Regulator versions: This maintenance guide is for the old style vertical Max-Flo that came on 2002-2003 Impulses. Most Impulses bought in 2004 or later came with the new style Max-Flo (same version that is used on the Shoker SFT and Nerve). A guide for the new-style reg can be found here.
Maintenance frequency: The Impulse reg requires occasional maintenance. The reg will be able to function good for a few games, but will eventually need some cleaning to keep it in top condition (depends on the situation). Suggested interval for maintenance would be every 4,000-8,000 pressurized cycles, or every month (approximately).
These are the things you'll need to disassemble and clean your regulator: assorted allen wrenches, pliers, Shocker lube, Q-tips, napkins/paper towel/cloth.
Regulator Disassembly:
It is always easiest to work with the regulator once it has been removed from the gun. For this you would have to disconnect your gasline and unscrew it from the vertical adapter. This is not required however will make disassembly much easier.
The regulator itself is divided up into two main sections: the input stage and the output stage. The input stage contains the poppet assembly and is accessed through the top of the reg body; the output stage contains the adjustment spring and related components and is accessed via the adjustment cap on the bottom. To begin with, unscrew the adjustment cap from the bottom of the regulator body, and let all the components of the output stage assembly fall out.
Also remove the brass piston from within the regulator body (you can use a small allen wrench or dental pick if needed).
Flip the regulator around and remove the two set screws on the side of the reg body using your 3/32" allen wrench. Then use a 7/8" wrench or large pliers to unscrew the ASA adapter from teh top of the reg body.
Tip the reg down to let the input stage components fall out. Be aware that the outer base seal o-ring may have remained seated within the reg body. You can remove it if you wish, but be sure not to scratch this o-ring or else you will be forced to replace it...
Regulator Maintenance:
The task is to clean all the components of the input stage as well as the internal surfaces within the reg body. Also clean the grease from the piston and its o-ring, and also the hole in the reg body where it goes. There is also a small o-ring on top of the piston; clean this as well (a q-tip works well).
You can also disassemble the base seat. Located within is a small o-ring (inner base seal) that needs to be cleaned or replaced if necessary. The outer base seal o-ring must also be in perfect condition. These two rings and their opposing surfaces are the key to the regulator's consistency and will cause noticeable problems if not useable.
Regulator Reassembly:
The regulator is specifically designed for the input stage to be installed before the output stage. Start by reassembling the input stage as per the following diagram, then drop it down into the rear of the reg body. Notice that the poppet fits into the angled end of the assembled base seat. Use no grease on any of the parts in the below diagram. Before you drop the input stage into the reg, be sure to drop the outer base seal o-ring down into it first.
Once the input stage is back into the reg, lightly re-grease the o-ring on the outside and on the inside of the brass guide plug, then place it on top of the assembled input stage, with the small end facing out. Use the provided diagrams if needed. Then re-grease the o-ring around the ASA adapter. Don't worry about overgreasing it. Finally, reinstall the retaining nut tight onto the back of the reg body.
For the output stage reassembly, first re-grease the piston o-ring then reinsert the piston into the reg body (with the raised end facing out). Once it's in, reassemble the spring pack group as per the provided diagram. Note that the domed end of the guide pin faces the piston, not the flat end. Then, simply screw the end cap back onto the regulator body.
O-Ring Diagrams:
If you need to replace any of the rings used in the regulator, here is a diagram of the sizes and durometers:
