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Regular Maintenance

The friction surfaces of the head and sockets should be kept clean and well lubricated with a good quality multi‑purpose or bearing grease. These are the surfaces where the arm sockets rub against the top and bottom plates of the head. See Figure 23. We recommend Equal-i-zer high performance lubricant.

Eq Owners Manual Web Images 2017 Fig23

They should be lubricated before each trip. Check for damage or abnormal wear at the beginning of each towing day and replace if necessary. Clean dirt and road grit from all friction surfaces regularly.

All nuts and bolts should be checked before each towing day and  be tightened or replaced if necessary.

Pay special attention to the angle set bolt. There is a break-in period for each hitch and towing configuration. This period is not the same for every towing configuration. With use, the spacer washers and rivet may compact slightly leaving a small gap between the angle set bolt and the shank. The bolt should be checked carefully through the break-in period and re-tightened as explained in Step 9. You will notice that over time the need to re-tighten the angle set bolt will decrease, but you should still check it regularly before each towing day as part of your hook-up routine.

Store your hitch out of the weather when not in use. Keep it clean and free from rust. From time to time, use a good quality rust inhibiting spray paint to touch up the finish and keep it looking good. Do not paint over the warning stickers. If the warning stickers become worn or unreadable, contact Progress Mfg. Inc. for free replacement.

Service Tech and Experienced Installer Checklist

  1. Park the loaded tow vehicle and trailer on a level surface.
  2. Install the hitch ball. If already installed, check that the ball is in good condition and is tight on the hitch head.
  3. Measure from the ground to the trailer coupler. Insert the adjustable shank into the receiver and secure it with the hitch pin and clip. Insert the spacer rivet with washers into the back of the hitch head to pre-load the angle of the hitch head. Slide the hitch head bolt channel around the shank and hold the hitch head so that the top of the hitch ball measures from the ground as close as possible to the coupler height. Insert the shank bolts, washers, and nuts to attach the head to the shank. Tighten the angle set bolt.
  4. Determine which coupler style you have before installing the link plates. Measure 32” from the coupler on the trailer frame. The link plate centers should be installed between 27”-32” on the trailer frame. Pinch the link plates tight to the frame and tighten bolts evenly. Install the L-brackets.
  5. Take initial measurements at the front axle for weight distribution. Lift spring arms onto the L-bracket. Retract tongue jack until the weight of the trailer rests on the tow vehicle.
  6. Check for good weight distribution and make needed adjustments.
  7. Check the trailer pitch and make adjustments.
  8. Check that all bolts and nuts have been properly tightened and that all pins and clips are securely in place.
  9. Give Owner’s Manual to customer.

Appendix A - Troubleshooting Guide


Noise is a normal occurrence when towing a trailer and using any weight distribution or sway control hitch.

The majority of hitch noise can be eliminated by lubricating the friction surfaces of the head as shown in Figure 23.

In some cases the friction on the L-brackets can generate noise. Lubricating this joint is not recommended. A better solution is a set of official Equal-i-zer brand Sway Bracket Jackets™. They quiet the ride and reduce wear without the mess of using a lubricant.

Customer Support:

For customer support, replacement parts and accessories we recommend that you visit your local dealership that is familiar with Equal-i-zer® brand products whenever possible. If at any time you need customer support and are unable to reach a dealership, please call our toll free customer support line at 1-800-478-5578 or contact us here.

Appendix B - Weight Distribution Adjustments

You should carefully consider the following items and their effects when setting up initially and when adjusting your hitch before each trip:

  • Rear Axle to Hitch Ball Distance: A longer distance here will transfer less weight distribution than a shorter distance with the same washer and L-bracket settings.
  • Vehicle Suspension: Soft suspensions, such as an SUV will react farther and faster to weight distribution adjustments than stiff suspensions like a 3/4 ton pickup. For a smoother ride, some vehicle suspensions are designed to be very soft with the first few pounds of payload, and to then stiffen as the load increases. This means that initially the springs move a long way with very little weight applied, then later move much less, even with a significant change in applied weight.
  • Trailer Axle to Coupler Distance: Trailers with longer distances will try to force distributed weight forward to the tow vehicle before absorbing it into the trailer suspension. Trailers with shorter distances absorb more of the distributed weight into their own suspensions.
  • Tongue weight: To operate effectively, your tongue weight should be at least 10% of the gross trailer weight. This helps provide the sway resisting friction force on the L-brackets and head sockets of the hitch that give it the ability to resist movement and thus to resist trailer sway.
  • Trailer loading: This is one of the most significant factors that influences trailer sway. Most trailers are designed to have a tongue weight of between 10% and 15% of the overall trailer weight. Always follow the trailer manufacturer’s guidelines for tongue weight. Trailers that are “back-end heavy” can often cause trailer sway. Trailer loading changes tongue weight dramatically, and loading can change dramatically from one trip to the next, or even during the course of a short weekend trip.

For example; full water fresh tanks that are tongue weight when you leave can empty and become full waste tanks that subtract tongue weight for the return trip. Shifting just 40 gallons of water from the front to the back of your trailer can change 330 lbs. of positive tongue weight to 330 lbs. of negative tongue weight.

Rear-load toy haulers are designed to have very heavy dry (empty) tongue weights so that when they are loaded with toys they become a more balanced load.

Front-load toy haulers are exactly the opposite. They have much lighter tongue weights without toys, and then can get very heavy when toys are loaded.  You must be careful not to exceed receiver hitch and tow vehicle rear axle ratings when towing a front-load toy hauler. All toy haulers may require significant changes to weight distribution setups between towing loaded and towing unloaded.

Cargo carriers, bike racks, and second trailers attached to the rear bumper of a trailer add weight to the rear of the trailer that automatically subtracts tongue weight. We recommend that you do not add weight of any form to the rear bumper of your trailer. We also recommend that you do not tow a 2nd trailer under any circumstance.

  • Trailer coupled attitude: Attitude or pitch refers to the angle that the trailer is tipped to. It is generally accepted that a trailer should be towed sitting parallel to the ground, or with the front (coupler) tipped slightly down. The front tipped too far up or down may be an indication of improper trailer loading, or a need to adjust the ball height or weight distribution settings.
  • Vehicle weight ratings: Each trailer and tow vehicle has a maximum Gross Vehicle Weight Rating (GVWR). The tow vehicle and towing equipment, including receiver, shank, hitch, and hitch ball all have maximum weight ratings for tongue weight and trailer weight. Tow vehicle and trailer also have maximum axle weight ratings. NEVER exceed any of these ratings.


Limited Lifetime Warranty: Progress Mfg. Inc. warrants the Equal-i-zer® hitch against latent defects in materials and workmanship under normal use and service, ordinary wear and tear is excepted, from the first date of purchase at retail for the ownership life of the original purchaser. If this product is latently defective it will be replaced or repaired when a proper return authorization is obtained and the product is returned with transportation charges prepaid to the Progress Mfg. Inc. manufacturing plant. Progress Mfg. Inc. shall not be required to replace or repair any products damaged as a result of improper installation, alteration, unreasonable use, or improper maintenance including, without limitation, loading the product beyond the factory rated load capacity. This warranty does not include labor charges nor does it include transportation charges for returning the product to the consumer. To the extent allowed by law, Progress Mfg. Inc. shall not be liable for any incidental, consequential, or any other damages including, without limitation, breach of any implied warranty, merchantability, or fitness for a particular purpose of any Equal-i-zer product. In no event shall Progress Mfg. Inc. be liable for any damages other than the replacement or repair of the affected part. Authorization and warranty procedure may be obtained by calling Progress Mfg. Inc. customer support at 1-800-478-5578.

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