Dual Cam Setup

I think part of the problem is that the snap up brackets are not square to the frame.

So when when you tighten the pinch bolt, the snap-up get pulled flush to the side of the frame, but then it's only touching the top of the frame at the outer edge.

My guess is, since the snap up is only touching the top of the frame at the outside, that the pinch bolt is taking on a lot of the force from the spring bar that is really supposed to be handled by the bracket itself.

If enough load is present, the the pinch bolt will start to bend the frame (or the bracket will bend - or both) and the snap-up will begin to tilt down even more as the frame gives way. Once that starts to happen the snap up starts applying a point load on the side of the frame at the bottom of the snap up. So the snap up only contacts the frame in 3 places once it starts to go 1) the pinch bolt, 2) the top outer edge, and 3) the center of the frame on bottom of the snap up.
#1 and 3 are basically point loads - the bottom of of the snap up has 2 points that contact the frame and the pinch bolt obviously has a small surface area.

If the snap up goes over far enough the keeper pin for the snap up takes all that load as well and begins to bend.


Is this speculation even in the ballpark?

UGH,

Simple round trip to the dealer and the snap up bracket bent. There's a bend in frame where the pinch bolt for the snap up goes as well as 2 smaller bends where the snap up ends on the outside and 2 small bends at the top of the dual cam.


Everything was tight - and not too tight - before I left.

Here's the snap up:



What a mess.

I can't find any evidence of binding. The only sharp turn was going in/out of the driveway - which we've done 10 or 15 times before.


Now I need to fix this....

I was thinking of getting 2 1/4x6x20 steel plates and sandwiching the frame with them and using a 3/4 x .120 wall DOM tube (.510 ID) as a bolt sleeve.

Since the frame is already bent, I don't see any other option other than to reenforce it.

I would add a bolt and sleeve near the top left and bottom right of the plate so it's secured near all 4 corners (bolt top left, DC lower left(2), Snap up upper right(2), bolt lower right - driver side ).

All the bolts would be torqued to 90 ft/lbs which would hopefully lock the plates in pretty well.

The upper snap up would be tapped and threaded into the outer plate and frame.

Is this a sound plan?

mrekim wrote:

JBarca wrote:

Also in case you did not know, on 1,200# and heavier TW's, is is best to bolt on the snap up brackets as the C clamp snap up setup has been known to spring open in turns.

I have the heavy duty ones, but they do have a hole for a carriage bolt in them. How do they spring open? Do they actually bend and pop off the frame?

I found some pics on the snap-up and and failures

The bolt on by Turk2500
Truk2500 bolt on snap ups on tube frame

Snap up failure
Snap up failure

I see you found pics of Fisherguy's welded nut plates. Good.

There are others pics on the forum, I found those quick. The top springs open. How far it opens depends on the loaded TW, the WD bar size, the angle of the turn. It "depends" on if it will fall off. If you catch it the minute it bends, odds are lower. If you find is a few hours later, the flopping around may allow it to come off.

You mentioned the cap on the end of the tube frame, it may be there more to keep water out and rusting the tube than structural. I have seen them both ways.

The riv nut that is pressed in from the outside behind the frame bracket, I myself have not used them, in steel anyway. I do not see any slits in the riv nut to see if they expand out like an expanding anchor. They "look" more of what looks like a serrated tooth swedge fit to help stop anti-rotation. They seem to be able to take 75 ft lb but do not know who well that are from pull/strip out.

You will have to make the judgment call on this one. I'm over cautious on hitch work and would go a bolted solution. If you have access to a 1/2-13 tap, here is an option.

- Align DC frame plate and hold with set screw from behind.
- Ideally using a 1/2” transfer punch, prick punch the frame plate favoring the top of the large hole in the DC frame plate. Want to stay out of the frame radius if you can.
- Using 27/64 tap drill, drill through both sides of the tube.
- Using 1/2" drill, drill outside hole to center. Do not go all the way through.
- Tap inside hole 1/2-13
- Create a 3/16 or 1/4" thick backer plate with clearance holes to span the 2 inside taped bolt holes.
- Screw in long enough grade 5 or 8 hex bolts. Gently tighten and watch the inside frame to not crush the tube.
- Install backer plate.
- Install nuts and lock washers on bolts and hold bolt head while locking the nut against the backer plate.

In your case you will have to start by using the self tapping screw holes already in place. This method will work without the tapped hole, however the tap helps create a thread lock with the nut and not crush the tube. If you are really into it, tap the plate just use like 3/8 or 1/2” for the tap plate.

Let us know how this comes out.

John

Reese's official response:

Reese Tech Support wrote:
Suggest kit 58507.

Here's the kit (click on it to go to Reese web site for kit):

Reese Rivnut Install Instructions wrote:

1. Place the dual cam bracket on the
frame at the correct spot for your
installation. See dual cam instructions.

2. Use the long ½” bolt to clamp the
bracket in position.

3. Using the holes in the bracket as a
guide, drill two 7/16” holes into the
frame.

4. Remove the bracket and drill the
holes out to 11/16”. Do not ream out
the hole. This needs to be a snug fit.

5. Put the Rivet Nuts into the holes in
the frame.


6. Place the bracket over the rivet nuts,
thread the ½-13 x 1-1/2 hex head
bolts with lock washers into the holes.

7. Tighten the long ½” bolt against the
frame, ½ turn after contact with the
frame.

8. Tighten the ½” bolts on the outside of
the frame.

9. Torque to 75 ft. lbs.

I'm not 100% sure I agree with these instructions. Every other rivnut I've ever set required you to set the nut (Collapse into frame) using a special tool (you can make one from hardware store parts) and then insert the bolt for fastening.

JBarca wrote:

Several Open Roads forum members have gone to through wall bolting on tube frames with a backer plate on the inside to prevent tube crush. Turk2500 has done this. He has pics of it, I'll see if I can find them. A search may turn them up.

I can picture this. I've also seen where the back side gets a bigger hole and a "pipe" is inserted into the frame with a length that ends up flush with the frame at the larger hole. A grade 8 washer is used on the side with the larger hole and the "pipe" prevents the frame from crushing.

JBarca wrote:

If the ends of the A frame rail tubes are open one member, Fisherguy, created a tap plate, a plate with 2 nuts welded on it and he then slid that down the open frame tube to hold the nut inside. He has pics on here as well.

Here's one pic (click to jump to thread):






This is another good idea. My A-Frame ends are welded shut, but I could see cutting an access hole for the plate in the end, sliding the plate in and then expoxy/jb welding the access hole shut. Is there any possible way the "caps" on the tube are structural?



I was thinking of getting some rivnuts.




You drill a properly sized hole (5/8 for these) and insert the rivnut. Then you collapse the rivnut and it clamps to the frame.


I was also thinking about a square U-Bolt. My propane tanks are mounted with screws, it would be pretty easy (I think) to move them up a little.

JBarca wrote:

While in your case, lack of grip or torque may well be the cause, if the DC frame plate is not dead tight and flush to the bottom of the A frame rail, this can and will allow the frame plate to rock around causing the problem and pulling on the screws. I thought you used a C clamp when setting up, so I'm thinking the self tapping screws are not going to cut it on your rig.

I did use a C clamp when setting up, and I don't think there was a gap when I finished... I wet out to measure any gap with a feeler gauge. I didn't measure it because I need to adjust some more. It looks like the inside, the side with the jam nut, slipped down some so there's a fairly large "angled" gap right now.


Here's a photo I found while hunting around for ideas that's similar to my "angled gap":

JBarca wrote:

Think forward to converting to bolts. Sooner or later they will rear their ugly head again.

This was just 4 hours of driving. This looks like a real problem. I'm going to have to do something asap.

JBarca wrote:

Also in case you did not know, on 1,200# and heavier TW's, is is best to bolt on the snap up brackets as the C clamp snap up setup has been known to spring open in turns.

I have the heavy duty ones, but they do have a hole for a carriage bolt in them. How do they spring open? Do they actually bend and pop off the frame?

JBarca wrote:
PS. How was camping in the new rig!

It went well. We had crummy weather so we spent a lot of time in the trailer. We were happy to have all that floor space.

The stripping of self tapping screws is a known problem. I myself do not have any faith in self taping screws on a hitch. My frame is channel iron so can easily use bolts and nuts with lock washers.

Several Open Roads forum members have gone to through wall bolting on tube frames with a backer plate on the inside to prevent tube crush. Turk2500 has done this. He has pics of it, I'll see if I can find them. A search may turn them up.

If the ends of the A frame rail tubes are open one member, Fisherguy, created a tap plate, a plate with 2 nuts welded on it and he then slid that down the open frame tube to hold the nut inside. He has pics on here as well.

Others have done other versions of this as well, just those 2 fellow campers I know and knew how they worked through it.

While in your case, lack of grip or torque may well be the cause, if the DC frame plate is not dead tight and flush to the bottom of the A frame rail, this can and will allow the frame plate to rock around causing the problem and pulling on the screws. I thought you used a C clamp when setting up, so I'm thinking the self tapping screws are not going to cut it on your rig.

Think forward to converting to bolts. Sooner or later they will rear their ugly head again.

Also in case you did not know, on 1,200# and heavier TW's, is is best to bolt on the snap up brackets as the C clamp snap up setup has been known to spring open in turns. Reese came out with heavy duty snap up to help offset this to create a no drill situation, however before that, if you called them, they told me there are no issues bolting them on. And I did.

I have had my original ones bolted on since 2003 and running 1,200# and now 1,600# TW's with 1,700# bars and have not had a problem with the snap up flaring open. I used carriage bolts as they fit in the square pre-punched holes Reese put in them. Others have used hex bolts. I suggest if you do drill them on, favor the top of the hole with the drill bit in the snap up so the bolt shank is touching the snap up verses the snap up having to sag down to meet it.

Hope this helps.

John

PS. How was camping in the new rig!

We had a 4 hour shakedown run. Most of the time it was windy. How windy? That's hard to say, gusts strong enough to pull the car or trailer door out of your hand. Strong enough to blow a baseball cap off.

I did feel like I was getting blown around some, but not as if the trailer was going one way and I was going the other, if that makes sense.

Now, possibly more importantly, after about 4-5 hours of drive time the 1/2-13 self tapping bolts for the dual cam were a little loose. They were originally tightened to 35 ft/lbs not the 50 ft/lbs specified in the install manual.

I don't understand how that manual can provide a torque value without knowing the wall thickness you are using. A thicker wall is going to support more torque vs a thin one....

As far as I can tell the bolt is going into 1/8" thick metal, that's really only 1.6 (13 threads/inch * 1/8 inch) threads for holding the bolt in. I don't have a warm fuzzy feeling about that.

I could not measure the wall thickness of the frame tube, but I measured the end cap and am assuming it's the same thickness as the frame tube.

There's no way my frame was going to support 50ft lbs. It's hard to explain but you can feel when your "pushing it". As you turn the bolt, it continues to get harder to turn and eventually it doesn't get any harder to turn and if you keep going, it just strips out. 35 ft/lbs was as much as I was will to "push it". I used red lock-tite and reapplied it when I re-torqued the bolts. I don't think there are enough threads for it to do it's thing though.

I'm going to see what Reese says about the self tapping bolts, but I think a different fastener might be be more appropriate.

JBarca wrote:

Also you said you only had 1 more notch of head tilt left,

Sorry, I meant that I was going to adjust 1 notch.

JBarca wrote:
I'm sure you now have a battery ~ 35 # and odds are high the dealer filled the LP which is 63# for 2, 30# LP tanks. So there is 98# of camper overhead before camping gear.

That sounds about right. I'm going to have to get spring upgrades onto the short list.

JBarca wrote:

As a point of ref, a 2005 EX, 4 x 4 V10 is 7980 GVW split 3620 front and 4360 rear axle with full fuel

Yes, its a diesel. The 3rd row seat is not in.

I found a Ford PDF file with some specs Weights are (front/rear/total):


Mine........................4360 3800 8160
4x4 W/7.3L V-8 Turbo Diesel 4062 3626 7688
4x4 W/6.8L V-10.............3575 3615 7190

Mine's not really that far off. ~500 lbs - considering people, fuel, the hitch and WD bars, added factory options.

I also found this (for diesel):

OEM Wheels (all options capacity 3415)
Front Spring Capacity 4700 (Door sticker value)
Rear Spring Capacity 5250 (Door sticker value)
Rear Axle capacity 6830
Front Axle capacity 5200

For the V10 they use a lower front spring capacity of 4100 lbs. So it appears that even Ford uses a strategy of swapping springs to improve load capacity.


An upgrade to F250 or F350 springs to leverage the underutilized axle capacity in order to support a fully loaded hitch and cabin seems pretty reasonable.

mrekim wrote:


Tongue Weight........1080
Trailer Weight.........7970
% Tongue Weight...13.5%

I'm still about 340lbs light in the front. I suspect I may be able to tilt the ball down one more notch. I can't get back to the scales to check, but as long as the front doesn't drop more than a tiny amt (1/4" or less) from no load I should be good - does that make sense?

Factory sticker weight was 7386, there's 49 gal of water in there (400lbs) so the trailer only has about 200 lbs. of "stuff" in it right now.

Your right on that the front of the EX is light. Use the tape measure to get the fender height back to unhitched as a good place to start. Heads up, the truck is not built equal left to right weight/height. So go back the same fender numbers on left and right before and after in returning back to unhitched.

Also you said you only had 1 more notch of head tilt left, well lets talk on that as if you really used all 14 degrees of that hitch head tilt there is a problem. But... I think you may fell your out of head tilt as the serrated washer will run out of teeth forged in the head, right? If so that is not correct. That hitch head can go a full 14 degrees back.

This is the 3 piece head at 15 deg but the all cast is 14.


Reese states the teeth must line up. However if you call them they will tell you the head can go all the back until you run out of radial slot in the bolt hole. In this position maybe only 1/2 to 3/4 of the teeth are engaged but there is still plenty to carry the load. Reese never said you had to have 100% teeth engaged for full rating. I suspect you have used approx 6 to 7 deg of rear tilt. You have a lot yet to go.

Also the TT weights, your 200# of stuff, might be less of stuff actually. The weight sticker of 7,386# is that what they state is UVW (unloaded vehicle weight) If so, that "normally" means no battery and no LP in the tanks. I'm sure you now have a battery ~ 35 # and odds are high the dealer filled the LP which is 63# for 2, 30# LP tanks. So there is 98# of camper overhead before camping gear.

The good news is your at 13.5% now and very little gear. My prediction of the TW going up quick once you start loading the camper I suspect will come true. It is not hard from where you are at to get to 15%

Your doing good. Keep it up.

John

PS, dog gone, your EX weighs a lot... It weighs more than my F350 empty and my buddies 2005 EX with the V10. And your fuel is low? You must have the diesel up front. Even your front axle weight shows it a lot more than the V10. And you might have the 3rd row seat in. As a point of ref, a 2005 EX, 4 x 4 V10 is 7980 GVW split 3620 front and 4360 rear axle with full fuel

I got the 1" other ball on and an initial pass at leveling and made it to a scale. This is with driver and passenger and 1/4 tank of fuel (so could have about 33 gallons (~234#) more):


.................Front Axle.....Rear Axle..Trailer Axles..Total
WD.................4020............4940........7260.........16220
No WD.............3800...........5440........6800.........16040
Truck Only.......4360...........3800.........................8160
Tongue Weight........1080
Trailer Weight.........7970
% Tongue Weight...13.5%

I'm still about 340lbs light in the front. I tilted the ball 1 more notch and got to a drop of 1/8" and 0" on the other side.

In about the same location it was +1/16, +1/8 before the adjustment. I didn't realize I could dial in the front in such small increments.


Factory sticker weight was 7386, there's 49 gal of water in there (~400lbs) so the trailer only has about 200 lbs. of "stuff" in it right now.