Maintenance frequency: Max-Flo Inline systems require only occasinoal maintenance. The reg is deisgned to put out many weeks of service without issues. If you find your pressure dropping off, though, then it may be time to clean the system. Suggested interval for maintenance would be every 15,000-25,000 pressurized cycles, or 3-4 months.
These are the things you'll need to disassemble and clean your regulator: assorted allen wrenches, Shocker lube, Q-tips, napkins/paper towel/cloth.
Regulator Disassembly:
The reg has two sections: the manifold and the regulator. The manifold is where the tank screws on; the regulator is the forward section of the entire assembly which houses the actual regulator itself. It is required that you remove the tank from the manifold to service the reg, so it must first be completely empty or you will never get it off (this would also be dangerous if there were any substancial pressure in the tank).
To separate the reg from the manifold, remove the four screws on the back of the manifold housing (5/32" allen wrench). Once the screws are out, you can pull the regulator out the front of the manifold. The regulator will usually pop off by itself (due to the poppet spring inside it) but if it doesn't come free you will have to put it out through the rear of the manifold.
The regulator itself is divided into two main sections: the input stage and the output stage. The input stage contains the poppet assembly and is accessed through the back of the reg body; the output stage contains the adjustment spring and related components and is accessed via the adjustment cap in front.
To begin, let the brass poppet endcap, poppet spring, and the poppet itself fall out the back (small end) of the reg body. Set them aside for cleaning later on.
Next, unscrew the adjustment endcap from the front of the regulator body. There are a number of components contained within the endcap, but you don't need to remove them.
The brass piston is located in the front of the reg body. You can try to get it out using your fingers, but if it doesn't come out then simply insert a small allen wrench into the back of the reg body and push it out the front. Be careful not to scratch any inside surface of the reg body.
Regulator Maintenance:
The task is to clean all the components of the poppet assembly as well as the internal surfaces within the reg body. Use a q-tip to clean the inside of the rear reg body, and also clean the base seal o-ring for the regulator (located imbedded within the flared section of the poppet); make sure it's clean and dry. This o-ring can be the cause for just about all regulator problems so it must be in good order. If it's damaged, the whole poppet will most likely need to be replaced ($25).
Now, clean the grease from the piston and its o-ring, and also the cavity wthin 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 good).
Turn your attention to the inside of the manifold. Located down within the cavity is an o-ring which seals against the reg body (input seal o-ring). If your regulator creeps or otherwise isn't regulating as it should, you may wish to replace this o-ring. Alternately, if your reg leaks out the front of the manifold (near where the adjustment cap is located), then you may wish to replace the large o-ring around the reg body (output seal o-ring).
Regulator Reassembly:
Start by taking a moment to place a small amount of grease on the end of the piston, then reassemble it as per the above diagram (the open end of the poppet guide faces the poppet). Drop the assembly into the rear of the reg body.
For the output stage, apply a good coat of grease to the piston o-ring then reinsert it into the front of the reg body (the piston end with the small o-ring goes in first, the end without an o-ring should face out). Once it's in, reassemble the spring pack group as per the provided diagram. Once the spring assembly is ready, screw the endcap back onto the regulator body.
Re-grease the output and input seal o-rings if you haven't already, then push the regulator section back into the manifold. Reinstall the four screws tight onto the back of the manifold.
Smartvalve Maintenance:
If you are unable to shut off the air flow into the reg from the tank, then the inner Smartvalve o-ring is to blame. You can only service the Smartvalve if the tank is removed from the manifold. If so, then you can remove the valve by unscrewing the small set screw from the rear of the manifold using your 0.05" allen wrench.
Pull the Smartvalve out the bottom of the manifold. Clean the old grease off the two o-rings around the valve (outer rings), then clean the inside of the manifold where the valve goes. Re-grease the outer o-rings as well as the inner o-ring visible down in the bore where the valve goes. Replace any o-rings if necessary.
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:
The tank seal o-ring (907/90) isn't one you will find in any local stores. Also, the fill nipple o-ring is a 6/90.
Demonstrational Videos:
This video shows disassembly of the reg, quick cleaning, and reassembly:
Max-Flo Inline maintenance, high-res (32-MB)
Max-Flo Inline maintenance, low-res (14.3-MB)
These other videos show maintenance of the smartvalve knob. Please note that the videos show the proceedure for a Max-Flo Micro system, which is slightly different. However, the o-ring removal and reinstall proceedure is the same.
Smartvalve maintenance, high-res (13-MB)
Smartvalve maintenance, low-res (5.8-MB)