Category 09 · Bulk tank parts

A leaking bulk tank outlet valve usually needs a seat, not a valve.

Bulk tank outlet valves in 2 and 3 inch with replaceable seats, and agitator seal and gearbox kits matched by shaft diameter. For herds and milk rooms across the United States who need the tank holding again before the next pickup, sold by inquiry from Middleton, WI.

Outlet valves per unitSeal kits per kitSeats sold separately

When a tank leaks

Have these ready before you call

Milk on the floor under the outlet, or a wet ring under the agitator bridge. Either way, the tank goes on holding milk, the hauler is due, and nobody wants to guess. The desk can usually match the part in one call if you have the list on the right.

The two leaks look different. An outlet leak drips from the valve spout or weeps round the stem when the handle is closed. An agitator leak shows as a drip down the shaft into the tank or a wet patch on the lid under the gearbox. The first costs milk. The second can put gearbox oil where it must never go, so stop the agitator and call.

Outlet size
2 or 3 inch. Measure the bore of the outlet or the OD across the clamp ferrule on the spout.
Valve type
Plug, butterfly or a valve with a screw-in seat. A photo from the side with the handle in view tells us.
Agitator shaft diameter
Calipers on the shaft just below the gearbox. Millimetres or thousandths of an inch.
Gearbox plate
Photograph the plate on the motor and gearbox, even if it's faded. Part of a number helps.
Tank capacity and age
Gallons and roughly when it was installed. Some older tanks use a seal size nobody lists any more.

Stainless outlet valve at the base of a bulk milk tank — Clamp cap on, handle closed. The seat is behind that face.

Item 09.1

Bulk tank outlet valves

Stainless bulk tank outlet valves in 2 inch and 3 inch, with a replaceable seat, a clamp-end outlet and a dust cap. Sold whole or as seat and seal kits.

Most of the time the body is fine and the seat has worn or taken a set from years of being cranked shut. We sell the seat on its own for that reason. A new seat and stem o-ring cost a fraction of a valve and go in with the tank empty and rinsed, in about half an hour.

Replace the whole valve when the body is pitted at the sealing face, the stem is bent from a hauler's hose being yanked, or the thread for the handle has gone. Match the new valve to the tank's outlet ferrule, not to what the old one looked like. A 2-inch valve on a 3-inch outlet needs a reducer, and a reducer at the bottom of a tank is one more place for milk to sit.

Outlet valve options
Detail	2 inch	3 inch
Body	304 stainless	304 stainless
Seat	Replaceable, EPDM or silicone	Replaceable, EPDM or silicone
Outlet end	2 in tri-clamp	3 in tri-clamp
Typical tank	Up to about 1,000 gal	Larger tanks, faster pickup
Also sold	Seats, stem o-rings, handles, dust caps

Price basisPer unit. Seats and seal kits priced per kit

Ask about this part

Hands holding an agitator seal and bushing above a gearbox shaft — Lip seal and bronze bushing, matched to the shaft by calipers.

Item 09.2

Agitator seal and gearbox kits

A lip seal and a bushing for the agitator shaft where it leaves the gearbox, matched by shaft diameter, with the gasket for the gearbox mount where the tank needs one.

The seal keeps gearbox oil above and milk vapour out. When it goes, you see an oily streak down the shaft or a wet ring on the bridge. Don't run on it. Oil in a tank of milk is a rejected load and a very long conversation with the co-op.

Always change the bushing with the seal. A worn bushing lets the shaft wander a few thousandths off centre, and a new lip seal on a wandering shaft lasts weeks rather than years. Check the shaft surface where the lip rides. If you can feel a groove with a fingernail, the new seal will leak along it, and the shaft needs a sleeve or a machine shop first. We will tell you that on the phone rather than sell a kit that fails.

What goes in a kit
Part	Material	Matched by
Lip seal	Nitrile or food-grade FKM, spring-loaded	Shaft OD and housing bore
Bushing	Bronze or food-grade polymer	Shaft OD and bushing length
Mount gasket	EPDM or fibre	Gearbox flange pattern
Common shaft sizes	3/4 in, 1 in, 1-1/4 in, and metric 20, 25, 30 mm

Price basisPer kit. Set by shaft size and bushing material

Ask about this part

Leak, cause, part

What the parlour technician on the desk asks first when a bulk tank call comes in. The part column is what usually fixes it. Your tank may prove the exception.

Bulk tank leaks we see most
What you see	Likely cause	Part to ask for	Urgency
Drip from the spout, handle closed	Worn or set seat	Outlet valve seat	Same week
Weep round the stem	Stem o-ring	Outlet seal kit	Same week
Leak at the clamp on the spout	Wrong or old gasket	Tri-clamp gasket, sized by ferrule	Next order
Oily streak down the shaft	Agitator lip seal	Seal and bushing kit	Stop agitator, call now
Agitator knocks or wobbles	Worn bushing	Seal and bushing kit	Before next milking if you can

From drip to delivery

Call or send
The measurements above and a photo. Phone is fastest when milk is on the floor.
Match
The desk confirms the part and whether a seat will do or the valve has to go.
Price and invoice
A firm price and lead time by reply. You approve before anything ships.
Out the door
Approved in by the early afternoon usually leaves the same day. Freight is extra.

What we won't take on

Refrigeration and compressors
A tank that won't cool is a refrigeration tech's job. We stock the stainless and rubber, not the cooling unit.
Guessing a seal size
A lip seal 1 mm out runs dry or leaks. Without a shaft reading we won't quote.
Rebuilt gearboxes
We sell the seals that go on them. Gearbox rebuilds go to a motor shop.

Also for the tank room: spray balls, sample valves, discharge hose and filters and strainers.

Bulk tank inquiry

Send the outlet size and shaft reading

Outlet size, valve type and, for the agitator, the shaft diameter and the gearbox plate. Photos help. Email them to [email protected] with your name in the subject line and we'll attach them to this inquiry.

Parts desk: (608) 355-8791

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Part

Delivery address or town and ZIP

Outlet size, valve type, shaft diameter

Where is it leaking?

The desk may contact me about this inquiry. I have read the privacy notice and the terms.

No payment is taken here. Prices are indicative until the desk confirms them.