When Wet Bolts Spin....What Then?

Does Grand Designs use the same size and grade wet bolts on all of it's trailers?

The wet bolts are supposed to be grade 5 according to MORryde. BUT, grade 5 bolts have three "tic" marks on the head, my original wet bolts do not have the "tic" marks. So, there is no telling what grade they are. This is only my theory and I'm not saying this is what happened but, I think GD had a shortage of grade 5 bolts during covid and used cheaper bolts so they could keep producing RV's. Now the customer is paying for it. Again - that is just a theory.
 
It's a decent theory, but doesn't explain the seemingly higher numbers of failed bolts in the 8,000 lb. axle applications. Cheaper bolts would also likely fail in less stressed applications too.
 
The wet bolts are supposed to be grade 5 according to MORryde. BUT, grade 5 bolts have three "tic" marks on the head, my original wet bolts do not have the "tic" marks. So, there is no telling what grade they are. This is only my theory and I'm not saying this is what happened but, I think GD had a shortage of grade 5 bolts during covid and used cheaper bolts so they could keep producing RV's. Now the customer is paying for it. Again - that is just a theory.

I ask because if the bolts on your trailer at 15K lbs are the same as my trailer at half that weight, I can see why they are breaking. It seems like the bolts are only breaking on the heavier trailers, but I may well be wrong.
 
I ask because if the bolts on your trailer at 15K lbs are the same as my trailer at half that weight, I can see why they are breaking. It seems like the bolts are only breaking on the heavier trailers, but I may well be wrong.

The broken bolt pulled out of mine had the 3 tic marks and were silver in color - same as the replacements from MORryde that GD sent.
 
It's a decent theory, but doesn't explain the seemingly higher numbers of failed bolts in the 8,000 lb. axle applications. Cheaper bolts would also likely fail in less stressed applications too.

On one forum or another, I had read one suggestion that the rear wet bolts seem to fail more frequently then the fronts especially on Momentums with no toys. So as I look at the weight/wheel on our coach, the RR carries the lightest load. My off-door side is 510lbs heavier from the factory build sheet and that is before putting anything in the fridge or pantry. Add a factory generator (Left front) and washer/dryer (Right Front), and that probably makes the RR even more lightly loaded. Given that our RR wet bolt was missing, I'll conclude that it was the first to fail and the LR break was a result of the RR spring hanging free. I would guess that there is a lot more up and down movement on the RR than any other wheel and the forces on that bushing/bolt are magnified to make it the first to fail. Agree/disagree? So would any suspension mod make up for that?
John
 
Hmm, I'll have to give that some thought. An interesting idea though.

And add a heavier suspension (more weight to throw around), H rated tires at recommended 125PSI capacity, no shock absorption and I think that poor wheel and anything connected to it took a beating.
 
Just thinking out loud: If, as you say, most of the problems with broken bolts occur at the rear, right rear specifically, I wonder about the forces in action on those spring hangers when the front tire hits bumps, and transfers forces to the rear springs and spring hangers. I'm not really all that cognizant about the forces in play with type of suspension we're discussing. But perhaps with the heavier weights being moved around, and the increases in unsprung weight, might be interesting to know what percentage the unsprung weight has increased, one has to wonder if the increased amount has overloaded the spring hanger. This may help explain the increased failure in trailers with 8,000 lb. axles, heavier tires/wheels, etc. Maybe they've reached a limit, unknowingly it would appear.
 
On the 310, there is simply no place to add weight to the rear (unless on the hitch), and specifically on the Right Rear. The only way I can add weight behind the wheels is to fill the fresh water tank. The refrig is located mostly over the left front wheel - as is the pantry. However, I'd guess the equalizer shifts some of that to the left rear.
 
Interesting thoughts, I am just going to throw this out. My RR bolts was sheared, but stayed "together". My LR is the one that sheared, half the bolt dropped off, allowing the spring to bend the bracket and drop off the remaining half of the bolt. The only reason the remaining half bolt on the LR was on, was due to the waste pipe being in the way, not allowing it to come out of the bracket.
 
Just went out to air up the tires for the winter and took a good look at the shackles - silver metal shavings all over the residual grease. Those were the replacement MORryde shackles sent by GD that came with the silver bolts pressed in. Not a good sign with 3800 miles on them.
 
That does not sound promising. Are you going to dig into it further? At some point?

Not sure how far to dig into it. It's parked until we head out to Elkhart in April - GD is going to do a complete suspension inspection and R&R as required. Makes me reluctant to touch it. The bolts do not look like they are spinning based upon the surface grease intact around the bolt head. On the other hand, I'd sure like to know what is happening and if these new bolts/bushings/shackles are toast, because if this same thing is just going to continue to happen I'll make the appointment with MORryde for that time period. But the other outlier is potential front frame flex issues - another item they are going to verify in April because of all the Goosebox manifold blowouts.
 
Sounds to me like you have things well in hand. Please keep us posted as developments occur. TIA. I'm really curious if they come up with a root cause of this whole thing.
 
I'd have expected to see brass shavings vs silver but wondering if a spring might be rubbing against the one of the shackles? As Hoopy Frood mentioned, I'd be curious as to what's happening. The whole spring / equalizer / shackle design is a weakness in my opinion. While it's not an independent suspension like Morryde's, the slipper spring system that I put on ours eliminated many of the moving parts that the OEM suspension comes with. The less moving parts, the better for me.
 
I'd have expected to see brass shavings vs silver but wondering if a spring might be rubbing against the one of the shackles? As Hoopy Frood mentioned, I'd be curious as to what's happening. The whole spring / equalizer / shackle design is a weakness in my opinion. While it's not an independent suspension like Morryde's, the slipper spring system that I put on ours eliminated many of the moving parts that the OEM suspension comes with. The less moving parts, the better for me.
It may not be an independent suspension exactly like the Morryde, but it is an independent suspension in that the wheels are no longer interconnected with an equalizer. I looked at it, and thought about it for quite a while, and haven't totally given up on the idea, but so far the changes I've made have worked well for us. Knock on wood. :)
 
I just watched the video mentioned above. Do I see side-to-side movement? Surely that can't be right? Does the rear spring seem to go up and over the front spring at one point?

Since we have a cheaper trailer, although nearly as heavy as some of yours, I'm starting to wonder about our suspension.
 

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