When Wet Bolts Spin....What Then?

roegs01

Senior Member
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Minneapolis Area
Last time I checked bushings etc. the hanger holes were barely holding the splined wet bolts. Next time I have things apart for an inspection I'm sure that I'll be at a point where the holes in my hangers will no longer hold the splined wet bolts from turning. Couple of thoughts..

1. I've already reversed the wet bolts so that the head is on the other side of the hanger. Thats a good temporary solution, but to be honest this whole idea of a fine spline to keep bolts (that are part of a regular maintenance plan) seems like a poor idea.

2. Replace hangers....I've thought about that and while its a solution, its temporary and at some point I could be back to writing this post all over again.

3. In one of the other rv forums, I read about a guy that took some 3/16" stock and cut it the same size as his hanger. He then machined a hex hole the same size as the wet bolt head. Once done, he slipped it over the wet bolt heat and attached the plate to the hanger with a small 1/4" bolt. This seems like such a great idea but cutting a hex hole in the 3/16" stock is a little beyond my capabilities. Anyone have any ideas on this for the common man?

4. On yet another forum, a guy welded some 1/4" key stock on the back of the hanger in such a way that it rested against a flat of the wet bolt hex head. Having a flat of the hex head against the key stock kept the bolt from turning. Again, a little beyond my abilities as I don't have a welder, but I guess I could tow my 2930 to a local shop and have them tack a couple pieces of key stock in place. If I did that, would it require removing the wet bolt and lowering the spring to prevent damage Never Fail bushings that I currently have?

5. One last thought....has anyone ever used tab washers (see photo below)? Putting a washer like this under the wet bolt head would allow one tab to be hammered against one of the hex flats the other tab screwed with a small machine screw into the hanger.



Capture 1.JPG
 
The tab won’t work.

If there are forces strong enough to spin that bolt, they will rip that tab apart.


Go to any welding shop and they can cut you any of the locking bars you described.

If you want to do it yourself, drill a hole the same size as the distance between two flats.

Then, use files to file it square - you only need to lock two sides.
 
Hmmm...I'm kind of liking the welded keystock idea BEFORE my hanger holes are opened up.
And in your position, that's what I'd do. Welded on keystock

Would be interesting to see if the hangers suffer any consequences if the keystock is added. Whether it's the condition of the roads or sharp turns, something should give. You would think the tires maybe? Something that also didn't occur to me is the larger, heavier, higher PSI Coopers that I have. Maybe the tires aren't as forgiving or they pass more of the road shock onto the suspension.
 
Last time I checked bushings etc. the hanger holes were barely holding the splined wet bolts. Next time I have things apart for an inspection I'm sure that I'll be at a point where the holes in my hangers will no longer hold the splined wet bolts from turning. Couple of thoughts..

1. I've already reversed the wet bolts so that the head is on the other side of the hanger. Thats a good temporary solution, but to be honest this whole idea of a fine spline to keep bolts (that are part of a regular maintenance plan) seems like a poor idea.

2. Replace hangers....I've thought about that and while its a solution, its temporary and at some point I could be back to writing this post all over again.

3. In one of the other rv forums, I read about a guy that took some 3/16" stock and cut it the same size as his hanger. He then machined a hex hole the same size as the wet bolt head. Once done, he slipped it over the wet bolt heat and attached the plate to the hanger with a small 1/4" bolt. This seems like such a great idea but cutting a hex hole in the 3/16" stock is a little beyond my capabilities. Anyone have any ideas on this for the common man?

4. On yet another forum, a guy welded some 1/4" key stock on the back of the hanger in such a way that it rested against a flat of the wet bolt hex head. Having a flat of the hex head against the key stock kept the bolt from turning. Again, a little beyond my abilities as I don't have a welder, but I guess I could tow my 2930 to a local shop and have them tack a couple pieces of key stock in place. If I did that, would it require removing the wet bolt and lowering the spring to prevent damage Never Fail bushings that I currently have?

5. One last thought....has anyone ever used tab washers (see photo below)? Putting a washer like this under the wet bolt head would allow one tab to be hammered against one of the hex flats the other tab screwed with a small machine screw into the hanger.



View attachment 48872

If you ALWAYS use a backup wrench when installing and removing the bolts, AND carefully match the bolt serations to the ones already present in the hanger, and use a ball joint press when doing so, they will last forever. They do not spin while in service.
You need to prevent spinning them when installing and removing them. That is when the damage is done,
 
My factory installed bolts did. WHY?
The primary reason would be that they were allowed to spin when installed, i.e. they were improperly installed at the factory. Or they were improperly torqued. Or they didn't have the proper locknut installed. Those are the only reasons I can come up with off the top of my head. :)
 
I get that in a perfect world the splines would always keep the bolt from spinning, but life happens which for me includes a slip of the backup wrench or a shop doing some suspension work. :rolleyes:

While I like the keystock idea, I'd be concerned that unless they are installed just right against the flat of the wetbolt head that there still may be some rotation of the wet bolt in the hanger hole, which in time may enlarge the hanger hole. I guess that's one advantage of the fine splines - they keep the bolt from doing any turning. My plan is to do the following for my next bushing inspection:

- Purchase 4 new wet bolts. I only need 2 per side as I have Roadmaster Slipper Springs.

- Purchase 4 13/16" open end flat wrenches (also called cone wrenches).

- Tack weld a flat wrench to each of the wet bolt heads. A tack on two of the flats will prevent any slop between wrench and bolt head.

- Install the new wet bolt and attach the flat wrench handle to the hanger. I may have to trim the handle length of flat wrench, but thats pretty easy. Probably use a self tapping screw similar to what's used to hold the coroplast in place.
 
Quite a bit of work with a question as to whether it's really all that necessary necessary. Spinning splined wet bolts are a pretty rare bird, provided they are installed correctly initially. If someone is frequently removing their splined bolts, that would be a different matter. JMO of course.
 
My factory installed bolts did. WHY?
They were damaged by the installer at the factory. Many think the serations on the bolt means you do not need to use a backup wrench.
An impact gun can destroy the hanger hole in a instant with a heavy trigger finger and no backup wrench
 
They were damaged by the installer at the factory. Many think the serations on the bolt means you do not need to use a backup wrench.
An impact gun can destroy the hanger hole in a instant with a heavy trigger finger and no backup wrench

I think you and [MENTION=42104]Hoopy Frood[/MENTION] are on the same page here. But if this is typical of installation at the factory I'd expect a whole lot more to break and not always the rears. There's a discussion on another forum (cross manufacturer) where some surmise the rears are always the ones that snap and it's on the heavy toy haulers with no toys or on a heavy floor plan such as ours which has zero storage in the rear all combined with the axle upgrades. Don't know if that is factual.
 
Quite the contrary, to my way of thinking. I think it's just the result of a careless individual worker who didn't have his wrench placed right, or it slipped. Not a frequent occurrence, and not common. But in all fairness, I'm just basing my thoughts on how rarely one reads about the splined bolt spinning in the hanger. Perhaps it happens more often than I opine.

I wonder what the weight difference is between the 7,000 lb. axles/spring combinations, and the 8,000 lb. axles/spring combinations.
 
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I think stripped wet bolt splines are much more common than some of you are thinking. Most people just don't know it as they don't do their own service work. The problem may appear later on as a broken bolt or hanger. In my opinion its just too easy to strip those fine splines - and not be aware that it happened. One slip of a wrench or impact driver and the spines in the hanger are toast.
 
I think you and [MENTION=42104]Hoopy Frood[/MENTION] are on the same page here. But if this is typical of installation at the factory I'd expect a whole lot more to break and not always the rears. There's a discussion on another forum (cross manufacturer) where some surmise the rears are always the ones that snap and it's on the heavy toy haulers with no toys or on a heavy floor plan such as ours which has zero storage in the rear all combined with the axle upgrades. Don't know if that is factual.
FWIW, I had a rear broken bolt. it did not spin. I have the 8K axles.
 
Quite the contrary, to my way of thinking. I think it's just the result of a careless individual worker who didn't have his wrench placed right, or it slipped. Not a frequent occurrence, and not common. But in all fairness, I'm just basing my thoughts on how rarely one reads about the splined bolt spinning in the hanger. Perhaps it happens more often than I opine.

I wonder what the weight difference is between the 7,000 lb. axles/spring combinations, and the 8,000 lb. axles/spring combinations.

The 8K axles are beefy. 3.5" tubes. The cooper tires are monsters as well. Changing a tire out on the road would require more muscle than this 62 year old with a surgically repaired shoulder has. A good reason for a road service rider on my ins. policy.
 
It does make one wonder if the increased unsprung weight of the 8,000 lb. axles, springs, and tires/wheels is proving to be too much for the OEM spring hangers?
 
It does make one wonder if the increased unsprung weight of the 8,000 lb. axles, springs, and tires/wheels is proving to be too much for the OEM spring hangers?
From reading on various forums, it's the bolt just as often as the hanger that breaks first. And most often seems to be the rear hangers/bolts.
The rear most suspension attachment point takes the most abuse. Especially when braking.
 
From reading on various forums, it's the bolt just as often as the hanger that breaks first. And most often seems to be the rear hangers/bolts.
The rear most suspension attachment point takes the most abuse. Especially when braking.
I don't know. From what I've read, ofttimes the broken bolt is discovered when the damaged hanger is examined. That would make it hard to determine which came first. A "the chicken or the egg" scenario. :)
 
We have had two wet bolts break and one of them caused the hanger to bend and have to be replaced on our 2021 GD397TH-R with 8k axles. This happens way too often and is most likely a design flaw. We are full time and have decided to spend the money and replace our suspension with the MORryde Independent suspension. It's a lot of money, especially having it done in Oregon, but the piece of mind is worth it. Now if I could only get GD to pay for it :)
 
Does Grand Designs use the same size and grade wet bolts on all of it's trailers?
 

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