Berkeley U30-74SS Hex Head Cap Screw - 3/8-16 x 1 in. Stainless
The Berkeley U30-74SS is the genuine stainless steel hex head cap screw specified across Berkeley and Pentair pump assemblies, with a 3/8-16 UNC thread, a 1 in. length under the head and a standard hex head taking a 9/16 in. wrench or socket. It is the ordinary-looking fastener holding together casings, covers, brackets and mounting hardware on the wet end of a pump, and it is the part most people never think about until the day it will not come undone.
A pump lives in precisely the conditions that finish off plain steel fasteners: constant moisture, splash, condensation inside the housing, and in marine work an atmosphere carrying salt. Corrosion does more than spoil the look of a joint. A rusting screw swells in its tapped hole and seizes, and when you come to open the pump for a routine seal change the head rounds off or the shank snaps flush with the casting. What should have been half an hour with a socket set becomes drilling, extractor work and thread repair, sometimes on a part that is no longer easy to source. Stainless keeps the fastener removable for as long as the pump lasts.
Stainless does ask for a little care on assembly. Its threads are prone to galling, which is a form of cold welding that seizes the screw permanently part-way in, and running one down fast with a power tool is the surest way to cause it. Start every screw by hand, keep the threads clean, use an anti-seize compound suited to stainless, and tighten steadily rather than with sudden impacts. On a casing or cover, work round in a cross pattern so the gasket or o-ring is compressed evenly. It is also worth remembering that stainless is not as strong as a high-grade alloy steel bolt, so it is easier to stretch or snap by over-tightening, and it should not be substituted into a joint that calls for a higher grade.
Key Features
- Genuine Berkeley (Pentair Pump Group) service fastener
- 3/8-16 UNC thread, 1 in. length under the head
- Stainless steel - stays removable in wet, splash and salt-air service
- Standard hex head for a 9/16 in. wrench or socket, no special tooling
- Used across Berkeley and Pentair pump and valve assemblies
- Pairs with a matching stainless lock washer where the parts list calls for one
Applications
- Berkeley centrifugal pump casings, covers and brackets
- Pentair pump and valve assemblies specifying 3/8-16 x 1 in. hardware
- Replacing corroded, rounded or seized fasteners during an overhaul
- Marine, dockside and raw water installations
- Irrigation, dewatering and transfer pump service
- Pump repair shops and maintenance spares stores
Specifications
- Brand: Berkeley
- Manufacturer: Pentair Pump Group
- Manufacturer Part Number: U30-74SS
- Part Type: Hex head cap screw
- Thread: 3/8-16 UNC
- Length: 1 in.
- Head Style: Hex, 9/16 in. across flats
- Material: Stainless steel
- Condition: New
Frequently Asked Questions
Q: Can I use a hardware store bolt of the same size instead?
It will thread in, but grade, head height and material all vary between suppliers, and in a wet-end joint the wrong material corrodes and seizes. Where the pump parts list specifies this fastener, fitting the specified part is what keeps the pump serviceable years from now.
Q: Why does a stainless screw sometimes seize on the way in?
That is galling. Under pressure, stainless threads can cold-weld to each other, and it happens most often when a screw is driven in quickly with a power tool or run into a dirty hole. Clean threads, anti-seize and slow, steady turning avoid it almost entirely.
Q: How tight should it be?
Use the torque figure in your pump service literature where one is published. Where none is given, tighten firmly and evenly in a cross pattern and stop there, remembering that stainless yields at a lower load than a grade 5 or grade 8 steel bolt and is easier to stretch than most people expect.
Q: How many will I need?
That depends entirely on which joint you are working on - a casing may use six or eight while a bracket takes two. Count what you remove and order a spare or two, because fasteners are the parts most likely to be damaged on the way out.
Not sure this is the right part? Send us a Picture of the pump plate on your pump and the CLR Marine team will confirm the correct cap screw before you order.
CLRMarine
