I'm planning on repairing the chassis legs on my 2003 Evo with 157k miles. The rust seems to be mainly in one area and hasnt spread across the whole frame rail. My plan is to disassemble the rear of the car: rear subframe, diff, fuel tank, etc, in my garage. One of my buddies is a professional welder who said it doesn't look too bad for a northeastern car and he's going to come cut and weld the frame in patches instead of an entire replacement. He's planning on doing the work end of May / early June. So I'll have to start taking it apart in my spare time very soon. I was wondering if anyone had any advice and tips related to the work. Has anyone else had their frame repaired in this way? I've seen one other thread where someone had a shop repair it instead of a full replacement frame. I'm looking forward to cleaning up and painting the rear diff , gas tank, fuel filler neck, and everything else I end up removing. I'm still doing research on paints and wax undercoatings to be used after.

Here's what we're dealing with on both sides.

 

Nice good luck. Please keep sharing as you progress.

I actually plan to do the same for my evo9 one day

 

I hope this thread can either turn into an inspirational "you can do this too" , or "do not try this at home". I am not an expert at anything, I just like to tinker.

Well I got the rear subframe down. It wasnt bad, about 3 hours. Then even with the subframe out of the way I still messed around with all the fuel tank connectors, hoses, and parking brake cables for another 3 hours until I got the fuel tank down. I cannot imagine doing that with the subframe on.

The damage was looking worse once I could see the other side of the frame rail. I was getting concerned the rust was spreading under the control arm bracket and I would have to source replacement rails. After wire wheeling / needle scaling, it's looking salvageable. I sent a dozen photos to the welder and he still has full confidence we can make it a lasting repair. I think I'll be setting up the sand blaster to get the metal as clean as possible, then treating with zinc phosphate, epoxy primer, bed liner, and lanolin coating inside the rails. The hole in the frame doesn't scare me much, this section is more manageable to patch weld.

 

I commend you for taking on this project. Something like this will make you appreciate how harmful salt can be when ignored. I know I didn't fully understand it until I looked underneath my old 4runner and found two holes in the frame. Now my brand new GX460 got coated with Fluid Film the first week of ownership. Knowing what I know I would never buy a rusted vehicle ever again because the salt damage can be extensive but not obvious.

 

Indeed. I have never worked on a rusty car to this degree before. My daily car is a 2022 civic SI I purchased new and intend to keep for a very long time. I will certainly be washing it and applying a generous coat of lanolin this fall.

 

Looks very similar to an evo of mine. People don't realize the level of reinforcement inside the chassis legs and panic. I found this video very helpful when patching spots:
Great work so far

 

Good to see a worthy evo 8 being saved. These cars are really at the point now where it’s worth doing this. Do quality work and it will be like oem. Looks like you know what you’re doing and really care about the work. Definitely following this thread.

 

It's solid plan! Research on rust prevention is key.


 

Consistently driving my super rusty evo with no issue also made me realize most peoples rear chassis legs are just fine.
But at the end of the day, finding a new shell made the most sense for me.
OP, good luck!

 

I just had this done to my Evo. Unfortunately they had to cut out the real bad spots and reweld new material in and then reweld everything back together. Important thing is after you do the work make sure you undercoat it so it won't happen again.

 

Thank you for the encouragement guys. I'm going to need it.

Do you have any photos of the process you could share?

 

Unfortunately no I just have a before and after pic. Mine were pretty much gone and looked like swiss cheese to be honest. They just just cut out all the holy parts and replaced them with new steel, then welded it back together and undercoated it. It was way cheaper to do that then spend 2100 dollars over seas to have the parts shipped to me brand new. I will see if i have any in my car log to post up here of the before and after.

Page 10

https://www.evolutionm.net/forums/ev...o-start-9.html

 

"yorkshire car restoration" on youtube has a video series where they do a lot of rust repair, including rear chassis legs on an evo 8. would be good to check it out

 

The chassis legs are repaired! He didnt have to cut out and replace as much as we expected, and he had both sides done in about 5 hours. Lots more grinding and then painting to do.

 

Nice job it looks really good. Thankfully you didn't have as big of a job as I did. Welding looks really nice and welds look nice. One thing I will say is undercoat it now while everything or you will have to redo it later down the road. One extra step to keeping it clean.