Adding a hydraulic dovetail to existing 24" gooseneck - Pirate4x4.Com : 4x4 and Off-Road Forum
 
Pirate4x4.Com : 4x4 and Off-Road Forum  

Go Back   Pirate4x4.Com : 4x4 and Off-Road Forum > General Tech > Tow Rigs and Trailers
Notices

Reply
 
Share LinkBack Thread Tools Display Modes
Old 04-27-2019, 10:18 PM   #1 (permalink)
Registered User
 
Join Date: May 2004
Member # 31211
Location: Montrose, CO
Posts: 1,195
Adding a hydraulic dovetail to existing 24' gooseneck

I have a 24' PJ lowboy tandem axle flatbed gooseneck that I bought from my nephew because he needed some cash. I was really looking for a 30'-ish goose neck to load up my cabover and crawler on. Cabover is right at 12' from the front wall to back bumper, and my crawler is 13' bumper to bumper.

I was thinking of ways to stretch the frame, but I'm really considering just reworking the back with a stout pivot and fabbing up a hydraulic dove tail, in the 4' to 6' range. I would then really consider moving the front axle to behind the rear axle to keep the weight distribution. Although, my pig of a cabover is about 3k lbs dry, so I will probably weigh everything before I decide to move the axle back.

I am curious about a couple things though. How big of rams would I need to lift, say, 4k lbs of weight sitting on the dovetail? With my crawler, I could basically pull all the way forward off the dovetail, raiser it and lock it, and then back up a bit. With my family rig (4 dr JK), I can't do that. Would have to be able to raise the dovetail with rear weight of Jeep on it.

Also, I'm wondering what is the best way to lock out the dovetail so I can tow the trailer with normal weight on the dovetail?

Also, any thoughts on using air over hydraulic cylinders for the dovetail. I have OBA on my tow rig, could add a bigger tank on the trailer and air line hookup. Already have quick connect at rear of truck.

Any thoughts are appreciated.

Last edited by charlieboyd65; 04-27-2019 at 11:18 PM.
charlieboyd65 is online now   Reply With Quote Quick reply to this message
Old 04-28-2019, 08:55 AM   #2 (permalink)
Registered User
 
Join Date: Aug 2011
Member # 196897
Location: Reno, NV
Posts: 92
I think it would be cheaper to buy a new 30' trailer, and tow better. 4K+ behind the rear axle, no thanks. I doubt air over hydraulic is going to do it either. I would think more of a pony motor. Electric hydraulic power may work as well. Where are you thinking of mounting the cylinders? I would think may be two 3-4" short throw mounted under the bed would work best and look the cleanest. You would need a super strong hinge at the dovetail and beef up the frame where the rams mount.

I am not saying it is not doable but at a cost and then still concerned about the amount of weight behind the rear axle.

Whats the GVWR of the trailer?
thedirtman is offline   Reply With Quote Quick reply to this message
Sponsored Links
Old 04-28-2019, 06:54 PM   #3 (permalink)
Zeus of the Sluice
 
Join Date: Mar 2003
Member # 17947
Location: Seabeck WA
Posts: 3,566
Send a message via AIM to jaluhn
How big of ram you'd need depends on the geometry of how you set it up and where exactly you plan on loading it. 4k lb 5' aft of the pivot plus another 1k 5' aft (ballpark) for the dovetail itself gives you 25k ft/lb, assume the rams are 1' below the pivot and you need 12.5k force per ram (assuming one on each side) - 3" ram @ 1800 psi or 2.5" @ 2500 psi will work.

Locking wouldn't be too hard, again depends on how you set it up. Bolt/pin on lock bar, telescoping tube with lock pin, etc etc. Could also get a ram with a pilot check valve in it and just hydraulically lock it, although I'd want a mechanical lock myself.

Air over hydraulic could be an option, yes.... but again depends on how. If you're thinking of a common bottle jack setup I don't think it will work since the oil is gravity fed to the pump and mounting it sideways would mess that up. Maybe add a remote tank connected to the stock pump fill port? Electric pump off a liftgate would probably be easier.
jaluhn is offline   Reply With Quote Quick reply to this message
 
Old 04-28-2019, 09:31 PM   #4 (permalink)
Registered User
 
Join Date: May 2004
Member # 31211
Location: Montrose, CO
Posts: 1,195
Quote:
Originally Posted by thedirtman View Post
I think it would be cheaper to buy a new 30' trailer, and tow better. 4K+ behind the rear axle, no thanks. I doubt air over hydraulic is going to do it either. I would think more of a pony motor. Electric hydraulic power may work as well. Where are you thinking of mounting the cylinders? I would think may be two 3-4" short throw mounted under the bed would work best and look the cleanest. You would need a super strong hinge at the dovetail and beef up the frame where the rams mount.

I am not saying it is not doable but at a cost and then still concerned about the amount of weight behind the rear axle.

Whats the GVWR of the trailer?
I agree a short throw ram is probably best. I will not have 4K behind the rear axle, probably two at most. I just want to be able to lift 4K with the hydraulics if need be. Trailer GVWR is 16K lbs.


Quote:
Originally Posted by jaluhn View Post
How big of ram you'd need depends on the geometry of how you set it up and where exactly you plan on loading it. 4k lb 5' aft of the pivot plus another 1k 5' aft (ballpark) for the dovetail itself gives you 25k ft/lb, assume the rams are 1' below the pivot and you need 12.5k force per ram (assuming one on each side) - 3" ram @ 1800 psi or 2.5" @ 2500 psi will work.

Locking wouldn't be too hard, again depends on how you set it up. Bolt/pin on lock bar, telescoping tube with lock pin, etc etc. Could also get a ram with a pilot check valve in it and just hydraulically lock it, although I'd want a mechanical lock myself.

Air over hydraulic could be an option, yes.... but again depends on how. If you're thinking of a common bottle jack setup I don't think it will work since the oil is gravity fed to the pump and mounting it sideways would mess that up. Maybe add a remote tank connected to the stock pump fill port? Electric pump off a liftgate would probably be easier.

Thanks, the your ram sizes, is close to what I was ballparking. Yeah, I was thinking about a 20 ton bottle jack, but I do like your idea of the lift gate hydraulics. Good idea.

To get me started, I could probably add a two foot dovetail, with no hydraulics and just a mechanical lockout. I could load my crawler, pull up to the camper (at which point the back tires would be on the trailer deck), then just lift the 2' dovetail and mechanically lock it, and back the rig up and strap it down. But, seeing a hydraulic dovetail, got me thinking about making it longer, to haul my 4 dr JK also (3 feet longer than my crawler).

I also saw a cool lockout system on a trailer with a hydraulic dovetail. It is a sliding "sled" that extends from the stationary bed into the dovetail once level and locks both into place. Video link: https://www.youtube.com/watch?v=zix_-PQIh9c

I might just start off with a two foot dovetail and see what I think from there.
charlieboyd65 is online now   Reply With Quote Quick reply to this message
Old 04-28-2019, 09:58 PM   #5 (permalink)
Registered User
 
YotaAtieToo's Avatar
 
Join Date: Dec 2003
Member # 25632
Location: Magalia, Jefferson State
Posts: 11,286
I would try to trade for a longer trailer before opening up this can of worms. Seems common for people to buy too long of a trailer for what they need. A hydraulic tail is massively overkill to load a jeep that should be able to crawl up with no ramps at all. Also, all the weight you add with that set up is taking away from your capacity.
YotaAtieToo is online now   Reply With Quote Quick reply to this message
Old 04-29-2019, 05:44 PM   #6 (permalink)
Registered User
 
Join Date: Mar 2003
Member # 17632
Location: West Sacramento, CA
Posts: 8,295
Why are you set on a moving tail? It adds needless complexity, and the frame of a small trailer isnít designed for such shenanigans. Why not just add 2, 3, or 4 feet to the rear and move your axles. It would be easy, and would add a minimum of weight to your trailer.
Travis..
__________________
18 Ram 2500 4x4 Big C and a 6 speed
87 Blazer on 35"s
crashnzuk is offline   Reply With Quote Quick reply to this message
Old 04-29-2019, 07:20 PM   #7 (permalink)
Registered User
 
Join Date: May 2004
Member # 31211
Location: Montrose, CO
Posts: 1,195
Quote:
Originally Posted by YotaAtieToo View Post
I would try to trade for a longer trailer before opening up this can of worms. Seems common for people to buy too long of a trailer for what they need. A hydraulic tail is massively overkill to load a jeep that should be able to crawl up with no ramps at all. Also, all the weight you add with that set up is taking away from your capacity.
I like the trailer and it's stout. 8" C channel behind the axles and 8" C channel plus 4" C channel in front of the axles.

I could just stretch the trailer a little I guess. It's not that big of a deal. Just thought having a lower dovetail would be nice. I also haul small excavation equipment for my business (mini x, skid steers, etc), nothing that need a tandem dual. Figured it might be nice for that also. However, I agree that it would add some unwanted weight to an already heavy trailer.

Quote:
Originally Posted by crashnzuk View Post
Why are you set on a moving tail? It adds needless complexity, and the frame of a small trailer isnít designed for such shenanigans. Why not just add 2, 3, or 4 feet to the rear and move your axles. It would be easy, and would add a minimum of weight to your trailer.
Travis..
I'm not really set on it. Just looking for some input and ideas. Thought it might be nice to have. My original idea was to extend the rear with a 16' tilt bed at the back, but it seemed like a hydraulic dovetail might actually be easier to pull off. The tilt beds really have to have all the weight just right.
The trailer frame is seriously stout, and don't think it would be a problem structurally. But yes, I agree about the weight. Might just extend the frame and move the front axle to the rear.
charlieboyd65 is online now   Reply With Quote Quick reply to this message
Old 04-29-2019, 07:35 PM   #8 (permalink)
Registered User
 
Join Date: Sep 2005
Member # 53528
Location: norcal
Posts: 14,959
Quote:
Originally Posted by jaluhn View Post
If you're thinking of a common bottle jack setup I don't think it will work since the oil is gravity fed to the pump and mounting it sideways would mess that up.
fwiw ive used a harbor freight pipe bender laying down on its side flat on the ground hundreds of times

https://www.harborfreight.com/16-ton...der-62669.html

Last edited by rockyota83; 04-29-2019 at 07:38 PM.
rockyota83 is online now   Reply With Quote Quick reply to this message
Old 04-29-2019, 08:52 PM   #9 (permalink)
Registered User
 
Join Date: May 2004
Member # 31211
Location: Montrose, CO
Posts: 1,195
Quote:
Originally Posted by rockyota83 View Post
fwiw ive used a harbor freight pipe bender laying down on its side flat on the ground hundreds of times

https://www.harborfreight.com/16-ton...der-62669.html
That's a good point. I used to have the HF kinker modded and mounted horizontally to an engine stand and never had an issue with it working on its side. Thanks for reminding me!

Last edited by charlieboyd65; 04-29-2019 at 08:56 PM.
charlieboyd65 is online now   Reply With Quote Quick reply to this message
Old 04-29-2019, 09:35 PM   #10 (permalink)
Registered User
 
Join Date: Sep 2005
Member # 53528
Location: norcal
Posts: 14,959
heres some pics for ideas

https://www.picclickimg.com/00/s/ODgxWDE1NjY=/z/HQoAAOSwzaJX-9ut/$/Brute-Trailers-Hydraulic-dovetail-gooseneck-tandem-dual-Dexter-_57.jpg

https://www.picclickimg.com/00/s/ODI0WDExMDA=/z/XU4AAOSwpLNX-9ux/$/Brute-Trailers-Hydraulic-dovetail-gooseneck-tandem-dual-Dexter-_57.jpg

http://www.norstarcompany.com/img/products/FHG03.jpg

https://d34ra0wvwxc5ex.cloudfront.ne...ail_v03QGm.jpg

http://s3.amazonaws.com/FreeClassifi...37607053_4.jpg

http://haytrailer.com/images/hydraulic2.jpg
rockyota83 is online now   Reply With Quote Quick reply to this message
Old 04-30-2019, 04:23 AM   #11 (permalink)
Zeus of the Sluice
 
arse_sidewards's Avatar
 
Join Date: Feb 2013
Member # 256962
Location: People's Republic of Taxachusetts
Posts: 3,440
Quote:
Originally Posted by rockyota83 View Post
fwiw ive used a harbor freight pipe bender laying down on its side flat on the ground hundreds of times

https://www.harborfreight.com/16-ton...der-62669.html
Because the fluid input is probably at the back so if you lay it down with the handle facing up it still gets fluid.
arse_sidewards is offline   Reply With Quote Quick reply to this message
Old 04-30-2019, 10:57 AM   #12 (permalink)
Registered User
 
Join Date: Sep 2005
Member # 53528
Location: norcal
Posts: 14,959
Quote:
Originally Posted by arse_sidewards View Post
Because the fluid input is probably at the back so if you lay it down with the handle facing up it still gets fluid.

wow are you like an engineer or something? please tell us more
rockyota83 is online now   Reply With Quote Quick reply to this message
Old 04-30-2019, 11:17 AM   #13 (permalink)
Registered User
 
Join Date: Sep 2000
Member # 1663
Location: BFE & turn left
Posts: 1,489
Is there a reason you need the dove to sit flat?
I have a 5' dove on my GN and set the rear of rigs on it all the time. The dove pops up if needed, but don't haul that way. I have ramps that slide under the center of the trailer, not flip over ramps.
maveric is offline   Reply With Quote Quick reply to this message
Old 04-30-2019, 09:48 PM   #14 (permalink)
Registered User
 
Join Date: May 2004
Member # 31211
Location: Montrose, CO
Posts: 1,195
Quote:
Originally Posted by rockyota83 View Post
heres some pics for ideas

https://www.picclickimg.com/00/s/ODgxWDE1NjY=/z/HQoAAOSwzaJX-9ut/$/Brute-Trailers-Hydraulic-dovetail-gooseneck-tandem-dual-Dexter-_57.jpg

https://www.picclickimg.com/00/s/ODI0WDExMDA=/z/XU4AAOSwpLNX-9ux/$/Brute-Trailers-Hydraulic-dovetail-gooseneck-tandem-dual-Dexter-_57.jpg

http://www.norstarcompany.com/img/products/FHG03.jpg

https://d34ra0wvwxc5ex.cloudfront.ne...ail_v03QGm.jpg

http://s3.amazonaws.com/FreeClassifi...37607053_4.jpg

http://haytrailer.com/images/hydraulic2.jpg
Awesome, thanks. I saw a few of those looking on line, but it's really nice to have some specs shown in the pics you posted. Although, now that I'm looking at those pics... With my trailer being a low boy and not a deck over, I'm actually not sure I have the room to mount a ram without it dragging over every single dip or bump I come across. I'll have to go take a closer look.

Quote:
Originally Posted by maveric View Post
Is there a reason you need the dove to sit flat?
I have a 5' dove on my GN and set the rear of rigs on it all the time. The dove pops up if needed, but don't haul that way. I have ramps that slide under the center of the trailer, not flip over ramps.
Not really. The trailer has flip up ramps mounted on a pretty beefy 1" bar/hinge setup in back. I figured I could build a dovetail to mount to that and it would be strong enough. If I'm going to built it off a hinge point, migh as well take advantage of the travel that's possible.

For my purposes, a hydraulic dove is not necessarily "needed," or even a dove tail for that matter. What I truly need is another 4 ft of deck. But like most members of this forum, what I need usually takes a back seat to what might I possibly do to make this a cool/fun challenge. I mean, I don't really need an old Jeep on tons and 40s, but it was fun to build and is fun to wheel.
charlieboyd65 is online now   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Pirate4x4.Com : 4x4 and Off-Road Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.

** A VERIFICATION EMAIL IS SENT TO THIS ADDRESS TO COMPLETE REGISTRATION!! **

Email Address:
Insurance
Please select your insurance company (Optional)

Log-in


Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Adding a gooseneck hitch to a dump bed Jrod-13 Tow Rigs and Trailers 6 04-30-2016 10:46 AM
Adding a spin on hydraulic filter to trans? DirtyComanche Jeep - Non Hardcore 18 04-14-2016 07:13 PM
Adding a DCDL to a 5 ton hydraulic top loader. cerial General 4x4 Discussion 7 07-04-2013 02:33 AM
Hydraulic 4x4 Four Wheel DRIVE metro2089 General 4x4 Discussion 13 03-17-2013 09:03 PM


All times are GMT -7. The time now is 05:07 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 ©2011, Crawlability, Inc.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.