Keep Your RC Ride Smooth and Stable: Learn How to Fill Your Shocks

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RC shocks are very important for every RC car. For an RC shock, it is crucial to fill the oil in them properly.

You might need to change or fill the RC shocks of your cars with oil whenever they get damaged or for regular maintenance. So, it’s very important to know about the oil filling procedure of RC shocks.

Do you know how to fill RC shocks?

There are some steps to fill them; such as taking the shocks out, removing of spring and cap, and cleaning the shocks. Then fill the shocks with oil, and let the air bubbles out. After that cycling, the shaft up-down, filling the oil if necessary, seating the bladder, and doing rebound tests. Then place the shocks in the car in the right place, etc.

Wait, it is just a summary of the process. To know more in a detailed way, keep on reading.

9 Steps of Filling Oil in the RC Shocks

If you are a fan of playing RC cars, then you should know about the filling procedure of RC shocks of your cars. 

Because you need to change the oil of your RC shocks after some months of the regular intervals. This is a part of regular maintenance and cleanliness.

Sometimes the RC shocks can get damaged. In that time you should buy new rc shocks and fill them with oil. That’s why it’s also important to know how to tell if rc shocks are bad.

Rc shocks are very important for the performance of the car. Besides, there are some ways to upgrade a cheap RC car.

So, now you know how important it is to have knowledge of the oil filling procedure of RC shocks. That’s why here we have gathered all the necessary steps and tips about the procedure to help you.

It will take 9 steps for you to fill the shocks with oil. We have explained all the procedures below. So let’s start knowing about how to fill RC crawler shocks.

Step 1: Take the Shocks Out

Shocks Out

First and most important step is to take the shocks out of your car. 

Take the shocks out from the car carefully so that no parts of it can get damaged.

Place the shocks straight in the shock stand

Step 2: Removal of Spring and Cap

Removal of Spring and Cap

After removing the shocks from the car, you need to remove some parts of it. 

There is a spring on the shocks. Remove it carefully. 

Then unscrew the cap which is on the top of the shock. There is a thing of some silicon rubbery material which is called bladder. Remove it too. 

Remove the bladder along with the cap carefully.

Step 3: Clean the Shocks

Clean the Shocks

Now let’s learn about an important step of the procedure. As the cap is being removed, you can see some oils inside the cylinder.

It’s time to know about how to clean RC shocks.

Empty the cylinder and remove all the previous oils from there. There will be some dirt and residues too under the rubbery boots. You should also clean them.

You can use a paper towel to clean the dirt and oils. You can also use a cotton bud to clean them. 

use a cotton bud to clean

You can also push the piston up and down to remove the excess oil from the cylinder. As a result, the shock will not contain any old oil and it will be ready to be refilled.

Step 4: Fill the Shocks with Oil

Now that you have cleaned the cylinder of the shocks, it’s time to refill it with oil. You should carefully follow this step because it is a very important. 

So, let’s learn how to fill Traxxas shocks with oil. By the way, do you know that there are some differences between Traxxas slash 2wd vs 4wd

First of all, before filling the shocks, it’s very important for you to know the properties of the oil. You can’t use all kinds of oil for filling the shocks.

The RC Shock oil is actually a silicon-based oil. It’s the best for the performance of your RC cars. It can be pricey but still, it is the best and preferred one.

Fill the Shocks with Oil

Some people try to use motor oil or other oils. But you should not do so. Because it can cause damage to your cars. So, as a consequence, after some time it can be a great hassle for you.

Here are some best RC shock oil for your RC cars.

Product 1
Product 2

Hope these will be perfect for you.

Now let’s get back to the part of filling it with oil. Before filling it with oil, push the piston all way down. 

Now fill the oil there very slowly. It will reduce the number of air bubbles there. The slower you will fill, the fewer air bubbles will be there. 

You should also know how full to fill RC shocks. You should never fill the cylinder fully with oil. You should leave some space there. Fill the shocks with oil for about 90% of the length of the cylinder.

Step 5: Let the Air Bubbles Out

Air Bubbles Out

After filling with oil, if there are any air bubbles in it, the shocks can’t perform well. So, it’s also very important to let the air bubbles out.

For that, you should push the piston up and down in such a way that it does not go above the shock oil and it stays inside the shock body. You should do it about 10 times.

This makes sure that no air bubbles are left there in the cylinder. It’s important to remove the air that might be trapped there or under the piston.

Now keep the shocks in the shock stand. The shock stand will keep them straight. Gently tap it with a small thin iron. It’s a part of removing the air bubbles.

Now keep the shocks for about four hours to make them thicker. The more you will keep them, the thicker they will be. So, if you don’t want thicker, don’t keep them for a long time.

Step 6: Cycle the Shaft Up 

Cycle the Shaft Up 

This step will help you to know if you have filled it correctly or not. It’s also an important step in how to fill oil shocks RC.

For this attach the cap and bladder to the top of the cylinder. Then push the shaft upwards.

If you have filled it correctly, then you can push the shaft upwards very smoothly. Then the shaft will go down by itself very smoothly. It’s called rebounding.

If you can’t push the shaft upwards smoothly, then you might have filled less or more oil in the cylinder. 

If the shaft will go down for about half or more than half of the length of the shaft, you have put less or more oil then. 

If the shaft will go down for about a quarter of the length of the shaft, then you have put the oil correctly. It is considered to be perfect rebounding.

Step 7: Fill or Remove the Oil Again

If you can’t push the shaft upwards smoothly or the shaft goes down for about half or more than half of the length of the shaft, you have put less or more oil there. 

So in that case, you will have to remove the excessive oil through a paper towel. Wipe out that excess oil.  If you need to fill some oil, then fill it again.

Fill or Remove the Oil Again

Here is a tip for you. If oils don’t come out from the cylinder while putting the silicon cap, then you might have filled less oil. So, if you face this, then you may have to fill some oil in the cylinder again.

Step 8: Seat the Bladder and Do Rebound Test

Seat the Bladder and Do Rebound Test

Seat the bladder very carefully. Push the shaft up again and perform the rebound test.

If you have got positive results from the rebound test, that means you filled the cylinder with oil perfectly.

Step 9: Place the RC Shocks in the Car in Right Place

Now put the cap by holding the shocks vertically and screw the cap carefully. You should do it carefully to reduce the chance of leakage and reattach the spring there. 

Then put the shocks in the car like previously it was attached. So, you have completed all the steps of filling the shocks properly.

That’s all. Now you know very well all the steps of filling the RC shocks.


What is the importance of grease in RC cars?

Grease can quickly reduce wear, resistance, and tear between the mechanical parts of your car by providing lubrication. You should choose grease depending on water resistance, performance, application, viscosity, temperature, stability, etc. Besides, never try mixing different kinds of grease.

Is a shock absorber important?

Yes, a shock absorber is very important for vehicle operations. It is an important part of the suspension of the vehicle. The main job of a shock absorber is to dampen or absorb the compression and to rebound the suspension or sp[ring. It also controls the contact of tires with roads all the time.

How can you know if the shocks are not good or damaged?

There are some symptoms by which you can easily recognize if the shocks are good or not. I the shocks are bad the car will bounce too much, and the car will roll all of a sudden whenever you will make a turn, you will face difficulties to control the car just because of hitting by a crosswind.


We hope that you know now how to fill RC shocks. Through the easy guidelines, you can do it by yourself.

It’s time to say goodbye. If you face any problems, you can share them with us in the comment section.

Until then, wishing you all the best!

About the author

Travis Murray

I am Travis Murray, and my love for RC began in 2017. It gradually turned into a passion, leading me to become an RC enthusiast and blogger. I write in-depth reviews and DIY guides for RC enthusiasts to provide troubleshooting tips and insider knowledge to help starters find the hidden gems in the hobby.
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