Avoiding disaster: Trailer coupler inspection & rebuild takes little time and money

Updated Aug 24, 2018

It’s easy to neglect a trailer coupler even though it’s that one small link that can lead to a big disaster should components suddenly fail.

A quick Google search on the subject revealed ‘Truck Trailer Hitch Failure Attorneys’ on the first page. Not a good sign.

And then there were the pictures: trucks and trailers mangled from coupler failure. Guess that explains the attorneys.

I noticed the coupler on my own trailer was getting rusty, but ignored it because I hardly ever used it. Plus, on those rare times when I did use it, the coupler latch still locked down on a two-inch ball and stayed put—or at least I thought. Turns out that was just tongue weight and merciful gravity.

Get down low–or use a mirror–and take a look underneath the coupler once in a while. Rust had devoured parts in mine which made it unsafe for towing.Get down low–or use a mirror–and take a look underneath the coupler once in a while. Rust had devoured parts in mine which made it unsafe for towing.

A recent inspection revealed that the catch underneath the coupler was not actually locking onto the ball. It was a rusty wasteland that should have been replaced a long time ago.

Thankfully it’s been a while since I’ve towed that old B&S boat trailer. It holds an equally old 19-foot Chaparral 198 F that my kids and I are restoring. Hopefully before too long it’ll be headed back to the boat launch.

To help step-up the boat project, I towed it closer to the house in the back yard. This was before I discovered the coupler problem. Thankfully, I had no problems moving it, but then again I had only towed it about 100 yards from another spot in the yard.

I came across the problem after getting out my clipboard to make our to-do list. Given all the rust on the coupler latch I decided to get down for a closer look. So glad I did. Underneath the coupler, a flashlight showed that the latch springs had rusted away and that the ball catch had been transformed into an ineffectual rusty lip.

It was time for a change. I grabbed my propane torch and got that rusty latch nut nice and hot before attempting to break it free. It came off fairly easy and brought down remnants of rusty springs and God knows what else.

Next, I wrote down the model number of the Fulton Class 2 coupler and hit the web. Complete, bolt-on couplers popped up below $20 but there was no way I was cutting through any of that perfectly good galvanized frame just to bolt on a bright and shiny replacement. Not going to happen. By modifying the search to include ‘repair kit’ Google came back with what I was looking for.

A few clicks later and I narrowed down my search on Amazon to Curt’s Class 2 ‘Straight tongue posi-lock coupler repair kit’ (#25194). With four-and-a-half stars out of 36 reviews it looked pretty promising. I compared it with my old latch and they looked the same. (I hate it when vendors don’t offer measurements of replacement parts, but items like this are fairly common, so for $6.26 and two-day Prime shipping, I made the buy and I’m glad I did).

Installation was fairly easy. I lubed up the ball catch shaft with some marine grade grease prior to installation. Keeping the two latch springs compressed while threading on the latch nut was a little challenging, but that was the worst of it.

Next up was ball catch adjustment. I grabbed an extra 2-inch ball, inserted it into the coupler and pushed down the latch lever. The ball was way too loose. To eliminate play I simply tightened the nut until the ball was nice and snug.

That’s it! Work done. Grab the clipboard and check it off the list!

Next up are wheel bearing rebuilds and a little rust removal and prevention on the leaf springs. Though I rinsed this trailer off every time it was doused in salt water, corrosion still snuck in, which reminds me of that F-150 rebuild we’re doing. Salty roads from up north took a toll on transmission and brake lines. No big deal. I’ve already replaced those too. That’s another clipboard and another list 😉

Curt repair kit did the trick! Old latch on the right was way past its prime.Curt repair kit did the trick! Old latch on the right was way past its prime.