Part 2 of Our Traxxas Shock Rebuild Series
Big Bore Comparison Chart
All Big Bore shocks feature hard-anodized aluminum bodies with friction-fighting PTFE-coated bores and titanium-nitride (TiN) coated shafts. Some sets include springs, others do not; click the image to expand the chart showing the different Big Bore sets, how they’re equipped, and the models they fit.

When to Rebuild
The seals that hold the oil inside of any shock are consumable parts that require periodic replacement. Shafts and pistons wear out too, but less quickly. Seal life varies with surface type and terrain, so there’s no fixed service interval. Shocks subjected to harsh terrain and dusty, gritty surfaces will wear seals out more rapidly than the shocks on a model that operates in smoother terrain and cleaner conditions. Regular inspection is key; rebuild if you discover any of the shocks:
- Are very wet where the shaft exits the body, or you can see oil has leaked out of the shock
- Have scored, scratched, or bent shafts
- Feel rough, lumpy, or otherwise not-smooth when compressed with the spring removed
It’s good practice to rebuild all the shocks together, even if only one or two shocks seems to be in need. Rebuild kits are inexpensive, and you’ll be assured all the shocks are operating equally well.

The 2362 rebuild kit includes seals, spacers, e-clips and diaphragms for two Ultra Shocks. The kit also works with Big Bore shocks, which use the c-clips and clear spacers.
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Required Parts and Tools |
Optional Items |
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Step 1: Remove the Spring Retainer, Spring, and Upper Retainer
Pull the spring up to take tension off the retainer, then lift the retainer off of the rod end and slip it off of the shock shaft. With the retainer removed, you can slide the spring, upper retainer, and any preload spacers off the shock.

Push the retainer off of the rod end and slip it off the shaft, then slide the spring and preload spacers off.
Step 2: Remove the Cap and Drain the Shock
You should be able to spin the cap off with your fingers. If it’s stubborn, pass a driver shaft through the screw hole in the cap to give yourself extra leverage. You can also wrap a rubber band around the shock body for extra grip if needed. Empty the shock oil into a disposable cup as you move the shock shaft through the body to help expel as much of the old oil as you can, then remove the diaphragm from the shock cap. If you can’t pop the diaphragm out with a fingernail, use a screwdriver. (The rebuild kit includes new diaphragms, so don’t worry about damaging the old ones.)

If the cap is hard to remove, grip the body with a rubber band and use a driver for leverage.


Step 3: Remove the Rod End and Shock Shaft
The rod end simply unscrews from the shock shaft. You’ll need to hold the shock shaft to prevent it from turning, but it’s important not to grab the shaft with bare pliers. Squeezing the shaft with pliers will damage the titanium nitride finish and may gouge the shafts, causing the shocks to leak. Here are two ways to hold the shaft without marring it:
Method 1: Side cutters (also known as diagonal cutters). Use the thin jaws to grab the shaft just above the rod end. Any marks on the shaft will be hidden by the spring retainer when the shock is reassembled.
Method 2: Pad the shock shaft with tape. Painters’ tape works well for this. Wrap about five inches of tape around the shaft to build up a thick pad, then squeeze tightly with pliers. The jaws may cut through a layer or two of tape, but won’t reach the shaft.



If your Big Bore shocks have bump stops, set them aside or replace worn ones with the 5482 kit.

After removing the rod end, push the shaft all the way into the body and grab the piston to remove the shaft from the shock body.
Step 4: Remove the Seals and Spacers
The seals are held in the body by a C-clip. The clip can be popped out with a small flat-blade screwdriver, but this technique can cosmetically damage the body. It’s best to use a pair of C-clip pliers (also known as retaining-ring pliers). These will remove the clip easily without damaging the body, and make it much easier to reinstall the clip later. Choose internal ring C-clip pliers with the following specs: ring diameter: 1/4 x 5/16 in. (6x8 mm), tip diameter: 0.025 in., Tip angle: 45° or 90°. Don't forget to wear safety glasses when removing the clip—it’s under tension and can go flying if it pops off the tool.


Squeeze the clip’s ends together, slide it out of the groove, and lift the clip out.

Use the shock shaft to extract the seals and spacers from the shock body.
Step 5: Lubricate and Install the New X-ring Seals
Coat the seals with shock oil before installing them. To avoid oily hands, place the seals in a plastic bag with a few drops of shock oil and smoosh them around from outside the bag. Once they are coated insert them into the shock body with the spacer in between the seals. The translucent washer goes on last, followed by the C-clip.



Install the new C-clip. To make the job easier, use a pencil eraser to press the washer down and fully seat the seal parts before installing the clip.
Step 6: Optional - Replace the Piston and Shaft
You don’t need to replace the shock piston with each rebuild, as plastic sliding against PTFE-coated aluminum in an oil bath doesn’t create a lot of wear. Likewise, the titanium-nitride coated shaft should outlast many seals. But if the piston fit is sloppy (or you want to swap the 2-hole pistons for 3-hole, or vice-versa), or the shafts are damaged or scuffed and no longer have their shine (which makes them prone to weeping oil), the parts are easy to replace. Use a flat-blade screwdriver with a 1/8” tip to pop the e-clip off the end of the shock shaft and release the piston. Use a new e-clip from the 2362 rebuild kit to secure the new piston. If you’re replacing a shaft, install the lower e-clip first, then the piston, then the top e-clip.

Twist the screwdriver to pop off the e-clip and aim it at a rag or into a cup.

Use needle-nose pliers to secure the piston with a fresh e-clip.
Step 7: Reinstall the Shock Shaft and Rod End
Lubricate the shock shaft’s threads with shock oil to help them pass through the seals more easily, then insert the shaft into the body. Wiggle the shaft to help it pass through the seals. Thread the rod end back onto the shaft, and the shock is now ready for filling.

Lubricate the shaft’s threads so they’ll pass through the seals more easily.

Remember not to grab the shock shaft with bare pliers when you reinstall the rod end.
Step 8: Refill the Shock
This step has is actually a few steps. Proper filling is essential to peak shock performance, so take the few extra minutes required to do the job properly.

Step A
With the shock shaft fully extended, fill the shock until it is about 3 mm below the top of the body.
Step B
Slowly cycle the shock shaft up and down to release any air bubbles trapped in or below the piston. When all the air bubbles have been released into the oil, set the shock aside to give the bubbles time to dissipate. (While you wait, you can move onto rebuilding the next shock.)
Step C
After the bubbles are gone, push the shock shaft into the body until this piston reaches the top of the oil. Add oil until the level is about 1.5 mm from the top of the shock body.
Step D
Insert the new diaphragm included with the rebuild kit. Some oil will be displaced, which is fine.
Step E
Install the shock cap and tighten it until it meets the shock body. Snug is all you need, don’t overdo it.

Top Tip: Use pliers with a rubber band around the handle to hold the shock upright while you wait for the air bubbles to dissipate.
Step 9: Check Rebound
Press the shock shaft all the way in, so the rod end meets the body. Release the shaft, and note how far the shaft extends on its own. It should extend to between one-third and one-half of full extension. If the rod end won’t reach the body, or you feel a lot of resistance as the rod end reaches the body, then there’s too much oil in the shock. Loosen the cap and compress the shock to push 2-3 drops out, retighten the cap, and test rebound again. If the shaft doesn’t rebound at all, or you can feel air bubbles in the oil, add a few drops of oil. Repeat until the shock rebounds correctly, and you can cycle the shock shaft in and out without hearing or feeling bubbles in the oil.

The shaft should extend to between one-third and one-half of full extension.

Fully compress the shock and then let go to check rebound.

Reinstall the spring, preload spacers, and spring retainer and your Big Bore shock is ready to go back on your model.
Coming Up in Part 3: How to rebuild GTR aluminum-body shocks.