Mueller Chattanooga Improved Fire Hydrant Bonnet


	Removing Bonnet From Chatta. IMPROVED Hydrants


	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 may not easily explain.


	Page Index Listings Maintenance & Repair Chatta. - IMPROVED


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	1934 - 1947 Improved Bonnet Design Bonnet had conventional packing with stuffing box and gland. Nozzle chains were attached to H63 Eye Bolt.

	Remove the (4) exterior bonnet Bolts/nuts. With a Operating Wrench, turn Operating Nut in the opening direction until the bonnet breaks free from the upper barrel casting and free from the upper stem. Remove bonnet casting. Loosen the (2) stuffing box Stud nuts when removing the stuffing box plate with conventional packing and tighten these two nuts after replacing this type of stuffing box plate.


	1948 - 1961 Open Oil Reservoir Oil Filled Open Bonnet designs. They all have a separate internal iron casting under the Bonnet.


	1948 - 1953 Improved Bonnet Design The first self-oiling reservoir (open type). Weather Cap added to operating nut. O-ring seals and oil have now replaced the old stuffing box. No oil filler plug. Nozzle chains attached below each nozzle.


	1954 - 1961 Improved Bonnet Design Self-oiling reservoir (open type) has been enlarged. Oil filler plug has been added - mounted in the straight vertical position.


	Typical Bonnet head. (4) bonnet bolts/nuts hold down the casting. Once removed the oil reservoir (stuffing box) casting is visible being held down by (4)-stuffing box bolts/nuts. Originally supplied with a bronze material weather cap.

LEFT ILLUSTRATION INDICATES

Bonnet Casting in RED. Held down by Bonnet Bolt/Nut in GREEN

Oil Reservoir Casting in YELLOW. Held down by Bolt/Nut in BROWN


	OIL PLUG VISUAL NOTE The left illustration shows the Oil Filler Plug mounted directly over the large offset portion of the oil reservoir pot. This bonnet is so designed that it cannot be brought flush with the barrel flange except when in the correct position. Remember when reinstalling the bonnet casting that you must line up the oil port hole with the reservoir oil pot.


	Removing BONNET CASTING From Mueller IMPROVED


		Pre-1962 Models Improved Bonnet Design

Remove the (4) bonnet Bolts/nuts.
With a Operating Wrench, turn Operating Nut in the opening direction until the bonnet breaks free from the upper barrel casting and free from the upper stem.
Remove bonnet casting.
Remove the (4) bolts holding down the stuffing box casting.
Lubricate the maintenance Brass Sleeve tool.
Screw the Brass sleeve down over the threaded area of the stem to protect the O-Rings from damage by the sharp threads.
Lift stuffing box casting off carefully.
Remove Brass Sleeve.


	The internal parts of the bonnet can be accessed by following the procedures listed under the "SR" design, or by just clicking here.

Reassembly consists of again using the Brass Sleeve to protect the O-Rings from damage.
Slide stuffing box casting over the brass sleeve and position and bolt to barrel.
Remove Brass Sleeve.
Pour Mueller Hydrant Oil into the oil reservoir until THREE-QUARTERS of a inch from top.
Replace assembled bonnet. Turn operating nut in it's normal closing direction to engage stem. Remember to make sure that the oil filler plug hole is aligned with the offset portion of the oil reservoir.
Bolt in place.


	Checking Oil Level for "Open Type" Chatta. - Improved reservoirs


	1948 - 1953 Bonnet oil can only be checked by removing the bonnet casting, as explained above. Oil is filled to within three-quarters of an inch from the top of the oil cast pot.


	1954 - 1961 Bonnet casting contains a straight-up vertical oil plug and port to the offset oil reservoir. You need to make a "Dip Stick" to insert into hole until it rests on bottom of the oil reservoir. Remove dip stick and note if oil is up to the mark made on the stick. If not, repeat until oil is up to the mark,

		MAKE YOUR OWN OIL CHECKING DIPSTICK Get yourself a one-inch piece of heavy wire or small brass rod and cut it 12" long. Make a one-inch loop on one end to act as a handle. File a small line all around the rod 2-7/8" UP from the opposite end. This line will indicate proper oil level when hydrant is closed.


	1962 - 1980 SEALED Oil Reservoir Oil reservoir is now part of the bonnet casting. Positive seals in bonnet and operating nut retain lubricant.


	1962 - 1965 Improved Bonnet Design The oil reservoir and bonnet casting design was changed. No longer a open-type, the new Sealed Oil Reservoir design is identified with a "SR" casting on top of the bonnet flange. Oil filler plug is now set on an angle. Bonnet is held down by (8)-bolt/nut sets.


	NOTE: Part H-102 Lock Washer was added in *late* 1965. If your Improved hydrant is dated 1965, it may or may not include the Lock Washer and related other changes that are illustrated under the 1966-1972 design.


		1962 - 1965


		Original "SR" BONNET DESIGN with parts and locations detailed. This is referenced for changes made later.

H101 Hold down nut O-Ring

H-100 Bonnet O-Ring. This design had the O-Ring located within a machined "groove" in the bonnet casting.

	Bonnet casting

Old-style Hold down nut.

1966 - 1972 Improved Bonnet Design
Part H-102 Steel Lock Washer was added (late 1965). This washer prevents the Hold Down Nut from backing-out as the hydrant is operated. It is installed between the bonnet and the hold down nut. Two Lock Washers are available, one for hydrants that open Left and one for hydrants that open Right.

The incorporation of this washer necessitates changes in the Hold Down Nut and Weather Cap. The former designs of these two parts are unavailable, only new style parts can be furnished. This new design Weather Cap, now 4-1/8" wide, is not as wide as the former but it will fit both old and new style hydrants. However, if ordering a new Hold Down Nut, it is necessary to also purchase the new Weather Cap. The old cap will not fit the new hold down nut recess which is not as wide as the former. The Lock Washer is required to be ordered as well.


	1966 - 1972


	Recess area (where bottom of Weather Cap casting fits into) has been narrowed. Older weather caps will NOT fit.

	H101 Hold down nut O-Ring

	Lock Washer H102 added

	H-100 Bonnet O-Ring. This design had the O-Ring located within a machined "groove" in the bonnet casting.

	Bonnet casting

	1966 - style Hold down nut.


	Indicates a change from the prior design

1973 - 1980 Improved Bonnet Design
The Bonnet casting and Hold Down Nut were redesigned. This design change consisted of changing from a O-Ring recess/groove in the Bonnet casting to a O-Ring groove in the Hold Down Nut and changing the machining on the inside of the Bonnet top from a counterbore with a small chamfer to a tapered counterbore.

The new design Hold Down Nut will fit an pre-1973 style Bonnet only if the H-102 Lock Washer is ordered and installed.


	1973 to End


	Recess area (where bottom of Weather Cap casting fits into) was narrowed. Pre-1966 weather caps will NOT fit.

	H101 Hold down nut O-Ring

	Lock Washer H102

	H-100 Bonnet O-Ring. This design has the O-Ring located within a machined "groove" in the Hold Down Nut. The size of the O-Ring did not change.

	Bonnet casting revised, per above.

	1973 - style Hold down nut with machined "groove" for bonnet O-Ring location change.


	Indicates a change from the prior listed design


	Removing BONNET CASTING From Mueller IMPROVED 1962 - 1980


	1962-1980 Models Improved Bonnet Design


	1


	Removing WEATHER CAP #H-52 From Chatta.- IMPROVED

The H-52 Weather Cap was constructed of bronze through the year 1973. Beginning in 1974 the material was changed to ductile iron and has a inside thread. This piece screws onto the H-51 brass Operating Nut which also has a mated threaded top.

The #131173 Wrench includes a cast portion that is devoted to removing/installing this part off of the operating nut. The wrench has a protruded dimple that will fit into a hole on the side of the weather cap casting.

To remove the weather cap from the H-51 Operating Nut, unscrew counterclockwise.


	As you can see by the picture above - left, the hydrant was repainted with the two pieces pretty much looking like a single piece. If you cannot loosen off the weather cap from the operating nut you can take a hammer and shear-off this casting H-52 and replace.


	2


	Removing HOLD DOWN NUT #H-53 From Chatta.- IMPROVED


	#H-53

The large end of the #131173 Wrench is used for removal and install of the brass Hold Down Nut #H53.

The large end fits over all design nuts and does not deform the brass nut when removing or installing, such as a large pipe wrench would do.


	INSTRUCTIONS FOR REMOVING THE #H-53 HOLD DOWN NUT MFG YEARS: 1934 - 1980 The Hold Down Nut is unscrewed out of the bonnet casting by turning it out the same direction as the hydrant normally opens. If hydrant Opens Left Turn: Remove nut by turning out Counterclockwise. If hydrant Opens Right Turn: Remove nut by turning out Clockwise.


	3


	Screw On the Brass Sleeve over the threaded end of the upper stem.


	Brass Sleeve now covers the sharp threads of the upper stem.


	4


	Now, remove the (8) bonnet Bolts & Nuts.


		5

	Remove Bonnet by sliding up and off the upper stem (protected by the Brass Sleeve)


	Improved Hydrant bonnet removed If you need to replace the Break Flange COUPLING, unbolt the broken flange set and lift the upper barrel up and over the upper stem. Note that the upper barrel can weigh 150 lb. or more


	Checking Oil Level for "SR" Chatta. - Improved reservoirs


	1962 - 1980 Bonnet casting contains a oil plug on the side. Remove plug and check or add oil until it is level-full with plug. Replace plug.

		Bonnet oil should ONLY be added or checked with fire hydrant in normal closed position.


	Testing Bonnet Sealing and Lubrication Functions

To insure the readiness for instantaneous use, all fire hydrants should be inspected and tested at six-month intervals.

Unscrew one nozzle cap slightly and tighten the others. Slowly open the main valve to its fully open position. Tighten the one loose nozzle cap when water starts flowing.

Inspect bonnet flange Gasket and bolts for visual indication that all is water tight.

Next remove the oil plug from the bonnet. If all is well, no oil or water should be exiting this hole. This confirms that the (2) Stem O-Rings (H93) are doing their job.

If oil and water exits this hole, both of the stem O-rings have failed allowing water to enter the reservoir system. Either they were damaged during the bonnet rebuild or if not rebuilt yet those O-Rings have dried out and require replacing. If you have fluid exiting around the outside of the Hold Down Nut, then the bonnet O-Ring (H100) also has failed. If fluid escapes from around the Operating Nut, then the Hold down nut O-Ring (H101) has also failed.


	Fully close the main valve, then remove a nozzle cap completely. Assuming that your hydrant has the self-draining system, examine the inside of the barrel to make certain that the drain valves have completely drained the water from the barrel.


	Proper shutdown of all Mueller hydrants is to fully close the main valve assembly, *then turn in opening direction approximately 1/4 turn to relieve the tension on the operating mechanism.*






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