Shocker Solenoid Inserts / Body Set Screws > Tech index > Shocker SFT > Parts of a Shocker > Solenoid inserts / body set screws
Tech index -> Shocker NXT -> Parts of a Shocker -> Solenoid Inserts / body set screws

When looking at the back of the Shocker body, you will notice two smaller screws located beneath the bolt guide. Within these screws are the marker's two air distribution manifolds, which are air chambers that direct pressurized air to different parts of the marker. The screws visible at the back of the body are actually the tips of two devices called solenoid inserts, which are inserted down each of the two air chambers.
Solenoid inserts

When removed, the length of the two inserts themselves is visible:
Solenoid inserts

The inserts themselves are thin shafts of aluminum with an end threaded 1/4-28 to screw into the body, and a 1/8" hex head to allow them to be screwed.
Tech Notice that the two inserts are not identical; they can't be interchanged. The left insert supplies pressure to the solenoid, and also directs pressure from the solenoid to the rear of the bolt sleeve (at two locations). The right insert supplies the fire chamber as well as directing pressure from the solenoid to the front of the bolt sleeve.

The left insert is fitted with a mesh filter which is designed to help clear the air heading through it. The filter may be crimped at the end or it may be flat circular (crimped end is seen in the above picture). The original pre-production Shockers didn't have any filters at all, but worked okay nonetheless.

Located around the lengths of the inserts are several 1x3-mm ID o-rings which seal the inserts with the inside surface of the chambers which they are screwed into. There are four o-rings on the left insert and two on the right.
WarningIf one or more of these o-rings is damaged or torn, the marker would experience leaking and/or shooting problems, and the problematic o-ring in mention would have to be replaced. This often happens when removing the inserts, so it is best to leave them alone unless otherwise called for.

Solenoid Insert Airflow: Tech
Provided below is a diagram which shows the airflow in and around the solenoid inserts, in case you are interested.
Solenoid inserts
The left insert carries air through the filter to the solenoid input (middle hole in the red solenoid manifold). The left insert is also hollow, and allows pressure to be shunted to the flared portion of the bolt sleeve, which acts as a small air reservoir to help resupply the solenoid during firing.
The right insert carries air to the fire chamber, which is used to propel the paintball when the marker fires.
The solenoid outputs air into one of two ports during normal operation (one port to open the bolt, the other to close it). While idle, the solenoid outputs pressure to the right solenoid insert, which carries pressure to the front of the bolt sleeve (to hold the bolt open). When the marker fires the solenoid is switched, which vents the air holding the bolt open and pressurizes the other port, which shunts pressure to the left insert (into the rear of the bolt sleeve, to close the bolt). This means that the solenoid inserts each have multiple pressurizing functions; they both carry air from the vertical adapter to a section of the firing assembly, and they both carry air from the solenoid to move the bolt in one direction each.

Airflow is demonstrated in the Shocker animations I've provided. You can trace the path of air pressure in the slow HE bolt animation:
HE bolt (slow)

Body Set Screws:
Located on the underside of the body are four small set screws. These set screws are used to seal internal air transfer ports which connect the solenoid insert chambers with the bolt assembly. The only way to correctly machine the Shocker body is to include these air transfer ports, which are then threaded and sealed with small 4-40 x 3/32" set screws flush with the bottom of the body.
There are two screws located around the rear of the body, one under the solenoid manifold, and a fourth in between the two.
Body set screws

The body set screws never require removal for any reason. The only exception would be if the loctite seal on one has broken down, causing a leak. If this occurs, the effected screw will need to be removed using a 0.05" allen wrench and a new loctite seal be applied (use liquid loctite only, no loctite sticks). Screw the screw flush with the bottom of the body, neither too deep nor shallow. If screwed too deep, the solenoid insert o-rings will get torn on the screw. If too shallow, the solenoid manifold and/or frame won't close with the body because the set screws will be sticking up.
Tech The inside port for the body set screw holes are visible down the rear of the bolt chamber inside wall. This picture shows three of the four ports (the fourth being at the front, shadowed out).
Bolt chamber

Warning When reanodizing the marker body to a new finish, these screws will have to be removed. If you strip them out during removal, you would have no choice but to drill them out, or reconsider reanodizing. The screws are steel and as a result will destroy a nearby section of the body if left in during the reanodizing process (this is known as as pitting).

Solenoid Insert Alignment:
The two inserts must be correctly positioned within the Shocker body. The general rule is to screw them in "flush with the edge of the body" with base model Shocker bodies. Private label bodies (most of which are flat on the back) require the inserts to be screwed approx 2-3 threads deep in order to be correctly aligned (see the below diagram).
Tech If the inserts are not aligned correctly, performance will suffer. Improper positioning will lead to air passages being slightly restricted, which decreases flow to or from the solenoid (depending on the port). In extreme cases the marker will leak as a result of the inserts being far out of position.
Solenoid inserts installed Solenoid inserts installed Solenoid inserts installed

For a visual representation, you can hold the solenoid inserts up to the bottom of the body and line up the o-rings to the set screws. The o-rings should be as far away from the set screws as possible (approx 2-3 millimeters). The following diagram is a CAD rendering of the a transparent Shocker body, so you can see the air ports and set screw holes (red). The blue lines mark the position of o-rings. Notice the position of the solenoid insert heads just barely sticking out of the body toward the rear.
Solenoid inserts

Special rod-shaped parts called solenoid inserts are used to direct airflow within the Shocker body.
Solenoid inserts must be correctly installed in order to function properly
Leaking o-rings on the solenoid inserts can cause poor performance and/or leaking.
There are four set screws located on the underside of the body; these are sealed with loctite and never need to be removed for regular maintenance.
The filter on the end of the left insert can be crimped or circular.

Related Links:
Solenoid inserts manual scan (Shocker SFT only)
Firing assembly (Shocker SFT only)