Your remote control cars shocks are crucial to the performance of your cars and trucks. Renewing the oil and bleeding the shocks properly is key to good operation. We all dread the dirty oil spill and slimy hands that go with emptying and refilling the dampeners. I hear every excuse in the book why we hesitate to service shocks; “I’ll do it at home late, its too much hassle at the track.” “I don’t have the right brand or weight oil in my box” “It won’t make that much difference!” and so on. But, your cars shocks are easy to freshen up and you will be pleased with the improved handling of the vehicle, plus it’s simple once you know how.
After you have removed your shocks from the vehicle you must first empty the nasty black oil. Easy of course, but first use a toothbrush to thoroughly clean the outside for all dirt, you don’t want it going inside when you open it. The oil wants to slime its way onto your pit table and make a mess of it. I like to use a zip type sandwich bag with the open end peeled back over a small container to keep it upright.
This keeps the oil from running away and then you can zip it closed when done and the wife won’t find a toxic oil spill in the kitchen trash, keeping you out of the dog house.
Next I use a few drops of fresh oil in the shock body and push the piston up and down while holding the shock upside down over the zip bag to swish out any dirt residue. Now set the body aside on a pit towel to let it drain for a few minutes.
Now that your shocks are clean, time to refill with new oil. Choose your favorite brand and weight of oil. Filling the amount of oil in your shocks body depends on the kind of shocks you have on your car. Kyosho and Losi shocks have cartridge style bodies filled from the bottom and perhaps your brand of shock does too, but some shocks like Associated shocks and others, do not have a separate cartridge and are filled from the top instead. The important thing is not the type of shocks but how much you fill them.
When filling cartridge style shocks you fill them just enough so that when you screw the cartridge in that the oil just barely oozes out. To fill top cap shocks, put enough oil to reach the top edge of the body but leaving a concave dimple in the oil not so much as to make the oil convex over the top of the body.
Once the oil is in you must bleed them. Bleeding is what gives you the proper operation and helps to prevent blow outs. On cap, top fill shocks screw the cap on finger tight and test the action of the shock buy slowly pushing the shaft upwards feeling for resistance. If the shaft does not reach full travel then you have slightly too much oil inside.
You must extend the shock shaft out and then open the cap and take a tiny amount of oil out, this is best done by just dabbing a clean cloth in the oil and not dumping the oil out and finger tighten the cap again. Then retest the action. If the shaft reaches full travel and does not “rebound” back out tighten the cap a bit and you have done good and on to the next shock. If it rebounds then you must repeat the procedure of take a dab of oil out until you get no rebounds.
Cartridge shocks take a slightly different technique to bleed but the end result of full travel and no rebound it the same goal as above. Fill the shock to a distance below the top of the shock body equal to the length of the cartridge plus a tiny amount.
Screw the cartridge in until you have a small gap that allows the air and extra oil to escape.
Now very slowly push the shaft down and bleed the air and oil out the gap until you reach full travel, without releasing the shaft tighten the cartridge finger tight and do the travel and rebound test as discussed above.
If you have to much oil then unscrew the cartridge and wipe excess from the piston and cartridge assembly, do not dump oil out. Repeat the procedure until you get the desired full travel and no rebound. When completed tighten the cartridge as instructed in your manual. Do not over tighten.
That was easy! Your car or truck will handle and perform much better now. If you continue to keep fresh oil in the shocks with regular maintenance then the seals will last much longer and the shocks will require fewer total rebuilds and save you money too.
The Big Pit