Trailer bolt snapped, why?

[Bret1972]

For the past two months I’ve just left my boat and trailer connected to my truck because I’ve been going out salmon fishing so much. I just pull it straight into my driveway and when I want to go out fishing I back it out and go. However, last night when returning home my truck broke down and I had to have my wife come in our other vehicle so that I could get my boat home and have my truck towed to a shop. When I began to jack up the trailer and remove it from my trucks trailer hitch a bolt gently just fell off onto the ground. I’ve never used the swinging function of the trailer hitch to save space because I’ve never had a need for it. So it’s never been used by me. Does the weight of the boat on the trailer put a lot of tension on this bolt? When I pull my truck into the driveway with the trailer attached should I be swinging down the trailer Jack to take some of the pressure off of the trailers tongue?
I’m going to go to the hardware store today to get a new bolt and nut, but it doesn’t appear like the one that was on there is a self locking nut or has any washers. I’m a little bit concerned that over time it may vibrate loose even though the original one never had that. What are peoples suggestions? And lastly, aside from checking every single bolt on my trailer on a periodic basis what can I do to maybe prevent this from happening again in the future?

 

[Dave LeGear]

Hard for me to see the top of the bolt, but it does not look like a grade 8 bolt. I would recommend (at least) a grade 8 bolt so it can handle the stress. This link should help you see grade markings...

https://www.boltdepot.com/fastener-information/materials-and-grades/bolt-grade-chart.aspx

Also checking all the bolts from time to time is good. Just make sure you do not over-torque them when you go to snug them up and spraying them down with both Salt Away after each dunking (the entire trailer) and spraying on some WD40 (Water Displacement Formula 40 for those who do not know what the label really means) on them is also a good thing. WD40 though is not intended to be lubricant...

Hope this helps?

 

[Bret1972]

Looks like the previous bolt was grade A325. A325 is step below the grade 8, which seems to be the top of the line. I was going to get stainless, but after looking at that website it seems like stainless is not as strong... I guess this is the kind of stuff most people don’t think about too much but it matters. Thanks for the link!

 

[Bret1972]

Went to ShoreLand’r website and found the bolts. The A325 have a larger hex head then Grade 5 or 8 do. Unfortunately you can’t order them from their website and There is no dealer for ShoreLand’r in California. I contacted their support and they linked me to an online trailer parts store, where I was still unable to locate the proper bolt. What a PITA and shame on ShoreLand’r for pushing it off with a link to an online trailer store... I could google that myself. I wanted to stick with the factory original stuff, but at this rate, I don’t think it’s gonna be possible.

Part Number Description
0140096 HH 1/2-13 X 1 3/4 CS GR5
1340100 WASHER USS FLAT 1/2
1440102 HEX LOCKNUT FLANGE 1/2-13 W/T

 

[Dave LeGear]

Most local NAPA stores should carry that bolt in a Grade 8, or can order it for you in short order

This or order them direct from Bolt Depot https://www.boltdepot.com/Default.aspx

Best,
Dave