Front fender rust - repair or replace???

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Jun 9, 2017
Denver, NC
Hi Folks -

I've got the typical rust on both front fenders... other than the normal rust and a few dents that could be persuaded with the right size hammer, they appear to be in good shape (no appreciable filler). Trying to figure out whether or not I should attempt to repair them or replace them? Of note, they are rhino lined underneath if that impacts your view??

I would have already replaced them with aftermarket steel but the shipping charges seem outrageous! Thoughts on level of effort to repair are appreciated (FYI I have a welder and have done a backyard paint job in the past though I'd prefer to never do one again!).

Here are a few shots of both sides:




Go for it and fix it!!! Save some money and you will be glad you tackled it
Thanks for the encouragement Varty Yo! I've looked for an FAQ and searched for others who've fixed theirs but haven't found anything yet... Any suggestions on where to look are appreciated!

I'm guessing I'd need to:
  • Blast away paint and rhino lining (no idea how doable removing the rhino linging is)
  • Drill out spot welds attaching the support to the fender skin
  • cut the cancer out... this seems to be the hardest part as there's nothing that will keep the fender in alignment (since the rust extends through the exterior lip of the fender). I do have a flanging tool but don't know if flanging the sheet metal is advisable in this case?
  • Piece the replacement material back in, tacking it and being careful not to overheat the material
  • Grind, grind, grind the spot welds...
  • Filler, light filler
  • Seal, prime and block
  • Rinse and repeat until smooth
  • Paint (my least preferred part as I 1) don't really know how to match the paint (PO does have a litany of PPG codes written down but not sure which is right) and 2) while I do have a compressor and an hvlp gun, I don't have an air dryer and worry about water contamination of the paint). Also, have never shot clear and don't know if I have base and clear now or one stage?
Thanks to all!
What year is the FJ40 ? If it is later than the mid 1970's , they were very prone to rust and repair may just be chasing forever. You can try , but as you dig , you may just buy a new fender somewhere.
Still alot of good steel to work with here. !st of all sandblast them to see what may be hiding
1978 so I'm guessing that's a vote for replacement? If so, it looks like the best I can do is the $600 range once shipped based on what I'm seeing from:

If there are other suggestions I'd be pleased to incorporate them!

Do yourself a favor and do a quick mud search on LCH......

Im not sure what your budget is, but there are still new OEM floating around for a few hundred more than CCOT or LCH.
1978, exactly when the rust monster has arrived. Could be earlier, but my 1969 fenders are still as they were. You can research this on here and see that as years went on , the steel changed and in the rust belt areas things got worse.
Anyway, you can blast off to see what you have as varty says, and then decide if the cost / value will allow repair.

( In my opinion, the 1983 FJ40drivetrain and perks installed in a 1968 / 1969 Fj40 would be the best of all. )
Before buying new aftermarket I would search craigslist first to see if you can find some oem replacements. I’ve heard mixed reviews on aftermarket fenders...

This is a plan I would try
I bought some aftermarket reproduction fenders at the beginning of summer. Wish I kept looking for oem but it was for the cruiser I was selling so I just wanted good oem looking ones
The spots you have rust on people on here have repaired. If you can weld and fix yourself I would try that. I wasted a lot of time just fitting the aftermarket fenders

A guy on here can ship from Europe for some coin but an option if you want New oem
Think I saw racer was having a production run a while back of oem ones. Might be worth messaging him

Edit if you do get aftermarket make sure they have the headlight bracket, my South American ones didn’t have it, even seller didn’t realize until I pointed out
my advice would be to wheel your truck some more where you want it to go, be it offroad in some rock-crawling park, be it on the sandy beach, or some hunting property you have access to: get yourself out there as much as you

it'd help if the goals for your build were defined before rather than discovering later that you don't like the outcome :doh:
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My original '78 front fenders were worse than yours. In my hast, I ordered CCOT fenders.. painted them... then went to mount... didn't fit right. I eventually repaired both OEM fenders and re -installed them. Should of just repaired them from the start.
Either way you need paint so that will not be a discussion.
A replacement fender will need tweeking on a 40 year old vehicle so you can expect work to make it fit, even more with after market fenders.
When you leave the fender on the 40 when cutting out the bad parts, replace one part at a time, the allignment will not be a problem. You can use a piece of angle iron and clamp it over the cut out during replacement to keep the edge straight.
Just weld slowly and hammer each time you have made a few tacks as they will pull the gap.
My ‘81 was rolled down a hill and had the fenders badly damaged and rusted. I was surprised how easy it was to straighten them out. Working on the rust issues now including the part you are looking at.
If you look at the ‘81 tread in my sig you will find some info on the fender repair. If you have questions don’t hesitate to ask. I’m not an expert or have a lot of experience in sheet work just learning as I go.
Just to add to what Michael said. I repaired our 75s fenders but I'm no expert by no means. I went as far as taking the support bracket off one of them, to make sure it was as clean as possible and to repair the support. Just make sure when you take it apart that its marked well, the fender will flex in that area also when its support is removed. Might tack a piece in before taking it apart then finish the back side while its off. If you go that route.
thats such an easy repair .here in salt country we do that all the time .you can buy disposable water filters for your air .ive repaired several using spray cans and clear if your careful other than a real body man you cant tell ..or you can fix the fenders and take them to a body shop and have them paint them .if you havnt bought paint in a while be prepared for sticker shock good luck
The tricky part is getting that fender support out of there, and take measures to ensure to seal that area and reinstall. I assume that that's where the rust originated is on top of your fender support.
I have an OEM fender that you could use for metal to repair those, $75 or fix mine if it is better than yours
OP - Those fenders are totally fixable and IMO should be fixed, if not by you then someone else - whatever you do don't toss them. Suggestions above are spot on - drill out spot welds, cut out rust, patch with appropriate thickness new metal, grind smooth, rust proof and paint. I have a set from a '78 FJ45 with the same rust issues that I will be fixing for my brother's '71 FJ40

But, new OEM fenders are out there. I just bought a set from Steve at EBI Cruisers last summer. They run about $350ea (Canadaian Funds). I paid the same price ten years ago for a new set as well.
I would totally fix those fenders. Use a cup brush on a polisher to remove the rhino lining. Remove the fender support by drilling out the spot welds and remove the underside signal bracket by removing spot welds.

This! Once you hit those spots with a wire wheel you'll know just what you're dealing with. Much easier to repair that vs purchasing an aftermarket fender and massaging it to fit as it should.

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