Bob's Resource Website (2007)

(Avanti Hog Troughs / torque boxes)

In order to mate the Avanti Fibreglass body to the Lark Frame, a formed steel channel was riveted and bonded to the outer, underside of the Avanti body, between the wheel wells.
Each channel (trough) contains 5 of the 8 body to frame mount bolts. The channel structures are referred to as 'Hog Troughs", are 16 gauge steel and riveted and laid in resin to various parts of the underbody. The roll bar is bolted to the trough, inside the body structure, at the rear, below the ashtray. At the front, the windshield pillar, also extends down to them. The air intake below the windshield on late 63's and onward, direct fresh air down a duct, between the body sections in the kickpanel area to the large grilled vent by the drivers left foot and the passengers right foot. These ducts terminate in the troughs and allow rain to flow past the vent into the trough. In cars with SUNROOFS, the drain tubes from the roof terminate in the troughs. These are a major source of trouble, which can be prevented by finding the tubes and extending them to the outside of the channel. Of course, this should be done early on to prevent any damage from starting, but it's never too late. Keep the tubes clean by blowing a small amount of compressed air, up, from the bottom. Never put anything down thru the tube to clean them, as it will probably lodge any debris tighter.

Replacing these troughs are very expensive and quite a job to tackle by yourself, so the best thing is to apply some preventative maintenance.

Here'a bad one!

Hog Troughs - What they are & Preventative maintenance

Here's a factory illustration

Here are new factory pieces oemlr.jpg
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Replacement parts can be purchased from various vendors and come in multiple piece, single piece, regular and stainless steel. There were even fibreglas units available at one time.

Never having to do the job myself, I can only report that, over the years of looking at these, if you did any kind of maintenance on your car, you'd have noticed trouble early enough to halt it. In the event you wind up with a car with rusted troughs, a quick evaluation of what's left structurally would determine your course of action.
If you can see rust holes, then you can bet there is a lot more damage that you can't see. A general test is to use the heel of your hand to check for any serious deflection which would indicate a weakened sidewall. At that point, I'd take a punch and try poking holes in the inner side panels to see what's been compromised. Since moisture naturally lies on the bottom of the channel, it would follow that the bottom is gone and starting up the sides. It would be possible to undo the body bolts on one side and lift the body slightly to replace the lower portion of the trough, using pieces of your own formed steel or parts from a vendor. This would apply if there was sufficient purchase to weld to, etc. If you're restoring an original Studebaker with bad troughs, then the only way to go would be to completly replace them, for authenticity value. Of course, you can patch them and hide it with undercoat....

An entire single piece replacement entails cutting away portions of the front fender Where the windshield pillar attaches) and a piece of the rear also ( where the roll bar attaches) . Multiple piece repair sections can be welded to the existing channel much easier.

Another area to check is the FRAME section in the rear wheelwell, where it starts the upsweep over the axle. If this section of frame has rust on the underplate, closely check the attachment point of the rear part of the trough, especially the rear leaf spring attachment point. Frame rust exhibits itself by a bulge between the lower plate and upper channel. The bulge is caused by rust expanding the plates. Areas of rust like this can be repaired by cutting away the bad lower plate and replacing it with small sections, either welded or bolted. The leaf spring perches are riveted on, but can also be bolted on replacement. The perches themselves usually do not rust, but the section underneath does. I've never seen a frame, which was rusted through on the side of the upper channel. If this is encountered, only a professional opinion would be acceptable as to the repair possibilities.

Preventative Maintenance- Various methods have been used to coat the inside of the metal to prevent rust.

As stated, the vents terminate in the troughs. The troughs are supposed to have drain holes on the underside. If there aren't any, then drill some, using a 3/8" bit. One suggestion is to plug the drains, remove the interior vent grilles and pour old engine oil into the troughs. Take a drive on a curvy road to slosh it around and then return and drain to oil.

Personally, I've sprayed light oil into mine using a garden sprayer and keep most of the holes capped with plastic plugs.
You can use a garden sprayer to coat the inside with phosphoric acid, which will destroy rust and leave a impervious coating. It would be best to do the oil coat afterwards anyway.
Not to steal any thunder from Ernie, read the below, regarding access holes cut in from above, under the carpets. An excellent idea and who would know. Even if they did, so what. it works...

Ernie Rizzolo- Aug 2001 My hog troughs look great from the outside. When I stripped out the interior I decided to get brave and took a 3" hole saw and cut 3 holes in the fiberglass above the troughs from the top.

I was disturbed to find a layer of heavy rust on both sides and part of the area where the roll bar connects rusted away on one side. I scraped the loose stuff off as best I could and vacuumed the debris out. I then poured Eastwood's Corroless paint in, It's their version of POR 15 ( of which I am also a big fan). I jacked the car up front and then rear and then side to side to coat as much as possible and then used cheap foam brushes stuck in the end of some 3/8 gas hose to slather it around even more. After the paint dried, I sprayed in Eastwood rustproofing until it dripped out from the drain holes. The holes will be covered soon with a stick on soundproofing material I got from JC Whitney. My car will not see much wet weather and is in a garage so I'm hoping the deterioration has been halted. But I can't emphasize strongly enough that from the outside the hog troughs looked and felt as solid as new. The area to cut the hole in is below the sill plates a couple of inches from the edge of the rocker panel. It's pretty easy to determine where to cut. I don't think you would have to remove the front seats but it would make it easier to get the carpet to stay out of the way. Cut the rear hole as far back as possible so you can get good access to the area where the roll bar comes in. The section behind the roll bar can't easily be accessed from the top. I sprayed rustproofing in through the drain hole in the bottom of the trough. The rustproofing tool I have has tips that spray like a lawn sprinkler without the rotation so you can stick it up in a hole and spray the sides. By the way the Eastwood rustproofing gun is relatively cheap and doesn't need a big compressor. It's worth the investment for the job I described and if you have any metal cars it's a bargain. erizzolo@gateway.net Ernie Aug 01

I replaced my hog troughs about 6 yrs ago on '63R1498 and this is how I was able to get to the pop rivets and the roll bar. First of all I "chiseled" the firbeglass out from the top of the rocker panels and drilled them out. Then I cut (with a hack saw) from the front of the rear wheel-well opening (approx 8" up) fwd to the door opening and then down and around the rocker panel (about 3/4" to 1" below the top of the rocker panel). Then fwd to the front of the door. Save these pieces as they can be re-installed with a butt joint when the new hog-trough is installed. As for the roll bar, once the cuts to the body panels are made, this will "expose" a "box" inside and aft of the door opening. This "houses" the roll bar. I cut a square opening in the back part of this box down low near the hog trough. Once this hole is cut you can then access the roll bar bolts at the hog-trough. The fwd inboard fastener you may have to access thru the "rear ashtray housing" with a socket and a long extension. If you install hog troughs (I bought mine from George Demetirus (sp?) at Olympius in Chicago) I suggest you "chase" all the threaded holes as this makes re-assembly much easier. Once the hog trough is installed, the roll bar can be bolted to it thru this box and is really quite easy. - Note - I sprayed inside my new hog troughs with aerosol "rubberized undercoating" for the obvious corrosion factor and also to eliminate any "low freq vibration or tininess(sp?)" from the hog trough prior to installation. After everything was buttoned up. I applied the same undercoating to the outside of the "troughs" - I suspect that if the original hog troughs lasted 30 yrs, these should last at leat 60 years due to occasional driving, garage storage and very little to no driving in rain and absolutly no driving in the winter (I live in Minnesota).

Hope this helps and good luck.
rgds, Ron Maracle '63R1498