Properly building your shocks the right way can take some practice. Not only is each step elaborate and full of experience-cultivated nuances, but building shocks correctly is also critical to performance. It can take a lifetime to hone the shock-building process, but thanks to TLR’s Adam Drake, we are now leaking some of the best pro building tips ever compiled. Although we are working specifically with Losi shocks, many of these steps and tips are transferable to other manufacturers. Sit back, relax, and grab a highlighter for notes; it’s time to build an awesome set of shocks the pro way.
Step One: ORGANIZE AND PREPARE THE PARTS
A complete set of shocks consists of some 80+ individual components. With so much hardware to account for, it is important to start the process by neatly organizing the parts. This will make the components easier to locate, especially when your hands are full and greasy with oil. Adam said, “I recommend cleaning the shock shafts and screws using Nitrotec cleaner, removing any oil, and allowing the thread-lock to work properly.” Finally, remove the pistons from the parts trees, and shear off any excess material using a hobby knife.
Step Two: INSTALL THE PISTONS
With the parts degreased and the pistons prepped, it is time to install the pistons. It is important that the pistons are fully secure and well-fastened. Adam recommends first to thread the 2-56 screws into the pistons. Then, put a drop of thread-lock on each of the 2-56 screws and a drop into the threads of each of the shock shafts. Adam uses Losi Shock Shaft Pliers to grip the end of the shock shaft and then screws the piston into the shaft. Finally, wipe any excess thread-lock off of the piston and shock shaft.
Step Three: BUILD THE BOTTOM CARTRIDGE ASSEMBLY
Adam uses Losi Green Grease on the O-rings to improve the seal and reduce internal friction. Losi offers two thicknesses of O-ring spacers. He prefers to use the thin spacer, as it results in less preload on the O-ring and has less friction. Install the O-ring into the adjuster nut, and then thread the nut onto the shock body. Measure the distance between the shock collar and the top of the shock body to ensure that both front shocks have the same amount of preload, and then do the same for the rear.
Step Four: INSERT THE SHOCK SHAFT INTO THE SHOCK BODY
After the cartridge and O-ring assembly is complete, it is time to feed the shock shaft and piston into the shock body. To avoid serrating the O-rings with the threads of the shock shaft, place a drop of shock oil onto the shock shaft and two drops on the O-rings. Rather than simply pushing the shaft through the cartridge, Adam said, “Make sure to twist the shaft while the threads are passing through the O-ring. It will help to make sure the threads don’t cut the O-rings.” A damaged O-ring can cause the shocks to leak and introduce air bubbles and debris into the internal bodies.
Step Five: ATTACH THE SHOCK ENDS
Attaching the shock ends is a critical step which is botched by many RC mechanics. Ideally, you need to install the shock ends perfectly without damaging the shock shaft in the process. Using a shock shaft tool is critical to getting a good grip and allowing you to twist the shock end onto the threads. It is also imperative that the shock lengths be equal on the fronts and rears, or the handling will become extremely unpredictable. Adam recommends to, “Measure the shock lengths with digital calipers to make sure both front shocks are the same length. Next, do the same for the rear shocks.” Correctly installing the shock ends with precision is the key to consistent handling.
Step Six: FILL THE SHOCKS
Using a shock stand, like the one pictured, is extremely useful and gives the shocks a good position to sit when filling them. Slowly fill the shocks with oil. Next, actuate the shock by moving the piston up and down. Then, place the shocks onto the stand and let them sit until the air bubbles surface and dissipate. Adam said, “To speed up the process, there are a few companies that make shock vacuum pumps that pull out unwanted air instantly.” Losi shocks use foam compensators, and while the shocks are breathing, Adam trims the edges of the compensators into a cone shape to add more surface area and cut down on the suction effect. Before bleeding the oil, Adam compresses the shocks to the desired rebound, usually ½-compression on the front and ¾-on the rear.
Step Seven: INSTALL THE SHOCK BOOT AND CUP
When putting finishing touches on a new set of shocks, Adam has some great advice. Protective shock boot covers are great, but difficult to slide over the shock end and onto the shock body. Adam recommends using Losi Nitrotec spray to lubricate the inside of the shock boots, which will make them much less di cult to work with. He also grinds off the corners of the inside of the spring cups, which serves two benefits: making them easier to snap onto the shock shaft, and preventing them from binding on the shock ends themselves.
Step Eight: BLEED THE OIL
Before installing the shock cups, the oil must be bled until the internal oil volume is perfect. Adam starts by placing the bladder onto the shocks to bleed any excess oil. He then pulls the shock shaft down 2-4mm to “help suck the bladder down and to hold it in place.” Wipe o any remaining oil residue on the shock body. Next, place the foam compensator on top of the bladder and install the shock cap by hand until it is completely tight. Test the shocks by making sure the front and rear rebounds are consistent. If they fail to rebound, more oil is needed, and if they rebound too much or won’t fully compress, more oil needs to be bled.
It is a little messy, tedious, annoying and difficult, but building shocks correctly is important. Although most shocks include an instruction manual, there are numerous subtleties to make the build easier and more effective. It is hard to imagine anyone with higher all-around accolades than Adam Drake. He is an accomplished racer and integral to the research and development for many of the top products on the RC market—making him an ideal consultant on building shocks. When you want good advice, go to the top, and after meeting with Adam for a couple of hours, now everyone can build shocks like a pro.