For now I will be doing mostly reliability mods and maintenance stuff. I do plan to install a 5th wheel hitch and make the subframe / box semi-easily removable. Down the line a small lift and super singles maybe, but I want to keep the truck stable, so that won't come until I've had a lot of real world driving with it fully loaded. If you have any suggestions for drivability / stability mods, I'm very interested.
2003 F550 No Limit
- Thread starter Krangmang
- Start date
Update 12/14/2024 in this post: https://expeditionportal.com/forum/threads/2003-f550-no-limit.246668/post-3198393
It's never a bad idea to start with an engine monitor with an EGT add on. Edge CTS3 is what I'm using. Even if you plan on leaving the engine stock the monitor has a lot of useful information. Monitoring EGT is a good idea for a heavy truck especially if you plan to tow.
Upgrading the trans cooler is a good idea if it hasn't been done. Mishimoto has a nice upgrade for the 7.3L, assuming this is an auto trans rig.
An expensive mod but worth it IMO for a heavy off road truck are the Dynatrac rebuildable ball joints. They are pricey but once installed they can be rebuilt in vehicle.
None are required but would be good reliability options.
Dynatrac has a few things I would like to eventually do, the ball joints are already on the list when they need to get replaced, but I'm also looking at the free spin kit. If I ever decide to run super singles I would want to address the hub wear for sure, those big heavy wheels and tires will put a lot more strain on them. Steering is also something I'm trying to figure out, getting better steering feel and less dead space in the wheel would be awesome. Adjustable track bar, and replacing all the bushings in the steering will happen at some point. I really haven't started to dig into the engine bay yet but that will happen sometime.
At least I don't have to worry about the Dana 135, that thing is massive.
At least I don't have to worry about the Dana 135, that thing is massive.
I'm headed back to work on the habitat more but I designed a bit of the heating and water system in the meantime: https://expeditionportal.com/forum/threads/2003-f550-no-limit.246668/post-3198399
Updates on the habitat and subframe coming in the next week.
Updates on the habitat and subframe coming in the next week.
I have a similar era 7.3. For steering mods, I put in a Red Head gear box, a new Saginaw pump conversion from Lee, hydro-ram assist, and an uprated hydroboost (also from Lee). The new gear box took away most of that sloppy steering phenomenon. The ram allows you to turn at low speeds while still using the brakes and eliminated the remainder of the sloppiness. An underappreciated function of ram assist steering is that it makes the world’s greatest steering stabilizer. The ram made highway driving so easy. Cross winds, passing big trucks, etc are no big deal. The hydroboost upgrade is key to get the most flow from the updated pump. I had previously replaced all the steering components before these bigger repairs. While the provided some peace of mind, it didn’t improve the steering feel. Also, FWIW, even with all these changes, the steering effort at parking lot speeds was pretty terrible but better than stock. The ram actually made the slow speed stuff easier (less effort) even if it didn’t make it faster to get from lock to lock.
I swapped to Warn hubs and skipped all the Dynatrac stuff. While super high quality, the factory stuff is so easy to service and so much cheaper, I didn’t see the point. YMMV.
Subframe update here: https://expeditionportal.com/forum/threads/2003-f550-no-limit.246668/post-3198394
I like the steering mods, I'm going to look into that. I have seen a few guys suggest you can build your own steering stabilizers, that seems doable, any ideas there?
Regarding building your own steering stabilizer - why? That is exactly why I did hydro-assist instead of replacing the factory steering stabilizer. My only idea for that generation Super Duty is to ditch stabilizers altogether and switch to hydro. All your junk is worn out anyway so might as well take this opportunity to upgrade.
I'm really not familiar with the process, I'll look it up before I comment further. I'm all about bringing systems up to current standards if its relatively economical.
DirtWhiskey
Western Dirt Rat
Hey Andy I'm thinking about going hydro assist on my 2001 F550 (2006 suspension and axle swap). I got my hydro boost ported by Vantech, have a Lee Saginaw conversion blah blah and my steering still stinks. I know I need a new Sbox but who did your hydro steer? Rebuilding my steering box, porting and hydro my next mod for sure. Wondering about which box and which hydro steer. I have MPT81 SS conversion and a dual stabilizer from PMF that I can't wait to get rid of. Even after my Lee swap it moans and just sucks.
I had some idiot named Andy do the hydro-assist in his driveway. Honestly, it wasn’t too bad but it wasn’t “easy,” either. The hardest part was finding a place to secure the fixed end of the ram while ensuring it is parallel to the tie rod. I needed some help from my fab shop to cut me some plate on their plasma table. The tie rod end was also a problem for me because I had a larger than stock Mag-Hytec diff cover. Factory should be much easier to clear and will allow you the use of a clamp mount rather than having to weld tabs on. Weld-on tabs means that every time you replace the tie rod ends (and therefore the tie rod, at least on a stock setup) you have to revise the tabs. Not the end of the world but does add some more labor to your maintenance schedule. As mentioned, I have a Red Head box but there are others out there that are easily as good and they can all send you a rebuilt box that is ported for hydro-assist.
On my setup with 35s, there was still a little moan when steering while hard on the brakes but overall, it is a big improvement. The low-speed (eg - parking lot maneuver) effort is still higher than I’d like (I want it Prius light so that it is easier for my wife to park). That said, my 2024 F350s slow speed steering feels the same as the 2000; at higher speeds, the ’00 is definitely better.
Lee should be able to get the rest of your setup in order for your hybrid setup. Redneck Ram set me up with mine - they would also be a good place for knowledge but I found that the Lee guys were easier to deal with.
Steering stabilizers are what you see on stock setups - it is just a shock that passively opposes the turning motion of the wheels. Hydro-assist replaces the stabilizer with a hydraulic ram that actively turns the wheels based on your steering inputs. When not actively pushing, it provides a lot of resistance to movement which helps it work as a stabilizer. Technically, the ram only pushes but because it is powered by the steering pump, it provides a tremendous amount of force on the return stroke so it functionally works in both directions. Full “hydro-steer” uses two rams and eliminates the mechanical connection between the steering wheel and the front axle. Full hydro is not safe for road cars due to the lack of redundancy and I’ve never seen it on a vehicle that sees regular highway miles.
Hydro-assist for your truck means a new steering pump (your stock C-II was garbage new and is worse today), brake booster, a steering gear box which is ported to accept the hoses to run a ram, and the ram itself. Because you have a diesel, the brake booster is run off of the steering pump; as a consequence, all of the flow from the pump runs through the brake booster first before going to the steering. Upgrading to a higher flow pump means you need a higher flow booster which are available at various speciality shops (I got mine from Vantech, too). I don’t consider myself too gifted in the art of fabrication so if I can install it, anyone can.
