OBS F250 slow adventure build

[underdrive]

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.

Well with my idea you can still use your current SS lines, the only difference between what I suggested and what you came up with (which, again, is exactly the factory '70s setup so tested and reliable) is my way you need an extra SS line and an extra hard line. The advantage though is that you don't have a long flexible line dangling there waiting to be snagged on something - which, admittedly, may not be a major concern at all.

For the rear you shouldn't need to do anything at all. The factory setup has the fronts and rears completely separate, the front line comes down from the master to the driver-side hose and splits off towards the passenger side there, the rear line comes down from the master and right into the RABS unit, and from there it shoots all the way back to above the rear axle. If your rear is currently t-eed off the front driver side then it's been monkeyed with, and you need to address that ASAP as should you lose front brakes it will take the rears out as well - with the factory split setup you can lose one axle and still have the other one in the game, pedal will sink nearly to the floor of course but you will still be building pressure in the good brakes.

 

[amgvr4]

We got the cance to do some more exploring today. I took the family up some forest service roads around Darrington looking for some new places to go shooting that are off the beaten path. Driving by the Oso slide is always a sobering reminder how destructive nature can be. The drive was pretty uneventful until I almost got stuck just trying to turn around on a section of road that was icy yet had a ditch with soft mud. Without 4x4 I got the heavy front end stuck into the soft ditch and the back tires just couldn't get enough grip to pull me out. I had to do some work with the shovel and back down the trail instead of turning around. If I had 4x4 it would have been no problem at all, so I have moved the front drive shaft up to the top of the priorities list.

There are several issues I have to work out to get power to the front. First is the transfercase output flange. I will probably have to order one of these so the double cv arrangement of the f350 shaft will bolt up. The factory part is no longer available and used ones are impossible to find.

http://www.ebay.com/itm/4407-TRANSF...Parts_Accessories&hash=item4614c9a0ae&vxp=mtr

The second is that the f350 shaft is too short. The f250 one is probably long enough, but with the single u-joint at the t-case there is too much angulation at normal ride hight for my liking. It might even contact the trans crossmember when the axle is at full droop. I decided to take a look at the two shafts side by side and see what the best way to lengthen the f350 one would be. Upon first glance I noticed that the diff side of the slip yoke was longer on the f250 shaft. I got excited thinking I might be able to just swap over the yokes and be done. Turns out the two shafts have different diameters and spline type. After some quick measurements I discovered the f250 slip is larger in diameter and has a longer spline engagement. The only thing that bothers me is the splines are much smaller and I'm not sure if they are weaker or not by design. I think my best option is to cut the f250 slip yoke off and weld them onto the f350 shaft. That should give me the extra length I need and even though I don't need a long travel slip yoke, the extra spline engagement will be nice peace of mind.

The slips, f350 top f250 bottom



F350 left f250 right. The slip yoke is what makes the 250 shaft longer. As an added bonus the f250 u-joint yoke is beefier as well


Dimensions for the f350 shaft




F250


The spline diameter is the only thing that is the same



Here are some pictures from the drive

 

[underdrive]

Nice digital calipers!

Regarding the yoke, we have a factory F350 yoke from a BW 1356 case, if you can wait till tomorrow I'll dig it out and measure it up - if it matches the dimensions listed in that ebay auction you may be able to save yourself some cash and try use a rear yoke out of a 1356-equipped Bronco (they have CV rear shafts due to length), should be the same thing as the F350 front CV yoke sans possibly the dirt slinger that hides the shaft seal.

Regarding driveshaft splines, seriously doubt the F250 front shaft is any weaker than the F350 one. It's true the splines are smaller, but there are a whole lot more of them now, and what's more important, the shaft's minor diameter is actually larger than the F350 one. What's that F350 shaft out of anyways, was it a Powerstroke truck? Cause you know for a fact the F250 one was matched to a PSD engine on the assembly line, if the 1-ton shaft was turned by a small-block it would make some sense for it to be smaller in diameters. In any case, the shafts being different OD is where the problem will lie, unless you turn the F250 splined end down to fit into the F350 tube (assuming it has enough flange thickness for that, which you'll find out once you've cut it off). Another option would be to make a sleeve to adapt the CV end off the F350 shaft to the larger F250 tube... Unless the F250 tube has 1/8"-thick wall and you can just chop the CV end off the F350 shaft together with some of its tube and just drop it into the F250 shaft - but there's no way you'll be that lucky, this is a Ford we're talking about here after all

 

[amgvr4]

Regarding the yoke, we have a factory F350 yoke from a BW 1356 case, if you can wait till tomorrow I'll dig it out and measure it up - if it matches the dimensions listed in that ebay auction you may be able to save yourself some cash and try use a rear yoke out of a 1356-equipped Bronco (they have CV rear shafts due to length), should be the same thing as the F350 front CV yoke sans possibly the dirt slinger that hides the shaft seal.

As far as I am aware of there is no alternate for the front output flange on the BW 4407 t-cases. Apparently they have a unique spline that is not found on any other t-case or application. I am pretty sure only the earlier trucks got the 1356 and the '94.5 and up got the 4407. My plan is to order one of the Ebay ones today and get the u-joints from napa so I will be ready to get this thing put together when the yoke shows up.

Regarding driveshaft splines, seriously doubt the F250 front shaft is any weaker than the F350 one. It's true the splines are smaller, but there are a whole lot more of them now, and what's more important, the shaft's minor diameter is actually larger than the F350 one. What's that F350 shaft out of anyways, was it a Powerstroke truck? Cause you know for a fact the F250 one was matched to a PSD engine on the assembly line, if the 1-ton shaft was turned by a small-block it would make some sense for it to be smaller in diameters. In any case, the shafts being different OD is where the problem will lie, unless you turn the F250 splined end down to fit into the F350 tube (assuming it has enough flange thickness for that, which you'll find out once you've cut it off). Another option would be to make a sleeve to adapt the CV end off the F350 shaft to the larger F250 tube... Unless the F250 tube has 1/8"-thick wall and you can just chop the CV end off the F350 shaft together with some of its tube and just drop it into the F250 shaft - but there's no way you'll be that lucky, this is a Ford we're talking about here after all

My gut feeling is the same as yours. I think that the F250 spline section is stronger mostly because it does not neck down as much after the splines. The smaller splines might be easier to strip, but since there is so much more surface area it should have more strength. My plan was to turn down the larger diameter of the F250 tube end to fit the smaller tube on the F350 shaft, but if there isn't enough material I will have to sleeve it like you suggest. It would be interesting to check a later F350 shaft and see if they use the same splines as my '96 f250 one and find out if the difference is production year related or axle type. The f350 shaft I have came from a '92 IDI truck that I got with first D60 I bought then later sold.

I also need to order the rear spring bushings and a few other odds and ends to get the back started. I made a point not to go out into the garage at all this holiday break and spend it with the family, but my fabrication fingers are getting twitchy to get the back end done.

 

[seanpistol]

Interesting!!

 

[underdrive]

As far as I am aware of there is no alternate for the front output flange on the BW 4407 t-cases. Apparently they have a unique spline that is not found on any other t-case or application. I am pretty sure only the earlier trucks got the 1356 and the '94.5 and up got the 4407.

Ah, OK. For all you know it could be like the differences between older BW and NP yokes, some have the same dimensions and numbers of teeth but the tooth profile is slightly different so they won't interchange - truly maddening experience this is. The driveshaft, I'd just sleeve it. Larger tube is stronger, and you don't have to worry about getting the splined end true to the tube.

 

[amgvr4]

Today I finally got around to putting the limit straps on the front. I wasn't really in a hurry since I have yet to fully extend the shocks yet. I am pretty sure that the only way I will be able to take full advantage of the shock travel will be to temporarily disconnect the top link on the passenger side essentially turning it into a three link setup. I will give that a shot here in the near future and see how it works. I also got a chance to mock up the drive shaft to figure out if my plan of switching the slip yoke from the f250 shaft to the smaller diameter f350 shaft with cv joint will work. Looks like it should be a perfect combo for what I need.

Here is the f250 shaft in. This is at ride hight, barely any clearance over the trans crossmember



There is really good spline engagement with the f250 slip yoke


There is too much angulation even at ride hight


The combination of the larger diameter tube and single u-joint causes the tube to hit the crossmember at only 8" of shock droop



Here is the f350 shaft in place. The spline engagement is less than desirable even at ride hight


U-joint is much better looking. The best part is that the longer joint assembly moves the shaft pivot to almost the exact same plane as the radius arm pivots. That helps the drive line length vary by only about .75" throughout the suspension travel


Much better clearance with the f350 shaft. This is at about 10" of shock droop



Definitely not enough engagement with the f350 slip yoke.


Angle looks better as well

 

[amgvr4]

Next I got the limit straps on. I limited the droop to about 10.75" so that when the straps stretch they should end up just shy of the full 12" of travel. The reality is that I will probably almost never get that close to full droop due to the bind in the radius arms. If I set it up so I can convert it to a three link for difficult trails then it might be a different story though

Hanging on the straps




Just a simple bolt through the frame up top


At ride hight



The lower is mounted with the top link bolt. This was about as easy as it gets and should work super well considering it will really ever be called into action.

With the straps on I finally got to try and flex it as much as possible. Up to now I was a little leery of over extending the shocks and damaging them. I went to the little dirt hill by my house that I got some before shots on with the d50. Looking back at them made me LOL! Man this thing was pathetic before. The pictures don't really do it justice for how well it flexes now.

Before

This was as high as I could make it up in 2x4 before the rear tires lost grip and started to lift






After

The bank was much softer today and the ground was wet so traction was limited compared to the initial test. Even so it was amazing how much better it did and this is far from using full travel of the shocks








I backed up on the same hill


This is the closest I have ever gotten to full stuff. It is actually on the bump stop here. It also rubbed on the back of the wheel well a little. I will need to trim them a little at some point




The hill was so soft the rear hardly flexed at all. It will be cool to see the improvement when the shackle reversal is done



I am pretty sure that with the rear done and 4x4 it will walk right up this hill without lifting any tires. Pretty cool for a one ton crew cab truck. I will defiantly get some video of it when it is all done

 

[amgvr4]

I got my bushings for the rear springs and t-case flange ordered and they should be here by the weekend. I might be able to get both things done this weekend if all goes well. I also spent a bunch of time looking at roof top tents over the Christmas holiday and my wife and I feel that would be the best solution for what we want to do with the truck. We looked at everything from a normal tent on the ground to a slide in camper and everything else had some draw backs that we were not happy with. I really like the CVT MT. McKinley 4 person tent and as a bonus they are within driving range in Bend Oregon.

http://www.cascadiatents.com/Mt-McKinley-Roof-Top-Tents.htm?m=87&s=615&&id=133

Depending on how tax season plays out and if I can sell my Volvo I might be able to get one by this spring so we can make good use of it this upcoming season. My plan would be to make a low rise bed platform or it to mount on that keeps it below the roof line when folded. That way we can stow all our gear below it comfortably.

 

[java]

That looks great. Im still amazed what people can build in their driveways!

When do you think it will be 4x4? NWOL is doing a snow run on the 17th

 

[underdrive]

That looks great. Im still amazed what people can build in their driveways!

I know right? Persistence is key, and willingness to give up some ground and drastically change directions if a way is found to make things work better. Like what the OP did here, how many times did he redesign the front suspension? LOL

When do you think it will be 4x4? NWOL is doing a snow run on the 17th

You must have missed it, his transfer case yoke and his rear spring parts are hopefully arriving by the weekend, so if the stars align for him on Monday he'd be rocking the 4x4 with a whole week to test things out quick and work any bugs out before your event.

 

[Sooper Camper]

I ran into constant issues with that cross member until I modified it to work with a longer travel suspension:

Are you sure the double cardan has enough travel? I clearanced the yokes on the stock t-case yoke and never had an issue. Double cardans usually have less angle capacity(if you've ever wondered how High Angle Driveline gets the extra angle...it involves a grinder). Also, shouldn't the female slip be at the t-case? That's how mine always was... good progress though, an RTT will be perfect for what you want to do, That's my plan with my truck as well.

 

[amgvr4]

Java;

Thank you for the encouragement. I often wish that I could work form the comfort of a nice clean heated shop with all the tools my heart desires, but there is a certain amount of pride that comes from knowing that it is being built in my driveway with a lot of improvisation. I really hope it is ready but the 17th, but That is my anniversary so I might not be able to make it. I will have to talk to the wife and see what she thinks, if we get back early enough there would still be time to go out for dinner! I will hop back on NWOL and see if I can get some more details and make it work.

Underdrive;

I appreciate that you are reading the thread closely enough to be able to help answer questions for me! That's true dedication, and all the very useful information you have added to the thread is awesome as well. I love the way good forums like this add so much to communities of enthusiast even though we are spread all over the globe.

Sooper Camper;

I may have to do a cross member mod similar to yours to get full articulation, but I wont know for sure until I get everything together. The CV helps a ton because it extends the u-joint with the most angle out several inches from the t-case. I will check the clearances when I have the new t-case yoke so I can actually bolt it up. So far I have only been able to hold it in place and is does not want to stay there since it is too short with the wrong slip spline. Also both the f250 and f350 shafts have the slip at the diff end of them so that is how I am planning on using my hybrid shaft. I am really looking forward to getting a RTT and hitting the trail this spring-fall, I just need to get some networking going with other people so we can make some multi-family adventures happen this year.

I may have my have gotten myself in trouble today when I saw one of the new Dodge trucks with the factory four link rear ends. It got me thinking about doing that to the rear of my truck in the future to complement the front. I might even be able to use the coil springs that I was going to use in the front of the truck as they would have a lot less weight on them in that back and I could still use my Fox 2.0 RR shocks I already have. The only thing I would need are some link brackets , jonny joints, and dom. Lol! My wife would kill me if I did that now, but If I make the shackle flip bolt on then I can always sell it later and go four link when I have some more time to do it right. I would probably cost less than a good set of Deaver leafs.

 

[snowaddict91]

My plan would be to make a low rise bed platform or it to mount on that keeps it below the roof line when folded. That way we can stow all our gear below it comfortably.

Nice, looking forward to see what you come up with! I have thought about ditching the topper and going this direction with some sort of quick release rack, but the topper seems a better fit with the dogs.

 

[Sooper Camper]

the linked Dodges do drive really nice, and I know where you can get a killer deal on all the parts you'd need for the links...