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Redline


Redline has become the industry leader in trailer parts and accessories through their dedication to customer service. They pride themselves on having parts in stock, shipping orders the same day they were placed, shipping orders correctly and being competitively priced.

  • Offers a full line of trailer products for enclosed, utility and boat trailers
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Expert Answers about Redline

  • Trailer Suspension Hanger Kit with the Most Lift for Tire Clearance Under the Trailer Bed
  • The # APT4 Tandem-Axle Hanger Kit will provide about 4 inches of clearance from the center of the trailer axle to the bottom of the trailer frame, with no load on the axle. This is assuming that your axle tube is 3 inches diameter. If your axle tube is smaller the height will be sightly less. The curve of the springs you select will have some affect also. I would recommend that you go with the APT5 hanger kit because all of the hangers are the same height and it will make it easier to...
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  • Constructing an Axle from Pipe and Spindle for Use on Homemade Trailer
  • The Redline Spindle # R104BT8 that you referenced has a 1-1/4-inch diameter stub that is 4-inches long. This spindle will fit an axle beam (pipe) with a 1-1/4-inch inner diameter. While you can certainly fabricate your own axle to go on your homemade trailer, assuming you have access to a qualified welder, I suggest you consider buying a complete axle assembly from etrailer. Apart from the savings in time and labor you also benefit from knowing the exact capacity of that system, something...
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  • Choosing/Sizing the Correct Trailer Ramp Spring for a Ramp Door
  • When selecting ramp springs for a trailer ramp, you will want to know the diameter of your hinge pin and how much space you have available in the hinge. A typical horse trailer or utility trailer ramp uses 3/4 inch hinge pins and would require two ramp springs with a 3/4 inch inner diameter. The ramp springs that we carry fit 1-1/2 inch diameter hinge pins and are designed for use with heavy-duty steel ramps like those on equipment trailers or car haulers. The spring slips over the...
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  • How to Determine Hub and Spindle Size
  • The spindle dimensions are as follows: A is the mounting dimension, B is the seal dimension, C is the inner bearing surface, D is the outer bearing surface and E is the diameter of the threaded portion of the spindle for spindle nut selection. Say you need a spindle and hub for a wheel with 5 on 4-1/2 inch bolt pattern and an axle that is 3500 lbs. For a single axle trailer you can use two of either the item # R20484, if your axle is round or item # SP20484 if your axle is square....
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  • Removing and Replacing Trailer Spindles
  • To replace a spindle, the old one would need to be cut off, and the new one welded into place. This is NOT a job for the do-it-yourselfer. The new spindle must be absolutely square with the axle in order to prevent premature tire wear and wheel tracking problems. I would recommend finding a welder who is experienced with trailer axles. Your local RV dealer or repair facility could probably refer you. In many cases, it's less expensive to simply replace the trailer axle itself. We offer...
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  • Where to Install Shackle Straps and How to Determine Axle Position When Building an ATV Trailer
  • For a 3,500 Dexter Straight axle the springs should be placed between 16 and 18 inches on center from the hub face (flat area the wheel mounts against). Placement of the spring centers in any other position will reduce the axle capacity. If you are using a different brand of axle you will need to contact the axle manufacturer for the full capacity spring center dimensions. If you are using double eye springs then the shackle straps will be located at the rear of the springs. The top...
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  • Parts Needed to Add Electric Brakes to a Utility Trailer with a 3500 Lbs Axle and Brake Flanges
  • You will need several items to add electric brakes to your Carry-On Utility trailer. Starting with the trailer you will need a hub and drum that matches the bearings and seal on your trailer spindle and your wheel bolt pattern. The only way to be sure is to check the bearing part numbers and seal part number, but with a 3,500 lbs Dexter axle that has brake mounting flanges you will most likely have the # L44649 Outer and # L68149 inner bearings and # 58846 seal. If these are the correct...
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  • Can Trailer Axles Be Mounted Above and Below the Leaf Springs on a Trailer
  • The best and safest way to have the axles orientated to the leaf spring is the way the trailer was originally manufactured. The trailer manufacturer will have tested the trailer with the original suspension setup for adequate braking and handling performance. If you flip the axles it could work fine, but since it has never been tested it is hard to say for certain. With that being said, you can have the axles on the top or the bottom of leaf springs. If you do have the axles on top of...
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  • What is the Torque Requirement for 1/2 Inch U-Bolts for Trailer Suspension
  • According to our FAQ on slipper springs, linked for referenced, the torque specs are as follows: Torque Ratings 1/2 inch Bolts: 45 ft/lbs - 70 ft/lbs 9/16 inch Bolts: 65 ft/lbs - 95 ft/lbs 5/8 inch Bolts: 100 ft/lbs - 120 ft/lbs The Replacement U-Bolt, # 1753223, uses a 1/2 inch nut so it would fall into the 45 to 70 foot pound category.
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  • How to Measure to Select the Correct Brake Shoes for a 6,000 lb Dexter Trailer Axle
  • You will need to measure to select the correct brake assemblies for your axles. You need to know that the brake assembly is compatible with the brake mounting flange and with the drum's diameter and depth. I added a photo showing how to measure a hub/drum for you, Typically 6,000 lb Dexter axles have a 5 bolt brake flange, like part # 4-44-1, and utilize 12 x 2 inch brake assemblies, like part # 23-106. The correct brake shoes for these assemblies are part # BP04-150. If you measure...
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  • Checking Electric Trailer Brake Magnets for Wear, Shorts, Amperage, and Resistance
  • I would check the magnets for wear before going on to test them with a meter. If the magnets show abnormal wear or if you can see the windings beginning to show through the friction surface of the magnet then they will need to be replaced. To further test your magnets, first make sure the trailer is not connected when performing this test. If the trailer is connected, you run the risk of shorting out the brake controller or various other electrical components. To test the brake magnets...
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  • Raising the Height of a Travel Trailer that Rides Close to the Ground
  • If the leaf spring stack on your travel trailer is currently mounted to the bottom of the axle, there is an over-under conversion kit that you could use to gain a few more inches of height. However, this will change the center of gravity on the trailer and can lead to an increased chance of trailer sway. For 3 inch round axles you could use # K71-385-00. And for 2-3/8 inch round axles use # K71-384-00. You should not have to do any welding to use these kits. You would not want to...
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  • Electric Trailer Brakes Lock Up When Trailer is Plugged in to Tow Vehicle
  • The easiest first step here would be to try the trailer on a different truck, and see if the same problem occurs. If the trailer brakes are free until the trailer is plugged in, I suspect that something is mis wired. I would suggest examine the wiring where the break away system was bypassed and make sure that the 12-volt accessory feed is not connected to the brake wire at some point. Are you by chance using a 7 to 6-way adapter? If so, there are two accepted ways of wiring a 6-way...
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  • How Does The EZ Lube Spindle # R20384EZ Work On A Boat Trailer
  • On the EZ Lube Spindle # R20384EZ you do not need a grease fitting for the hole on the inside end of the spindle. This is an EZ lube spindle which is designed to allow you to put grease onto the bearings by using the zerk fitting on the threaded end of the spindle. You will not want to block the hole that is on the inside end of the spindle. When the hub is installed on the EZ lube spindle it will form a cavity around the wheel bearings and when you pump grease into the spindle through...
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  • How to Pick Out Replacement Hubs for a Boat Trailer
  • In order to pick out the correct hub assembly for a trailer you are going to need know a few key pieces of information. The first thing you will need to know is the bolt pattern of your hubs. Since the figure you came up with doesn't match any of the 5-bolt bolt patterns I am going to need to to recheck your bolt pattern. For further info on this check out the FAQ article I attached on this. Next thing you will need to know is what spindle you have on your trailer. In order to do that...
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  • Spring Hanger Spacing Dimensions for a Tandem Axle Slipper Spring Suspension on a 14,0000 lb Trailer
  • The hanger spacing for a tandem axle trailer suspension setup can be determined, but you need to take into account the axle spacing needed for the overall diameter of your wheel and tire combination and the springs you will be using. Lets say that you plan on using 4 of the 5-Leaf Slipper Springs, # SP-232275, for 7,000-lb Trailer Axles, and that your wheel and tire combinations are the Karrier ST235/85R16 Wheel and Tire, # AM32764. The AM32764 wheel and tires overall diameter is...
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  • How to Wire Trailer Brake Magnets
  • As long as one of the wires coming from the back of the hub is a ground and the other is a power, it does not matter which wire on the magnet goes to which wire from the back of the hub. I have included a link to a video of a magnetic brake replacement video that may be helpful. It is for a different size brake, but you it shows the whole process.
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  • Minimum Trailer Tire to Fender Clearance
  • Generally speaking you will want to have 3 inches from the top of your tire to the fender of your trailer to accommodate for suspension travel. Having a little more wouldn't hurt, but I wouldn't recommend any less than 3 inches. I attached a review video for this fender for you to check out as well.
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  • What is the Maximum Amperage Draw of Trailer Brake Magnets on a Tandem Trailer with Four Brake Drums
  • Maximum amperage draw for 4 Brakes that are 10 or 12 inch diameter is 15.0 to 16.3 amps at 12 to 13 volts. The 14 gauge wire may be sufficient but for maximum braking effectiveness at full load capacity. I would opt to run 10 gauge wire. Larger wire will only help the effectiveness of the trailer brake system and 10 gauge is what we use when installing trailer brakes even on single brake axles with 7 inch brake assemblies. We offer Jacketed 2 Wire, 10 Gauge, Brake Wire, item # 10-2-1,...
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  • Side Wall Vent Recommendation for an Enclosed Trailer for Maximum Air Flow
  • Since heat rises I would at the very least put a set of the Trailer Vents # HMAV2-AVT2 near the top of the trailer to get the hottest air of the trailer out. What you could do for maximum air flow in your trailer is have a set facing forward in the front of your trailer near the bottom of the side wall and then have another set facing rearward at the top/back of the trailer. This will maximize getting cool air into the trailer and hot air out.
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  • Advice For Installing Leaf Springs on a Double Axle Trailer
  • The easiest way to accomplish this would be to start on one side of the trailer and get the springs in place before bolting the axle to the springs with the u-bolts. Have the axle up on jacks or blocks so its weight is not bearing on the springs. Once the springs are in place on both sides, the shackles will be in the correct orientation so you can attach the axles. The key is to do one side of the trailer at a time. I have included an FAQ article on double eye and slipper springs below.
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  • Do Trailer Drums have to be Turned when Replacing Electric Trailer Brake Assemblies
  • If the surface on the inside of the drum where the shoe pads make contact isn't smooth then a brake shop may be able to turn the drums. If that surface or the surface where the magnet makes contact (called the armature surface) is discolored then the drum will need to be replaced. In most cases, unless there is damage or discoloration, the drums will not have to be serviced or replaced. If you are unsure then the safest thing to do is take the drums to a brake shop to have them inspected.
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  • Spring Hanger Spacing with the Tandem-Axle Trailer Hanger Kit for Double-Eye Springs # APT9
  • The distance on center between the spring hanger bolt holes for dual axle setups, with the # APT9 Tandem-Axle Trailer Hanger Kit, should be 29-1/2 inches for double eye springs that measure 25-1/4 inches on center between the spring eyes and for axles that are 3 inches in diameter. This will put your axle spacing somewhere between 33-1/2 and 34 inches. You will also need to determine the position of the axles before welding the spring hangers into place. The general rule of thumb for...
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  • Replacement Trailer Ramp Springs
  • We have several hinge pins like # HP412G that I have linked for you, but it sounds like you need actual springs. We have some heavy duty ramp springs like # RS16933RH and # RS16933LH if you happen to have a heavy duty equipment trailer like what they haul tractors and other large equipment on. For an open utility trailer you may be able to use a tailgate assist like # RA-27C. Or for an enclosed trailer we have springs that are similar to garage door systems. I have linked those as well....
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  • Clips and Clamps to Attach Wires and Wiring Harnesses to the Bottom of a Trailer Frame
  • There are many ways you can secure wires to a trailer. I would not recommend the use of tape as it will wear out quickly when exposed to the elements. Soldering is also not recommended because it is a more permanent method and you may need to change wires or move them in the future the hot solder would also melt the coating on the wiring, causing a short. If you can find some large enough, wire ties could be a simple solution. We have several clamps and clips that could work for this...
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  • How Tight Should Shackle Bolts Be Tightened On Trailer
  • There should be enough free play in the shackles to allow them to move. There is no specific torque rating for shackle bolts. The first thing you should make sure of is that the bolts you use are long enough so that when installed you will have at least 2 threads protruding from the nut. Next, make sure that the nut you are using is a locking nut, so that it cannot work loose and fall off. If the bolt you are using has knurls at the bolt head you will want to tighten the bolt...
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  • Where is Trailer Suspension Equalizer Length Measured
  • The equalizers in trailer suspension hanger kit # AP233 are 5-3/4 inches long measured from the center of one spring eye to the center of the other spring eye. I have included a picture illustrating this for you.
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  • Recommended Wet Bolts With Screw-In Zerk Grease Fittings
  • We offer 2 wet bolts that may work for you because they have screw-in Zerk fittings. The first wet bolt I recommend is part # 34007-187-00. This is a step wet bolt designed to work with 1-3/4 inch double eye leaf springs. The overall length of this bolt is 3-7/16 inches and the usable length is 3 inches. This is a 9/16 inch diameter bolt. These are sold individually so you would need to enter the quantity you need when ordering. The other wet bolt I recommend is part # 126A1. This...
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  • Determining the Capacity of a Square Trailer Axle
  • Square axles can be tough to determine capacity. Often times the same spindle fits a range of axle capacities. The best way to determine the capacity is to get the inner and outer bearing numbers stamped into the metal of the bearings. Going by those numbers, wheel size, and bolt pattern, we can determine the probable axle capacity. I have included some links that might help. There could also be a plate on the axle itself that lists the capacity. The most common place to find axle capacity...
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  • How Many Locking Lug Nuts are Recommended Per Trailer Wheel
  • One locking lug nut per wheel would be the most efficient way to do it. These are sold in pairs because each axle has two wheels (one per wheel). If a thief was willing to dedicate the time to defeat one locking lugnut, a second one would not make a big enough difference to convince them to stop, so it would be a bit of waste to have 2 per wheel.
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