Hydraulic Surge Couplers

Hydraulic Surge Couplers

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Demco Surge Coupler (Bulldog Head)

TextModel DA91 is a heavy duty surge brake actuator for trailers with two or four wheels. When brakes are applied on the towing vehicle, forward inertia of trailer toward towing vehicle applies brakes on trailer in direct relation to manner brakes are applied on towing vehicle. Brake towing vehicle hard and brakes on trailer are applied hard.  Master cylinder push rod spring assembly protects system from hydraulic pressure overload.

Part #
21-111 Demco 2" Surge Coupler (Bulldog Head) - 7000 lbs.
21-112 Demco 2 5/16" Surge Coupler (Bulldog Head) - 7500 lbs.


Demco DA10 Surge Coupler

Part #
21-406 Demco DA10 Surge Coupler w/ Levelor Channel - 10K (requires adj. coupler head)
21-406-A Replacement Master Cylinder Kit - Includes Gasket, Bolts, & Boot
21-406-B Replacement Master Cylinder Cap - Includes O-Ring
21-303 Bolt & Nut (2 required)

Atwood Surge Coupler

Atwood Hydraulic Surge Brakes add safety and convenience to trailer towing.  Less complicated than other systems, the Atwood brake system provides such benefits as no "in car" hook up, no hand controls, and no special car to trailer wiring.  These features, plus automatic braking, smooth performance and simple operation are combined to provide a low cost, convenient brake system.

Part #
21-200-Disc 2” Atwood Surge Coupler - 6,000 lbs. capacity - Disc
21-200 2” Atwood Surge Coupler - 6,000 lbs. capacity
21-200-8K 2” Atwood Surge Coupler - 8,000 lbs. capacity
21-200-A Replacement Master Cylinder Only
21-200-C Replacement Filler Cap Only
21-200-G Replacement Shock Only
21-200-B Master Cylinder Repair Kit


Part # Description
21-405 Balcrank 6K w/Leveler Channel (Bolt On)

Titan MD-60

The Titan MD-60 coupler has a 6,000 pound capacity (max. G.V.W.R.) and 600 pound tongue load.  It is designed for a 3” wide trailer tongue.  The unique adjustable feature allows it to fit either an 1 7/8” ball or a 2” ball.

Part #
21-410 Dico Model 60 Multi-fit Surge Coupler (1 7/8’ - 2” ball)
21-411 Replacement Multi-fit Repair Kit Only
21-412 Replacement Lever Lock Repair Kit Only
21-306 Replacement Master Cylinder Kit Only
21-306-2 Replacement Master Cylinder Repair Kit Only
21-307 Replacement Filler Cap Only
21-308 Replacement Shock Only

Titan MD-10

Part #
21-400 Dico Model 10 Surge Coupler w/ 2 5/16” Head - 10K
21-401 Dico Model 10 w/ Leveler Channel
21-305 Replacement Master Cylinder Rebuild Kit (MD10/20)
21-305-1 Replacement Master Cylinder Only (MD10/20)
21-320 2 5/16” Coupler Repair Kit Only (MD10)
21-414 Replacement Shock Only (MD 10)
21-321 Replacement Filler Cap & Gasket Only (MD10)
21-309 Replacement Cover (MD10)

Titan MD-20

Part #
21-300 Dico Model 20 Surge Coupler w/ Channel (20,000 lbs.)
21-300-1 Dico Model 20 Surge Coupler w/ Pintle Ring (20,000 lbs.)
21-300-2 Dico Model 20 Surge Coupler w/ 2 5/16” Head (20,000 lbs.)
21-300-3 Dico Model 20 Surge Coupler w/ no Head (20,000 lbs.)
21-305 Replacement Master Cylinder Rebuild Kit (MD10/20)
21-305-1 Replacement Master Cylinder Only (MD10/20)
21-310 Replacement Shock (MD20)
21-321 Replacement Filler Cap & Gasket Only (MD20)
21-309 Replacement Cover (MD20)

Adjustable Head Sets

Head Assembly

  This coupler can either be used in conjunction with the surge couplers above or with the leveling channel .  G.V.W.R. 12,000 lbs.

Part #
21-302 2 5/16” Head Assembly


Heavy duty steel construction, multi-position mounting in either 3 position, 5 position channel or weld style.  
Zinc-plated easy latch mechanism allows for quick engage/disengage of coupler.
Capacity: 12,000 lbs. M.G.T.W. (2-5/16") --- 10,000 lbs. M.G.T.W. (2")

Part # Description
21-302-1 2 5/16" Coupler, 12K, Bolt-On, Painted (12K)
21-302-2 2" Coupler, 10K, Bolt-On Painted (10K)
21-303 Bolt & Nut GR5

Designed for "tag along" trailers used primarily in the construction business,
BULLDOG forged adjustable couplers allow level towing behind a variety of towing vehicles.
The height of the trailer tongue may be quickly adjusted to match the height of the hitch ball for safer, smoother towing.  Couplers fit inside a 2 7/8" wide channel. For leveling channels, see below.

Part # Description
21-302-4 2" Adjustable Forged Head - (7K)
21-302-3 2 5/16" Adjustable Forged Head - (12.5K)

  • Unique cast steel shield prevents damage to coupler latching mechanism
  • Patented Wedge-LatchT design act like a vise, keeping the trailer ball locked in the ball  pocket
  • Hardened steel field serviceable ball clamp provides years of trouble free towing and  eliminates need to replace coupler
  • Fast, convenient latching simplifies hook-up and saves time.  No more fighting calm shell  style latching mechanisms
  • Rust resistant grey dip primer ensures total coverage and excellent corrosion resistance
    Part # Description
    21-302-6 2 5/16" Adjustable Cast Head - (14K)
    Note: Bolts and nuts included.  For leveling channels, see below.

Capacity: 2,000 lbs. maximum vertical load / 12,000 lbs. M.G.T.W.
3" I.D. eye 1-9/16" eye section.

Part # Description
21-301 Buyers 3" Pintle Ring Assembly

Leveling Channel  

Part # Description
21-304 4-Hole Leveler Channel
21-430 6-Hole Leveler Channel w/Gussets
21-303 Bolt & Nuts (2 required)
21-430-1 6-Hole Leveler Channel w/o Gussets

Hydraulic Lock-Out Solenoid

When installed between the hyd. surge coupler and the brake line, it makes it possible to back-up without activating the brakes.

Part # Description
18-976 Hyd. Brake Lock Out Solenoid  

Hydraulic Line Kit

Used to hook hydraulic actuators to hydraulic braked axles.
Part # Description
21-500 Single Sprung Axle Plumbing Kit
21-501 Single Torflex Axle Plumbing Kit
21-501-1 Single Torsion Line Kit
21-600 Tandem Sprung Axle Plumbing Kit
21-601 Tandem Torflex Axle Plumbing Kit
Sort By:
2 5/16" Adj. Cast Head Coupler - 2 5/16" Adjustable Cast Head - (14K) (SKU: 21-302-6)
2 5/16” Adj. Forged HeadCoupler - Bulldog 12.5K 4B6M (SKU: 21-302-3)
2 5/16” Coupler - Buyers - 12K (SKU: 21-302-1-Kit-Buyers)
2 5/16” Coupler - Buyers- 12K (SKU: 21-302-1)
2 5/16” Head Assembly 12K (SKU: 21-302-T-Kit)
2 5/16” Head Assembly 12K (SKU: 21-302)
2" Surge Coupler - Atwood (8K) (SKU: 21-200-8K)
2” Adj. Forged Head Coupler - Bulldog, 7K (SKU: 21-302-4)
2” Coupler - Buyers, ADJ COUPLER HEAD 2" BUYERS 10K (SKU: 21-302-2-Kit-4H)
2” Coupler - Buyers, ADJ COUPLER HEAD 2" BUYERS 10K (SKU: 21-302-2)
2” Surge Coupler - Atwood (SKU: 21-200-Zinc)
2” Surge Coupler - Atwood (SKU: 21-200)
2” Surge Coupler - Atwood - Disc Brakes- (SKU: 21-200-DISC)
3” Pintle Ring -12K Buyers (SKU: 21-301)
4-Hole Leveler Channel... Heavy Duty Steel Construction / 8978 (SKU: 21-304)
6-Hole Leveler Channel, LEVELER CHANNEL 6-HOLE W/GUSST (SKU: 21-430)
6-Hole Leveler Channel, (8978XL) LEVELER CHANNEL 6-HOLE NO GUSSETS (SKU: 21-430-1)
6K w/ Leveler Channel - Balcrank, 6K SURGE COUPLER W/CHANNEL BALCRANK , (Bolt-On) (SKU: 21-405)
7k 2” Forged Coupler w/Bolts & Nuts (CTA190) (SKU: 21-302-4I)
Bolts/Nuts - (Titan Brand) (SKU: 21-303)
Bolts/Nuts, (SKU: 21-303-1)
Brake Lock Solenoid, (SKU: 18-976)
Demco 2 5/16” Surge Coupler - Bulldog (SKU: 21-112)
Demco 2” Surge Coupler - Bulldog, (SKU: 21-111)
DEMCO DA9150 8K ACT W/2" ADJ BULLDOG 7K CPLR, for DRUM brakes (SKU: DA9150-2HBC)
Lever Repair Kit - Titan (SKU: 21-412)
Master Cylinder Rapair Kit, Atwood (SKU: 21-200-B)
MD-20 Surge Coupler - Titan (SKU: 21-300)
MD-20 Surge Coupler - Titan, Dico Model 20 Surge Coupler w/ 2 5/16” Head (20,000 lbs.) (SKU: 21-300-2)
MD-20 Surge Coupler - Titan, Dico Model 20 Surge Coupler w/ no Head (20,000 lbs.) (SKU: 21-300-3)
MD-20 Surge Coupler - Titan, Dico Model 20 Surge Coupler w/ Pintle Ring (20,000 lbs.) (SKU: 21-300-1)
Pintle Ring Assembly 12K Adj. BUYERS (SKU: 21-301-B-12K-KIT)
Pintle Ring Assembly 20K Adj. WF / 16137 (SKU: 21-301-HD)
Repair Kit - Titan (SKU: 21-411)
Replacement Filler Cap (SKU: 21-200-C)
Replacement Shock, SHOCK FOR ATW 2"SURGE COUPLER (SKU: 21-200-G)
Shock - Titan (SKU: 21-414)
Single Spring Plumbing Kit (SKU: 21-500)
Single Torflex Plumbing Kit (SKU: 21-501)
Surge Coupler - Titan, SURGE COUPLER DICO MD 60 2" MF (8605001 ) *INCLUDE PRODUCT MANUAL RN (8605001) (SKU: 21-410)
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Greenville, SC