Rust damage --- what's patchable and what needs welding? - PeachParts Mercedes-Benz Forum

bob_98sr5 · #1 09-04-2007, 03:07 AM

Hi gents,

I took several days this week and over weekend (a few hrs at a time due to +100F heat) to do a tear down of the interior to discover how far the rust damage is. Here are some shots:

front driver's side

middle support

rear passenger

rear passenger wheel well

front driver's shock tower

What is most troubling to me is the piece that attaches from the center and runs/connects to the inside of the rocker panel channel. that's where the rear left seat bolt sits on. it is coming apart because of the rust. The shock tower looks like its salvageable

I've been reading about the various methods including the POR15 and the Miracle Paint patch/fiberglass resin products as well as using pop rivets and welding patch panels. If I had to guess, i'd say the only thing fiberglass patchable is the wheel well area. As for the floor panel and the rocker, my guess is that at the minimum, the center support will need to be replaced and welded. Thoughts?

My question related to the rust is what sections do you guys think look spatchable and what sections look like they should be welded?

However, the thing that concerns me are the lines. Why? if there is to be any welding, then those lines will have to be removed. As if it hasn't been hard enough to find a shop (i've visited 7 in my area---only 2 will consider the work), i can see my bill shooting sky high just on removing the wiring.

My second question is: can the wiring be cut and then later soldered together? and for those vaccuum tubes, would cutting it and then attaching a connector work? my guess is yes, but I'm going to defer to the experts.

I will visit the two body shops on Wed, but i'd like to get some expert feedback before then.

Thanks,
Bob

bob_98sr5 · #2 09-04-2007, 10:33 AM

bump for the morning crowd...please help!

rs899 · #3 09-05-2007, 07:51 AM

hey, easy now.

Keep in mind that this forum isn't all that popular- probably better to post on tech forum for starters.

But, you really need to tell us what we are supposed to be looking for/at....

Is this a W124 or ????

The pictures are very detailed...perhaps some scale of the damage is needed. A few smaller shots would help to get a sense of the magnitude of the damage.

I think you will need to be doing a lot of welding here. There may be a few areas that could be addressed with pop riveting/metal bonding ( I do some of that with Fusor 108B), but it's hard to say without seeing the big picture- where are the supports/what kind of shape are they in.etc.

Chad300tdt · #4 09-05-2007, 08:56 AM

Bob,

I'm not an expert in body repair, but I have used POR-15 and done some welding. IMO you should weld in new metal for everything you showed in the pics. The only thing that I see could be fixed with POR-15 and fiber mesh is the top hole on the wheel well, but there is so much more damage right below that hole that needs welding. POR-15 isn't recommended for holes larger than 2-4 square inches. I'm not a fan of pop rivet repair, but the wheel well might be OK. Looks like you have alot of time consuming work ahead. Good luck.

bob_98sr5 · #5 09-05-2007, 12:29 PM

rs and chad,

thanks for your replies.

the reason i posted in this body repair subforum is b/c thats where it belongs. i recognize that this subforum does not get alot of views, but i dont want to cause the mods any needless work and moving it here. i do that as a mod on my forum on a daily basis. but if the mods historically dont care about posting in the proper subforum, i'll post something like this in the diesel tech forum

rs: yes, its a W124, 87 300D. when you say you need "smaller" pictures, do you mean more detailed pics? i can take more pics, but its such a pain to remove that seat. if i were to put the damage in words, the rust seems to have spread from the inside near the front and spread backwards to the wheel well in a very linear manner. the rust gap (where its eaten away at the metal) is about 4" wide. what i think i am going to do is to try to cut the donor vehicle's floorpan 6" from the center of the seat to the inner part of the rocker panel channel. I'll also take some of the rocker panel with it and weld it to the good metal. i know that is not a very good description, but i'll photoshop some lines later tonite to help this description along

i also have to be concerned about melting the wires. i dont want to unplug or splice any of those, so i'll have to get creative on how i am going to tackle this issue. i believe the best course of action would be to make sure the cut lines of the patch panels are far enough away from the wires. that would mean i'd have to cut farther away from where the rust ended than what's probably recommended.

after doing some more reading last night, i believe the best course of action woudl be to cut the donor metal panel(s) a little larger than the rust hole and secure by using a combination of:

- some sort of metal adhesive with rust inhibiting properties for the patch overlap
- pop rivets to secure
- butt welding

what do you guys think?

thanks again for your replies,
bob

rs899 · #6 09-05-2007, 12:57 PM

bob-

What I meant was I was having trouble visualizing the big picture. How much good metal is left that is structural. Your pix are a bit too exclusive- especially since I am not familiar with W124s.

I am going to try some rivet bonding on my Citroen DS19 that has bad side chassis rails. Here is an article I found:

Apr 24, 2007
By: Bob Zweng, LORD Fusor
Automotive Body Repair News

Today, passenger vehicles are assembled with more adhesive, seam sealer and foam than ever previously imagined. As such, it is important for technicians and estimators to realize that replacing these adhesives, sealers and foams post-collision is critical for returning vehicles to pre-loss condition, as well as avoiding the “diminished value” tag.

However, technicians often struggle with deciding what to bond and what to weld, often leading to improper repairs. But, by using a few simple rules of thumb, technicians can confidently use metal bonding adhesive products to bring vehicles back to pre-loss condition, reduce cycle-times and increase shop performance.

The first step in this process requires the technician to discern whether the panel needing replacement is structural or non-structural. In most cases, auto/truck non-structural panels include roof panels, quarter panels, door skins, cab side panels and rear body panels. Patch panels to repair corrosion, tears or holes in metal would typically be considered non-structural.

If the part doesn’t affect the structural integrity of the vehicle design, then it is likely non-structural in nature. On the other hand, structural parts may include frame rails, aprons, core supports, rocker panels, pillars, inner quarter panels and floors. With easy part identification, the choice to weld or bond is fairly straightforward.

Since methyl methacrylate (acrylic) type metal bonding adhesives are trusted by many OEMs for the assembly and replacement of non-structural metal bonding panels, the technician only has to identify the structural characteristic of the part when deciding the best method of repair.

For example, a door skin is a non-structural part and can be bonded complete with most metal bonding adhesives without the need for welds. Nearly all auto/truck roof panels, quarter panels and rear body panels are considered non-structural as well and many times can be adhesively bonded, weld-free, using acrylic-type metal bonding products.

When working with structural areas, the best method of joining metal panels may vary. However, the use of metal bonding adhesives has become commonplace in structural areas when used in conjunction with traditional metal joining methods. In some scenarios, frame rails, aprons and pillars are assembled in the factory with adhesive, and welds metal bonding adhesives, coupled with squeeze-type resistance spot welding (STRSW) equipment, can be utilized when installing structural members and panels, which helps bring the repaired vehicle back to factory specification and results in an “invisible repair.” Rivet bonding is another method of joining structural metals along with adhesive.

Tips to follow when using adhesives to bond metal:

• Some adhesive manufacturers suggest that door skins, quarter panels, roof skins and rear body panels can be bonded completely without any welds. This helps speed repairs and eliminates the need to dress MIG welds.

• Typically, pick-up truck bed side skins can be bonded along the upper rail and wheelhouse, but should be welded or weld-bonded at the front and rear bed posts. Full bedside replacements (inner and outer panel assemblies) should be welded or weld bonded only.

• Patch panels are great candidates for adhesive bonding as it offers a quick and easy solution for technicians who perform classic car restorations and rust repair. The use of metal bonding adhesives in this type of spot repair application helps minimize interior trim damage and panel warpage often seen when welding.

• As a rule, metal bonded panels are much easier to remove and replace than MIG welded panels. The use of a heat gun capable of reaching 400- to 500-degrees-Fahrenheit, along with a chisel enables the body technician to remove a previously bonded panel cleanly without causing further damage to the inner flanges.

• Structural panels such as frame rails, floors, pillars and rockers should either be welded, weld-bonded or rivet-bonded, according to the OEM, for the purpose of restoring the vehicle to factory condition. Contact the adhesive manufacturer technical support hotline or the OEM for up-to-date repair recommendations.

A key best practice when making sound collision repair judgments is to bring all the stakeholders together on the same playing field. A well informed decision team consisting of the insurance company, shop manager/estimator, vehicle owner and technician will go a long way towards maximizing the latest adhesive technology and best repair methods to ensure a high-quality, lifetime repair.

Bob Zweng is the senior technical service representative for LORD Corporation. He is I-CAR trained and ASE Master Certified. He can be reached at +1 248 30-6910 or bob.zweng@lord.com.

http://www.lord.com/Home/ProductsServices/Adhesives/FusorAutomotiveAftermarketProducts/RepairProcedures/tabid/3411/Default.aspx

And above is a list of repair procedures (including rivet bonding ) from Fusor. I have used their 108B on a lot of repairs, but nothing structural. Depending on how bad yours really is, you may be able to do this for some of it, but I think you probably need some welding too.

Rick

bob_98sr5 · #7 09-10-2007, 03:33 AM

chad and rick,

again, thanks for all your help and advice. the article was definitely a good read.

we have a tandem garage, so space is at a premium. so basically on sat and today, i cleared out some shelves to make some room. why didnt i do that before!?!?

so today, i removed the front wheel and practiced again on one of the easier holes in the front wheel well. here's a rust hole i cut out and then primed. I am going to cut/prime before i do any metal repair. priming is to keep it from rusting, of course:

before

during

after

Oh yeah, a new heat gun definitely helped. Harbor Freight has nothing on this Milwaukee

it even has a cooling setting that you turn on to cool the jets, so to speak.

Ok, now to the big concern: remember the small rust hole by the spring perch? Well i took the heat gun to it and removed some of the undercoating and tore away at the joint sealant. i was not happy with what i found, but i think it might be salvagable. that's where i need some expert help/advice and first-hand opinions here:

original hole

damage at top section

global view w/ rust highlighted

global view with focus on inner perch

in the last 2 pics, i took a wire cup brush on my drill and went at it. later, i put some naval jelly on it to remove the surface rust. what you see is the remaining rust. i was not able to put my screwdriver or my hammer through it, so that is the good news. what concerns me though is how do you treat this? Can POR-15 make this rusted portion truly inert to the point where it won't break? And also, can this be welded with some sort of supporting bracket or brace to the good metal to keep the structural integrity of the perch? Is this the product that Whunter keeps mentioning in all of the W210 spring perch failures?

I've read more than my fair share of horror stories about the spring perch failures. i'm looking to repair this asap.

oh also, is it a bad thing that i am removing the sealant? for some paranoid reason, in the back of my mind, i feel like the spring will shoot out at me if i remove any more.

thanks,
Bob

Pete Geither · #8 09-10-2007, 05:46 AM

IMHO most of the rust holes I see need professional repairs done with a mig welder. The spring perch area could develop into a disaster, as could the areas around the seat. If you are not proficient in mig welding, please take it to a pro for repairs, your life or someone elses could depend on it. I am all for DIY where applicable, but I see shoddy welding every day where someone didn't know what they were doing and it usually just costs them double to get it done right. You show a willingness to do things right, so if what I said makes sense, give it some thought. I can't teach someone to weld over cyberspace.

bob_98sr5 · #9 09-10-2007, 11:56 AM

peter,

thanks, ill have the body shop next to my mechanic take a look at it. peter, does the rust look too bad that the existing perch cannot be welded to the good metal? if you wouldnt mind commenting on that, i'd appreciate it. i want to be well informed when i go in.

also, the other option i have but might be more costlier is to cut out the perch and some surrounding metal and weld it on. i have 1/2 a donor mercedes available that i purchased from a junkyard.

bob

Pete Geither · #10 09-10-2007, 04:46 PM

Just about anything can be welded and repaired,,, you just have to get to good metal to tie in to. Those spring perches can certainly be made 100% again.

junqueyardjim · #11 09-11-2007, 07:24 PM

Referring to Bob's original question of course. Bob starts this thread with these hard to define, super over sized pictures of what appears to be a junkyard automobile that someone kept running long after it should have been retired. But after a couple of lines about what he has been doing, he pops the question,
"My question related to the rust is what sections do you guys think look spatchable and what sections look like they should be welded?" A quick answer is, None of them.
I think the question should have been, "Do you think I should try to repair and restore this car?" Following that he could have provided some pictures of the whole auto, and further enumerated its salient points. We have none of that, only after quite a little "entitlement heat", (where is this BS coming from) are we even told a model number, W124. Secondly the author could have enumerated his skill level. But none of that is considered by so many of those who start threads. It is just a give it too me now and yesterday isn't even quick enough. Well, after reading the whole bleeding thread, I can tell you what Bob's skill level is. So far as auto repair is concerned it is right at zero. Sorry if I broke someones bubble, but that is where it is. Have I met Bob? No, but from reading the thread, I know where he is at.
So, here is how I think we should look at this car and its rust problem. It is true that every thing can be repaired. As long as time and money exist, there is a way to make it right. Would I spend a dime to repair that car? Never! Heirloom, special car, got it from my Great grandma, whatever. Get rid of it! If you really like that model, buy one that needs an engine or transmission. Nut and bolt stuff can be learned by less then an artist or a highly trained craftsman. If there is anything on that car worth saving, take it off so you can use it on a rust free unit that you should buy. Is the engine great? How do you know? If it is, pull it and save it. You don't have to be a specialist to do that. However, if you have the TIME and MONEY to restore it do it, and then you can tell me I'm all wet. In the meantime don't get all in a knot because no one can really come up with a decent answer to your problem. I really think that is why answers were not coming forward.

Pete Geither · #12 09-12-2007, 04:31 PM

That is a pretty brutal critique Jim, and you do put forth a lot of good points. My look on Bobs' situation is that he has shown a sincerity to do the job properly, and if his skills are not up to the task, he will consult a professional. We are just trying to help folks here, and give them the best advice we can. Which is what you did, of course.

FRANKNBENZ · #13 09-23-2007, 06:20 AM

Noble Forum Fellows,

Car is pretty well shot, body-wise. Good points all on using this one as a parts car and swapping out or over any guts that still work. Also very good points on safety...hey, I might be on the same road with this thing... Might be more cost and time effective to get a nearly clean southern or desert car.

Or, just for grins, dive in.

One previous car, now deceased

had the exact same driver's seat rust through problem. At the welding shop I removed the seat and an apprentice MIG-ed in a 2mm plate, large portion for the floor, bent 90 to affix to the chassis main tube under the door. Prime, paint, undercoating and just keep inspecting for new signs. Ran her for five more years.

I didn't then but do know now that his welds up against the chassis tube heated spots inside and certainly burnt off the dipped on primer. That's a caution, long term.

This and other forums helped me greatly with mechanicals and AC so I took the plunge and got a Lincoln 3200HD flux and MIG combo set at Home Depot. $450 plus $35 for cylinder deposit and the first load of CO2+Argon. I installed a spec 20Amp 120V circut to the home garage IAW code, got a heavy duty extension cord, some old cookie baking sheets to practice on... you get the idea. The Lincoln rig will weld up to 5/16" steel at 20% cycle time. And with some adjustments, it will do stainless and aluminum. Except for the engine block and maybe the door hinges, there is nothing thicker on a W123 (my cars). I am guessing you can work around all wire and vac lines.

MIG is science, art, technique, and luck. The Lincoln rig comes with a how-to manual, more at the library, get a night class at an Adult Ed Center

. If you have the time, you can become proficient enough to tackle all the holes in that car.

Today I did two patches in the trunk area -- spots under the plastic boot no one bothers to check until too late. One's about 1x2 inches, the other 2x3 and bent at 70 degrees. I used 1mm sheet stock salvaged off the deceased. Worked out pretty well. There is some foam and bonding agent between two rusted parts which I removed. Once the patch is tacked in place and a bead applied all around, I fill in any gaps with rigid spray foam instulation, trim, shape, prime, paint and or undercoat, depending which side of the repair.

Against all odds, I seem to be getting better with each repair.

I have done five so far on the varous vehicles and figure, based on what the welding shop charged me for that first floorboard fix, I have already recouped my investment in the rig. Besides, there is the pride of having done it yourself.

Yours will be a heck of a lot of work...but it is possible.

Do consider all safety issues as have been mentioned. I follow Clint's admonition that a man has to know his limitations.

bob_98sr5 · #14 12-07-2007, 05:32 PM

Quote:

Originally Posted by junqueyardjim

Referring to Bob's original question of course. ... I really think that is why answers were not coming forward.

Jim,

I will say that as someone who quotes a Biblical verse in your sig line, I find it exceptionally hypocritical as a Christian that you exhibit some very presumptuous and judgmental thoughts in your post. I'm sure you can find a few that address "Lest ye be judged..." for some perspective. When you became a Believer (as am I), did you always ask the right questions in the manner in which a seasoned Pastor could answer your question? Did you ever respond in a Bible study in a way that manner have not been Biblically correct? Did you feel stupid, but learned from the experience? Or were you berated until you learned the right way to ask things, the right way to answer, the right way to etc, etc? Or did you take baby steps to grow in your faith, but stumbled along the way and LEARNED with good mentoring and 'coaching' from your community?

I will refrain from ripping into you as you did to me. it does no good purpose. I'm trying to fix up this car, not have an internet ego/tech battle royale. People have generally been pretty good to me, though my frustration did come out in this thread. I apologize to you and to any other members who took offense to my rant. I was frustrated by previous researched tech posts that fell on deaf ears and it came out. I will not do that again.

That said to all of the other members who are interested: I wanted to revisit this thread because i am coming to the point where I will begin welding and patching. Unlike the previous comment above, the body is indeed salvagable, says the body shop guy. Yes, it has taken a lot of time, but again, this is a project car for me. It will cost me about $1600 to get everything right, but $1200 of it came back as a refund from the seller.

At this point, i have cut out all the rust in the vehicle and am in the process of cutting the donor vehicle's body parts into shape to fit for seam welding. I still need to pull the rear axle off and inspect for further rust though, but after poking around down there with an ice pick, i am pretty confident that the rust on the suspension was limited to the axle itself as well as the suspension mount. All other surface rust i've sanded down and then treated with rust bullet.

i've been practicing like crazy on scrap sheet metal and I have the technique down. Not saying that i'm perfect, but i can spot and seam weld alright. for the spring perch and the rear triangle rear axle mount, that's going to be done by the body shop guy. thanks to all the guys for the warning on galvanized steel too. i had no idea.

i'll be starting some fiberglass patches on the non-structural areas too like under the wheel well. of note, i believe the mercedesstore.com and the POR-15 kit are one in the same. at least they look like it in their respective manuals. who knows if the formulation is differnet though. but i tested the stuff and it really works. it can be as stiff as you want to make it.

Fortunately for me, Ive had the benefit of working on this car for the past 3 months with a quite bit of consultation from a very cool local bodyshop guy and an auto mechanic who are taking an interest in the biodiesel aspect of this project. also, the auto mechanic has made a great introduction to his junk yard parts guy who has sold me a rust free rear subframe, lower control arms, and other misc parts for pretty cheap. We are trading knowledge and expertise, so to speak. also, thanks to Peter, Franzenbenz, At2, Sixto, etc with helping along the way with my project car here and in other posts. i work well with both constructive and positive feedback/advice.

Bob

Pete Geither · #15 12-07-2007, 07:58 PM

Well best of luck to you Bob. If I can be of any help, don't hesitate to PM me.