A Pictorial Guide To Rebuilding 1963-1982 Torque Arms
One of the services I offer here at Corvette Repair is the rebuilding of the rear torque arm assemblies. At the most basic level, that would sound like just the replacement of the rear wheel bearings and seals, however there is actually far more to it just that due to the age of these cars and their often checkered maintence histories.
Most people just bring their Corvette in asking for new rear wheel bearings. We are to remove the rear torque arm assemblies, rebuild each unit on the bench and install them back into their car. Add in a rear alignment and the job is done.
Sounds simple enough, however most people say "How come it's so expensive." or "What's involved in replacing the rear bearings". I also should mention that I have a lot of customers who prefer to do as much of the work on their Corvette as they can either for general maintenance or full restoration.
Because most people want to know what exactly is involved in replacing the rear wheel bearings I decided to create a basic overview of what it takes to do the job. The following picture show the steps involved and I will try to explain as simply as possible what is it takes without getting into a lot of detail.
For example, the process of removing the spindle requires a good ten ton press with a bearing splitter and a nice home built fixture. This makes the job go a lot smoother than beating the spindle out with a large hammer and cutting the bearings out with a torch, which is how shops without the proper tools do the job.
Also, I won't go into detail about setting up the proper spindle end play on final assembly. All of the above is explained pretty well in the Corvette Service Manual. However, if you have any questions, just email them to me and I will try to explain in more detail.
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Rear Assembly and Torque Arm factory diagrams.
These large diagrams will take a while to download over a modem.
1- This is a typical example of what the rear torque arm assemblies from a disc brake 1965 to 1982 Corvette look like after being removed. 1963 thru 1964 cars are basically the same, but with drum brakes. There are other differences in the design of the arms and castings over the years, but all year torque arm units are similar enough that this web page is applicable to all C2 and C3's.
These two units were taken out of a fairly nice 1967 Corvette. They appear fairly rusty and crusty looking, but as you will see below they aren't in that bad of condition from a cosmetically perspective once they have been bead blasted and cleaned up. However serious hidden problems exist, more below.
2- This photo shows a quick check of the rotor run out before disassembly of the torque arm. This can tell you quite a bit about the assembly.
High run out can mean a couple of things. The spindle could be bent from hard contact with an object such as a curb. Runout can also tell you what kind of condition the rotor is in.
For example, if you see only .002 or .003 run out, the spindle is probably ok and you should keep it matched with the existing rotor. If the bearings are so loose you can't get a reading, move on disassembling the torque arms.
3- The first step is to drill out the rivets which attach the rotor to the spindle. This is real simple, however, it is very important to drill each rivet exactly on center if you want a nice job.
A 67 Corvette torque arm which is still fastened together to the rotor with the original factory rivets is actually a pretty rare find these days.
4- This picture shows what the bearing support and rear parking brake assembly looks like after the rear spindle has been pressed out.
5- This is a good picture, which shows a rear torque completely disassembled before clean up. At this point I give all the parts a quick check. The rear torque arm is placed in a fixture and checked for straightness. The spindle is given a quick visual check, then placed in a lathe between centers and checked for run out.
6- This is a quick check to make sure the rear caliper bracket is straight using a dead flat reference granite table.
7- A quick check of this spindle tells us two things. First of all, whoever removed this spindle the last time used a torch. If you look very close you will notice a cut mark in the bearing surface. Any time you find this throw the spindle away.
Second, You can see that the inner bearing had spun on the spindle destroying any possible press fit. This is another good reason to discard this spindle.
8- Guess what? The bearing on the second spindle was also starting to spin. Discard this spindle also.
Finding hidden problem like spun bearings and torch cuts in the spindles is common and is the main reason why rebuilding torque arms can get expensive. Quality replacement parts cost quality dollars. There are a lot of poor quality imported bearings, bushings and other parts out there. Avoid them or you'll be doing this rebuild again all to soon.
9- A little better close up shot of the first flame cut spindle.
10- After it has been determined the rear torque arms are straight, drill the old rubber bushings out. This arm really looks rusted in this picture, but it isn't as bad as you might think.
11- This is a good picture because it shows what the parts look like before and after clean up. The silver parts are their natural color after being hot tanked and bead blasted.
After all the parts are cleaned up the castings are again checked for straightness and cracks. The arms are checked very closely for cracked welds and internal rust. These are actually turning out to be ok.
12- This shows what the new torque arm bushing should look like after being installed and properly flared.
13- Here we see all the parts after clean up and final inspection. Also included is what I call the torque arm parts kit. Each parts kit includes all the required new parts to rebuild the rear torque arm assembly plus new parking brake hardware. Also note the two new spindles on the right. Use only the best quality when it comes to spindles.
14- This picture shows what the rebuilt torque arm looks like right before installing the spindle, bearings and seals. This is a good view of the new parking brake hardware.
15- Pressing the inner bearing into place on final assembly.
16- Completed assembly with the spindle flange in place and torqued.
17- In this picture there a couple of things to notice. First I use a torque plate and five lug nuts to simulate the use of a wheel. It is important to check the run out using this procedure because without the proper pressure your readings will not be correct.
The second thing to notice is that this rotor has been turned and that any reading under .005" is good. If your reading is over .005" shim the rotor or you will have brake problems.
A quick review of what has been done to the torque arms at this point:
- Removed the TA's from the car
- Dissasembled and inspected everything
- Replaced two bad spindles
- Installed new parking brake hardware
- Bead blasted, cleaned and painted everything
- Installed new bearings and seals
- Turned rotors
- Reassembled and re-inspected everything
- Reinstalled the TA's into the car
- Sent the car out for a rear end alignment at a Corvette literate alignment shop
So what appeared to be just a "simple" and inexpensive bearing replacement job was actually a complete overhaul of a pair of 34 year old torque arms in dire need of repair. This particular job is very typical of what is necessary to make these vintage Corvettes safe and fun to drive once again.
Cleaning up errors (in this case the flame cut spindle) made by other shops somewhere in the deep past is a common occurance. Even when the work was done properly, bearings are a wear item and if not replaced when they should have been by the previous owners of the car, spun bearings can happen, which ruin the costly spindle.
Costs associated with doing this job correctly rise in direct proportion to the quality and frequency of the work done prior to the car being driven into the shop. That makes estimating the costs to do this particular job complex, as the potential for hidden damage to spindles, parking brake hardware, rotors or bent arms or caliper brackets is high.
It is also wise to take 5 minutes when removing and reinstalling the torque arms to give the rear suspension components (bushings, shocks and spring), the brakes (calipers, hoses and pads), and the half shafts (u-joints and yokes) a quick visual inspection for any problems that might be developing.
