Trailer Undercarriage Repair Made Easy

When we bought Summer Dance, easily the most dangerous damage to the overall package was the trailer spring hangers. The trailer was a 1981 Trail Rite that had been used to put the boat in the salt water of Puget Sound for 30 years of its life. However, in spite of a paint job that the previous owner had brushed on to sell the boat, the frame hadn’t receive proper maintenance. Consequently, the passenger side spring hangers were about 50% corroded away, 100% in small spots. The driver side hangers weren’t quite as bad.

The picture below shows one of the hangers with a small hole through it. The wood/bungee cord/electrical tape arrangement is part of a 2×6 that I hastily wedged between the spring and the frame to reinforce the hanger (a different story). At least that’s what I was thinking. In reality, it was probably psychological reinforcement more than anything. Call me crazy, but I towed the boat 250 miles home like that (including Snoqualmie Pass) after purchasing it. In case you’re wondering, the bearings and springs were new, the tires good. If not, I wouldn’t have made the trip.

BEFORE – rusted through!

Before towing it another mile, those hangers had to be replaced. Fortunately, the spring hangers on each side are welded to a single piece of 2×2 steel angle to form an adjustable slider assembly that is U-bolted to the frame. The bolts can be loosened and the sliders moved forward or backward to fine tune the tongue weight and trailer handling. This meant that I could fabricate new sliders without taking the trailer back on the road to a welding shop and without cutting.


I found some replacement hangers made by Redline on eBay and Redline U bolts at North 40 Outfitters, which has a surprisingly good selection of trailer repair parts in stock. Hangers that long are hard to find, most are shorter. But the length is necessary for the keel to clear the axle at compression.

New spring hanger for comparison
New spring hanger for comparison

I purchased the steel angle along with some other stock for the tongue rebuild and mast crutch projects. A local drag racer welded the hangers to the angles for me. I primed and painted the new sliders in my jumbo paint room (barn).

Primer drying on the new weldments
Primer drying on the new weldments


Next came the hard part, getting the old sliders and U bolts off. The U bolts took a lot of persuasion; too much for several of them and the nuts sheared off. The spring hanger bolts came off easily since they were relatively new with the springs. The sliders then lifted off to reveal all the rust that occurred between the rails and the sliders. I used a claw hammer to knock off the layers of rust (1/4″ thick in places) to get down to solid metal.

BEFORE - knocking chunks of rust off underneath the old sliders
BEFORE – knocking chunks of rust off underneath the old sliders

There wasn’t a lot of the original metal left under the sliders, I’d say 1/8″ thick on average. I used an angle grinder to remove the remaining loose rust and to smooth up rails. I was feeling okay about the damage until I came to a soft spot about an inch in diameter. A little light poking punched a hole through the C channel. Further probing revealed two other weak spots on the edge of the bottom channel flange.

BEFORE - discovered this through hole while grinding the rails smoother
BEFORE – discovered this through hole while grinding the rails smoother

These areas will be U bolted under the new slider but might mean the end of the road for this trailer. I chose to press on and finish the project.

BEFORE & AFTER - old vs. new sliders and fasteners
BEFORE & AFTER – old vs. new sliders and fasteners


After priming and a couple coats of fresh paint, the new sliders bolted up easily after I took care to be sure the axle was aligned perpendicular to the frame center line.

Besides the bunk board replacement project, the other fabrication project for the trailer is the tongue rebuild that was planned for another post. However, that might get scuttled if I’m not going to proceed with this trailer.

The Bottom Line

Suggested price: $?
$tingy Sailor cost: $202.45
Savings: $?

Have you started an ambitious repair project on your boat only to give up on it?

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.