Ugly Undercarriage

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Fredensborg

I like music, languages, weaponry, and freedom.
7173 Mustang Supporter Member
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Jun 27, 2013
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Location
Zimmerman, MN 55398
My Car
1973 Mach 1
1980 Bronco
A couple modern Fords
   So as I have been spending a lot of time under my car lately cleaning and reprinting my axle housing, I can’t help but notice the now ugly contrast between my clean rear end and ugly undercarriage.

   Now I’m not doing a complete restoration at this time, and honestly…who the hell besides me will be laying under this thing and looking up there anyway? But nevertheless it bugs me a little bit.    
 

  Is it worth is to just quickly clean this up and hit it with some Rust-oleum or am I just wasting my time and making a bigger pain for myself in the future if I spray it? Might there be a benefit of preventing or slowing any continued growth of this surface rust? Is there any particular product that works particularly well for this? 
 

   I know this is the classic, “mission creep” that people have mentioned on here but I just figured I ask. Seeing some of the super clean undercarriages on here leaves me drooling! 
 

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Looks like a good product, if I were to apply this it wouldn't interfere with any potential repainting of the car would it? I assume this would come off in a chemical bath easy enough right? Do you just go hog wild with it and spray everything under there? I still have some blue paint on my frame rails, should I just hit everything with it?

 
You might want to consider looking for a place that does dry ice blasting.  These systems do a remarkable job of removing crud from anything while not damaging the underlying materials.  It works by firing dry ice pellets at high velocity at the target.  The pellets evaporate from solid to gas on impact, taking debris with it.  It is safe to use on rubber and electrical parts.  Your undercarriage will be a lot cleaner and you will have a lot better idea of what needs to be done.

 
Rust Encapsulator can be painted over, but when you first apply it, it will show the underlying rust texture on the metal.  When painted over, that texture will likely still show.  Same with Ospho-like products.  Ideally, you need to use some sort of a blasting agent to get back to smooth metal, although any rust pitting will still show as texture.

The Concours Crowd likes Evaporust, but it will be difficult to apply to an undercarriage unless you have a rotisserie.

 
You might want to consider looking for a place that does dry ice blasting.  These systems do a remarkable job of removing crud from anything while not damaging the underlying materials.  It works by firing dry ice pellets at high velocity at the target.  The pellets evaporate from solid to gas on impact, taking debris with it.  It is safe to use on rubber and electrical parts.  Your undercarriage will be a lot cleaner and you will have a lot better idea of what needs to be done.


Rust Encapsulator can be painted over, but when you first apply it, it will show the underlying rust texture on the metal.  When painted over, that texture will likely still show.  Same with Ospho-like products.  Ideally, you need to use some sort of a blasting agent to get back to smooth metal, although any rust pitting will still show as texture.

The Concours Crowd likes Evaporust, but it will be difficult to apply to an undercarriage unless you have a rotisserie.
And therein lies the rub. I'm just looking to sharpen it up a bit under there for now, not looking to go crazy and really tear into it. Someday I'll tear this car completely down, but that time has not yet come. I want to enjoy this car with my son for the next few years first. Does this metal look horrible? I'm no metallurgist, rust just looks like rust to me...I'm assuming that in the future I could blast or chemically dip the car and everything will be good to go for a proper paint job. Am I wrong in this assumption? Just looking to stop what's going on and minimize any future metal damage.

 
If you want to go over it in a few years I would not paint something over it you have to struggle with in the future to remove it. I would think about something that would prevent the rust to go further and protect the metal from stone chipping, moisture and other dangers. I think about something like a special grease, the products from Fluid Film for example, or similar. It makes your rust a little darker, protects the metal against further rusting and you could better remove it again with something like ice blasting. Otherwise I would do it the right way with brushes, rust remover/acid and then two good layers of a good black anti-corrosive paint, that protects the metal of outer environment. 

If you want to have it quick and dirty just for looks then buy some cans of Dupli Color undercarriage or engine paint in black and make some spritzzz here and there. But you have to do it every year since the rust will come through slowly again  :thumb:

From the pictures I think your undercarriage rust is only on the surface, so it's not bad and easy restorable, more a visual thing. What would bother me more is the rusty fuel evapor line. Please have a look at your fuel and brake lines - if they have some deeper rust pitting I would better change them. That's more important than the look of your undercarriage  :thumb:

 
From the pictures I think your undercarriage rust is only on the surface, so it's not bad and easy restorable, more a visual thing. What would bother me more is the rusty fuel evapor line. Please have a look at your fuel and brake lines - if they have some deeper rust pitting I would better change them. That's more important than the look of your undercarriage  :thumb:
Yeah, I didn't even know what that line was till I read your build thread. A couple years ago I had a shop put in a new gas tank, I should have done it myself but I had it in the shop because I couldn't figure out why it wouldn't stay running...they cleaned out and freshened up the entire fuel system from the tank to the carb (including a new tank)...but they must not have bothered to hook up that vent/evap line, maybe the aftermarket tank doesn't have a vent on it? I'll check it, I might even take the tank off this winter and see how bad the rust is above the tank as well, and hook up that vent line of course. :)

 
I'm with Tim.  If you think you might really get into a full restoration on the underside I would not put any coating on it that you will struggle to remove later.  You might just consider brushing on some Ospho and call it a day until you're ready to blast and restore.  You can get Ospho at most hardware stores, it brushes on easy and is inexpensive.

I'm sure the days of winter driving and intentional rain driving are behind you anyway so serious further deterioration is unlikely.

 
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Ditto on the Eastwood encapsulator. I recently removed my rear suspension and fuel tank, and did some basic prep work/degreasing before applying it. Obviously the surface texture isn't great without some kind of blasting prep, but my car is not a show car by any means. All I was looking for was rust protection really, and the product seems to do that well from my experience. The slightly better appearance is just an added bonus imo.

 
You can always spray and wipe some Eastwood Metal Prep. It will help in cleaning the corrosion and give you some mild rust protection. If you go this route wear a face shield and mask. This has acid and you don't want it in your face, less in your eyes.

 
I won't bother put anything on aside spraying some oil from a can if you need wait a couple of months, because if you treat it well with eastwood or any rust converters. To do it right, you will in fact do not that much less work than doing it durably and you will have near as much work to protect or remove stuffs to do it.
And once it's all shiny black, you will postpone to do it right! I know I would :O

From what I see on picts, rust that is flagged "light" in replies... well, I know i would not wait too long because the trunk floor is really not that thick (0.85mm) and that rust is eating it alive real fast!

 
Everyone has good points on this, but I think there is a missing part to this scope creep initiative...the exhaust! You've cleaned up the axle and it shows how scuzzy the undercarriage is. But once the axle and undercarriage are 'tidy-ed up' along with the spiffy newer gas tank, the exhaust will stand out! I would say if you spend time sanding/prepping/brushing stuff on, drop the tank and exhaust to get at everything. Get new mufflers/pipes, new brake/gas lines, and it will look pretty darn nice.

And, since it is a Ford, most of the front is already protected by what used to be motor oil.

 
I'm with Tim.  If you think you might really get into a full restoration on the underside I would not put any coating on it that you will struggle to remove later.  You might just consider brushing on some Ospho and call it a day  

I'm sure the days of winter driving and intentional rain driving are behind you anyway do serious further deterioration is unlikely.
You are quite right that this car’s days of being driven in anything but beautiful weather are basically over. It lives in my heated, but not air conditioned garage all year but it does get pretty damn humid in Minnesota, so I just worry about this getting worse over time. How big of a pain in the ass will it be to take off whatever I apply later? If I send it out for a blast or dipping in the future? 

From what I see on picts, rust that is flagged "light" in replies... well, I know i would not wait too long because the trunk floor is really not that thick (0.85mm) and that rust is eating it alive real fast!
Yeah, that’s why I was asking if this is really bad rust or not…I have no idea. There are no holes in any of it, but it looks bad enough to me I guess. 
 

Truth be told, I don’t know how long it will be before I can tackle a “real” restoration. But it will be at least a few years. My youngest is 9, so I’ve got at least 10 years (or more) before I’ll have time to really get after it. 

 
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Just curious but is the floor in your garage concrete? When you park it in there, you may want to put down a layer of cardboard or some kind of vinyl sheet to keep moisture away from the underside.

 
Most of the metal prep / rust converter that is sold is just phosphoric acid.  You can get a gallon of it for about $15 at your local big box supply store (it is in the concrete section).  It does etch concrete, and is acid so keep that in mind if you choose to use it.  A cheap garden sprayer makes a great tool to apply it.  It will remove electroplating so be sure to keep it off of new hardware.  
 

It would stop the surface rust and is something that won’t hinder any future efforts to prep and paint.

 
Just curious but is the floor in your garage concrete? When you park it in there, you may want to put down a layer of cardboard or some kind of vinyl sheet to keep moisture away from the underside.
Yes it is, there’s usually a few pieces of cardboard under it for oil leaks under the engine bay. Probably wouldn’t hurt to put cardboard under the whole thing though, good idea! 

 
Linoleum! 

Or for the younger crowd...vinyl sheet flooring.

 
Carpet remnants will work as well.  Check with your local carpet stores: almost every one will sell remnant pieces ranging in all sizes.  I'd stay away from shag carpets unless you have a disco ball hanging in your garage in which case you should get shag.

 
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