how to fill rc shocks

How To Fill RC Shocks Efficiently in 6 Steps


The shocks of your RC have not been functioning properly as before. It’s time to change the old oil in the shocks and replace it with clean oil.

What you want to know is how to fill RC shocks?

Remove the old oil from the shocks and fill half the shock with new oil. Make sure to release the air bubbles inside the shocks by moving the pistons. Fill the rest of the shock with oil and seat the bladder on top of the shock.

It’s okay if you’re still feeling lost. We have explained everything in detail. This article will provide you with a clear visual of the method.

Let’s go-

Filling The RC Shocks With Clean Oil

There will come a time when you will need to change the oil in your shocks. It may happen due to the oil inside the shock going bad due to collecting dust. A good and new RC shocks can also get damaged due to contaminated oil and require taking apart. 

Experts recommend changing the shock oils a couple of times every season. Depending on the usage, the number can vary.

Before filling the shock with new oil, we need to clean off the shock. Doing so means that we need to get rid of the old, dusty oil first.

Follow these 7 easy steps to fill your RC shocks-

Step 1: Cleaning The RC Shocks

Cleaning the shocks will make sure no dust particles will remain in them. To do so, we need to-

Dismantle the springs from the shock after carefully taking them from the car. Clean the oil and dirt under the rubber boots of the shock shaft.

After you are done disassembling the shocks, empty the oil in a single-use cup. Use a paper towel to absorb the oil. Place the cap on the towel after removing it from the shock.

Pump the shock shaft a few times. This will remove the excess oil under the piston. Place the shock in an upside-down position to seep out the remaining oil.

This will clean the shocks from the old oil and make it ready for refilling.

Speaking of shock oil, here are some of our top picks for shock oils-


You can store some of the shock oils in your RC toolkits for emergency refilling.

Step 2: Oiling The Shocks

After you’re done cleaning the shock, extend the shock shaft all the way down. Fill the shock with clean oil until the shock is 90% full.

Step 3: Releasing Air Bubbles

Pump the shock shaft up and down about 3-5 times from underneath the piston. Doing this will release the air bubbles inside the shock.

Rest the shock vertically for five minutes with the shaft fully extended  This will make sure that not a bit of old oil remains in the shock.

Step 4: Setting The Shaft

Set the shaft according to the desired rebound. Push the shaft all the way in for no rebound.

Place the shaft halfway for a 50% rebound. Ensure that both the left and right shocks have the matching rebound. Running the least amount of rebound in the shocks will provide maximum consistency in overall performance.

Step 5: Filling The Shock With Rest of The Oil

The next step is to top off the rest of the shock with oil. It’s not necessary to fill the shock completely. Fill the shock just enough to place the bladder on the top without any air underneath. This step is as crucial as finding the top quality shock for your traxxas slash 4×4. 

Overfilling the shock with oil won’t necessarily hurt performance. The oil will just spill out of the shock and make it a little messy.

Step 6: Seating The Bladder.

Keeping the shock shaft to desired rebound position, push the bladder down onto the shock. Use your fingertip to seat the lip of the bladder on the frame of the shock.

If done correctly, a small amount of oil will spill out. No spilled oil will mean that there might still be some air trapped underneath the bladder. If that is the case, remove the bladder and repeat step 5. 

If the bladder is seated properly, pull the shaft down by 20mm. Doing this will suck the bladder down and help it hold it in place. Wipe off the excess oil that spilled out.

Step 7: Closing The Shock With Cap

Hold the shock vertically and screw the shock cap.  An adjustable wrench can be used to hold the shock button while you tighten the cap.

This will help keep the bladder safe from leakage. 

And with that, you have successfully filled your RC shocks with new oil. That was actually easier than it sounded before. This will enhance your RC experience and keep your shocks from wearing down.

RC cars like Traxxas and Redcat have slightly different shocks. So the process might vary a bit depending on the shocks.

You can easily fill the shocks by yourself. So make sure to fill your shocks with new oil 2-3 times every season. This will keep your RC car in good condition.


Question: Should my RC shock rebound after filling it with oil?

Answer: Yes, it should rebound slowly and fully compress. If the shock rebounds too fast, then it has too much fluid. If it has no rebound, then the shock doesn’t have adequate fluid.

Question: What does thicker shock oil do?

Answer: Thicker oil improves the performance for higher traction surfaces. It helps to steer faster and increases accuracy.

Question: How do I make my RC springs softer?

Answer: Using a smaller gauge wire will ensure a softer spring within the same overall dimensions. Don’t heat the spring to soften the metal. It won’t give you any softer spring.


We’ve learned how to fill RC shocks. This will help you to properly renew the oil of your shocks to improve RC performance.

Make sure to choose your oil based on the driving surface of the RC. We hope that this article will be useful for you in the long run.

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