After the winter is over I'd really like to clean the underside of my truck. Now this isn't just cleaning the dirt off but removing the fluid film sprayed on over the years. My truck doesn't see winters anymore and working on it is a sloppy mess in the summer. Not to say I wont coat other areas again when needed. I just want to get it clean.

So, knowing the above, any suggestions on the how to of this.

Pressure washer on a light setting?
Warm/Cold water? (warm probably helps remove FF better)
Detergent type and kind?

Anything else to consider.

 

Find a big puddle and hit the gas through it. That's how I do it.

 

Unless you lift the bed and cab it's unlikely water will get that stuff off.

if you really want it off, take it to one of those professional undercoating places that pressure steam cleans as the first step.

me personally would be worried about blowing away the lube in my universal joints and rod ends

 

I don't necessarily want to use a high pressure wash. I have multiple nozzles and it's fully adjustable. I'm just sick of being covered in dirt filled fluid film every time I go under my truck. I'm not expecting to get every drop off of it, just the majority.

 

Soak it with Simple Green and blast away. You won't hurt anything other than the grime.

 

Take some ramps to the car wash and blast it off. Those are relatively low pressure and high volume and most have heated water on the soap cycle.

 

I know i'm going to get soaked, so I just lay on a creeper and go for it.
I took the Wand of my Pressure Washers Handle and just use the Grip with a Adjustable Nozzle on the end. For me it's easier to get into tight areas.
As far as the De-Greasers go, Purple Power works well and its Bio Degradable.

 

Step 1. Recon mission: On a creeper crawl under truck with light, search out all dirt hiding spots. Cab rockers, bed rails, above gas tank, inner rear wheel wells, under the hood, in front fender inner structures etc…

Step 2. Go into house change into swim suit (warm day), don a pair of safety glasses. Install a 6 pack of favorite working fluid in cooler with solidified water for proper cooling.

Step 3. Drink one bottle of working fluid. Get back under truck with creeper and hose and rinse all nooks/crannies with water until water runs clean. (Remove spare tire before this step and clean it out, leave it down until step 7).

Step 4. IMPORTANT: Keep said hose away from rear inner wheel wells where its attaches to the outer quarter skin. Only use compressed air there. Why… because the rocket scientist, (AKA designed-in obsolescence team) at Ford put a sponge like material towards the rear of the arch to hold water for you and other contaminants so the wheel well exhibits accelerated rot through due to moisture retention within 5 years. Again brilliant spot to apply said sponge…wheel well on a 4x4 pick up…brilliant! GAH!

Step 5. Drive truck to heat things up and spin water off ujoints and other components where water can wick in. Allow truck to dry for days. Can use compressed air to follow up the water flush to blow out standing water. Remove 2nd bottle of working fluid sit back and admire the pile of crud washed from under your beloved crud collecting investment.

Step 6. With spare still removed take it to your nearest “Krown” or “Corrosion Free” dealer and have the entire truck sauced up. Tell the technician to apply copious amounts of sauce to sponge like substance in rear wheel well. When he asks why that shzitt is there hand him a bottle of working fluid and smile. (note 3 bottles of fluid remain unless you’ve selected option 6.1). You won’t regret having it rust proofed with either of these processes. Stay away from the process which sprays the tar like substance on the underside.

Option 6.1: If you’re real ambitious and own tyvec suits, buy a few gallons of fluid film or LPS3 and a sprayer and sauce it up yourself. (If you go this route increase working fluid to a 24 pack and a bottle of Jack, the one with the built in handle!).

Step 7. After truck is done dripping rust coating for a week or two, (don’t park on concrete), purchase the Ford rear wheel well plastic liners and install. Install spare. Note apply grease to the plastic well metal fasteners to slow down rust.

Step 8. Repeat the above annually if you live in the rust/salt belt.

Step 9. Celebrate: Drink remaining working fluid(s) before the solidified water turns to liquid and rest assured you’ve just done your best to preserve your investment to hopefully the 10 year mark (salt belt). 20-30 year mark in Phoenix.

 

The model year of the Super Duty frame could be relevant to the choice of cleaning method.

The OP has a 2008 with an E-Coated frame, whereas previous model years (99-07) were wax coated. The E coat is thinner, the wax coat is thicker. The e coat is harder, the wax coat is softer. The e coat could crack or flake with extreme frame flexion, where the wax coat is flexible and adapts.

However, the wax coating is generally messier, and can be easily stripped off with the use of certain cleaning solvents, that wouldn't have any effect on the adhesion of E coating. Likely, the e coating could probably withstand higher spray pressures, narrower fan spray patterns, and closer spray nozzle distances, than wax coatings. However, like powder coating and paints, e coatings can end up getting "sprayed off", especially if a crack in the coating has already formed, due to the coating being less ductile than wax.

 

I've never lived near or experienced a corrosive environment. When I lived in N.Calif the Hwy Department (Cal-Trans) used Sand where necessary. All we did was spray off the undercarriage and all was well.

 

I use a 40* spray nozzle on my power washer so I javelin a nice broad fan and not a paint peeling pencil point. I drive the truck up on a set of car ramps (I modded them so the are twice the height as normal) and I sit under the front bumper and wash everything down, I take a little drive and then spay simple green all over wait a few minutes and then wash again. After a day of drying I make sure the rockers etc and not mud weeds etc stuck in them, use my compressor to spray all the nooks out and then spray the undercarriage with fluid film. I have not found anything to take the old fluid film off, I've tried simple green spary9 purple power NOTHING WORKS! so I get a old Tire brush and scrub off what I can while I power washing the truck .one day I'd like to buy a hot water power washer but they are TOO expensive for my wallet

 

use a few lawn sprinklers positioned under the truck, leave em' stew for a while, thats what we do to our plow trucks on warm days

 

Not a bad idea honestly......

 

Not really interested in a recoat mainly just removal. I know of the sponge as it rotted my 06. Also I have a dually so I have wheel well liners and really not even sure that sponge exists on mine because the bed body is a tad different in terms of the SRW. Your bedsides have a flare built into them where my bed is literally just a straight edge from what I remember.

 

Hmm. I hope that's not the case but if it is then so be it.