Gaskets trap water?

[Pitter Patter]

Do gaskets like the hood hinge gasket trap water and cause rust?

I’m doing reassembly and questioning whether some of these gasket products are a good thing or a bad thing. Did the FJ40 have hood hinge gaskets from the dealer or is this something people started selling?

If the hood hinge needs a gasket then why not the windshield hinge? What about the door hinges? Makes no sense to me. What parts actually benefit from gaskets? People put gaskets on the rear badges but not the hood skirt/curtain badges. Huh…?

I hate rust and here’s a couple of pics of why. Some PO did a respray and they caulked in ways that trapped water so I’m a pretty petty princes about doing this right. Three years of body work and a full paint job later to rid this of all the rust. So yeah, me = sensitive sally when it comes to rust.

Any advice is appreciated.

 

[FJ404345]

Every gasket, rubber, decal, molding, mounting base where can come water/humidity between it and a part of the sheet metal and can not or nof fast enough leave will cause oxidation eventually.

 

[pb4ugo]

The factory used gaskets on the cowl side of the hood hinge. Im not sure about the hood side though. It's also a good idea to use permatex on the screw threads too. The cowl side holes can leak into the cabin.

 

[pb4ugo]

When i removed the hood hinges there was no evidence of rust. There was just the factory primer coating.

 

[charliemeyer007]

Maybe treat the rubber gasket with "real red rubber grease" to form hydrophobic layer to repel water with out degrading the rubber, I got mine from England on ebay.

https://www.ebay.com/itm/272398105549?mkcid=1&mkrid=711-53200-19255-0&siteid=0&campid=5337589904&customid=&toolid=10001&mkevt=1

"Real" red rubber grease is a specialized, castor oil-based lubricant thickened with bentone or calcium, explicitly designed to protect natural and synthetic rubber components from swelling, hardening, or cracking. It is used for assembling hydraulic brake and clutch components, suspension gaiters, and O-rings, providing excellent water resistance and compatibility with brake fluids (DOT 3, 4, 5.1). [1, 2, 3, 4, 5]

 

[Pitter Patter]

Thanks everyone, I’m leaning toward less gaskets, more painted surface on painted surface. Not like I’m taking these brackets and hinges off regularly. It seems like they will dry out better if they don’t have a rubber surface???? Love the recommendation on the bolts to prevent water getting in that way.

 

[igotta40]

When I assembled my sheet metal body parts and hinges, doors, tailgates hood etc I used rubberized undercoat. It was some pretty tedious work doing all the masking and stuff but it was worth it.

 

[anothernz45]

Have cut heaps of rust out of my 45, the problem I found was almost non-existent metal protection on those faces with gaskets, the roof and the back panel of the cab being the worst. My windscreen frame was pretty good, though. My guess is that the body panels were shipped from Japan with a light coat of olive etch primer, stitched and bolted together over here(NZ) and then the top coat sprayed over the assembled body. A bit of dust, then moisture and you've got a nice little hidey hole for rust. If you're doing a serious rebuild you'll be dealing with either new metal or sandblasted and repaired to bright metal, 2 pack epoxy prime and topcoat those panels before assembly and you've given them the best chance of a long life, along with pumping fishoil/lanolin everywhere. The seam under the rear windows I waxed the top face then used a urethane bonder on the gaskets so no moisture can get at anything.

 

[Living in the Past]

In the early years Toyota used felt for the gas tanks inside the tub. Two ways to look at it, felt will absorb moisture if it gets wet. But being to breath it will dry out if humidity is low enough. Rubber on the other hand will not absorb moisture but moisture gets trapped between rubber and steel the metal will rust. I would use rubber but be sure the metel surface is painted heavy enough so doesn't rub to bare metal.

 

[Pitter Patter]

Based upon what I’ve heard here I’m skipping the rubber gaskets for the hood and door hinges. Your point about felt makes sense. Mine has fire hose type material that was under the radiator housing and the battery tray, cleaning that up and re-installing because as you said, it can dry out. I live in western Washington state so lots of rain and it will be driven in the rain a lot.

Fortunately not too much humidity, but they do salt the roads in the winter now so I’ll put it away when it snows and I’ll drive the more disposable 4Runner

 

[sogncab]

Have cut heaps of rust out of my 45, the problem I found was almost non-existent metal protection on those faces with gaskets, the roof and the back panel of the cab being the worst. My windscreen frame was pretty good, though. My guess is that the body panels were shipped from Japan with a light coat of olive etch primer, stitched and bolted together over here(NZ) and then the top coat sprayed over the assembled body. A bit of dust, then moisture and you've got a nice little hidey hole for rust. If you're doing a serious rebuild you'll be dealing with either new metal or sandblasted and repaired to bright metal, 2 pack epoxy prime and topcoat those panels before assembly and you've given them the best chance of a long life, along with pumping fishoil/lanolin everywhere. The seam under the rear windows I waxed the top face then used a urethane bonder on the gaskets so no moisture can get at anything.

This.

Toyota barely painted the things you see, and didn't even try on the things you don't.

 

[SteveH]

To the OP: After you paint it, hand-rub axle grease into the rust-prone underbody spots (any place 2 panels meet). I made/added rear wheel guards (using mudflap rubber) to keep mud/sand/water out of the rear turn signal/tub area, and buried those areas in grease beforehand.

Beyond that, keep the truck inside, don't wash it excessively, and blot out any water that sneaks in during washing. Don't drive it in salty weather. Years ago, people I knew with FJ40s only drove them on the crappiest weather days, which just made me cringe.