Reply
 
Thread Tools Search this Thread Display Modes
 
Old 02-27-2016, 06:33 PM   #1
RFP
4 Rivet Member
 
RFP's Avatar

 
2014 23' International
Hurst , Texas
Join Date: Jan 2016
Posts: 465
How many times can the hitch head bolts be torqued?

In the process of setting up our Reese SC hitch, I have made several adjustments (and readjustments!) to get it 'dialed in' correctly... many of you are already so familiar with this exercise.

In the process, I have twice fully torqued the two main hitch-head-to-shank bolts to the full torque spec (250 ft. lbs.), and dang, that's tight.

Knowing next to nothing about the 'mechanical engineering' aspects of all this, I'm wondering if repeated (twice) torquing to this spec has compromised the bolts' integrity in any way.

Should I replace the bolts with new, or should I just use the ones I have and go and worry about something else?

Thanks,

Rob
__________________

__________________
2014 23D International Serenity - "Fortune Cookie"
2015 Ford F150 3.5 EcoBoost, Max Tow - "Cookie Monster"
And some stuff

Fortune Cookie: https://www.flickr.com/photos/rfpd30...57663633667345

"The Black Swan": https://www.flickr.com/photos/rfpd30...57648991024725
RFP is offline   Reply With Quote
Old 02-27-2016, 07:55 PM   #2
Rivet Master
 
GMFL's Avatar
 
2014 23' International
Dadeville , Alabama
Join Date: Oct 2015
Posts: 599
Images: 1
You are good to go. As long as they have never been over torqued they will be fine
__________________

__________________
GMFL is offline   Reply With Quote
Old 02-27-2016, 08:17 PM   #3
Rivet Master
 
tjdonahoe's Avatar
 
2013 31' Classic
billings , Montana
Join Date: Feb 2010
Posts: 1,840
Big bolts will be fine
__________________
tjdonahoe is offline   Reply With Quote
Old 02-28-2016, 05:29 PM   #4
3 Rivet Member
 
1990 32' Excella
jonesboro , Arkansas
Join Date: Aug 2002
Posts: 245
I agree 13 years ago I went thru all the adjusting on our first long trip. Same bolts are still in
__________________
joel is offline   Reply With Quote
Old 02-28-2016, 06:22 PM   #5
Rivet Master
 
J. Morgan's Avatar

 
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton , Arkansas
Join Date: Mar 2013
Posts: 5,040
Images: 11
To the greatest extent, the only bolts that cant be tightened over and over and over are torque to yield bolts which would not be used in this application.


Talis gentium ceciderunt.
__________________
The fact that I am opinionated does not presuppose that I am wrong......

J. Morgan is offline   Reply With Quote
Old 02-29-2016, 11:48 AM   #6
4 Rivet Member
 
1977 31' Sovereign
Lynnwood , Washington
Join Date: Jan 2015
Posts: 311
When it comes to the heavy stuff, I use grade 8 fasteners: bolts, washers, and lock nuts. Once tight, it's tight. No worries.

BTW - If your hitch bolts hafta be re-torqued, it's because they've stretched. And once stretched, they shouldn't be reused. Even grade 8 head bolts on certain motors will stretch, and as a consequence, they hafta be replaced.

Tom
__________________
TomKirk is offline   Reply With Quote
Old 02-29-2016, 12:02 PM   #7
3 Rivet Member
 
2017 30' Flying Cloud
Spotsylvania , Virginia
Join Date: Jan 2015
Posts: 127
10 yrs ago I questioned Reese about this very situation and they told me to torque them only once. I purchased a new set of bolts when I had to change hitch height when purchasing another trailer.

250 foot pounds is a lot of torque and the material will stretch and weaken when torqued down repeatedly. I believe the new set of bolts at the time was $20+/-.

Anyhow that's my 0.02 worth.
__________________
KWN306 is offline   Reply With Quote
Old 02-29-2016, 12:47 PM   #8
Rivet Master
 
SteveH's Avatar
 
2005 39' Land Yacht 390 XL 396
Common Sense , Texas
Join Date: Sep 2007
Posts: 5,311
I would estimate that only one in ten hitches is adjusted perfectly the first time the bolts are tightened.

How many have you heard of breaking?
__________________
Regards,
Steve
SteveH is offline   Reply With Quote
Old 02-29-2016, 01:31 PM   #9
Rivet Master
 
J. Morgan's Avatar

 
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton , Arkansas
Join Date: Mar 2013
Posts: 5,040
Images: 11
Quote:
Originally Posted by KWN306 View Post
10 yrs ago I questioned Reese about this very situation and they told me to torque them only once. I purchased a new set of bolts when I had to change hitch height when purchasing another trailer.

250 foot pounds is a lot of torque and the material will stretch and weaken when torqued down repeatedly. I believe the new set of bolts at the time was $20+/-.

Anyhow that's my 0.02 worth.

That MIGHT be the company acting in CYA mode.


Talis gentium ceciderunt.
__________________
The fact that I am opinionated does not presuppose that I am wrong......

J. Morgan is offline   Reply With Quote
Old 02-29-2016, 01:39 PM   #10
Rivet Master
 
1996 25' Excella
Tillsonburg , Ontario
Join Date: Aug 2014
Posts: 787
Quote< "BTW - If your hitch bolts hafta be re-torqued, it's because they've stretched. And once stretched, they shouldn't be reused. Even grade 8 head bolts on certain motors will stretch, and as a consequence, they hafta be replaced." >

I think the OPs point was that he had re-torqued twice while trying the zero in the adjustment, not that they had loosened off.
I believe the bolts have Belleville Washers which are dished to provide continual resistance to overcome metal creep. The bolts are usually stable but washers tend to be soft unless matched to the bolt service, and continual working will even eventually cause the metal in the hitch head to creep thus requiring a re-torque once in a while.

I had loose fittings everywhere on my hitch head after a trip to Louisiana. Had them re-tightened using an impact wrench at an RV shop. I never had that problem again in 8 years.
JCW
__________________
JCWDCW is offline   Reply With Quote
Old 02-29-2016, 05:29 PM   #11
Rivet Master
 
Alphonse's Avatar

 
2010 28' Flying Cloud
Lower Alabama , USA
Join Date: Mar 2012
Posts: 649
Quote:
Originally Posted by SteveH View Post
I would estimate that only one in ten hitches is adjusted perfectly the first time the bolts are tightened.

How many have you heard of breaking?
How many have you heard of breaking?[/QUOTE]

Actually saw some in October that were broken on a Reese. They likely had been over torqued but who knows. They were cracked at the bolt head and the hitch was a dangling mess. The owner bought new Grade 8s and put them in.
__________________
Alan
"If you must choose between two evils, pick the one you never tried before!"

Air #64439
Southeastern Camping Unit WBCCI #5033
TAC AL-8
2017 Canopenian
Alphonse is offline   Reply With Quote
Old 02-29-2016, 06:02 PM   #12
RFP
4 Rivet Member
 
RFP's Avatar

 
2014 23' International
Hurst , Texas
Join Date: Jan 2016
Posts: 465
Quote:
Originally Posted by Alphonse View Post
Actually saw some in October that were broken on a Reese.
Yikes, that's what I have!

Quote:
Originally Posted by Alphonse View Post
The owner bought new Grade 8s and put them in.
Sounds like "cheap" insurance!
__________________
2014 23D International Serenity - "Fortune Cookie"
2015 Ford F150 3.5 EcoBoost, Max Tow - "Cookie Monster"
And some stuff

Fortune Cookie: https://www.flickr.com/photos/rfpd30...57663633667345

"The Black Swan": https://www.flickr.com/photos/rfpd30...57648991024725
RFP is offline   Reply With Quote
Old 02-29-2016, 06:28 PM   #13
Rivets?
 
nvestysly's Avatar

 
1992 29' Excella
2010 22' Interstate
Van By The River , Georgia
Join Date: Feb 2002
Posts: 1,522
I wouldn't hesitate to tighten - loosen - tighten your screws numerous times. I've done it on our hitch a dozen times. I did it again recently when we installed new axles on the trailer and the tongue height and hitch needed to be adjusted.

Take a look at the information on the table shown HERE.

I presume you have grade 8 bolts, that's what I have and I would expect hitches to come with that hardware. The bolts on my hitch are 3/4" diameter (1-1/8 hex). The clamp load in the chart is just over 30,000 pounds!

The chart shows the torque for various friction factors of K=0.15, 0.18 and 0.20. The torque ranges from 282 - 376 LB-FT depending on the friction factor. Back when I was designing bolted joints I typically used K=0.20 as an approximation but the friction does vary depending on the material and plating. Regardless, the clamping load is intended to make the bolt act like a large rubber band - extending the bolt within it's yield curve as the nut is tightened and then returning to it's original length when the nut is loosened.

I wouldn't tighten and loosen indefinitely but a few times doesn't seem like a problem in my mind.
__________________
Lucius and Danielle
1992 29' Excella Classic
1996 GMC Suburban C2500 7.4L
2005 Chevrolet Suburban K2500 8.1L
Got a cooped-up feeling, gotta get out of town, got those Airstream campin' blues...
nvestysly is offline   Reply With Quote
Old 02-29-2016, 06:40 PM   #14
Rivet Master
 
2015 25' Flying Cloud
2016 30' Flying Cloud
Blenheim Ontario , Ontario
Join Date: May 2015
Posts: 1,264
Quote:
Originally Posted by RFP View Post
In the process of setting up our Reese SC hitch, I have made several adjustments (and readjustments!) to get it 'dialed in' correctly... many of you are already so familiar with this exercise.

In the process, I have twice fully torqued the two main hitch-head-to-shank bolts to the full torque spec (250 ft. lbs.), and dang, that's tight.

Knowing next to nothing about the 'mechanical engineering' aspects of all this, I'm wondering if repeated (twice) torquing to this spec has compromised the bolts' integrity in any way.

Should I replace the bolts with new, or should I just use the ones I have and go and worry about something else?

Thanks,

Rob
[From a former Premier Fastener Agent, and retired Canadian Aircraft tech; (A.M.E.);]

I advise you to replace the bolts with Grade 8 bolts, nuts, AND washers, [160 KSI STRENGTH], and torque them to the hitch mfr's spec of Grade 5 bolts. [125 KSI]. This will eliminate the possibility of stretching and bolt loosening in one case; but not another.
The other possibility is to check the fit of the hitch shank to the head mount. There is probably too much play, which will collapse inward under bolt tension and work load. This will cause loose bolts and a great chance of fatique breaking. [I measured .040"play in my Husky Hitch.]
I had a piece of .042 steel plate in hand, and after greasing it, and sharpening one edge, drove it into the space with a brass hammer.
I then torqued up my [grade 8] bolts, and have towed a heavy rig for the last six years; no problem. Check tightening the torque several times proved no looseness. It works fine, and I have a clear mind on the subject.
__________________

__________________
MelGoddard is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
1973 Airstream Land Yacht Sovereign -- Many Many Many Upgrades!!! eBay Watch Airstreams on eBay 0 06-18-2013 07:30 PM
How many times have you used the spare tire? adonh Tires 75 05-14-2013 06:57 PM
How Many times per year? Mainstream Community Polls 10 05-12-2009 08:50 PM
OT: How many trailers is too many? Amazing short video. SilvrSausage On The Road... 1 09-10-2008 05:44 PM
How many times have you hit... drboyd Interior Restoration Forum 29 11-30-2003 05:19 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 10:09 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.