Dexter EZ Flex Failure

[Geronimo John]

In 2018 I picked up a new travel trailer with twin 3,500 pound rated Dexter axles with EZ-Flex and shocks all around. On our first summer's travel the center bolt that fixes the EZ-Flex to the frame lost its nut and walked 95% out of the assembly. The only thing that kept the EZ-Flex bolt in was two threads.

Had the center bolt fully dislodged fully, the consequences could have been lethal.

On our trailer MFG forum I have found two others who have had the same problem as well.

Have any of our members from our Fiberglass RV Community also had the same problem?

Thank you!

[Raspy]

John,

The nut on that Easy Flex bolt/upper pin, should be Locktited in. Same with the spring eye pins and shackle pins.

Glad you caught it before is came out completely.

[Geronimo John]

@Rapsy:

Thanks for the tip.

When I picked up the trailer at the factory, I took note of the suspension bolts had yellow paint strips as observed from under the trailer on initial inspection.

I picked up the trailer, and immediately began a coast to coast summer voyage. The first time that I touched the Center Bolt of the EZ-Flex was after it nearly fell out at the very end of our trip. So if I had not done it, that pretty much means that the spline were damaged at the factory. I suspect caused by not properly backing up the bolt head when torqueing.

At no cost the factory Service Team air mailed me a replacement bolt and nut. I installed it, but the splines were destroyed. None the less, I for sure used Locktite on the threads and torqued it to specifications.

The next summer, after about 8,000 miles, and LOTS of in-trip inspections, I found the nut was again gone. Fortunately my inspections at every stop caught it before the bolt had walked out of the EZ-Flex.

Since neither Dexter or the trailer manufacture are willing to admit screwing this up, I am thinking my only option is to just replace the 9/16 splined head bolt with a longer one that has enough smooth shank to span from outside to outside of the mounting tabs, and allow with washers to double nuts (Or use a castellated head and cotter pin). The bolt must draw the mounting tabs together to put pressure on the EZ-Flex center bolt bushing. As per suggestions from the owner's forum, I'll use Never-Seize on the bolt to ensue that the bolt does not impact the bushing.

But just for peace of mind, I am asking that if other EZ-Flex users have have had similar issues to kindly let me know.

Regardless, I thank you for the input. PS: Sure like your HQ=19! .

John




GJ

[Raspy]

John,

Wow.

A new longer bolt is a good idea. Those bolts are hardened and a replacement one must be too. But a hardened bolt will be hard to cross-drill for a cotter pin.

It seems something must be happening since even the locktited nuts want to come off.

How about welding the end of the bolt, after the nut is on? You could always get it off by grinding the weld off if needed later. A MIG weld would be quick with minimal heat and very secure.

I worried about mine coming off, but they never did. The design seems minimal to me, with no good way to secure the nuts.

[ehoepner]

The question that needs to be asked:

Why is this bolt coming loose even after having used locktite on it.? I have never had a bolt come loose after using locktite on it.

There has to be a lot of vibration coming from somewhere on the trailer.

Start by getting the tires balanced.

[Geronimo John]

The trailer rides nicely on Michelin LT tires. The tires show zero vibration from my end, and according to my chase vehicle they have no out of balance issues that he can see.

I do take it up graded fire roads a lot, but that's why they put four shocks on the two axles.

It has me puzzled for sure.

[Raspy]

John,

Do the bolt holes in the frame seem to be severely worn? Maybe you should take the equalizer assembly out and look at the bushings. Those bushings are pretty fragile and the grease holes can get clogged with metal that gets rubbed off the bushing surface. It might be that the equalizer has been turning the bolt.

Is there any evidence of Locktite on the threads? Maybe the locktite was applied over oil and didn't get a grip on the metal.

[Geronimo John]

Without the splines in the hanger bracket, the hole is slightly larger than new. But beyond that I did not see any abnormal wear in the hanger bracket.

The first failure was on either Dexter or the MFG. My foot prints are not in that field.

After the first failure, the trailer mfg Service Team sent a new nut and bolt. They were very clean. However, the Locktite was applied after insertion so it is possible it picked up an oil residue .... as I only wiped the threads just before applying the Locktite. Sure could be my oops in that case. I'll use brake cleaner next time before applying the Loctite.

It's highly probable that the bolt is being turned by the EZ Flex bushing. I'll get a bushing set (or 2) for my spare parts box.

In May, I'll pull it apart and give it a good cleaning and inspection. I suspect that it is quite likely that the bushing inherited the splines. Should that be the case, I'll need to replace the bushing before hitting the road. With two incidents under my belt, replacement of the bushing and the longer bolt concept is making a lot of sense.

Good suggestions and thoughts.

Thank again.

[Geronimo John]

Drats. Replacement center bolt bushing is steel and they do not seem to sell them.....

[Raspy]

Originally Posted by Geronimo John

Drats. Replacement center bolt bushing is steel and they do not seem to sell them.....

Dexter may not sell them, but it should not be hard to find them. The kit includes bronze bushings, as far as I know. Mine did. But steel would be fine too, as long as it gets greased occasionally.

Maybe you should pull out the equalizer and measure the hole diameter and the length of each bushing. There are two in the EZFlex equalizer, and only one in the heavy duty kit. Then measure the bolt OD and you can look for bushings at McMaster-Carr, or other places.

Bronze is softer than steel, but steel might be harder to press in. Also, the grease hole has to be lined up wit the zerk fitting.

I hope you can get to the bottom of this repeated problem.

[redbarron55]

The bolt and nut should be "Killed" which really means wacking it with a cold chisel to deform the threads where it cannot loosen.
Sometimes killing the bolt and nut would include a spot weld.
At the least an elastic stop nut.

[Geronimo John]

Thanks Red Barron. Killing the bolt would work.

I would prefer the longer bolt approach and double nut (Maybe adding a cotter pin as a foot stomper!). This bolt must compress the trailer hangers to fix the EZ-Flex sleeve so that it will not turn. Without the bolt splines, it must be restrained only by the clamping pressure of the center pivot bolt alone. Periodically I will need to remove the bolt. With my preferred approach, I don't need a pile of the shackle bolts used originally.

I have reviewed again a fellow trailer owner's (BCN...) concern with using Never Seize on the EZ-Flex center bolt flanks (Not the threads) as suggested by Dexter for I assume to be not damaged splines. With damaged splines, I am thinking I need to ponder a bit more.

I am also going to look into bolts with heads designed to resist turning. Not sure what they are called, but have seen them long ago. Or, maybe a metal hex fixture to go under the nut with an arm to fix it.

[Alex Adams]

Originally Posted by Geronimo John

I am also going to look into bolts with heads designed to resist turning. Not sure what they are called, but have seen them long ago. Or, maybe a metal hex fixture to go under the nut with an arm to fix it.

Wouldn't a star lock washer work between the bolt head and the hanger?

[Bonnie RB]

Gero-John, Does the through spacer sleeve project beyond the two spring hangers? It's imperative that the trailer hanger compression by the splined bolt is applied to only the sleeve through which that splined bolt is inserted.
Jon MB (the other half to Bonnie RB )

[Geronimo John]

Sure would be better than nothing or a washer!
I'll add that to my longer bolt double nutted approach. On both ends of the bolt!

[Geronimo John]

John MB:

No, the Ez-Flex sleeve resides inside the two hangers and inside the Ez-Flex machined surfaces. The thru bolt compresses the hangers to fix the sleeve stationary and the center bolt was intended to be stationary by the compression forces of the bolt and the splined end of the bolt.

There are two zerks at the top of the Ez-Flex to lubricate the Ez-flex and sleeve "bearing". So, by design, the fixed bolt and outside surface of the inner sleeve create a "wet" lubricated surface around which the Ez-flex rotates left/right as the individual axles take a beating.