Undercarriage coating question

miesk5 said:

Yo
As BigBlue and DriftwoodBronco advised.
And;
Stormfinder's 95 Frame swap into an 85
Only major diff between earlier years is that 92-96 have Convolutes in front (often called da accordion sections; it is part of the SRS Design).

Project Phoenix - Stormfinder's 4BTA Diesel Bronco...

The Body Mounts are a pia; so be ready to spend time and get bruised..
see LINKs for the mounts and other info in my site @ Loading
including;
Cleaning & Rust Proofing
Frame Service; Drilling Precautions, Straightening, Reinforcing, Member Replacement, etc.

Differences from 80-96, Strength & Dimensions; "...This got me thinking and I just found my Standard Catalog of 4x4s book. It has info on every model year domestic 4x4. It doesn't really specifically talk about frame differences from year to year, but it does have a Chassis Features section for each Bronco year. Here's what it has: (1980-1985) Separate body and frame, box-section welded frame. 3.95 in. section modulus (1986) Separate body and frame, single channel, 5 cross members, welded frame. 3.66 in. section modulus. Maximum side rail section: 6.95 x 2.12 x 0.170 in. (1987-1989) Separate body and frame, single channel, 5 cross members, welded frame, 36,000 psi steel. 4.27 in. section modulus. Maximum side rail section: 7.01 x 2.12 x 0.202 in. (1990-1992) same as 87-89 but also notes low carbon steel (1993-1996) Separate body and frame, single channel, 5 cross members, welded frame, 3.66 in. section modulus. Maximum side rail section: 6.95 x 2.12 x 0.170 in. low carbon steel..."
Source: by BurntOrange at FSB 400/AOD/NP205 into an '81-'86

Diagonal or X-Frame Checking Method
NOTE: An alternate method of checking frame alignment is to use a frame gauge.

Frame alignment can be checked without removing the body from the frame (5005) by using the diagonal or X-frame checking method.

This method should be used to identify misalignment prior to any attempt to straighten a frame.

Place the vehicle on a clean, level floor and set the parking brake.

Select at least four points along the left frame side rail (5015) and transfer these points to the floor with a plumb bob. If desired, paper can be taped on the floor along both sides of the vehicle below the frame. Mark the points on the floor as accurately as possible.

Locate the corresponding points along the right frame side rail (5016) and transfer these points to the floor in the same manner.

Move the vehicle away from the marks on the floor, and measure diagonally between all points on the floor. Both measurements should be equal within 6.35mm (1/4 inch).

Measure between corresponding points parallel to the frame side rails. These measurements should be within 3.18mm (1/8 inch) of each other.

The squareness of the frame side rail web to the floor at the spring hangers and at the steering gear mounting location should be within 1.59mm (1/16 inch). The squareness of the frame side rail web to the floor at all other points should be within 3.18mm (1/8 inch). The web and flange should be square at all other points within 3.18mm (1/8 inch).

Any point on one side rail should be within 3.18mm (1/8 inch) ahead, behind, above, or below the corresponding point on the opposite side rail. The frame side rail should not be bowed more than 3.18mm (1/8 inch) for each 2540mm (100 inches) of frame length. The overall width of the frame should not vary more than 3.18mm (1/8 inch).

An alternate method of checking frame alignment is to use Rotunda Laser Measuring System 073-00451 or equivalent.

Before checking frame alignment, inspect all frame members for damage, cracks, twists, or bends.

Check all welded connections for cracks. Inspect all rivets, bolts, and body support brackets for looseness

If a damaged frame member is to be replaced, new bolts, Property Class 9.8 metric (Grade 8) fasteners and rivets required for replacement of parts should be of the same specifications as the original bolts or rivets. In cases where it is necessary to substitute a bolt for a rivet, use the next larger size bolt.

Click to expand...

paul rondelli said:

That is one clean ass rust free Bronco my friend.

I have been using POR15 on exposed metal surfaces after completion of any work. The stuff is fantastic. It creates a hard shell that keeps everything off the metal. I coated the undercarrige on my brush mower last year. This is the push 6hp craftsman that I use to cut down tall weeds/ little trees/ Kudzu ..... whatever. I sling waaay too many rocks and pieces of trash to consider the operation even remotely safe ... and the POR15 has held up to all the abuse.

It does not do very well in direct sunlight and will fade fast ..... but it is still hard as a rock.

I buy the little quart cans and after the repair is completed, I go back as coat everything before reassembly.

I absolutely hate rust ... so this is a life long battle for me.

Click to expand...

SRWillis said:

That's a very clean chassis, you can tell you're not in the rust belt!

I wouldn't use Line-X or any other bedliner type product under there. How would you get anything apart? And besides that, as mentioned above, if it's not applied properly it will start coming off and moisture loves to stay in those areas.

I use Fluid Film because I heard good reports of it on here. You're supposed to re-apply it once a year, but it keeps things from rusting. I use the clear stuff because a friend gave me a good deal on some, but they also have black which I thing would look good. @BroncMom uses another product, so maybe she'll chime in.

You just mention the chassis, and you may have already addressed these areas, but I think the biggest concern you have is areas in the body that hold dirt, and hence moisture and causing rust: rear fender lips, the rear of the rear quarters, tailgate, bottom of front fenders, etc. I'm sure you've noticed those areas on other Broncos. I did the best I could blowing those areas out with compressed air and apply Fluid Film. Fluid Film will also 'creep' some, going into seams, etc.

Click to expand...

BigBlue 94 said:

The biggest issue with coating the underside is getting it all cleaned properly. Any gunk that is coated over is where the failure will start.

Im in the process of doing this very thing for another member. Using eastwood platinum rust encapsulator followed by their chassis black. Its gonna be quite a pain to clean, so i suspect line-x would be doing minimal prep. I like their product though.

Personally i would go the eastwood route if you can do it yourself. You have a good base and painting it will keep it that way.

Click to expand...

Burntoutaccountant said:

Eastwood all the way. The biggest thing to note is that Eastwood paint is EXPENSIVE. I want to say the gallon of the platinum was $225-250 by itself.

I'm not a huge fan of POR 15. Go the Eastwood route.

Click to expand...

BigBlue 94 said:

That isnt all that expensive. I mean yeah its a lot, but hell we use tinting colorant that runs almost 100 per quart. Do it right and do it once. Look up the history on that Mystic Blue that was used on the 2000 mustangs. You couldnt even buy it. Had to have a feller from ford bring it, watch you paint it, like a hawk, and take whatever remained back to ford. It was thousands of dollars a quart.

Click to expand...

Burntoutaccountant said:

I’m actually aware of that color. I had the opportunity to buy a terminator in that color and pass because it had rust. I really regret that decision now. I talked to the Restomod Store and they said the exact same thing you did about not being able to find the color.

Click to expand...