OBS F250 slow adventure build

[Regcabguy]

We've got a really nice square Fummins in San Diego. Same body configuration as the Op's in white. It roared past me on the freeway awhile back. I still like the older square Fords with wind wings.

 

[underdrive]

The rear cab mounts on these crew cabs are pretty close together- in the ball park of two feet (I've never measured them). They are also REALLY soft and flexible. Aftermarket rear cab mounts can be really stiff. I've heard of guys actually taking aftermarkets off and putting factory ones back on.

Ah yes, I forgot to mention that, thanks for catching it - this problem is even more evident with polyurethane mounts. However, I seem to recall hearing through the grapevine that factory mounts are either running low on stock and priced way high, or straight not available. Haven't personally verified that as our needs are not quite dire yet, but when the time comes if factory is not an option then we'll drop the poly in and inboard the rear mounts as far as they'll go - won't make the truck ride any nicer, but it will allow the frame to do its thing without taking the cab along for the ride.

I guess that is the great debate, is there anything detrimental about frame flex or is it part of the engineered function of the frame? If it doesn't cause any real problems then I am fine with it. My full length sliders I want to build will help and once the rear is done it won't put so much of the load on the frame since the suspension will move more freely.

I wouldn't think you will hurt the frame if you leave it unboxed. It's designed to twist, if anything by boxing it you may make it too rigid and cause it to develop cracks. Of course it also depends on how you box it... It's your call, if you got another project that's been demanding your attention I'd focus on that and don't worry about the frame. And like you said sliders will help some, especially if you overkill them good. Regarding the rear suspension, our plans as of right now involve ditching the stiff 1-ton packs and going with a high-arch halfton ones for ride comfort when empty, then gain the cargo capacity back with a pair of air springs on top of the leafs. Springs will be filled/dumped individually via 1/4" air lines, and there will be a larger (likely 3/8") crossover line between them with a valve - on pavement valve is closed and each air spring does its own thing, when suspension flex is needed valve is open and air can transfer side to side allowing the axle to hug the terrain better. Eventually the front axle will receive the same treatment as well. Ah, the endless possibilities OBA setups allow for... lol

Good luck with the radius arms. Actually just thought of something, would it be possible to just bolt them to the inboard side of the inner plate you have now, then add a new inner plate to that (and reinforce the heck out of it accordingly of course)? Basically that will move the RAs right around 2" inboard without messing with your coilover mounts. So when you look at your new RA mounts with the RAs removed, instead of the two current vertical plates the RAs fit between, there will be three vertical plates - your outer one remains in place, your currently inner one also remains in place but becomes a middle one, and then you have your new inner plate. To someone else it would look as if you have two mounting positions for the RAs, but only you'll know that the outer one (aka your current one) cannot be used due to tire clearance issues... If you use long enough bolts to pass through all three plates (gonna need spacers around them between outer and middle plates where the RAs currently live) that will help with overall strength as well. What do you think, yay or nay?

 

[amgvr4]

I was thinking about trying something like your inboarding idea. I am not sure if there is enough angulation in the jonny joints to account for moving the pivots. I'm going to try the easy way first and se where that gets me.

 

[underdrive]

What if you inboard both the bushings at the axle and the pivots at the frame together, can you do that? Should keep everything at about the same angles as they are now.

 

[Seabass]

Underdrive... I hadn't heard they were running low on stock of factory mounts. But, these trucks are getting older now- and I'm fine with that. Both of my current OBS trucks have many years of service left. I've actually managed to "supplement" my factory cab mounts. Both of my trucks began to sit low on the passenger rear. So I jacked the cabs up and slipped a John Deere 4430's front upper cab mount bushing right beside the factory cab mount on the outboard side of the trucks factory mount. It's just sitting there. No holes no nothing. There's a pocket there in the floor pan and it's still double thick since it's so close to the factory mount. There's also a rivet in the frame there that locks the extra mount in place when the cab is set back down. I ran a really thick heavy duty zip tie all the way around both mounts for those occasions when I'm really twisting the frame and the cab come off the frame enough that the extra mount could possibly fall off. On both trucks the tractor cab mount was just enough to line the body lines up. I can't believe how well it works. The tractor mounts really compress- I can't tell that they are hurting anything. There's no metal sleeve in it that I could find-I'm pretty sure the cab bolt on the tractor had a shoulder. So it should never hurt anything if it gets completely crushed.

Here's a pic of one. It kinda shows the JD part number. I had them laying around from a tractor repair where I thought I needed them but didn't. I can't remember what they cost- they could be higher than the factory mounts for all I know. But it shows another option to keep running. I did them three years ago on my work truck- 75%off road 25% paved roads. It's used hard! They are still in it and it sits level and nice. So now I'm gonna quit cause I've high jacked this thread over cab mounts. Sorry guys.

 

[underdrive]

Looks like "FR-59872-0"? That's some good info there, soft and fat rubber mounts may just be what does the trick for our truck, she rides really rough when empty so every little bit of insulation will help. Thanks!

 

[Seabass]

Underdrive I've got a few more pics of that cab mount- that looks like the part number to me. I'll try to get a pic of that mount nestled in the pocket under the cab. I never dreamed they'd work that good so I never took pictures of them going in.

 

[Sooper Camper]

Looks great! Get a little weight in the back/soften it up and it will balance out much better when you articulate it.

I wouldn't worry too much about frame flex, all these older trucks do that by design. Just keep an eye on the old I-beam cross member rivets, those are the ones most prone to stretching/ovalizing in my experience. I had to replace some of them with bolts on my old Bronco, but once the bolts were in an torqued never had an issue after that.

 

[amgvr4]

What if you inboard both the bushings at the axle and the pivots at the frame together, can you do that? Should keep everything at about the same angles as they are now.

I could try it in single sheer without any weight on it to make sure the angles would stay the same. I will take a look at it to see if the old driver side leaf mount is in the way or not. I have mulled over the idea of using some modified f150 rear springs to add more flex and a better ride. I also was thinking of getting some air springs and making quick disconnects for them so I could have them in there only when I need them. The front is so nice right now and the back is buck board stiff. It would be cool to have a better balance for 90% of what I do with the truck.

Seabass;

I appreciate the info you are providing so I don't consider it a hijack. The entire point of this build it to help other people with these trucks learn how to make them awesome! Thanks guys.

 

[underdrive]

For the air springs, you may wanna look into lower buckets made by Daystar IIRC - basically your air spring bolts to the frame and the bucket bolts to the axle, when the spring is inflated the bucket centers it over the axle. However, if you flex the suspension a lot when your down-travel exceeds the length of the air spring it will "disconnect" (kinda, since it was never truly connected to it in the first place) from its bucket and allow the axle to proceed further drooping. Then when compression follows and axle moves back up again, the spring meets the bucket and centers in it and all is good. The obvious downside is that while the spring is separated from its bucket it does not help carry any of the load placed over the axle.

What we have planned for our truck is a full set of 7" springs, double-bellows up front (capable of 9" extension) and triples in the rear (capable of 14" extension). With the rear shackles moved down to trailer hitch level and the 2" lift blocks removed and the extra-thick leaf packs replaced by the thinner halfton ones there should be plenty of space for the triple-bellow springs between the axle and the bottom of the frame rails. They can't fit on the outside like some people run them because they are too fat and leave only about 1/2" clearance to the tire on one side and the frame rail on the other, way too close for comfort IMHO. Front springs will be under the frame rails as well, protected from the tires by the shocks.

 

[amgvr4]

First trip up the mountain

Well I couldn't wait any more to get the truck out in the mountains and test it out. Since the rear is still not done and I don't have a front drive line it was not a full test and there are several obstacles that I want to try but I need 4x4 to clear them. I am still in need of a f350 transfer case drive flange and I need to lengthen the f350 drive line to accommodate the shifting of the axle forward. The wife wanted some free time to go shopping so I took the kiddos up to the top of Mt. Pilchuck to see if there was any snow to play in. Mt. Pilchuck or "mountain Pilchuck" as the girls have named it is our go to exploring area since it is only about 45 min away and offers plenty of fun stuff to do. Some of the water crossings were as large and deep as I have ever seen them, but the truck had no problem at all in 2x4 making it everywhere we went. I love these tires! They were excellent when I had them on my pathfinder and they are on this truck as well. They have so much grip in the snow and mud and I never felt like I would have needed 4x4 for anything that we did. There was even a large washout that I have several pictures of on here that I have always needed 4x4 to make it up. It always caused enough flex to lift the pass side rear tire and force me to engage the transfercase. Not this time, with the new front end I was able to walk up it with only minimal wheel slip and no running start. The truck was also much better on the terrible braking bumps that made the dirt road almost un-passable before. The ruts and washboards were so bad with the d50 that it would bounce me almost off the road unless I was going 5-10 mph. Today I was able to hold a steady 20-25mph no problem and the pot holes were very manageable when you have 5" of plush coilover to soak them up.

In a testament to the many hours I spent making sure the track bar and drag link were the same length and angle I had zero bump steer or unwanted contact of any kind. I would like to come up with a better way to route the brake lines just for piece of mind. The best solution would be to make a single drop line in the center of the axle and get rid of the current configuration. I also might try and figure out a way to bolt a f350 front sway bar on so that it is easily removable just to ad a little more stability on the windy mountain roads. It is not that bad, but I would like it to be easy for my wife to drive it if needed and not worry about the body roll freaking her out. She is a good driver and has driven many of my ridiculous rigs over the years, but ultimately this truck needs to be as family friendly as I can make it. We are going to make a big effort to go camping as much as we can this upcoming year so I will also have to test it out with a load to see how that changes the dynamics.

My old pathy tore it up in 2x4 with its Goodyear MTRs



The old junk on my favorite washout



The same washout today




I fount a new little run of burms with a deep puddle that I really want to try when it is 4x4 again. I did some hard parking while checking it out.




The kiddos having fun


There was a good 8" of snow at the top and it was coming down pretty good.


The truck photo-bombed this one. lol

 

[underdrive]

I would like to come up with a better way to route the brake lines just for piece of mind. The best solution would be to make a single drop line in the center of the axle and get rid of the current configuration.

That is exactly how '70s trucks are set up. There's no functional downside to it, since these trucks don't have front ABS you can do whatever you please. If it were my truck I'd run the line off the master to the frame-side mount of the trac bar, short piece of stainless hose to get on the bar, solid line till bottom end of bar, another flexible hose to get on the axle, then split there for passenger side caliper hose, run solid line along axle to driver side, and end with the other caliper hose there. You can flex the heck out of your suspension and brakes won't care one bit.

 

[Seabass]

Man I've enjoyed your build! It's so great to see you using it after all that work. And it's also great to see your kids with you while you play! Congratulations on a job well done- I am really looking forward to seeing the rear finished up. Are you planning a topper or slide in? Or are you pulling a camper? I'm just curious. That truck would be mad sweet with a flat top topper and a custom basket on it- kinda like my setup- only yours would be better because you'd probably build it your self ant it'd be a lot stronger. Anyway- carry on!

 

[seanpistol]

Can't wait to see what you do with the rear.

 

[amgvr4]

Man I've enjoyed your build! It's so great to see you using it after all that work. And it's also great to see your kids with you while you play! Congratulations on a job well done- I am really looking forward to seeing the rear finished up. Are you planning a topper or slide in? Or are you pulling a camper? I'm just curious. That truck would be mad sweet with a flat top topper and a custom basket on it- kinda like my setup- only yours would be better because you'd probably build it your self ant it'd be a lot stronger. Anyway- carry on!

Thanks I try to keep it worth a read. The kids love going out exploring and will really like camping as well I think. The prospect of a chance to play in the snow didn't hurt either! Right now the plan is to find a good deal on a used standard height canopy and build a simple sleeping platform in the bed and try that out. If it is too crammed with the five of us I will make a simple sleeping platform from pvc tubing for my son to hang in the cab. I would love to make a roof rack for over the cab to mount some recovery gear and throw in some gear bags when needed, however my real motivation is probably more for looks than anything else. I love the look of a crew cab with a roof rack on top! I wanted a FWC slide in for a bit, but with my recent run in with the HOA it appears that I have no place to keep one so that is out of the picture.

That is exactly how '70s trucks are set up. There's no functional downside to it, since these trucks don't have front ABS you can do whatever you please. If it were my truck I'd run the line off the master to the frame-side mount of the trac bar, short piece of stainless hose to get on the bar, solid line till bottom end of bar, another flexible hose to get on the axle, then split there for passenger side caliper hose, run solid line along axle to driver side, and end with the other caliper hose there. You can flex the heck out of your suspension and brakes won't care one bit.

I am not sure exactly how I will do it, but I never though of doing what you are suggesting. That is a pretty clever idea you have there. I will probably do some variation of a new hard line from the MC to to a single SS line over the center of the axle, then down to a tee on the axle itself. With this method I can still make use of the SS lines I had made fort he calipers and only need two simple hard lines and one simple flexible. I will need a new hard line for the rear since they are teed off the drives side front from the factory.

Can't wait to see what you do with the rear.

Same here, lol! After the front went from a simple shackle reversal to coilovers and radius arms who knows what I will end up with. Though my wife would kill me if I turn this into anything more complex than a shackle flip and spring referb.