Maintain Trailer Spindle Sleeves

Nothing keeps trailer boaters up at night like the fear of being stranded on the side of a busy roadway without the tools, parts, or knowledge to remedy a situation on the fly. And while most are prepared for dealing with a flat tire, a burned-up hub caused by bearing failure presents a more difficult situation to handle – and a headache to match.

The standard trailer hub system has served boaters well for decades, as bearings that are adequately greased and sealed can provide thousands of trouble-free miles between maintenance. However, if the grease that keeps this well-oiled machine moving is allowed to escape, water inevitably takes its place, and problems are never far behind, with the worst-case scenario being bearings that overheat, disintegrate, and stop a trailer dead in its tracks.

Trailer hubs contain inner and outer bearings that ride on the axle’s spindle – the smooth tapered end of the axle – which are contained by bearing races pressed into the inside of the hub (Photo 1). An inner seal rides along the inside sealing surface of the spindle, and a dust cap or bearing protector mounts on the outside of the hub to keep the grease in and contaminants out, acting as an “outer seal.” Bearing protectors keep water out by using spring action to create positive pressure within the hub, countering the vacuum effect of warm hubs submersed in cooler water. A bearing protector is often universally referred to as Bearing Buddy, a proprietary name, and the most commonly used brand for marine applications. However, alternative brands now exist.

Basic spindles require grease to be packed in the hub manually or with a grease gun through the bearing protector, while the modern Posi-Lube system features a zerk fitting on the end of the spindle that pushes grease through a small channel within the spindle, then out of a hole in the rear of the spindle and back out of the front of the bearings. (Note: When using a spindle sleeve on a Posi-Lube spindle, you must also install a bearing protector, as the replacement sleeve will cover the lubrication hole used in a Posi-Lube system.) An alternative oil-bathing hub system is less common, but it bathes the bearings in motor oil as the wheel rotates as opposed to packing them with bearing grease.

Regardless of the type of spindle your trailer has, the critical component that keeps grease from escaping and water from coming in is the inner seal – usually double-lipped rubber style with a metal flange. These seals are remarkably dependable when riding on a perfectly smooth surface, but over time, the sealing surface can become grooved, pitted, or corroded (2), allowing grease to escape and water to intrude, ultimately leading to bearing failure.

The warning signs that your inner seals are no longer sealing properly are hubs that continually need grease or, more obviously, seeing leaked grease on the back of the wheels, tires, and adjacent parts – usually in a splatter pattern (3). If not addressed, unsealed hubs, especially those used in saltwater, will inevitably corrode internally and overheat before ultimately failing – sometimes at the most inopportune times.

While axle replacement is a surefire way to ensure your spindles perform as new, there are a few lesser-known products that provide a new sealing surface for your existing spindle, prolonging the life of your axles and allowing the hub to once again make a watertight seal that keeps grease in and protects your bearings.

Bearing Buddy makes a three-piece seal sleeve kit that is purpose-built for boat trailers, but there are other aftermarket sleeves, often called Speedi Sleeves, that achieve similar results and can be purchased inexpensively at many auto parts stores. While also effective, these sleeves can be complicated to install and require slightly more mechanical skill, so in this article we are focusing on the Bearing Buddy kit that can be easily installed by the average DIY boater.

For trailers with axles that are in safe and serviceable condition except for poor sealing surfaces on the spindles, these seal sleeve kits are a great way to get some added life out of them while keeping your rig safe and reliable on the road.

Installation

NOTE: Slight variations of the spindle/hub system exist, namely with different styles of retaining nuts and washers. These instructions pertain to the most commonly found design. If your trailer is equipped with brakes, the calipers will usually need to be removed before taking the hub off.

Choose the proper size kit, which contains a stainless-steel spindle sleeve, O-ring, and neoprene seal for two spindles (4). If you don’t know the size of your spindles, use a caliper to measure the inside diameter of the hub and/or seal surface or reference the bearing part number stamped on the inner bearing cone once disassembled.

1. Jack up the side of the axle you are servicing with an adequately sized jack, placed as close to the hub as safely possible (5). Remove wheel (6).

2. Remove the dust cap or bearing protector. Lightly tap from alternating sides until it gradually “walks” its way out. Use a hammer and wood block or a hard rubber mallet to avoid ­damage (7).

3. Wipe away excess grease using a clean shop towel or rag to expose the parts, then use a pair of needle nose pliers or dykes to remove the cotter pin, using the edge of the hub as a fulcrum point (8).

4. Remove the castle washer (9), spindle nut (10), and spindle washer (11), then remove the hub assembly from the spindle (12). Some spindles may simply have a castle nut and washer or other style of key washer to prevent the nut from backing off.

5. Place the hub face down and remove the existing inner seal using a seal puller or large flathead screwdriver (13), remove the bearings, and inspect for any signs of corrosion, pitting, or other abnormalities, such as discoloration or signs of metal shavings in the hub. If there are any signs of damage or excessive wear, the bearings and races must be replaced. To remove the races, use a punch to tap in an alternating circular pattern until they work their way out, then reinstall new ones in the same fashion.

5. Place the hub face down and remove the existing inner seal using a seal puller or large flathead screwdriver (13), remove the bearings, and inspect for any signs of corrosion, pitting, or other abnormalities, such as discoloration or signs of metal shavings in the hub. If there are any signs of damage or excessive wear, the bearings and races must be replaced. To remove the races, use a punch to tap in an alternating circular pattern until they work their way out, then reinstall new ones in the same fashion.

6. If the bearings appear to be in good condition, remove the old grease from the hub, repack the bearings with new grease, and reinstall them in the hub. Bearing packing devices can be found at most auto part stores, but if one is not available, you can also manually pack them by depositing grease in a gloved hand, placing two fingers through the bearing, and using a repetitive “wiping” motion to force grease up through the bearing until fresh grease can be observed exiting the top of the bearing on all sides (14). There are many brands of bearing grease available and almost all work well, however, be sure to select one designed for marine use and do not mix grease types or brands.

7. With the bearings repacked and seated in the hub, use a hammer and wood block to carefully tap the new seal into place. Keep the seal level with the hub face and if it becomes crooked, do not force it (15).

8. Clean away old grease and debris from the spindle and sealing surface, then sand any severe imperfections, if possible (16).

9. Slide the stainless-steel spindle sleeve over the hub so it’s snug over the old sealing surface. Follow with the O-ring and lightly grease all the spindle surfaces (17).

10. Fill the hub with grease and slide it onto the spindle. Replace the spindle washer and spindle nut, hand tightening it until snug, then use pliers for another quarter turn or so to seat the bearings. Rotate the hub back and forth to ensure there is no play or sloppiness, then loosen the nut just enough so that the hub spins smoothly and the holes line up for the cotter pin to be inserted. Place the castle washer over the nut and install the pin, bending back both ends (18). Overtightening the spindle nut can lead to premature bearing damage.

11. Lightly tap the bearing protector into the hub using a wood block or rubber mallet (19), then inject grease with a grease gun until the piston or blue indicator ring protrudes far enough that you can rock it with your finger (20). Do not overfill, as excessive pressure can damage the inner seal. When full, slide on the cover, or bra (21).

12. Reinstall the wheel, torquing the lug nuts to the manufacturer’s suggested torque specifications.

With the spindle sleeves installed, you are ready to hit the road! After the first few miles, check the back sides of the hubs to ensure they are no longer leaking, and check the bearing protector pistons to see if they have moved inward. If they have, add more grease as necessary, as the hubs will push any air pockets out past the pistons until all the air has escaped and the hub cavity is full of grease. This may take a few cycles.

Your bearings should be repacked and inspected every 3,000 to 4,000 miles or annually, whichever comes first. With fresh grease and spindle seals in place, hit the road with confidence, knowing you have taken the proper steps to avoid any dreaded side-of-the-road hub repairs.