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Bulldog
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Complete kit bundle containing all necessary components for your project. Professional-grade components designed for reliable performance and long-lasting durability.
Designed for utility, horse/livestock, cargo, and construction trailer applications, BULLDOG Collar-Lok Heavy Duty Couplers are the strongest in the industry. The BULLDOG design features the only automatic and continuously tight ball fit in the industry. A variety of coupler styles, tongue mounts, and latches allow configurations to match virtually any trailer. Adjustable couplers assure level operation for trailers when pulled by a variety of different vehicles.
| BRAND: | BULLDOG |
| PART NUMBER: | 028630 |
| WARRANTY: | LIMITED 5 YEAR WARRANTY |
| WEIGHT: | 10.3 LBS |
| CAPACITY: | 12,500 LBS. |
| MODEL NUMBER: | 4B6M |
| MATERIAL: | STEEL |
| COLOR: | GRAY |
| MOUNTING HARDWARE INCLUDED: | NO |
| MOUNTING HOLE DIAMETER: | 0.656 IN. |
| SAFETY CHAINS INCLUDED: | NO |
Keywords: BD028630-10PK bundle kit, complete kit, professional components, industrial kit, BD028630, Bulldog
Founded in 1920, Bulldog has become the standard for heavy-duty trailer connection hardware in agricultural, military and utility service. The line covers gooseneck hitches and couplers, A-frame and channel-mount trailer couplers with the Wedge-Latch mechanism, and heavy-duty jacks, built for unmatched strength, reliability and safety under demanding loads.
Bulldog was founded in 1920 and has spent more than a century supplying the connection hardware that heavy trailers depend on. Its market has always been the demanding end: agricultural, military and utility applications where a coupler failure is not an inconvenience but a serious incident. The brand summarises its position as Tough and Tested, and it sits within the Horizon Global towing group alongside Reese, Draw-Tite, Fulton, Tekonsha, Bargman and Wesbar.
Gooseneck equipment is the brand's signature. Gooseneck hitches mount in the truck bed over the rear axle, which places the load where the chassis can carry it properly and allows far tighter turning than a receiver hitch permits. Matching gooseneck couplers attach at the trailer end, in round tube and square configurations across the capacity range used by livestock, equipment and flatbed trailers.
The conventional trailer coupler range is built around the Wedge-Latch mechanism, which uses a wedge to take up wear between coupler and ball rather than relying on a fixed clamp that loosens over time. That matters on a trailer accumulating hard miles, where slack in the coupling shows up as noise and shock loading. Couplers are offered in A-frame form for standard tongues and in channel-mount form for straight tongue and fabricated frames, with adjustable channel versions that let a coupler be positioned to suit the tongue height.
Heavy-duty jacks complete the line, sized for the tongue weights that gooseneck and equipment trailers generate. Across the range the emphasis is consistent: forged and heavy-section components, load ratings backed by testing, and hardware specified for agricultural, military and heavy-duty commercial use rather than occasional recreational towing.
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The Bulldog Collar-Lok™ coupler is a trailer tongue coupler that connects a trailer to a towing vehicle via a hitch ball. It is available in three styles: L-Style, H-Style, and M-Style. The coupler uses a collar mechanism with a retaining pin to secure the hitch ball in the ball pocket. It is rated according to SAE J684 standard for towing safety.
The Bulldog Collar-Lok™ coupler is available in four models: 2B, 3B, 4B, and 5B. Each model has different minimum tongue overlap requirements: 2B, 4B, and 5B require 8.5" minimum overlap; 3B requires 6.5" minimum overlap. The coupler is also available in three style configurations: L-Style, H-Style, and M-Style.
Minimum tongue overlap depends on the model: Models 2B, 4B, and 5B require 8.5" minimum overlap; Model 3B requires 6.5" minimum overlap. For bolt-on installations, one model shows 2.5" minimum overlap with the note that the tongue may fit over or into the coupler. The coupler internal stop must be butted against the end of the trailer tongue for maximum overlap.
No. The manual shows a 3.0" channel as "(Not included)" in the parts diagram. The channel must be obtained separately. The number and size of fasteners required to attach the coupler to the channel must be specified by the trailer manufacturer.
Use only the proper ball for the coupler as indicated on the coupler body. If you are uncertain which ball size is correct for your specific coupler model, contact Cequent Performance Products at 1-800-632-3290 or www.cequentgroup.com.
The coupler comes with a retaining pin and supplied bolts. The exact number and size of bolts depend on the model. Grade 5 bolts with locknuts are required for bolt-on installation. Additional fasteners may be needed depending on the channel and trailer manufacturer specifications.
Yes. All welding must be performed by an AWS (American Welding Society) certified welder. This is stated as a requirement multiple times in the manual and is critical for safe installation.
Weld-on installation: The coupler internal stop is butted against the end of the trailer tongue, and a 3/16" weld is applied around the interface between coupler and tongue with no undercut or washout. Bolt-on installation: The coupler internal stop is butted against the end of the trailer tongue, and Grade 5 bolts with locknuts are torqued to SAE proof load specifications with no deformation of the trailer tongue end allowed. The trailer manufacturer must specify the number and size of fasteners required.
The manual does not explicitly state whether drilling is required. For bolt-on installation, holes must be present or created to accommodate the Grade 5 bolts, but the manual does not specify the hole sizes or whether drilling is the installer's responsibility. The trailer manufacturer must specify the number and size of fasteners required.
Grade 5 bolts must be torqued to the following SAE proof load specifications: 3/8" diameter bolts: 23 ft-lbs; 1/2" diameter bolts: 55 ft-lbs; 5/8" diameter bolts: 110 ft-lbs. These specifications apply to both initial installation and periodic retorque checks.
Yes. Before mounting the coupler, confirm that there will be no interference from the tow vehicle, tongue, ground, and any other mounted accessories while stationary or in motion. Check for interference in both open and closed positions before installing, and check again after installation is complete.
The weight capacity is stamped on the coupler body or shown on decals. Do not exceed the lesser of the mounting bracket, coupler, hitch, vehicle, ball, or trailer weight ratings (including load). Never exceed the maximum rated capacity. If you are uncertain about the capacity, contact Cequent Performance Products at 1-800-632-3290 or www.cequentgroup.com.
No. Do not tow if the ball is not fully seated in the coupler ball pocket and/or the coupler is not closed. Always visually check that the hitch ball is fully seated in the coupler before towing.
Before towing, perform the following checks: (1) Check vehicle, channel, hitch, hitch ball, and coupler for signs of wear or damage and that the coupler handle opens and closes freely. (2) Replace bent, broken, or worn parts before using. (3) Check that the hitch ball is fully seated in the coupler ball pocket, close the coupler, and insert the pin behind the collar or through the latch. (4) Check channel hardware for wear and proper tightness; replace bent, broken, or worn hardware and tighten to appropriate SAE proof load specifications using only Grade 5 hardware. (5) Ensure trailer safety chains are properly connected to the towing vehicle and trailer according to SAE J684. (6) Ensure all trailer lighting is hooked up and working properly.
The following procedures should be performed at least annually: (1) Check welds and mounting bolt torque. (2) Grease the ball pocket. (3) Oil pivot points with SAE 30 wt. motor oil. (4) Inspect retaining pins and replace if necessary. Additionally, keep the ball pocket and mechanism clean at all times, and when parking or storing the trailer, keep the coupler off the ground so dirt and foreign material will not build up in the coupler ball pocket.
Oil pivot points with SAE 30 wt. motor oil. This should be done at least annually as part of regular maintenance.
Always secure the load, vehicle, and trailer by blocking the wheels before latching or unlatching the coupler. Additionally, use caution when uncoupling as the tongue may rise suddenly due to negative tongue load.
Do not use the coupler. After installing the channel and/or coupler, if coupler operation has been impaired in any way, do not use it. If the coupler and/or channel is deformed or damaged, replace the complete coupler and bracket.
No. Do not allow children to play on or around the coupler or the load being supported.
No. Operator and bystanders should never position any part of their body under any portion of the coupler or the load being supported.
To couple: (1) Block trailer wheels. (2) Align hitch ball beneath coupler. (3) If the coupler is closed, open it by removing the pin behind the collar and sliding the collar away from the ball pocket. Ensure the coupler cap is open and holds the collar back. (4) Lower the trailer onto the hitch ball. (5) Visually check that the hitch ball is fully seated in the coupler. (6) After the hitch ball is seated, carefully close the coupler cap. Ensure the collar springs toward the ball pocket and captures the coupler cap. (7) Reinsert the pin behind the collar. Do not tow without the pin in place. (8) Always secure safety chains to the vehicle before towing according to SAE J684.
To uncouple: (1) Block trailer wheels. (2) Open the coupler by removing the pin behind the collar and sliding the collar away from the ball pocket. Ensure the coupler cap is open and holds the collar back. (3) Raise the trailer from the hitch ball.
To couple: (1) Block trailer wheels. (2) Align hitch ball beneath coupler. (3) If the coupler is closed, open it by removing the pin in the latch and lifting the latch. Ensure the coupler cap is open and holds the collar back. (4) Lower the trailer onto the hitch ball. (5) Visually check that the hitch ball is fully seated in the coupler. (6) After the hitch ball is seated, carefully close the coupler cap and lower the latch. Ensure the collar springs toward the ball pocket and captures the coupler cap. (7) Reinsert the pin in the latch. Do not tow without the pin in place. (8) Always secure safety chains to the vehicle before towing according to SAE J684.
To uncouple: (1) Block trailer wheels. (2) Open the coupler by removing the pin in the latch and lifting the latch. Ensure the coupler cap is open and holds the collar back. (3) Raise the trailer from the hitch ball.
To couple: (1) Block trailer wheels. (2) Align hitch ball beneath coupler. (3) If the coupler is closed, open it by removing the pin behind the collar and sliding the collar away from the ball pocket. Ensure the coupler cap is open and holds the collar back. (4) Lower the trailer onto the hitch ball. (5) Visually check that the hitch ball is fully seated in the coupler. (6) After the hitch ball is seated, carefully close the coupler cap. Ensure the collar springs toward the ball pocket and captures the coupler cap. (7) Reinsert the pin behind the collar. Do not tow without the pin in place. (8) Always secure safety chains to the vehicle before towing according to SAE J684.
To uncouple: (1) Block trailer wheels. (2) Open the coupler by removing the pin behind the collar and sliding the collar away from the ball pocket. Ensure the coupler cap is open and holds the collar back. (3) Raise the trailer from the hitch ball.
The coupler comes with a Limited Five Year Warranty from Cequent Performance Products. The warranty covers material defects in both material and workmanship for five years from the date of purchase, provided installation and use are in accordance with product instructions. The warranty does not cover normal wear and tear, damage from abuse, neglect, misuse, accidents, misapplication, overloading, improper installation (including welds), improper maintenance and repair, or product alterations made by anyone other than Cequent. To make a warranty claim, contact Cequent Performance Products at 47912 Halyard Dr. Suite 100, Plymouth, MI 48170, 1-800-632-3290, and provide the product model number and purchase receipt.
No. The purchaser/owner must not alter or modify the product. Any modifications made by anyone other than Cequent Performance Products, except those made pursuant to product instructions and in a workmanlike manner, will void the warranty.
Replacement parts are available through Cequent Performance Products' Customer Service Department at 1-800-632-3290 or 47912 Halyard Dr. Suite 100, Plymouth, MI 48170. Use only Cequent Performance Products' parts or parts of equal quality for repair. Please specify the product model number when ordering.
The coupler is available in models 2B, 3B, 4B, and 5B with different minimum tongue overlap requirements (2.5" to 8.5" depending on model). Confirm your trailer tongue length and coupler model compatibility. Contact Cequent Performance Products at 1-800-632-3290 if uncertain.
For weld-on installation: AWS certified welder and welding equipment. For bolt-on installation: Grade 5 bolts with locknuts (size and quantity specified by trailer manufacturer), torque wrench, and socket set. The coupler comes with a retaining pin and supplied bolts. A 3.0" channel must be obtained separately.
Torque Grade 5 bolts to SAE proof load specifications: 3/8" = 23 ft-lbs, 1/2" = 55 ft-lbs, 5/8" = 110 ft-lbs. Retorque annually as part of maintenance.
No. Do not tow without the pin in place. The pin must be reinserted behind the collar (L-Style and M-Style) or in the latch (H-Style) after the coupler cap is closed and before towing.
Check that the hitch ball is fully seated in the coupler, the coupler is closed with the pin in place, the coupler handle opens and closes freely, all hardware is tight, and safety chains are properly connected. Replace any bent, broken, or worn parts before towing.
Perform annually: check welds and mounting bolt torque, grease the ball pocket, oil pivot points with SAE 30 wt. motor oil, and inspect retaining pins. Keep the ball pocket clean and store the coupler off the ground when not in use.
Check the coupler for signs of wear or damage. If the coupler and/or channel is deformed or damaged, replace the complete coupler and bracket. Do not attempt to use the coupler if its operation has been impaired in any way, as this indicates a structural or mechanical problem that could lead to coupler failure during towing.
Do not tow. Ensure the trailer wheels are blocked and the coupler is fully open. Lower the trailer slowly onto the hitch ball, ensuring the ball enters the ball pocket completely. Visually verify that the ball is fully seated before closing the coupler cap. If the ball will not seat fully, check that the correct ball size is being used for your coupler model and that the ball pocket is clean and free of debris.
Do not tow. Inspect the retaining pin and replace it if necessary. The pin is critical for securing the collar in the closed position and preventing the coupler from opening during towing. Replacement pins are available through Cequent Performance Products' Customer Service Department at 1-800-632-3290. Specify the product model number when ordering.
Stop towing immediately. Check the mounting bolts for proper tightness using a torque wrench and tighten to the appropriate SAE proof load specifications (3/8" = 23 ft-lbs, 1/2" = 55 ft-lbs, 5/8" = 110 ft-lbs). Check the welds for cracks or damage if the coupler is welded. If the coupler or channel is deformed or damaged, replace the complete coupler and bracket. Do not resume towing until the problem is resolved.
Clean the ball pocket and mechanism thoroughly. Remove any dirt, grease buildup, or foreign material that could impair coupler operation. Once clean, grease the ball pocket as part of regular maintenance. If debris has caused the coupler to bind or operate improperly, do not use the coupler until it has been cleaned and its operation verified to be free and smooth.
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