Suspension bolts

[Scott'n'Wendy]

I'm wondering about the strength of wet bolts. On this and other forums I have read numerous posts about wet bolts shearing. I don't ever remember reading about leaf spring bolts shearing on cars/trucks of the 70's, 80's, 90's. Or even on today's trucks.
So my question is - Should we be using wet bolts? The drilling of the holes in the bolt seems to make them weaker. I don't like weaker on my suspension. Or do we need to schedule their replacement like the bushings?

[TucsonJim]

I change all suspension components every 30,000 miles. It's served me well.

I don't recall seeing many wet bolt failures on any of the forums or pages.

Jim

[TedS]

The failures I've seen on this forum have been through the cross-drilled hole in the bolt.

[Scott'n'Wendy]

Ajg617 and Dallas are a couple recent ones on this forum and there are more on the other forum, and other rv forums have their share as well.

[Cate&Rob]

Buried in this long thread (about post 60) is some discussion about broken wet bolts. https://gdrvowners.com/forum/operati...00-miles/page5 Agreed that we don’t see many examples because the bolt is usually “gone” by the time the failure is discovered.

Rob

[Scott'n'Wendy]

Thanks Rob
That thread is what started me on the "should I use wet bolts anymore" thinking.

Your comment, post 80,

01-13-2023, 08:33 PM
As ridiculous as “tear down and inspect every year” sounds . . . I have disassembled my suspension at least 5 times in the 8 years we have owned this rig. For a lot of different reasons of my own doing. Changing springs, changing equalizers, changing bushings . . . and so on. At every teardown the bushings were trashed. Different spring manufacturers, OE plastic bushings, Never Fail plastic bushings, bronze bushings. Didn’t matter. Sometimes only 5000 miles between tear downs. The problem is the incredibly sloppy fit of trailer suspension components. I can see how an LCI engineer would advise that their suspension system has to be rebuilt every year.

Rob

Well, that means none of the mentioned bushings made it through a second season without destruction. Potentially less than one season but I'm just averaging your teardowns. So how much does the ability to grease affect longevity? In my mind, very minimally. Solid grade 5 bolts have an excellent record without greasing.
As of this writing, I think I will buy new bronze bushings but use grade 5 shoulder bolts without weakening holes.
Install and forget about greasing every 5000km. Swap out bushings every other season.
Cate&Rob TedS Jlawles2 thoughts?

See if I can get three engineers to agree.....or maybe two out of three? lol

[Wileykid]

I was also one that had the shackle bolt failure this year. After fixing everything, I went to a nylon bushing that is common in commercial trailers, and a solid grade 8 shackle bolt. Everything else will probably fail around the bolt now. I only had one trip with the new set up, and it looks fine, the telling will be after next season. If I have more failures, I will look into the IS system.

[Yoda]

Interesting discussion. At the National Rally I talked with MorRyde and Dexter about component quality and wet bolt failure. While MorRyde did not admit outright they had a issue with the wet bolts, he mention supply chain quality issues. In most of the failures it was a Morryde or Lippert bolt. on heavier units if I remember correctly. Both MorRyde and Lippert us the same supplier (made in China) per the MorRyde guy which makes sense given all the trailer manufacturers there..

In talking with Dexter they make thier own here in the US and are stronger than other manufacturers - at least that is what I was told. They also do in house testing. Their bronze bushings are also made of a a slightly harder material from what I was told too. If you compare theirs are a bit darker in color. Now all this could be BS, but I will probably order replacement wear parts from Dexter when I next service the suspension. Dexter also has HD 1/2" thick shackles too, but don't make a kit like MorRyde does.

Now as a side note I know when you pull the nuts off the wet bolts you should not reuse them. Some folks say replace the wet bolts too as re-torquing them with a new nut will induce additional stresses when they stretch for the second time. Don't know if that is true either.

Keith

[Cate&Rob]

Scott'n'Wendy

I an currently running custom made steel bushings. Info buried in posts 45 and 52 of this thread .https://gdrvowners.com/forum/operati...f-spring/page3. I have two “seasons” and about 5000 miles on these and they seem to be working well. They are taking grease evenly with no signs of the bushing (or bolt) being sacrificial, (by way of any bits of metal being in the expelled grease). Of course, I can’t do a physical inspection until we get home from Florida in the Spring, when I will (yet again) disassemble things.

I agree with your point that if the bushing material is sacrificial (ie “self lubricating” plastic or bronze) . . . adding grease is not going to provide much benefit. Solid bolts do make sense in this situation.

Rob

[Cate&Rob]

Yoda

WRT replacing the wet bolt at every disassembly . . . I don’t think that 40 ft lb is going to stretch a 1/2” diameter bolt.

Rob

[TedS]

I believe the shackle bolts are 9/16-18 grade 5. 40 ft-lbs will not permanently stretch those.

I've got to say I'm not a fan of wet bolts. The idea may be good, but the execution is not. The movement of the bushing is low limiting the pumping of grease sufficient to carry the load. The wet bolts seem prone to failure. They require greasing periodically because the grease leaves the area. Give me a solid bolt and self-lubricating bushing(DU bushing or UHWW bushing) for the typical oscillating loads.

[Country Campers]

Scott'n'Wendy

Do you have an estimate of how many failures that you have seen posted?

Brian

[Scott'n'Wendy]

Country Campers Not really. I've been pondering why we use wet bolts for a while seeing as the bronze bushings barely outlast nylon and reported bolt breaks. Over the last year or so I've just been noting them in my head thinking 'hmmm..there's another reported bolt failure". Recently Dallas reported the same thing. Just made me think that I've noticed a lot over the last year. Some are reported as a broken hanger. But when you see a pic of the spring eye with no hanger on it you know the bolt sheared off. So...maybe 15-20? By no means a scientific survey...lol

[Country Campers]

Just wondering on the number if you have "seen" more than I have. I think it is either a case of "bad" bolts or some circumstance causing the failure. I agree that the grease hole would be a place of failure but would also think that the amount of wet bolts out there in the world if an issue was there it could mean 1,000s of complaints. My previous TT never was greased for the 7 years we owned it, not even sure if it had wet bolts or not. I never did a bearing repack either. We mostly weekend camped and with in a couple hours of home. I will continue to grease and hope for the best.

Brian

[Yoda]

Just wondering on the number if you have "seen" more than I have. I think it is either a case of "bad" bolts or some circumstance causing the failure. I agree that the grease hole would be a place of failure but would also think that the amount of wet bolts out there in the world if an issue was there it could mean 1,000s of complaints. My previous TT never was greased for the 7 years we owned it, not even sure if it had wet bolts or not. I never did a bearing repack either. We mostly weekend camped and with in a couple hours of home. I will continue to grease and hope for the best.

Brian

Brian take a look at this search https://www.google.com/search?client...in+RV%27s#ip=1. It appears the are more than reported here, PS note the dates and sources of the bolts.....seems to be a China syndrome if I am thinking correct tonight..... been a long day.. Finished winterizing the trailer and my hay field irrigation system.