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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: | 028585 |
| WARRANTY: | LIMITED 5 YEAR WARRANTY |
| WEIGHT: | 9.85 LBS |
| CAPACITY: | 12,500 LBS. |
| MODEL NUMBER: | 4B6M |
| MATERIAL: | STEEL |
| COLOR: | GRAY |
| MOUNTING HARDWARE INCLUDED: | NO |
| MOUNTING HOLE DIAMETER: | 0.656 IN. |
| MOUNTING HOLE QUANTITY: | 4 |
| CHANNEL WIDTH: | 3 IN. |
| SAFETY CHAINS INCLUDED: | NO |
Keywords: BD028585-5PK bundle kit, complete kit, professional components, industrial kit, BD028585, 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's hitch ball. It is available in four models (2B, 3B, 4B, 5B) with different minimum tongue overlap requirements. The coupler features a collar mechanism that captures and secures the hitch ball, and is rated according to SAE J684 standard. It is designed to support a maximum rated load that varies by model and component.
Minimum tongue overlap depends on your coupler model: 2B, 4B, and 5B models require 8.5" minimum overlap; 3B model requires 6.5" minimum overlap. One model allows 7" minimum overlap, and another allows 2.5" minimum overlap (tongue may fit over or into coupler). Ensure the coupler internal stop is butted against the end of the trailer tongue for maximum overlap before securing.
Use only the proper ball size for your coupler as indicated on the coupler body itself. If you are uncertain which ball size is correct, contact Cequent Performance Products at 1-800-632-3290 or www.cequentgroup.com. Using an incorrect ball size will prevent proper seating and safe operation.
A 3.0" channel is shown in the installation diagrams but is noted as "not included" with the coupler. The channel is required for proper mounting. You must obtain a 3.0" channel separately. The number and size of fasteners required to attach the coupler to the channel must be specified by your trailer manufacturer.
The coupler is supplied with bolts and a retaining pin. Grade 5 bolts with locknuts are provided for bolt-on installation. The retaining pin is used to secure the collar mechanism in the closed position. Additional fasteners may be required depending on your specific installation; consult your trailer manufacturer for the number and size needed.
Yes. All welding must be performed by an AWS (American Welding Society) certified welder. This is a mandatory requirement stated multiple times in the manual. Improper welding can result in coupler failure and safety hazards.
Before installation, confirm that there will be no interference from the tow vehicle, tongue, ground, or any other mounted accessories while stationary or in motion. Check for interference in both open and closed coupler positions. Ensure the coupler internal stop will butt against the end of the trailer tongue for maximum overlap. After installation is complete, check for interference again and verify that coupler operation has not been impaired in any way.
Weld 3/16" around the interface between the coupler and trailer tongue. Ensure the coupler internal stop is butted against the end of the trailer tongue for maximum overlap before welding. Do not create undercut or washout while welding. All welding must be performed by an AWS certified welder.
Torque grade 5 bolts with locknuts 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. No deformation of the trailer tongue end is allowed. The number and size of fasteners required must be specified by the trailer manufacturer.
Before towing, perform these checks: (1) Inspect the vehicle, channel, hitch, hitch ball, and coupler for signs of wear or damage; verify the coupler handle opens and closes freely. (2) 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. (3) Check channel hardware for wear and proper tightness; replace any bent, broken, or worn hardware and tighten to appropriate SAE proof load specifications using only grade 5 hardware. (4) Verify trailer safety chains are properly connected to both the towing vehicle and trailer per SAE J684. (5) Verify all trailer lighting is hooked up and working properly. (6) Weigh your trailer plus added load and ensure it does not exceed the lesser of the mounting bracket, coupler, hitch, vehicle, ball, or trailer weight ratings.
The maximum rated capacity varies by model and 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). Weigh your trailer plus added load before towing. If you are uncertain about the capacity, contact Cequent Performance Products at 1-800-632-3290 or www.cequentgroup.com.
The coupling procedure varies by coupler style. For L-Style and M-Style couplers: (1) Block trailer wheels. (2) Align hitch ball beneath coupler. (3) If 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) 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 per SAE J684. For H-Style couplers, the procedure is similar but uses a latch and pin in the latch instead of a collar pin.
The uncoupling procedure varies by coupler style. For L-Style and M-Style couplers: (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. For H-Style couplers: (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. Use caution when uncoupling as the tongue may rise suddenly due to negative tongue load.
Keep the ball pocket and mechanism clean. Perform the following procedures 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. When parking or storing your trailer, keep the coupler off the ground so dirt and other foreign material will not build up in the coupler ball pocket.
After installation is complete, verify that coupler operation has not been impaired in any way. Check for interference again in both open and closed positions with the tow vehicle, tongue, ground, and any other mounted accessories. If coupler operation has been impaired in any way, do not use it. The coupler must be rigidly attached to the trailer in order to support its maximum rated load according to SAE J684.
Critical warnings include: Never position any part of your body under any portion of the coupler or the load being supported. Do not allow children to play on or around the coupler or load. Do not tow if the ball is not fully seated and/or the coupler is not closed. Do not use the coupler if its operation has been impaired in any way. Never exceed the maximum rated capacity. Always secure the load, vehicle, and trailer (by blocking wheels) before latching or unlatching the coupler. Use caution when uncoupling as the tongue may rise suddenly due to negative tongue load. Do not alter or modify the coupler. The purchaser/owner must ensure installation is performed according to these instructions.
The coupler is available in four models (2B, 3B, 4B, 5B) with different minimum tongue overlap requirements (2.5", 6.5", 7", or 8.5"). Verify your model and that your trailer tongue meets the minimum overlap requirement. The hitch ball size must match the coupler body specification. Contact Cequent Performance Products at 1-800-632-3290 if you are uncertain.
No. The 3.0" channel is not included and must be obtained separately. The coupler is supplied with bolts, locknuts, and a retaining pin. Your trailer manufacturer must specify the number and size of additional fasteners required.
Yes, if you are installing a weld-on coupler. All welding must be performed by an AWS certified welder. For bolt-on installation, you do not need a welder, but you must use grade 5 bolts with locknuts torqued to the specified SAE proof load values.
Torque 1/2" grade 5 bolts with locknuts to 55 ft. lbs. according to SAE proof load specifications.
No. Do not tow without the retaining pin in place. The pin must be reinserted behind the collar (L-Style and M-Style) or in the latch (H-Style) after the hitch ball is seated and the coupler cap is closed.
Perform maintenance at least annually: check welds and mounting bolt torque, grease the ball pocket, oil pivot points with SAE 30 wt. motor oil, and inspect and replace retaining pins if necessary. Keep the ball pocket and mechanism clean at all times.
A coupler handle that does not operate freely indicates impaired coupler operation. Do not use the coupler. Check for interference from the tow vehicle, tongue, ground, or other mounted accessories in both open and closed positions. If interference is found, correct it. If no interference is found or if correcting interference does not resolve the issue, the coupler may be damaged or deformed and must be replaced. Contact Cequent Performance Products at 1-800-632-3290 for replacement parts or service.
If the hitch ball is not fully seated, do not tow. First, verify you are using the correct ball size for your coupler as indicated on the coupler body. If the ball size is correct, check that the coupler is fully open by removing the pin and sliding the collar completely away from the ball pocket. Ensure the coupler cap is open and holding the collar back. Then lower the trailer slowly onto the ball. If the ball still does not seat fully, the coupler or ball may be damaged or deformed. Do not tow. Contact Cequent Performance Products at 1-800-632-3290.
If the collar does not spring properly toward the ball pocket, the coupler operation is impaired. Do not use the coupler. This indicates either a mechanical failure of the collar spring mechanism or interference preventing normal operation. Check for any obstruction or interference around the collar and cap. If no interference is found, the coupler is damaged and must be replaced. Contact Cequent Performance Products at 1-800-632-3290 for replacement.
Yes, this is normal and expected. The manual specifically warns: "Use caution when uncoupling as tongue may rise suddenly due to negative tongue load." This occurs because the trailer weight creates a downward force on the hitch ball, and when the ball is released, that force is suddenly removed and the tongue springs upward. Always block the trailer wheels before uncoupling and use caution to avoid injury or property damage.
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