is my car done? rust issues
 

So at a right turn today i heard a loud clunk.

when i got back home i saw that one of the mounts for my guide rod bracket was rusted through and gave way.

This is the part of the car frame that the guide rod bracket bolts up against, and holts a captive nut inside.

I hit it with a screw driver and saw that there was not much good metal left. I am luckey because i recently made a 700 mile trip.

anyways with this being a pretty hefty suspension component/mount is this car done for?

Pictures? Probably dead.

Any time a car reaches the point of rusting where a major structural failure occurs (I would classify suspension components falling off as major) it is a definite cause for concern and time for a thorough inspection of the whole body to find any more rust that might be hiding under body seam joints or undercoating as they won't always make themselves visible without good checking.
My 80 has a known rust issue before I ever got it back on the road, wasn't bad enough to retire yet but wasnt really worth sinking much into either as it's time was definitely limited with hefty underbody rust. I just reinspected it yesterday, it appears the undercoat has some fresh looking rips in it where a gap has appeared between the floorboard and the front subframe runners that go under the footwells, knowing my rocker has bad rust in the same area, it will need a hefty looking and may result in finally retiring the car if it really is separating as it looks to be. Just means I have to step up the restoration of the 82 a little,lol.

Living in an area where they buy road salt by the barge load, I know what you mean about rust. Eventually, most of these cars are going to have some serious rust. When it gets into structural areas (like suspension mounts), it is time to take a good look and decide. Most rust damage is repairable/replaceable. Only issue is cost. And a note here, this is the kind of repair that must be done right. If your DIY repair fails and you cause a wreck, your liability is unlimited. So have a good look at this and other rust on the car and decide if the car means enough to you to have it all fixed right. Probably, it is time to retire the car. If you have a nice interior, perhaps you can find a used rust-free southwestern car with a dead interior.

I agree with the others. The rust in that area is probably not an isolated occurrence. These cars have a heavy pvc undercoating that hides growing problems. If you're really attached to the car, I would start prodding & poking everywhere for underlying problems. The best & correct fix for the guide mount on the frame is probably to re-weld one from another car exactly where it goes. I went through my entire car when I cracked a rear trailing arm due to water getting inside from rot in between where the spring sits on it. I used about a quart of POR-15 on the car. Good stuff. The rust wasn't that bad, but it was just about everywhere being originally from Erie, Penn. I looked in every orifice with an inspection mirror-felt like a doctor, but I eventually saved the car, Paul.

It can be repaired, Cut out the old rust and have a welder come in and repair that guide rod mount. That seems to be the weakest spot on these cars, I have had several that have rusted in that area.

My "nice" daily driver has had repairs done in that area. It does depend if the unibody rails are all rusted out though, rust on the underbody is usually eventually terminal, but you could keep it going for a few more years.

thanks guys. I bought a welder today and going to the metal store to get some scraps to practice to make sure i get some strong welds down. I designed a bracket that will tie the good remaining metals together and should keep it going. there seems to be enough metal around the area to make this work, the area seems to be holding together pretty well right now (as i drove it to school). its only when i take some major bumps while i am at full lock can i hear the clunk.

now i wish i could have someone teach me how to arc weld. I have studied up on internet sources so far and have done it one other time (practice)

No offense intended by the following statements, you really do want a good welder to do this, I tried to do it myself for about 6 hours, The arc welder just ended up burning through the metal, and not making good welds. My buddy a good welder had the welding done in about 2 hours, he used a mig.

You dont want to learn to weld on the frame of a benz.

Good luck,

I have some rust on the underside of my car. If I peel off the undercoating, where and how can I get more to paint on?

Rubberized rocker paint in a spray can will get you by for small areas.

i second this, welding is not as easy as it sounds, i dont doubt ur abilities, by all means go for it if u feel confident, but just remember, this could be ur life or someone elses life that ur taking just to save few hundred bucks, and in witch case u do get professional help, continue with the welding, it can come in handy during many situations!

I do this 8 hours a day, 5 days a week...
 

Perhaps I should set up a mobile rig that travels across america and fixes your guys' rust issues! I'd be a millionaire in weeks! :D

MIG MIG MIG....and make DAMN sure you disconnect the battery.
Arc is too hot even for frame structures...

My 2c :)

Somebody replaced the section of frame right where the guide rod mounts to the frame on the driver's side of mine. It looks like they used c-channel or box channel. Not the best welding I've seen on it, but it seems to be holding just fine. So it can be done and apparently you don't have to be the greatest welder to do it. Which reminds me, I need to check it again to make sure it is still holding just fine :idea2:

I was thinking as I was washing my Jeep today... the next new car I get (if I ever get a new one), I'm going to coat the entire undercarriage in grease and oil.

update:

well i really needed to get it done. because i had to drive a 300 mile round trip for a job interview tomorrow. I used and arc welder and welded a bracket to it. i also filled in some of the metal that was missing.

it seems to be holding well and my wheel clunking is gone. I was driving it around town before. and it clunked when i made a right hand turn (this rust in on the passanger side) and stepped on the brake hard.

I tested the strength by jacking the car up using this point and it seems pretty strong. next week i will add a bracket all around it for added piece of mind. perhaps bring it to a professional.

but all in all its good. and my 300SD lives another day/

Due to all the engine and tranny leaks my 82 has had in the past, it came to me with this process already quite well accomplished (and a VERY well preserved underbody), part of me hates working on really greasy things (aside from fire risks) so I want to steam clean it while I have the engine /trans out, yet part of me hates to do that as I reopen the can of worms that invites rust,lol it's a catch 22. All in all it's going to get cleaned, it's just really too oily, going to rot out all the bushings/grommets if I don't.