Seat Removal


	Centurion® Super Centurion-200® Super Centurion-250®


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	If you have ordered any Mueller boxed Repair KIT or Hydrant Extension from L&C, included are detailed instructions for installing the Parts KIT ordered. Most Kits include illustrations for removing old assemblies. The following LC HELP Files answer many questions that the Instruction List or Mueller Operating Manual may not easily explain. Special Tools are required for many repairs.


	MAIN VALVE REMOVAL Mueller CENTURION Series

The Centurion series Main Valve Assemblies (left picture) are removed or installed from above ground using a Mueller Seat Removal Wrench.

Two styles of Seat Removal Wrenches are available. The SHORT type is the most common used. A LONG style is also available. See below for descriptions of both types and their purpose.

The Bonnet must first be removed as the normal operating position for the Seat Wrench is mounted where the bonnet was bolt on.

Click the Bonnet link for help on removing that first.


	SEAT REMOVAL WRENCH - Short Type







				Before beginning the process of removing the Main Valve Assembly (B-assy) and the bronze Seat Ring (A-assy) the service technition must understand how these parts operate within. The animated picture to the left shows how the B-assembly travels up and down within the Seat Ring during operation of the fire hydrant.

								"B" ASSEMBLY


		Main Valve Assembly is pulled UP when hydrant is in the Closed position. This position must be used to remove the seat assembly.


	Main Valve Assembly is pushed DOWN when hydrant is in the OPEN position. DO NOT try to remove the seat assembly while in this opened position.


	"A" Seat Ring

Before beginning service work to the lower Main Valve assembly and Seat Ring the water source to this hydrant must be turned off. As stated above, the top Bonnet Assembly of the broken hydrant is removed first. During disassembly of the Bonnet parts the Lower Stem assembly, which includes the "B" Main Valve may drop down to the opened position. It must be understood that you cannot remove the Seat Ring and Main Valve assembly if the "B" Main Valve is in this position. You will only break or bend and jam the upper valve plate bronze casting before the Seat Ring will break loose from its matted threading.

When using the following "Short" type Seat Removal Wrenches care should be used to confirm that this assembly is pulled all the way UP so full turning torque pressure created will unscrew the Seat and not just break more parts and the need for the old style Long style Seat Removal Wrench illustrated below.

These tools are used to remove the Main Valve Assembly from any version of the Mueller CENTURION hydrant series. Wrench self-centers on upper barrel flange or at ground line flange.

Sent complete with (2) operator bars.
Fits both valve opening sizes of Centurion hydrant Main Valve Assemblies.

CURRENT DESIGN as of June 2001

Two basic modifications have been implemented; First. a third leg was added to the center spider to help generate more positive torque. Second the entire wrench was shortened. This design utilizes the Operating Nut (which now is threaded onto the upper stem) to keep the Main Valve Assembly up and in the closed position during seat removal.

FORMER DESIGN
The Upper Rod is held in place with a internal rubber compression sleeve. Top handle is tightened to achieve compression hold.

Brass Operating Nut

Once the bonnet assembly is removed slide slotted-end of the Seat Wrench over top of Upper Stem and engage the slot with the horizontal pin that is a part of the Upper Stem.

If you have the Former design Short Seat Wrench, it includes a "T" handle screw yoke and a rubber compression sleeve, tighten "T" handle firmly to compress the sleeve around the upper stem.
OR
If your Seat Wrench is the Current style pictured, replace the brass Operating Nut back on the threaded Upper Stem and screw on till it is tight against the top of the seat wrench. This process will raise up the Main Valve Assembly to it's fully closed position where it needs to be for seat ring removal.

Lower the support yoke onto top flange of the Upper Barrel and tighten thumb screw to hold the Main Valve in the closed position.

Shut off water at gate valve ahead of the hydrant.


	Short style Seat Removal Wrenches can be used at the top of the Upper Barrel (left picture) or at the Ground Line flange (right).


	Turn Seat Wrench Counterclockwise 6 to 7 complete full turns to unscrew and remove the Main Valve Assembly and Lower Stem as illustrated.

Pull up and out the entire Main Valve Seat Assembly as pictured.

Your now ready to inspect and replace all Main Valve Assembly parts.


	SEAT REMOVAL WRENCH - Long Type


		This tool is used to remove the Main Valve Assembly when repairs are required. Wrench self-centers on upper barrel flange. Sent complete with bronze Stem Extension piece (on top of wrench in dark blue), and (2) operator bars. This heavy-duty long style wrench is lowered all the way down the hydrant barrel and engages with the Bronze Seat Ring (pictured in yellow).



	The wrench was designed for use with All Years of the Mueller "Improved" style fire hydrants. It can be used on the Centurion series as well. The "Seat Ring" is factory installed at 350 Foot Pounds of torque. This long style wrench puts all your effort directly on the seat ring.

The wrench will fit ONLY ONE SIZE of seat ring - depending on what size spider HUB is attached to the bottom end. The Hub is the casting piece that rests onto the Bronze Seat Ring. Each casting Hub is marked as to what size it will fit. You can change the casting Hub to the other size. The Hub piece is held in place with a compression screw. RE: If you have both 4-1/2" and 5-1/4" Main Valve Sizes in your system but your Spider Hub Casting is for only 4-1/2" size, you can order a separate Hub Casting to fit the 5-1/4" seat ring size. Refer to our Special Tools for a parts listing of this Long type Seat Removal Wrench parts.

Remove the Bonnet assembly per instructions on the Bonnet Maintenance page.
Insert Seat Wrench so it engages the lugs on the Seat Ring. Screw the seat wrench Stem Extension piece on to the hydrant upper stem until pin engages to the top of seat wrench. Shut off water at the gate valve. Turn wrench Counter Clockwise to unscrew the Seat Ring and Main Valve assembly.
Lift stem, complete valve mechanism, and seat wrench as a unit out from hydrant barrel.
Remove lower stem nuts while the stem and valve assembly is still in seat wrench. Replace damaged or worn parts.

Reassemble and use the seat wrench to hold the valve assembly while tightening the lower stem nuts firmly to stem.
Loosen seat wrench Stem Extension piece so seat ring has some float in seat wrench. Replace complete working parts and seat wrench assembly into hydrant barrel.
Screw seat ring in place by turning the seat wrench Clockwise. Turn water on at gate valve. Remove seat wrench.
Reinstall the Bonnet assembly by reversing procedure that you did to remove it and its internal parts.
Fill sealed oil reservoir with oil until it is level full with plug. Replace oil plug.






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