Anatomy of a Jeep CJ Frame

A Jeep frame may seem like a simple part that's just some steel welded together. But it's actually a complex part that contains many different parts that work together to support the entire vehicle. Take a look at this Jeep CJ frame.

An Overview of Each Part of the Jeep CJ Frame

Jeep frame

The Jeep CJ5, CJ7, and CJ8 all had their own unique frames, of course. But the design of each frame was very similar. Wondering what each part of the frame does? We got you. Check out this complete list of frame parts, along with a detailed description of each one.

  • Crossmembers (Front, Middle, and Rear): Crossmembers are important structural components of your Jeep. They support your Jeep's tub, as well as connecting the two frame rails.
  • Spring Shackle Mount & Rear Spring Hanger: These parts go hand in hand to support the leaf spring. During on road driving, the shackle mount and spring hanger see a lot of forward and rearward forces as the spring flexes. When off-road, they also see a lot of sideway twisting forces as the axle articulates. These components are much beefier than stock.
  • Rear Shock Mounts: These parts support the upper end of the rear shock absorbers. The lower end of the rear shock absorbers are mounted to the axle. The shock mounts are also beefed up to handle the forces generated by large tires, wheels, and heavy axles.
  • Muffler Hanger: This is yet another important part of the frame. It supports your muffler.
  • Front Spring Hanger: Like the rear spring hanger, the front spring hanger supports the leaf spring. These are also beefed up to handle larger tires and axles.
  • Body Mount: This is where the body of the car is attached to the frame.
  • Motor Mount Holes: This is where the engine mount bracket goes. Basically, it helps hold the engine in place.
  • Shock Mount Bolt Holes: These holes are for the upper shock mount brackets.
  • Brake Line Holes: These holes allow you to pass the brake lines through the frame. This protects the brake lines from damage, especially during off-roading.
  • Front Sway Bar Mounting Holes: These holes are for the OE style sway bar mounting brackets.

Why it's Important to Have a Well-Built Jeep Frame

Frame jeep

We've covered why each component of the frame is important, but we haven't talked about why the entire frame needs to be built well.

True alignment is very, very important. If the frame is not perfectly square and perfectly flat, the entire vehicle is thrown off whack. More specifically:

  • A slightly twisted frame means that the drivetrain won't be perfectly aligned. Over time, this will cause premature wear to drivetrain components such as u-joints and engine/tranny mounts.
  • The Jeep's body gets twisted, as well. This results in panels not fitting correctly and doors not closing right.
  • Alignment will never be perfect. You'll see uneven wear on the tires, shocks, and suspension.
  • A bent frame puts a constant strain on the tub and body mounting points, which causes fatigue and cracking.

To sum it up, a twisted or slightly misaligned frame causes stresses throughout the entire vehicle.

What Happens When the Frame Rusts Out?

When you have an old Jeep, the frame will rust out eventually. There are two ways to fix it:

  1. Sand, grind, and paint the old frame
  2. Replace the frame

The first option may work if there's a minimal amount of rust on the frame. However, it will likely rust out again eventually. If your frame is heavily rusted (or if you're looking for a permanent solution), then replacing the frame is the best thing to do.

If you want a strong and perfectly aligned frame made just for your CJ, look no further than Throttle Down Kustoms. Here's a quick link to our 1976-1983 CJ5 frames. They, and our CJ7 and CJ8 frames are built to be sturdier and more reliable than OEM frames all the while keeping true to the OE specs. All TDK frames are built with thicker metal that's CNC mandrel bent and CNC laser cut for better than OEM precision.

Feel free to reach out to us with any questions about CJ5, CJ7, or CJ8 frames. We would love to share our expertise with you!