How often should trailer wheel bearings be repacked?

Annually, or every 12,000 miles, whichever comes first. This is the maintenance item most commonly skipped and the one with the most serious consequences. A dry bearing overheats, seizes, and can separate the hub from the spindle at highway speed. It is also a common ignition source, which is why you see burnt-out trailers on the shoulder. It is inexpensive work and it prevents an expensive and dangerous failure.

Why do my trailer brakes grab or pull to one side?

Usually uneven adjustment, a contaminated shoe on one side from a leaking bearing seal, or a magnet that is worn or partially failed. Electric trailer brakes rely on both sides applying equally, so any imbalance shows up as pulling. It can also be the brake controller in the tow vehicle being set too aggressively, which is worth ruling out before dismantling anything.

Can a bent trailer axle be straightened?

Occasionally, and we are cautious about it. Axle tubes are heat treated and straightening can compromise that. On a modest bend in a heavy axle it can be done and measured. On anything significant, and on any axle where the spindle itself is bent, replacement is the correct answer, because an axle failure at speed on a loaded trailer is a serious event.

How much does this work cost?

Bearing repack is $300 to $700 per axle. Electric brake service is $400 to $1,200 per axle. Axle replacement is $1,200 to $3,500 per axle including parts. Suspension work runs $600 to $4,500 depending on system. Air suspension repair on a coach runs $800 to $5,500.

My motorhome rides badly and wanders. Is that suspension?

Possibly, and possibly not. Wandering on a coach is commonly a combination of tyre pressure, alignment, worn steering components, air bag or shock condition, and sometimes a frame that has moved. It is worth diagnosing as a system rather than replacing shocks and hoping. If the vehicle has been in a collision at any point, the frame is worth measuring before spending money on suspension parts.

RV and Trailer Brake, Axle and Suspension Repair

Running gear on trailers and coaches is the most neglected system in the category, and it is the one where neglect produces the most dangerous failures.

The reason is visibility. An owner sees the roof, the paint and the interior. Nobody looks at a bearing until it fails, and when a bearing fails on a loaded fifth wheel at 65 miles an hour the outcomes range from expensive to catastrophic.

Wheel bearings, stated plainly

Repack annually or every 12,000 miles, whichever comes first.

A bearing running without adequate grease overheats. As it overheats it degrades whatever grease remains, which accelerates the process. It then seizes, and a seized bearing either shears the spindle or welds the hub to it. Either way the wheel departs or the trailer catches fire, and both happen regularly enough that you can see the evidence on the shoulder of any interstate.

It is cheap work. It is the single highest-return maintenance item on any towable and it is skipped more than any other.

While the hub is off we inspect the seal, the spindle, the brake shoes and magnets, and the drum, because all of them are visible at that point and none of them is visible otherwise.

Brakes

Electric drum brakes on most trailers and fifth wheels. Magnets, shoes, drums, adjusters and wiring. Failures are magnet wear, shoe contamination from a leaking bearing seal, out-of-adjustment shoes, and corroded wiring or grounds. Electric brakes depend on both sides applying equally, so any imbalance presents as pulling.

Electric over hydraulic on heavier trailers and toy haulers. Adds an actuator, a pump and hydraulic lines to the failure list.

Surge brakes on some trailers, actuated by the coupler under deceleration. Mechanically simple and they seize when neglected.

Air brakes on commercial vehicles and larger coach chassis. A different discipline with its own inspection requirements.

Contaminated shoes are worth calling out: a leaking bearing seal puts grease onto the friction surface, and once that has happened the shoes are finished. Cleaning them is not a repair.

Axles

Axle work covers bent tubes, damaged spindles, worn or failed brake mounting flanges, and complete replacement.

We are conservative about straightening. Axle tubes are heat treated, and straightening can undo that. On a modest bend in a heavy axle, done properly and measured, it is defensible. On anything significant, and on any bent spindle, replacement is the right answer. An axle failure on a loaded trailer at speed is not a risk worth taking to save a few hundred dollars.

Overloading is the usual cause. So is running on a flat, which loads the remaining axle far beyond rating on a tandem.

Suspension

Leaf spring on most trailers. Springs sag and break, shackles and bushings wear, and equaliser components on tandem axles wear enough to let the axles fight each other.

Torsion on many lightweight and European-influenced trailers. Rubber cords degrade with age and UV, and the failure mode is a progressive drop in ride height that owners rarely notice until the fenders are sitting on the tyres.

Air suspension on coaches and commercial chassis. Bags, valves, height control, compressors and lines. A coach that sags overnight has a leak, and finding it is a straightforward but methodical job.

Shocks on everything, and they are commonly dead on coaches with high mileage, which contributes to the wandering and pitching owners describe as steering problems.

What it costs

Job	Typical range	Hours
Bearing repack, per axle	$300 to $700	2 to 4
Electric brake service, per axle	$400 to $1,200	2 to 6
Brake controller and wiring diagnosis	$400 to $900	2 to 4
Axle replacement, per axle	$1,200 to $3,500	5 to 14
Leaf spring and suspension rebuild	$600 to $2,500	3 to 12
Torsion axle replacement	$1,400 to $4,000	6 to 16
Air suspension repair	$800 to $5,500	4 to 22
Full running gear overhaul, tandem	$3,500 to $8,500	16 to 35

Mechanical labor is $260 per hour. See the pricing page.

When the problem is the frame

A coach or trailer that wanders, wears tyres unevenly or tracks crooked is frequently blamed on suspension and is sometimes reporting a chassis that has moved.

If the vehicle has been in a collision at any point, or has been used for heavy towing, or has had a previous repair that never quite resolved the symptom, it is worth measuring the frame before spending money on suspension components. That is covered under frame straightening, and doing it first can save replacing parts that were never the problem.

Estimates are $150 and credited back against an authorized repair.

Bring us the job the other shop turned down

We work on all years, all makes and all classes, from Class A diesel pushers down to enclosed cargo trailers. Estimates are $150 and are credited back against an authorized repair, so the money goes toward the work rather than to a shop that never touches your vehicle.

23281 La Palma Ave, Yorba Linda, CA 92887 | (949) 799-3387

Brake, Axle and Suspension Repair