Harbor Freight Trailer Weld Fail

[doggiema]

I bought a harbor freight trailer (1720 lb) 4 years ago and a few months ago the welds that attach the U shaped bracket with the pins in them under the body .....FAILED on the freeway. I paid to have it repaired. Now the weld on the hitch receiver is beginning to separate. I regret buying this trailer. I don't know if it's fair to hope the rest of the welds don't fail. I want to post pics but I need to figure out how to make my files smaller.

[Dan242]

While prepping mine, I thought those welds were suspect, way too small of a weld. I did additional welding on them.

[KCStudly]

That actually looks like metal fatigue to me. Most of the welds are still intact but the lower portions of the main channels have torn and separated.

Classic case of metal fatigue from what I can see. In fact it looks like what weld was there was too short to take loads, so it put all of the stress on a shorter portion of the base metal. I bet that the designers specified a full length weld there all along both sides of the bracket, but production cheaped out and ran the bead shorter because it was faster and easier.

Have you weighed your trailer fully loaded?

How many miles would you estimate that you have put on?

[Camp4Life]

Ouch! Glad nobody got hurt though right? For those bolt-together trailers, would it be best to drill and bolt the welded parts, and weld the bolted parts?

[Camp4Life]

Ouch! Glad nobody got hurt though right? For those bolt-together trailers, would it be best to drill and bolt the welded parts, and weld the bolted parts?

[dogscats]

Drill a small hole at the end of the crack. reweld then box the frame. It's folded cheep steel
look for any place that has cracked paint box that area

[KCStudly]

The cross sectional tensile strength area of a 3/8-16UNC bolt thru the threads (the mode of failure that would occur in this scenario if the bracket were to be bolted on, as suggested) is a mere 0.0775 in^2. So even if you used two Gr 5 bolts (92kips yield, 120kips tensile failure) that's 18600 lbs each side.

Okay, that sounds like a lot for a 1500-1700 lb trailer (you could in theory lift 10 of them off the ground), what we often tend to forget is that dynamic loading (that jolting change in direction that occurs with a jarring pothole or speed bump taken a little too fast) can multiply the affect several times over, typically 4 or 5 times. So that's not a bad Safety Factor (SF), but not crazy over built either.

Let's look at the weld instead. Let's assume that the weld fillet is 3/16 inch "thick" and 1-1/2 inches long on each side. That's a cross sectional area of 0.5625 for both welds. Even for mild steel, with a yield of 36kips and ultimate tensile strength of 78.3kips, that's 44000+ lbs per side.

Welding is stronger, quicker and easier. For my money and time I would not bother bolting it. Something else happened here. Fatigue is fatigue and putting more holes in it isn't going to solve that.

Didn't Big Mike just have a similar failure not too long ago?

[Dale M.]

Ouch! Glad nobody got hurt though right? For those bolt-together trailers, would it be best to drill and bolt the welded parts, and weld the bolted parts?

Best solution would be to stay away from the Chinese cheap trailers and go with full welded , real steel trailers ... Sure they cost more, but you are now seeing the results of the trend that started quite a few years ago... Expect to see more in future...

If you really look at the trailers that were built 50-75 years ago with lots of metal and rugged construction are still going, now we are beginning to see failure on the new modern light weight cheap trailers... Its only the beginning...

Scan through the site the failures are few now, but look at any writings where people are having a problem, its only the beginning...

Dale

[Dale M.]

I want to post pics but I need to figure out how to make my files smaller.

If you are on a PC (not Apple) get FREE software called IRFANVIEW, it has feature that with a couple on mouse clicks you can reduce the size of the file both in pixels ( X by Y) and size in k-byte... Just do not reduce size of or modify the "origional" picture always save image you have worked on as a new image...Once you change the master picture you have changed it forever and you may not be able to recover it from changes if you get it wrong... I always work on "copy" of origional picture...

http://www.irfanview.com/

Dale

[Dale M.]

It would seem the tongue (attachment) design is weak...May I suggest you modify it by adding a length of square steel tubing from hitch back to at least 3 cross member of trailer (to at least over axle) and that would really reduce its wanting to pivot at where it attached on outside rails and put strain on forward most brackets that attach tongue to chassis (front cross member)...

Dale

[OP827]

That actually looks like metal fatigue to me. Most of the welds are still intact but the lower portions of the main channels have torn and separated.

Classic case of metal fatigue from what I can see. In fact it looks like what weld was there was too short to take loads, so it put all of the stress on a shorter portion of the base metal. I bet that the designers specified a full length weld there all along both sides of the bracket, but production cheaped out and ran the bead shorter because it was faster and easier.

Have you weighed your trailer fully loaded?

How many miles would you estimate that you have put on?

Without going into calculating frame stress vs. bearing capacity, I agree that it looks like a fatique crack caused by direction changing (up and down) stress in that area. Trailer or its back could be overloaded, creating such changing stress.The fact that the trailer in the picture tipped on its back says that the trailer may not be ballanced, its back is heavier than its front, i.e. the trailer tongue is not loaded with 10-15% of the total trailer weight. As for the failed weld and metal section, that weld should not even be located accross the C-channel section, because it had weakened the load bearing C-channel section and created stress concentration area. That weld could also be made with some undercut (quite common on hi-amp welds), thus aggravating the situation. Instead it should be welded 90 degrees to where it is , i.e. along the shelf section, which would work better and possibly avoid this situation. I see that area only shows rust, which means no weld there. Whoever welded or designed the trailer welding did not think of it. I wonder if all HF trailers are made like that with this particular weld being across the C-channel or it is the only one isolated case, maybe we should ask people to check that weld on their trailers to reduce the chances of this occuring with other members of this great forum.

[doggiema]

I appreciate all the responses. I don't know how to weld and don't know anything about welding so I don't understand some of the points made. I have heard that a good weld holds together better than unwelded metal.
As to loading it....I keep the kitchen very, very light. The ice chest as well as dry food (cans, oils, beverages,etc) are always stored in the truck cab. The stove and lightweight food like chips and bread, cast iron pan, etc are stored in the front of the trailer. I don't know if that makes for the balanced tongue with 15% of the weight, but it has been my goal. The trailer pulled down easily after the frame broke and stayed down. We were going 55 on the freeway and the force of that is likely the reason the trailer was tilted back. I am so glad no one was hurt. Wakes me up in the middle of the night in a cold sweat thinking about how it might have been otherwise.
I have not weighed it but I made lightweight my top priority. The counter top is a hollow closet door, the pans aluminum, plastic cups, all the lightest and least amount of items I can bring while still having my idea of "Glam camping". If I had to guess....less than 1,500 lbs, greatly overestimated if anything.
We have gone camping once or twice a month during the summer months and put an average of 300 miles on it each trip. Two full summers. The first year it took it's first trip at the end of the summer; more or less 3,000 miles. We don't drive more than 3 hours one way on three day weekends and a two week vacation once a year where we venture further.....Burney falls, above Lassen was the farthest we ever went. And the frame broke on the first outing this year. It was on the freeway going north/west just before the Richmond Bridge toll booths out of Berkeley. I will send more pics now that I have figured out how (I hope I can remember what I did): the re-weld by a friend; I made sure he was strongly aware that I didn't want to kill anyone: that it must not come apart again. And also the failing weld on the the tongue. It looks to me that it is cracking apart right down the weld, but I would appreciate an opinion from someone who knows better.
Metal fatigue? What might I have done to cause this, if that is possible. The roads aren't the best here in the bay area for sure, especially coming home from the sierra foothills where we usually camp when heading in and out thru the Livermore area. Where all the windmills are, over those hills. Horrible pits in the freeway. Otherwise we are very careful not to take it on unpaved / rough roads.
I talked to a manger at harbor freight that said she would exchange it for me. That is absolutely not going to happen. I put way too much work into putting it together and don't want to have to spend all that time removing it and assembling and installing it. Did I say that already in my first email? I want to get the tongue re-welded AND I want to feel that I can trust that to be the end of it falling apart. I agree that this is just the beginning of this type of problems surfacing with these Harbor freight trailers. I would clearly not recommend purchasing these trailers from China.

[Padilen]

Sorry your going through this. Not that this will help you. But this isn't just a Harbor Freight problem. Tilt deck snowmobile trailers fail. Had it happen, and seen it happen to others.


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[Woodbutcher]

Take the replacement frame. You now know what to look for. Then get it welded and upgrade the tongue by extending it back to the first cross brace. You will not have another problem.

[Nobody]

I have a similar problem with my HF 1800# trailer that I built my TD on in 2006. Couple of months ago (during Mike's post on the Mad Dash collapsing at exit ramp) I was inspecting my trailer chassis & noticed what apeared to be a small break at 'top' of the weld on driver side where the 'U' channel for the tilt lock was welded to the 'C' channel of the chassis side rail. I'd thought the passenger side was intact but on closer, recent inspection I find the same tiny 'break' at the top of that weld also. Both of these breaks are at the jct of the weld with the underside of the 'C' channel side rail, & are only on the outside weld. Both welds on the inner side of the tilt lock appear to be secure & intact. I still think the 'breaks' may have occurred several years ago when I was 'rear ended', but have no idea why only the outside welds were affected. Both 'breaks' appear to be old, i.e. there is dark rust at the break & tho I haven't been able to force them open there appears to be rust inside the breaks also. I added a piece of 2x2x1/8" tubing to modify/extend the tongue while I was building the TD, & it has proved very solid & durable, so it may have reinforced the inside welds enough to have prevented a break (if it was actually caused by the collision), & also to have prevented inside breaks if due to normal wear & tear??

I agree that doggiema's incident appears to be more metal fatigue or failure of the base metal (similar to what Mike's welder found when he repaired Mike's trailer), rather than actual weld failure, tho doggiema's pic does appear to show a failure of the tiny weld 'bead' that secured the outer part of the 'U' to the base metal (my trailer is constructed differently in that the 'U' is welded to the underside of the chassis rail directly while his appears to have some kind of 'strap' atop the 'U' between it & the chassis rail?? If these 'breaks' are as old as I think, we've towed the TD more'n 10K miles since, over some pretty rough roads/trails without incidence. In any case I'm gonna grind down the 'broken' weld beads & re-weld both places before the TD goes on the road again. I'll keep plenty of water & a hose handy in case I 'get happy' with the arc tho I don't really expect any difficulty. I'm not really good at 'overhead' welding so I may take it to a professional for this job. 'Sides, I ain't as young as I was when I built the TD, & that makes a difference too. Not as agile gettin' outta the way of those sparks... I'll hafta de-mount the front BAL stabilizers in order to get my 4" grinder to the broken weld.

Upon further inspection it appears there is some orange discoloration around the inner weld on the passenger side even tho it appears intact on the outside, so I may have some separation between the weld & the chassis rail so I'll just re-do or have done, all the welds while I'm at it. I just spent over an hour crawling under the trailer, inspecting every joint. All the other welds are secure, & every 'nylok' nut is still tight. Every place that I put a lock washer while assembling the trailer is still secure, & in the same position I left it. We've towed the TD near 30K miles since building it in 2006, & our grandaughter & her husband have towed it more'n 1.5K, all with no chassis problems whatever. I think the tongue modification is due a great deal of credit for its durability considering doggiema's misfortune but I'll not tempt fate 'on the road' again 'til it's re-welded to my satisfaction.

pass side tilt lock weld, outer


Pass side tilt lock weld, inner with 'orange' discoloration indicating rust inside the weld


my tongue mod