Holiday Rambler (Roadmaster / Monaco / Beaver) Trailing Arm Failure

A trailing arm is a major chassis component which in the rear-end of a motorhome transmits the thrust from the axle to the frame of the motorhome.


Certain Roadmaster chassis have trailing arms which may have a defect that renders them susceptible to cracking or catastrophic failure.

Broken Trailing Arm

This trailing arm is from a 2004 Holiday Rambler Neptune motorhome.  The arm broke on the driveway apron of a gas station, but was not immediately percieved by the driver.    The driver proceeded along a 35 mph city street in light traffic and began to notice that the rig was "extra bouncy" going over bumps.   When the driver had to brake moderately for a stoplight, he noticed severe skew in the vehicle aspect to the road - it seemed like the rig pointed to the right about 10 degrees, even as it was moving fairly straight.    The driver stopped on the side of the road to look under the vehicle, focusing on the front shocks.  Noticing nothing, he proceeded slowly to a parking lot where he could get under the rig and inspect more carefully, with a flashlight.   He saw the broken trailing arm and knowing that he was only a few miles from our shop, decided to drive slowly to bring the rig in. ( Road service towing would have been a more prudent choice! )


We inspected the rig and concurred that the trailing arm was broken, and contacted his extended warranty provider on his behalf.  They sent a claims adjuster who took pictures of the broken arm and the claim was subsequently approved,  with Monaco replacement trailing arms listing in the $800 range.   When we attempted to order the arms from Monaco, we were informed that they were no longer available, but that a specialty vendor had upgraded replacement arms for this chassis, however the upgraded arms list for over double the cost of the no longer available Monaco arms.   We contacted the extended warranty provider, they required us to obtain written confirmation from Monaco that the factory parts were no longer available.   Upon recept of the faxed document (after an extra week of waiting and phone calls!) the extended warranty provider approved the additional charges for the upgraded arms.

Cutting the old U-Bolts

To replace the trailing arms,  the rig is jacked up, and the rear axle supported on jackstands.  The Trailing arm is attached to the frame in front of the axle, and to the axle by 2 large U-Bolts.  The left and right trailing arms are connected to each other behind the axle with a cross member.


To remove a trailing arm,  the cross member is removed, the airbag and shock asorber unbolted from the trailing arm and the U-Bolts removed (or cut - they are replaced with new ones in the trailing arm kit).   The arm will then swing down, supported by one large bolt at the front.

Dangling trailing arm

The front bolt is carefully removed, and the trailing arm (or piece of one) is lowered away from the rig.  This is usually easier with two people.


The new trailing arm is moved into place.  While one person can lift the arm to carry it,  two people and an adjustable workstand make positioning the arm into the rig easier and safer.   It is unlikely for a single person to be able to do this safely.


Once the trailing arm is lifted into place and attached with the front pivot-bolt, the U-Bolts, spacers, shims, support-plate and nuts are used to attach it to the axle.  Everything is checked for proper fit and placement, and then the torque wrench comes out.  The really big torque wrench.

The really BIG torque wrench
Sometimes it takes two to torque.

After the big hardware is torqued up properly,  the airbags, shocks and cross-member are reattached and torqued.    A thorough visual inspection of the completed job, and the general area ensure a satisfied client.

Installed Trailing Arm