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A grade 5...yes. A grade 8...no. A cheap no name bolt?.....who knows.
I need to crawl under the trailer and look at the bolt heads. This breaking at the grease hole is getting me worried. Like it never reportedly happened through the 2010's...but starting to happen now?
Attached picture of some recently acquired suspension bolts. The chrome one is an LCI part. The black one is from an RV parts supply. Both are marked as Grade 5 bolts . . . and, I would think . . . should bend before they fracture.
(BTW, if you are at the Rally, you can examine these bolts in person )
Attached picture of some recently acquired suspension bolts. The chrome one is an LCI part. The black one is from an RV parts supply. Both are marked as Grade 5 bolts . . . and, I would think . . . should bend before they fracture.
(BTW, if you are at the Rally, you can examine these bolts in person )
Rob
I agree with you Rob.... The black oxide bolt looks like a better bolt to me though. Something about the mottled chromate coating making me think cheap.
Unfortunately we are unable to be there this year.......Maybe I'll come check out the 303RLS-B17G and it's spare parts next year.
Gotta admit...this issue has me thinking about solid bolts when it comes to replacing later this fall...or maybe next spring...don't want to commit too early to anything..lol
Fall time is great fishing, bird seasons open up, deer...where did I find the time when I was working!?!
2018 Dodge 3500 6.7 Cummins w Aisin and 9 cup holders
2021 303RLS
Electricians were created because engineers need heroes too...
Attached picture of some recently acquired suspension bolts. The chrome one is an LCI part. The black one is from an RV parts supply. Both are marked as Grade 5 bolts . . . and, I would think . . . should bend before they fracture.
(BTW, if you are at the Rally, you can examine these bolts in person )
Rob
Well that isn't comforting. The black ones were the ones that broke. The chromate coated ones were sent as a replacement by GD. I sourced some additional bolts from a local supply shop and they also were black.
New shackle bracket to replace the bent up one, almost done. The rear bracket on the other side was slightly bent also, so they are going to replace it also. You can see the nylon bushing that are going to be used, and a solid grade 8 shackle bolt
SNIP Both are marked as Grade 5 bolts . . . and, I would think . . . should bend before they fracture.
SNIP
Rob
It might be helpful to discuss fatigue failures in steel. Cyclic (repeated) stresses can cause fatigue cracks to develop, which work their way further into the part until a complete failure occurs (see the "beach marks" discussed earlier). Relatively high cyclic stresses will cause failure at a much, much lower total number of cycles than lower cyclic stresses will. If the cyclic stresses are kept below a certain value, the component will tolerate an infinite number of stress cycles (see "endurance limit" on the chart below). The graph of this behavior is called an S-N curve. A typical steel S-N curve is below. What can be seen is that, as the stress goes up (vertical axis), the number of cycles expected to failure drops logarithmically (meaning very rapidly!). If the cyclic stress is kept below the line called the endurance limit, the component will not fail in fatigue no matter how many cycles it sees.
Alas, the challenge in this application is understanding the various stresses the bolts will see. As I've previously mentioned, I believe the largest stress they see is during tight turns. I doubt that much engineering analysis went into understanding this...
Back to Rob's comment about the bolts bending before failure - it is only true for single or low cycle stresses to failure.
(BTW, when was the last time anyone worried about the leaf springs or shackles in their 200k mile, 20 year old truck?)
Ottertail, Minnesota
2022 Imagine 2500RL VIN 573TE3029N6637046
2022 Ford F-150 Lariat, SuperCrew, long box, max tow
(BTW, when was the last time anyone worried about the leaf springs or shackles in their 200k mile, 20 year old truck?)
I was thinking the exact same thing last night. When I bought my '73 Challenger in '83, the rear springs were definitely flattened out. But the previous owner had added shackles to the rear mount to prop up the ride height. Same bolts. Saw lots of 70's cars like that in the early '80s. Don't ever remember anybody talking about their springs or bolts breaking. Some guys with more money than the rest of us 20 yr olds had them re-arc'd and kept on using them for years. Still I don't remember any spring or bolt breakages.
Guess they " just don't make'm like they used to"
2018 Dodge 3500 6.7 Cummins w Aisin and 9 cup holders
2021 303RLS
Electricians were created because engineers need heroes too...
Well that isn't comforting. The black ones were the ones that broke. The chromate coated ones were sent as a replacement by GD. I sourced some additional bolts from a local supply shop and they also were black.
Well, I'm once again to go out on a limb here and state. It seems Dexter may have changed their sourcing for the bolts, much like what they have done with their springs. My replacement Dexter springs have China on them. Perhaps they sourced their bolts also from China and they are starting to fail now. It would be interesting if Rob could get those bolts he posted to someone that has a Rockwell hardness tester. I used to have access to one when I was in the aviation industry and I found a number of non spec hardware through the years. This was way back when when the Chinese stuff started to show up in the US. They were not as good as masking the garbage then as they are now. I started a number of FAA investigations on suppliers.
Grand Design Imagine 2450RL 2020 born 7/2019
TV - 2007 Toyota Tundra 5.7 4X4 Limited w/Towing PKG under 30K miles, hanger queen until now
It looks like a common wet shackle bolt. The knurl under the head is gone, rubbed off. The break is centered in the bolt length where the grease exit hole is located.
(BTW, when was the last time anyone worried about the leaf springs or shackles in their 200k mile, 20 year old truck?)
Well, the axle under my 20 year old 3/4 ton truck has bolts that are about 1.5X bigger in diameter. IIRC they are right at 1" diameter for an axle system that is rated at approx 6,500 lbs.
Joseph
Tow Vehicle: 2024 GMC K3500 Denali Ultimate Diesel
Coach: 303RLS Delivered March 5, 2021
South of Houston Texas
Here is a picture of several of the bushings that were replaced. Interestingly enough, the front right had no bushing, not sure if there was any at all.
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