basic processes still apply.

After the rear axle is removed from the car, you must inspect it. If the rear axle has a valid factory ID tag, it tells you what you are dealing with. You can determine the gear ratio, type of differential (open or Traction-Lok), build date, and plant code from it. There are also other identifiers, such as the “base code,” which signifies the particular axle model, plus other codes related to interchangeability.

A further visual inspection might reveal signs of leakage and other possible problems such as rust or damage to the housing. Leakage from seals, gaskets or the vent tube usually show up as a dark area on the axle tubes. If it was a very gradual seepage of fluid, it could still appear relatively dry. More serious leaks are moist to the touch and are pretty obvious. There may also be leakage from other sources like wheel cylinders. Since you are rebuilding the rear and putting in all new seals and gaskets, etc., leakage is generally not a concern unless it’s due to the sealing surfaces having been damaged in some way, such as by rusting, warping, or otherwise missing metal. Such problems need to be repaired.

 

Our rear axle assembly showed signs of minor seepage from the axle seals as well as from the vent tube. We also suspect the wheel cylinders for the brakes contributed a bit. All leaks were likely due to the car having sat for such a long time without being driven. Seals get hard from sitting and the vent hose was broken, also from having lost flexibility due to age. The important thing is all of the metal was great; no warping, no rust, etc.

Disassembly

A rear axle assembly is not especially complicated, but it requires specialized equipment due to the sheer force needed in some of the disassembly procedures. If you don’t have some heavy-duty tools such as impact guns and 1/2-inch-drive sockets at your disposal, you should consider farming the job out to a shop that does, preferably one that specializes in axle work. You’ll

also need some decent upper-body strength and, ideally, some form of fixturing to hold the rear securely while you work on it. You can build a fixture inexpensively from wood or, if you’re

handy with a welder, steel plate and tubing. A large workbench also serves the purpose but it won’t be quite as convenient for some of the tasks.

Refurbishing the Rear Axle Housing and Axles

After all of the major parts have been separated, they can be put in the parts cleaner to remove most of the grease and grime. We won’t be reusing things like bearings and seals so we just left them on for now. The time needed in the tank varies based on the condition of the parts, but generally it shouldn’t be too long if you have a decent parts washer. If you do leave any rubber or soft parts on (like our pinion snubber bumper) make sure the temperature isn’t high enough to cause any damage.

The first order of business is making sure the axle housing is straight. After we knew the axle housing was viable, we proceeded with the process of restoring it to virtually new condition by stripping it down to the bare metal. Similar to what we did with the axle housing, we made sure the axles we intended to put in it are good to go as well, primarily regarding straightness.

Rebuilding the Center Section and Differential

The center section and differential are what gives the rear axle assembly its personality. The center section determines its strength and performance while the differential mostly delivers driveability and traction characteristics. The ring-and-pinion gear set, of course, affect all of these and also can be the source of the most common problem with rear axles: unwanted noise. I’ll go through the process of making our original components better suited to our intended use as a weekend cruiser.

 

Rear Axle Disassembly

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY – STEP #01

The disassembly process begins with the removal of the axles. First, remove the nuts that hold the axle bearing retaining plates on. Then you can also remove the smaller parts, such as the vent hose fitting, plus the various brake lines and related brackets, etc. Be sure to keep these in a secure place as replacements are not always readily available and those that may be don’t always look the same as the original Ford factory parts.

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY – STEP #02

You need a slide hammer to remove the axles from this type of rear end because of the interference fit between the axle bearings and the housing and the parts’ age. Other types of rear differentials use different retention methods and may not require this. Watch out for the loosened brake assembly.

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY – STEP #03

With the bearing free of the housing, remove the axle and the brake assembly. Look for any irregularities (color, texture, smell, etc.) in the gear oil. Ours was especially dark because the car sat for so long. Inspect each tube end to make sure there are no signs of rust or pitting. A little scuffing from the beating is fine. The bearings have a press fit and should not move; there shouldn’t be any signs that the bearing was spinning. If there is any damage to the bearing race area the tube end can be cut off and a new end can be installed. An axle shop should do this work.

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY – STEP #04

Use a seal puller to remove each axle seal. Always use a new seal whenever the rear is worked on and/or the axles are removed. It’s cheap insurance against leaks. This combination slide hammer and seal puller made the job extremely easy. Just turn the knob and slam! Then, once you have all of the nuts and washers off the center housing, it can be removed. It usually needs to be lifted on one side and then rocked back and forth to clear the studs. Be careful when using a screwdriver or other wedge to separate the center housing from the main housing because you must not scratch and/or dent the gasket sealing surface, which will cause a leak. A few hits with a soft mallet might help to dislodge the center section and gears from the housing.

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY -STEP #05

After the axle housing is cleaner, check it for straightness. First, insert a precisely sized bar into the housing so that it bridges the center section openings where the axle’s tubes attach. Second, slide stepped plugs onto the bar at each tube end to see if they fit properly within it. If the tube isn’t straight, the plug won’t go in.

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY – STEP #06

Straightening the housing requires a specialized press and fixturing. Pressure is applied close to the center housing, one side at a time, until the axle housing is straightened. The accepted tolerance varies by the specific axle because of tube diameter and length, but it generally is only a few thousandths of an inch. Let a pro with the right equipment and the expertise/feel do this. After the housing has been properly straightened, the plug goes in fully.

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY – STEP #07

After the housing has been straightened it can be fully cleaned in the “Steelabrator” machine. This process is similar to media blasting except that the material used consists of very fine steel balls and the part being processed is secured to a rotating fixture. The process is fairly quick and takes place in an enclosed fixture. After being subjected to the Steelabrator, the axle housing is about as pristine as you could want it to be. It will require some additional cleaning to remove residual media that remains inside the part, but it sure beats going at it with a wire wheel or even trying to media blast it outdoors.

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY – STEP #08

To replace the axle bearings, they must be pressed off. You need to use a hydraulic press and retaining fixtures. The forces involved with this procedure are very high, so be extra careful. With the bearings off, inspect the axles to ensure there is no scoring/scratches, pits, or other type of damage in the area the bearings will again rest upon. Also make sure there’s no groove where the seal was.

 

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY – STEP #09

As with the axle housing, each axle is also checked for straightness although a different procedure is used. Each axle is checked for runout with a dial gauge after it has been secured in a special fixture. The axle is simply rotated and the maximum deflection on the dial is noted. A runout of ± .005 inch is normally desired. One of our axles was out of spec at .007 inch while the other was fine at .003 inch. Stock axles normally run .003 inch or so.

 

MUSTANG RESTORATION: REAR AXLE DISASSEMBLY- STEP #10

To straighten a bent axle, pressure is applied to the center of the axle after it has been rotated to the point with the largest error. This takes some experience and judgment to get right, but the guys at Currie Enterprises were able to get ours down to only .001 inch after just one try. A good thing to do when reusing axles is to take some ScotchBrite or emery cloth and lightly polish the area on each axle where the bearings go. It smoothes the surface and ensures a better fit with the bearing. The axles also get the Steelabrator treatment before they are reinstalled. This helps reveal flaws and to lesser extent, help stress relieve the surface of the axles. As long as the axles are straight and free of any such problems about the only thing that would prevent them from being reused (at least in an unmodified vehicle) would be damage to the splines. Either way, the center housing design makes the driver side axle shorter.

 

Differential Disassembly

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #1

To start disassembling the center section, remove the bolts that hold on the pinion retainer housing and the pinion snubber. The pinion snubber on our car is a factory piece, which is relatively rare and hard to replace. This is also a good time to remove the pinion nut. While this is a fairly hard-to-find part, Currie Enterprises offers new ones with the correct flange and sealer already applied for most Mustang applications.

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #2

On the opposite side of the center section, remove the adjusting nut locking tabs and their bolts prior to removal of the main bearing caps. With the bearing cap bolts out, carefully remove the caps and the adjusting nuts. Then lift out the differential assembly with the attached ring gear.

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #3

To remove the ring gear from the differential, remove the bolts and then use a soft-faced mallet to knock the ring gear off. Strike different areas around the ring gear from the rear—don’t keep striking it in the same place.

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #4

To remove the pinion gear and its bearing retainer, securely hold the center section and then place a large rod or punch at the center of the pinion gear at the pilot bearing. Tap it with a hammer to loosen it. There is a threaded hole in the center of the pinion gear that works fine for this. With the pinion and retainer housing free from the center housing, remove the flange from the pinion gear shaft using a puller-type tool. The pinion gear and bearings can then be separated from the pinion retainer.

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #5

The outer bearing races can be pressed out of the pinion retainer. Replace these with new parts. There are two of them with one facing each way. They seat in machined pockets on either side of the central lip. These can be installed now because there will be no other work done to this part. Use a large enough soft metal tool to avoid damage while pressing them in.

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #6

The pinion retainer housing has an O-ring groove on the collar that sits inside the center housing. This is because variable thickness shims are used to ensure the proper preload of the pinion bearing stack. A regular gasket would not work because it would not be precise or durable enough. The shim can usually be reused as long as it provides the proper fit. The O-ring that seals the pinion retainer, however, should always be replaced.

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #7

Use the proper size of drift or the appropriate size of socket to remove the pilot bearing from the center section.

 

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #8

We decided to upgrade from the conventional/open differential to a limited-slip style. The limited slip provides better traction off the line, especially when using stock-size tires.

 

 

MUSTANG RESTORATION: DIFFERNTIAL DISASSEMBLY- STEP #9

New tapered roller bearings must be carefully and fully pressed onto both sides of the new differential. A properly sized sleeve/tool, which only contacts the inner race of each bearing, must be used to avoid damaging the bearing.

 

 

Differential Assembly

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #1

If the original ring and pinion gears are in good shape, they should be reused because they are typically a matched set from the factory. Here, we see the marking/dimple on the inner surface of the ring gear, so it can be properly aligned with the pinion gear during installation. We’ve highlighted it with yellow grease paint to make it easier to see as we drop in the differential. The ring gear bolts are different for a conventional differential than a limited-slip differential. The former uses the larger headed bolt while the latter uses the longer bolt and washer combination. These bolts do not interchange. Virtually every bolt in the rear axle assembly should also be assembled with the appropriate type and amount of thread locker applied.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #2

First, the ring gear must be installed onto the differential. Thread-in the bolts and then use a star pattern while tightening them to gradually draw the ring gear onto the differential. Gradually tighten the bolts around the ring gear so it doesn’t bind or stick as it draws onto the differential. It works best to slowly go from bolt to bolt and only make a turn or two at each point. When the ring gear is finally seated, use a torque wrench for the final tightening to the appropriate spec. It’s best to do so in a couple of steps and to use the star pattern here as well. It takes longer, but pays off in less noise and wear.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #3

Like the ring gear, the pinion gear also has a marking to help ensure proper alignment during installation. We mark this with some grease paint also.

 

 

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #4

After a new bearing has been pressed onto the pinion gear, the appropriate spacer must be placed next to the bearing before it is assembled with the other bearing and the pinion retainer housing. Unless there is damage or excessive wear, the spacer, like the shim that goes between the pinion retainer housing and the center section, should be reused. These components must have the correct dimensions and must be assembled properly for the pinion to be correctly positioned such that the appropriate amount of gear backlash can be obtained.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #5

After the bearings and spacer have been properly assembled into the pinion retainer housing, a new seal can be installed as well. The seal only needs to be lightly oiled and gently tapped into place.

 

 

 

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #6

The sealing surface of the flange should be lightly buffed to remove any surface imperfections prior to pressing it onto the pinion gear. So long as there are no deep grooves or scratches, this part is almost always reusable. Even with minor wear and/or grooving, add-on sleeves can restore the flange sealing surface to the proper finish and dimensions. These are usually lightly pressed on and held with adhesive.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #7

The flange and its integral deflector get pressed on over the new seal and bearings. The seal should easily ride over the surface of the flange due to the light lubrication we applied previously. With the flange completely seated on the pinion gear, install and torque down the pinion nut.

 

 

 

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY – STEP #8

It’s time to install a new pilot bearing. This is another example of where it makes no sense to reuse the old part, so put in a new one. Apply pressure to the outer race to ensure it is fully installed. After it’s completely seated in the housing, install the spring clip/retainer.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #9

Temporarily assemble the pinion retainer assembly onto the center housing using only three of the five bolts. Apply some grease to the contact surface. This helps prevent the new O-ring on the pinion retainer housing from snagging or otherwise getting damaged when the housing is mated to the center section. Be sure to wipe off any excess that may get onto the surface where the shim goes. Start by first placing the original shim or an appropriate substitute on the housing and then carefully lower the assembly into the housing. Verify the gear backlash at this point.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #10

Rotate the pinion gear, so that the index mark is facing where the ring gear goes. Assemble the outer bearing races onto the bearing cones and line up the yellow index mark on the ring gear with the one on the pinion. This ensures that the appropriate teeth stay lined up as you lower the ring gear onto the pinion. Place the adjusting nuts next to the bearing outer races.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #11

All the components should look like this before the bearing caps go on. The index marks served their purpose regarding lining up the correct teeth on the gears, but they’re barely visible now. The adjusting nuts must be snug against the bearing races and not tilted before putting the caps on.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #12

Install the bearing cap bolts but don’t fully tighten them. Make them just snug enough, so they don’t move when you move the adjusting nuts or when you rotate the gears. The gears should be able to move smoothly.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #13

Measure the gear backlash by setting up a dial indicator as shown. For used gears, you should see about .012 to .013 inch, with a maximum of .015 inch. New gears should be in the .010- to .012-inch range. These figures are for our particular setup. The Ford shop manual provides the data for other cars.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #14

After determining that the gear backlash is within acceptable limits, it’s time to check the meshing of the gears. Apply white grease or a lash checking compound to the ring gear and spin the gears to spread the compound between the gear teeth. Examine the pattern to ensure it has been evenly spread, thus indicating the gear teeth are meshing properly. Turn the adjustment nuts on each side of the differential to reposition it until you achieve the correct meshing pattern. You want the pattern to be even and centered on each gear tooth. The full checking procedure and related pattern charts can be found in the manual.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #15

With the proper mesh set, install the locking tabs and their retaining nuts. You may need to rotate the nuts slightly so the tab will fit properly. This small amount of change won’t affect the adjustment as long as you only move the nut to the nearest hole for each tab. In general, it is better to turn the nuts so they move toward the bearings, rather than away from them.

 

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #16

Carefully tighten the bearing cap bolts to the final torque specification for your particular application. It’s best to do one cap at a time and do so in a couple of steps rather than trying to reach the final figure in one shot.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #17

Next install the stock pinion snubber and the remaining pinion retaining housing bolts. Install the pinion snubber bolts and use thread locking compound. After they have been installed and torqued, remove the remaining two bolts that were previously installed. Apply the thread locker to them and then reinstall and torque them the same as the others.

 

MUSTANG RESTORATION: DIFFERNTIAL ASSEMBLY- STEP #18

A good tip is to remove the fill plug and re-insert it to make sure it hasn’t seized up over the years. If it’s hard to remove, use a suitable penetrating lubricant to help break it loose. A very small dab of anti-seize compound on the threads (and only the threads) can facilitate removing this plug later. The center section and associated parts can now be spray painted to prevent surface rusting. Be careful not to get too much spray on the surfaces where the U-joint bearings will rest because it could make their installation problematic. Be sure to keep paint off the gasket surface.

 

Axle Assembly

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #1

Clean the axle housing with a wire brush and wire wheels to remove all residue from the Steelabrator process. Pay special attention to the area behind the studs where the center section mounts. The folded-over lip in that area can easily retain the residue. Blow the housing out extensively with compressed air.

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #2

As an added measure of safety, install a reasonably strong permanent magnet to the bottom of the axle housing. The force of the magnet should be more than adequate to keep it in place, but using some suitable epoxy or RTV as well can’t hurt. The magnet helps capture any stray residue from the Steelabrator and attracts most of the fine metal particles that are produced by normal wear.

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #3

Inspect the tube ends to verify they are clean and install the correct bolts to retain the brake backing plate. Different factory retaining bolts and axle bearing sizes were used for different vehicles. Lower-performance and/or smaller cars got the smaller bearing (like our 1968 GT). These cars use the larger flanged bolt (left). This bolt wouldn’t clear the larger bearing cup used on heavier and/or higher-performance vehicles, so they came with the smaller flange retaining (right). Both types were used on first-generation Mustangs.

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #4

New axle seals can be installed. Lubricate the seal at the sealing lip and on the outer diameter, so that it goes into the axle housing easily, and the axle goes into it more easily. Use of a proper installation tool such as shown is highly recommended to avoid seal damage that may result in leaks. Be sure to fully seat the seal.

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #5

Put on the center section gasket. Run a fine bead of RTV sealer completely around the sealing surface of the housing. Make sure you fully surround each stud with bead of sealant. Place the gasket over the studs and lightly tap it down onto the sealant underneath, and then apply more RTV in a similar fashion to the top of the gasket.

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #6

Install the center section onto the housing. Reuse the factory copper washers beneath the nuts if possible. If they were too worn/damaged, aluminum versions are available. Torque the nuts to the correct spec. The two lower nuts have to be tightened by hand.

 

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #7

The refurbished brake backing plates can be installed next. Put the correct fiber gasket between the backing plate and the axle flange.

 

 

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #8

If the axle studs need to be replaced because of damage or age, this is the time to do it. Disc brake cars use slightly different studs than drum brake cars because discs require a small shoulder at the base of the stud so the threads don’t contact the rotor. You need a shop press to remove and install the studs.

 

 

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #9

After installing the new retaining plates (for the brake backing plates), the axle bearings can be pressed on. Axle bearings should only be pressed onto an axle once because they shed some of their material as they are installed and bearings are cheaper and easier to replace than axles. On a used axle, you may need to use some thread locking compound (even under a new bearing) to make sure the fit is right.

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #10

Each axle can now be installed in its respective tube. As was the case with taking them out, a slide hammer or similar tool is needed to press fit the bearings to the axles. Be sure to fully seat the bearings. When driving the bearing on, the sound on impact changes when the bearings fully seat. The retaining plate nuts can then be installed and properly torqued down.

 

MUSTANG RESTORATION:  ALEX ASSEMBLY- STEP #11

Install new brake drums, and you have a completely refurbished and enhanced rear axle assembly. Typically, the brake lines and other parts are installed and then the whole assembly is painted and prepared for installation into the car. Since we will be upgrading the brakes in Chapter 9, we leave the rear unpainted for welding on extra brackets and related items. If your plan were to install the axle in the car without such changes, it would be ready to go after painting it and putting on the brakes lines, vent hose, etc.

 

Our car didn’t have any obvious issues with the rear axle assembly, so it was reasonably quiet and smooth. We simply felt it was appropriate (it had been sitting for so long) to make sure it would provide seamless, reliable performance to match the rest of the restoration. We also wanted to upgrade it to a limited-slip differential to better exploit the higher-performance engine upgrades. As has been the theme so far, we stuck with mostly original Ford parts but chose them wisely to get the optimum balance of the factors for a weekend cruiser.

Using a limited-slip differential rather than our original open unit is the only real deviation from a straight-up use of the rear axle assembly. This change doesn’t really affect the overall restoration because the process of rebuilding the rest of the axle is essentially identical; the differential is pretty much a drop-in component.

The vehicle we’re restoring does have one of the more-popular rear axle assemblies and the procedures I show for it illustrate the concept, if not the specific details. From the outset, I’ve made it clear you need to get the specific information for your exact car. This is especially true with the rear axle assembly because it requires strict attention to detail during assembly even though it is a relatively big, heavy component.

We were fortunate to be able to reuse our original ring-and-pinion gears. Factory gears, even used ones, often tend to have fewer problems than aftermarket gears, especially with noise. They may not always be as strong, but that’s not a concern in our situation or for most projects. When rebuilding a rear axle, you need to decide if you want to change ratios, put in stronger components, and/or change the type of differential you’re using (as in our case). We kept it simple and retained the original parts except the differential. Our emphasis was on restoring the car with a stock look and a few mild upgrades to improve overall performance and driveability. The following procedures relative to properly adjusting the gears and so forth are relevant to this type of situation and to more-aggressively upgraded restoration projects.

 

Reassembly

After all of the subassemblies were properly prepared, we began putting the rear axle assembly back together. We made sure the housing and axles were all straight and had no issues. We installed all new seals, bearings, etc., to ensure our rear axle gives us years of trouble-free service. We upgraded to a limited-slip differentialusing OEM Ford components for improved performance. Last, even though we decided to stick with the original gear set, we thoroughly checked and adjusted all of the various parameters and settings to ensure smooth, quiet operation in the car. Other than the brakes (Chapter 8), we’re mostly done at this point. The details for rebuilding a rear axle assembly for a first-generation Mustang vary by specific application but the general concepts are common. And you still need the Ford shop manual to get specific data for any given application. What I’ve shown should help identify the main topics of interest, whether you decide to try to rebuild the rear yourself or you send it out.

Written by Frank Bohanan and Republished with Permission of CarTech Inc