Announcement

**Scott'n'Wendy** · 03-28-2022, 06:32 PM

Originally posted by Cate&Rob View Post

. . . but I don't think this will make any difference to the loads where it fractured.

Rob

I agree. Wonder what Reese will say about this. To me, (electrician, not mechanical engineer) this seems like the wrong spec bolt for the application.

**Jlawles2** · 03-28-2022, 07:46 PM

Personally I would have preferred to see the bolt / pin in double shear (clevis style). But it is a proven design and Rob has put quite a few miles on the head, I think this may be the 2nd or 3rd truck it's been in pulling the same camper.

Engagement of the threaded portion will not affect the way it's loaded, and most likely not it's life expectancy either. That bolt in single shear with the isolator allowing bending will eventually lead to fatigue failure o the part. I remember doing a lab while in school where we took a sample, put a bit of bending in it, then spun it with a motor until it gave up. Cyclic loading of the component lead to the failure.

**Cate&Rob** · 03-28-2022, 07:58 PM

Originally posted by Jlawles2 View Post

Cyclic loading of the component lead to the failure.

Agreed that the break is cyclical loading fatigue. Makes me wonder (again) whether a Grade 5 would survive better.

Another thought for everyone towing a fifth wheel . . . where do you attach your break-away switch pull cable? Mine is above these pivot points. I may have to rethink this.

Rob

**Jlawles2** · 03-28-2022, 08:16 PM

Typically I use the snap on the break away as a lock for the latch handle. Basically i replace the lock in the still image of the video https://www.pullrite.com/isr_SG_HIW with https://www.tractorsupply.com/tsc/pr...1?cm_vc=-10005 that is on the end of the breakaway. Probably something similar to what you are doing. I guess I could hook it to the cam pins on the hitch, but with the slider, that could lead to the switch getting activated by accident during turns as the whole head moves back.

**Yoda** · 03-29-2022, 12:16 AM

Originally posted by Cate&Rob View Post

Agreed that the break is cyclical loading fatigue. Makes me wonder (again) whether a Grade 5 would survive better.

Another thought for everyone towing a fifth wheel . . . where do you attach your break-away switch pull cable? Mine is above these pivot points. I may have to rethink this.

Rob

Rob - sorry to see this
It appear where the brake occurred is where the inner washer sits against the bushing. Is it possible the washer acted as a knife against the bolt if it got inside the bushing housing and was held in a rigid position?
The only way I can see this happening if the bushing degraded allowing the washer to be against the cast housing. Did you travel any rough roads lately?

Just thinking
Keith

ON edit Now I am confused my R20 head is held on with clevis pins - not bolts!

Manual link here https://www.trailerpartsnz.com/dm_do...16.pdf&fid=406
Hopefully you can get Reese to respond.

**Jlawles2** · 03-29-2022, 06:28 AM

Cate&Rob Yoda Rob, is that an R16 head? Kinda what it looks like in the original pics. Keith, is your head a single ear per side or a double ear on each side?

**Guest** · 03-29-2022, 06:55 AM

If the unit could be converted to hardened pins or through bolted it would be far better than threaded bolts and bushings. Isolators may harden over time and if the bolts are slightly loose they would end up in pure bending since the clamping support from the bushing would be gone. In the videos below they change the isolators which fall out and have to drive in the new isolators. So they tightened up the clearances there as well. A call to NHTSA may help folks to avoid a disaster.

https://www.youtube.com/watch?v=jkukS-bSIWU

https://www.youtube.com/watch?v=wtkmZF6dkIU

Jim

**familytruckster4** · 03-29-2022, 08:01 AM

If that were mine I would have replaced it with a socket head cap screw. They have more sheer strength due to the difference in how they are made. Normal grade 8 hex head cap screws have "cut" threads such as the type done with a round die. A socket head cap screws is thermal forged and the threads are "rolled" instead of being cut. This keeps the grain structure intact and makes them inherently stronger.

**Yoda** · 03-29-2022, 10:30 AM

Originally posted by Jlawles2 View Post

Cate&Rob Yoda Rob, is that an R16 head? Kinda what it looks like in the original pics. Keith, is your head a single ear per side or a double ear on each side?

Double ear

**Jlawles2** · 03-29-2022, 02:14 PM

Yoda Keith, double ear means the pin is mostly in shear and you have 2x as much vs a single ear.

Cate&Rob Rob, wonder if you can upgrade to the larger head (if you have a 16K) and get the double shear pins vs bolts.

**Cate&Rob** · 03-29-2022, 02:35 PM

familytruckster4
That is a GREAT piece of advice! Going to a rolled thread fastener will be far better than one with cut threads.

Yoda Jlawles2
About the time I saw the picture of Keith's 20K hitch, I realized that my 16K is not the same in the isolator support area. I think I have found the "weak point" that they redesigned for the higher capacity hitch. Upgrading the the 20K head . . . hmmm . . . Keith, what are you doing with your old hitch when you get your new one (wink, wink )???

Rob

**Yoda** · 03-29-2022, 03:44 PM

Originally posted by Cate&Rob View Post

familytruckster4
That is a GREAT piece of advice! Going to a rolled thread fastener will be far better than one with cut threads.

Yoda Jlawles2
About the time I saw the picture of Keith's 20K hitch, I realized that my 16K is not the same in the isolator support area. I think I have found the "weak point" that they redesigned for the higher capacity hitch. Upgrading the the 20K head . . . hmmm . . . Keith, what are you doing with your old hitch when you get your new one (wink, wink )???

Rob

I sent you a PM. I still have it.

My new B&W 25K OEM companion is sitting in my garage.

**Jlawles2** · 03-29-2022, 06:18 PM

BTW from what I know most US fasteners of the mass production style are rolled threads where metric or euro fasteners are cut threads.

**Country Campers** · 03-29-2022, 07:12 PM

Comparing your hitch to Keith's I would prefer Keith's. Double support on the pin is way better than the end of the bolt holding everything, just my opinion.

Brian

**Cate&Rob** · 03-29-2022, 09:00 PM

Originally posted by Jlawles2 View Post

BTW from what I know most US fasteners of the mass production style are rolled threads where metric or euro fasteners are cut threads.

Joseph . . . you might be right. These 5/8 - 11 threads on the failed bolt do look rolled rather than cut.

Rob

Announcement

Broken Pivot Bolt - Reese Hitch

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment