Should I start looking for a new shell?

[JMortensen]

When it comes to rust and bodywork, I really don't know my ass from a hole in the ground.

 

I took the following pics today:

 

I've been really afraid of rust since I had my Z painted. It was supposed to be taken to bare metal, then epoxy primed, then painted. About 2 years after the paint was done cancer showed in the usual places. I had sections just in front of the rear wheels cut out. Actually had the body guy give me the rusty metal he cut out. That's where the rust came back FIRST.

 

Right now I'm preparing to stitch weld the frame rails, and I find this. I don't think this is major, but I didn't think the other rust was that bad.

 

Is this a big deal? Somewhat normal? Should I worry about it? Is there anything I can do to fix it?

 

The thing is that I push this car HARD. I don't want to go through all the hassle of stitch welding this chassis and have it rot out from under me in 5 years.

 

If this is not a big deal, is there a better way to clean off these frame rails then what I'm doing? I've tried Roloc pads with a 90* die grinder. I've tried paint stripper (Home Depot variety). Now I'm onto a wire brush on the die grinder. It seems to work the best, but there are areas that I just won't be able to get the grinder into that need to be cleaned.

 

Any other suggestions? A better paint stripper?

 

Thanks everyone.

[Guest DiZeased_240]

Rust truly seems to be the devil with these cars. Unfortunately, paint stripper will not remove rust. It must be removed by grinding, wire brushing or sand blasting. There are some products on the market that claim to turn rust into black iron oxide and keep it from spreading. From my experience it's better to remove it instead of covering it up.

 

Do you have access to sandblaster? This will work well for the frame rails and undercarriage but do not use it on the exterior body panels. They can be easily be warped by blasting.

 

After removing rust, do not let the exposed metal sit for any period of time. It will begin oxidizing almost immediately, even your finger prints can make the car rust. Use the epoxy primer or an acid etching primer for the first coat. There are varying opinions after this point, but I use black chassis paint from NAPA and then truck bed liner(I roll it on the undercarriage). This technique has worked very well for me.

 

Rust sucks to remove, good luck.

[JMortensen]

The problem is that the rust is not on top of the frame rails, it is creeping out from underneath.

 

I really can't dip the car, and I can't take all of the frame rails off to clean inside. Just not possible at this juncture.

 

Maybe I should just forget about stitch welding paint up what I stripped and start putting away a little cash for a new shell???

[JMortensen]

Anyone else? Advice please!!!

[Tim240z]

Drill out the spot welds and pull of the rails. Inspect and replace, or put in subframe connectors.....That rust in the pictures really doesn't look that bad at all.....

[jeromio]

That is pristine compared to my car. I did remove both frame rails. Actually, the driver's side was fine - but I pulled it off anyway. It had some surface rust inside, but not too bad. If you do pull it, I recommend buing that spot weld removal tool that Eastwood sells. I used a drill bit and it was an ordeal. I replaced both of my rails with folded 14ga steel primed inside. I realize that much of the primer/coating will have been burned from welding, but, oh well. I also routed my fuel and brake lines thru the rail.

 

If your's is an early car, you can put in extra long rails and fold them over and up to make subframe connectors.

 

My work guesstimate is about 1 weekend per rail including all prep and paint, etc. Add an extra weekend if you choose to re-route lines.

[JMortensen]

I appreciate the advice, but you guys realize that this is the subframe under the rear deck that we're looking at, not the frame rails under the floorpan, right? Just making sure we're on the same page.

 

If it were just the frame rails under the floor it wouldn't even be an issue. I guess I can just pull the sub frame off and clean and weld it back the same way, but I'd have gaps to fill where I cut them away on the sides and back.

[Drax240z]

Umm, Jon I'll forgive you because you are new to this area, but in the pacific northwest that is a "rust free Z". Seriously. Don't panic about it. Sandblast it or chemically neutralize it, dry the heck out of it, reseal it and you should be fine for many years to come.

[JMortensen]

I guess I'll be needing to remove the subframe then to sand blast it? Cause I know I won't be able to really get inside the rails without removing them. Right? Or is there some kind of expanding foam rust neutralizer that I can spray inside the rails...

 

I didn't think it was that bad, I just didn't know how to deal with it.

[dot]

In the Toronto area we have corrosion issues to the point a small industry has been built around it. They spray oil on the inside areas that are imposable to reach by drilling ½ inch hole and inserting a sprayer that looks like a power washer. When I had my Z apart in the eighties I covered the wheel wells and supporting frame parts before the external panels were replaced with a no smell grease. The oil gradually seeps out from the inside. It’s not a good plan if you are into a pristine look but it sure stops the rust.

The oil they use is similar as winter grade chain saw oil.

 

 

This a link for what they do.

http://www.krown.com/

[JMortensen]

That looks very interesting dot. Maybe I could finish up my mods and take a day trip up to BC next spring. I think that may be just the ticket.

 

Anyone have any easier method of paint removal for the rails?

[slownrusty]

When I lived in Toronto I used to swear by the Krown oil coating just before winter....helps bolts from seizing too and keeps brake and gas lines from becoming fluffy!

 

I miss Toronto, but I DO NOT miss the crappy 5months of salty damp snow filled winters though.

 

Yasin

[datsunlover]

Dude.. Toronto gets NOTHING for snow!!! Go north 1.5 hours to Midland; I have rebuilt entire floor's and whole quarters, ect ect on countless vehicles over the years due to all the rust caused by the winter driving up here. Literally, the cars dissapear up here!! I'll get some pics of my boss's son's car; 89 Sunbird, 130K, but never been oil sprayed. It's almost unbelievable.. the whole front of the rocker is GONE up to the door hinge, and right back to the rear wheel well. Dot can atest to this kind of thing, Im sure he's seen it!

JMort; seriously man, just clean as much as you can, spray something on there to nutralize any remaining specks of rust, and paint it. It's actually in better looking shape than my 93 King cab man!! Heck.. if mine was even CLOSE to that good, I'd just drive it as is!

[260DET]

That looks like surface rust resulting from inappropriate surface preparation prior to painting. But if the paint is very old it could have deteriorated so much that moisture was able to seep through to the metal underneath.

 

On our old cars the visible bare metal should be treated with diluted ???? phosphate, called Deoxidine, Metal-Prep and others, allowed to dry until a light white powder appears on the surface, then hit with primer immediately.

 

It doesn't look too bad at all Jon, there does not seem to be rust breaking through from inside, just surface rust. For underbody metal I'd use something like fishoil as a primer although that can take ages to 'dry' sufficiently to overcoat. Anyway, something that neutralises the rust and won't easily chip.

[ToplessZ]

Go to Advanced AutoParts they sell some stuff that is rust remover and surface prep about five dollars a bottle and it works great. You can put it on as many times as you like. It is kind of green in color in a see through bottle and is in the paint section. I dont know what its called off hand but have used it many times and it works great.

[JMortensen]

OK, I'm going to stitch her up today with any luck, then treat the rust and paint, then hopefully do the Krown thing in the springtime.

 

Thanks for all the advice. I sure got a lot more views when I changed the title from "minor surface rust on frame rails" to "should I start looking for a new shell?"

 

Anyway, thanks again all.