Coupling Selection

A Gates hydraulic hose coupling usually consists of two primary components:

1. a FERRULE placed over the end of a hose.
2. a STEM inserted into the end of a hose.
Hose, Ferrule & Stem - Coupling Selection

Ferrule Selection

Ferrule type designations (PC, PCS, PCM, C4, etc.) correspond to the stem hose end type designations (16PCS-16MP, etc.).

Always consult Gates Crimp Data Charts for correct ferrule recommendations. For example, C12M hose can be coupled with either PCS1F or PCS2F ferrules and PCS stems. PCS1F ferrules require no skiving. You simply crimp the coupling to the hose.

The number "2" before the "F" in ferrule designations means that two steps are needed for correct hose coupling:

1. Skiving to remove the cover from the hose end
2. Crimping phase

Always install the correct ferrule for a specific hose and stem combination. For instance, there is an important design difference between an 8PC2F-2 ferrule and an 8PC2F-2C ferrule which is vital to the compatibility and performance of the hose assembly.

Always refer to Gates Crimp Data Charts for the right hose, stem and ferrule combination. Example of ferrule description:

Dash SizeStem TypeNo Skive (2=Skive)FerruleMaterial (S=Steele) (A=Aluminum)

Stem Selection

Different hoses may require different coupling styles. To make your selection, determine the correct stem to be used. There are two functional ends of the stem to consider:

1. the hose end for hose attachment.
2. the thread end for port attachment.

References to the coupling type(s) recommended for a specific hose are listed on the individual hose data pages; for example, C13 (G5K) hose specifies Global Spiral™ and PCM couplings.

Stem selectionThe thread end of a coupling (or adapter) can be identified by comparing with the coupling being replaced or by measuring the port or thread end to which it is to be attached.

See the thread end identification nomenclature listed in Tables 1 and 2.


Table 1. Coupling and Adapter End Style Code
ABAir Brake JISJapanese Industrial Standard
BO-Ring BossKKomatsu Style (Japanese 30° Seat)
BJBanjoLHLong Hex
BKHDBulkheadLNLong Nose
BSBite SleeveMMale
BSPPBritish Standard Parallel PipeMFAMale Flareless Assembly (Ermeto)
C Caterpillar Flange DimensionMKBMetric Kobelco
CCClamping CollarMMMetric Male
DHDIN HeavyMNMetric Nut
DLDIN LightMPGMale Special Grease Fitting
FFemaleMSPMetric Stand Pipe
FBOFemale Braze-on StemORO-Ring
FFFlat FacePPipe Thread (NPTF or NPSM)
FFNFemale Flareless NutPLPress Lok®
FORFlat-Face O-RingPWXPressure Washer Swivel
FFSFemale Flareless Sleeve RReusable
FGFemale Grease ThreadSSAE (45° Flare)
FKX Female Komatsu Style SwivelTSTube Sleeve
FLCode 61 O-Ring FlangeTSNTube Sleeve Nut
FLCCaterpillar Style O-Ring Flange (Code 62)XSwivel
FLHCode 62 O-Ring Flange HeavyZParker Triple Thread
FTFemale SAE Tube2222 ½°
FLOSFlange O-Ring Special (Code 62)3030°
HLEHose Length Extender4545°
HLECHose Length Extender (Caterpillar)6060°
HMHose Mender6767 ½°
IInverted Flare9090°
JJIC (37 Flare)110110°


Table 2. System Stecko Adapter and Press Lok® Coupling End Style Code
O-Ring Boss or Backup
Male or Medium
Banjo Bolt
"O" as in O Ring
Pipe Thread
Ball Valve
Banjo Washer
Double Y

Coupling Dash Size and End Style

Coupling Dash Size is a shorthand method of denoting the size of a particular end fitting.

See Table 3.

Example: 12MP denotes a 3/4" male pipe end fitting. The corresponding thread description for a 3/4" pipe thread is 3/4-14 NPTF solid male.

Example: 12FJX denotes a 3/4" female JIC swivel (37 seat) end fitting. The corresponding thread description for a 3/4" JIC thread is 1 1/16-12 JIC 37 flare swivel female.

Example: 12FL denotes a 3/4" SAE standard pressure (Code 61) flange fitting. This is the standard fitting description for a 3/4" SAE standard pressure flange.

Thread End Catalog Descriptions

Gates coupling ends shown are industry standards. See detailed catalog listings for availability of specific hose/coupling combinations, detailed descriptions, thread end configurations such as swivels and bent tubes and special ends.

Table 3 Thread Size Dash Numbers
Dash SizeThread Sizes
NPTF-NPSMSAE (45 Flare)JIC (37 Flare)
SAE O Ring Boss
21/8 - 27--
3--3/8 - 24
41/4 - 187/16 - 207/16 - 20
5-1/2 - 201/2 - 20
63/8 - 185/8 - 189/16 - 18
81/2-143/4 - 163/4 - 16
10-7/8 - 147/8 - 14
123/4 - 141 1/16 - 141 1/16 - 12
14--1 3/16 - 12
161 - 11 1/2-1 5/16 - 12
201 1/4 - 11 1/2-1 5/8 - 12
241 1/2 - 11 1/2-1 7/8 - 12
322 - 11 1/2-2 1/2- 12


"O" Ring Flange dash numbers are determined by nominal flange size, or diameter of flange head which determines the "O" Ring size.