Working on disassembling the early 70 240 parts car,  the doors were surprisingly in nice shape, no filler, just some surface rust and a little 1" area of rust on the leading edge of the passenger door where water collected, pretty easy repair.  The bottoms were solid and they should clean up nicely.   When removing the hardware, I noticed the Ziebart plugs in the door jambs.

Appears the process worked well for the doors.    Have never seen the on a Datsun before.

 

 

NICE! I never heard of Ziebart but it helped very good against rust. Over here in Europe we have Dinitrol..  The 280zx i restored was done with Dinitrol or something like it.. It had a lot of plugs were the stuff was sprayed into the hollow parts.. thats why i bought this one and at the end i used the stuff again!

Ziebart uses a 'wax' application (parrafin?).  A comparable treatment in England is called Waxoyl.  Ziebart was the leading rustproofing treatment in Canada and the US back in the 1970's, but it's popularity became increasingly challenged by competitors using light oil products (Rust-Chek and Krown are two of the leading franchises).  All require drilling access holes in strategic locations to permit the treatment to be sprayed into closed sections (typically, rocker panels, A-pillars, and B-pillars).  Doors, on the other hand, are treated by inserting the wand into the door through the window opening. 

One good thing about Ziebart is that the treatment doesn't drip after it's been applied (the oil-type applications drip for 2 or 3 days).  Ziebart had some issues when the treatment was (allegedly) found to crack after a few years, leading to water/salt entrapment and premature rusting.  Not sure if this was true, although I think I recall a class-action lawsuit being launched.  One thing's for sure:  Ziebart was a lot better than the brush-on 'rubberized' undercoating that a lot of Z owners applied to the underside of their cars when they first noticed rust appearing.  That stuff just accelerated the rust.  And we all know what a b____ it is to remove 45 years later on.

2 hours ago, Namerow said:

when they first noticed rust appearing.

Yeah and then you are to late.. haha.. btw, i had to remove the complete floor to de-rust it haha.. now it's new 0.8mm steel with sink-paint.. nothing else and now 22 years old and a little fly-rust..so i need to do something about it but no hurry.. No undercoating whatsoever! (I hate those black layers of gunk.. when you see that it's rusty then your to late.. just a bit of waxoyl or so .. something where you can look through! I also do the floor with some WD40 every few years.. it makes .. if there is some tar ..  like under my other cars soft and prevents drought cracks in the coating!  Because thats the worst thing there can happen.. the water gets into the cracks and ruins the steel!

Btw, i just took a look and it's called: "Teroson ML"  that was used very effectively on my 280zx.. the floor/chassis was almost completely in perfect order.

And here is the newest of those wax/oil sprays and one of the best I have used, none of the product comes out of the front of the tip of the clear plastic wand, only out of the sides so as you pull it out of the frame or channel all of the wax goes where you want it.  Unlike the Eastwood frame spray you can easily do an entire car with one can, Eastwood takes 5-6 cans.  Gotta love SEM products.

 

@S30Driver, sent you a PM.

18 hours ago, grannyknot said:

Unlike the Eastwood frame spray you can easily do an entire car with one can, Eastwood takes 5-6 cans. 

One can? I used about 8 or so! but i have done ALL parts and cavity's sometimes more than once.. that damn car is NOTGONNARUST !!!!   Hahaha 😂

I even had to alter the weight in the paperwork... NO just kidding! 🤣