Urgent question regarding aluminum oil pan repair

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Hi all,I am working right now (as I write this) on the repair of a hard to find aluminum oil pan.  It was hit with a rock while crossing a dirt road somewhere in the outskirts of Phoenix.  It had about three minor cracks and two major ones.My method is to drill out the ends of the cracks, bevel them and fill them in, usually from both sides.  I clamp it to my table and weld them in small increments to avoid overheating the casting.  As an added measure I lay water soaked rags on the pan Near the weld area to absorb the heat,  technique taught to me by one of the welders on this forum (his handle escapes me at the moment) when welding cast iron.  I now incorporate this technique when welding crack prone items.However in this case I am reluctant to weld the crack on the inside owing to the fact that the cracks are so long and I can't clamp it when welding the inside.  I am going to cut a piece to put over the hole, tack it from the inside and weld form the outside and leave the inside as it is.Any thoughts on this?  Should I weld the inside and just do it in tiny beads (1/2" long at a time) or something like that?I will check back to see if anyone has seen this posting and get some ideas.  Otherwise I am going to leave the inside unwelded to play it safe from cracking or distorting.Thanks,Tony Attached Images
Reply:I have fixed some similar stuff, I would do as you did with the cracks drill the ends, v the outside weld it then v the inside and weld it. I wouldn't really worry so much about the heat input on that thing its pretty big and will probably be fine if you just take breaks between each crack to let it cool.In terms of that hole I wouldn't patch "over" it I would use a cutting wheel and use those ribs as guides to make a "square" hole then cut/bend a piece of aluminum plate to fill it then butt weld the outside and inside.Also I would use 4043 filler on this Attached ImagesLast edited by chrisbmx68; 05-23-2012 at 03:52 PM.
Reply:Tony, suggest leaving the inside cracking un-welded at the moment.(Hopefully you're using 4043, which is more compatible to AL castingthan the 5000 series fillers.)There's more suspense in store, when that big patch is welded.As you're aware, the flatness of the pan gasket flange has everythingto do with function after the repair. I check flatness in front of the customerwhen the part comes in, then check it again at the end.I'll do water spray with air blow-off intermittently to stop the heat expansion/contraction scenario.As I recall, I had a pan in that resembled the above--and it would consistentlycrack outside the weld and in other areas-despite keeping the castingtemp, very low. Very thin casting, highly restrained--it was a no go.(Do 100 repairs and bomb on one--then 'the guy can't weld AL')Blackbird
Reply:Hello fellas (and any ladies present),I finished welding it out and am going to leave the cracks unwelded on the inside as I am concerned I may distort the pan since I am unable to restrain it.I did all the welding (except the tacks) on the outside and the pan was clamped down in four places.  I never welded more than an inch at a time and allowed it to cool before starting another bead.As stated, I used wet rags for heat control.  So far there are no new cracks and the pan's flange is true.I was not aware that 4043 is the rod of choice for these types of repairs.  I recently decided to switch to 5356 as my rod of choice for aluminum repairs and fabrication for the added tensile strength.  I did notice that one of the tacks cracked.  I assume if it was going to crack it would have done so already or can I expect that cracks may develop in use?  I hope not.Here are the shots of the finished item.  I'm sorry I didn't check my post sooner or I would have done as chrisbmx68 suggested.  It is a cleaner looking repair to make a symetrical patch as he described.  I just layed the patch inside and welded away.  The bead on the inside of the patch is because it cracked on me when I bent it.I used a torch to apply heat to the patch while I gently pounded it with a hammer to bend it into shape.  I have done many such bends but this one cracked so I welded it.  The crack didn't go through to the front so I didn't put a bead on the outside.Thanks for your suggestions.TonyPS:I have been working feverishly to get my rig back together as I am in the process of installing a new (to me) welder.  I moved up from an old Miller AEAD-200LE to a Miller Trailblazer 251-T.  I ran into it by accident and couldn't pass up the deal on it so I took the plunge.  I am a little disappointed when I found out that the Trailblazer is only 200 amps AC at 60% duty cycle as opposed to my old AEAD-200LE which is 225 and 100%. On the other hand it has the built in remote, the CV (mig) capability and can produce power while welding.  Plus it has a 240volt outlet on top of the 120 volt ones.  My old one couldn't weld and provide power.  The trailblazer was $1700 complete with High Frequency external box, 150 feet of cable, large argon bottle, torch  mounted remote amperage control and a 150 amp air cooled torch with protector sleeve.  It has only 300 hours on it. Attached Images
Reply:I would have used 5356 myself but what do I know......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Another trick ia to make the patch with asmall flange all around and weld the edge of the flange, it'll look something like a frost plug. That way when it pulls it'll flex the flanges rather than put the patch in tension.....Mike
Reply:Originally Posted by mrmikeyAnother trick ia to make the patch with asmall flange all around and weld the edge of the flange, it'll look something like a frost plug. That way when it pulls it'll flex the flanges rather than put the patch in tension.....Mike
Reply:Another good trick is to back it with a piece of 11ga copper plate and start building rings of 4043 until you've closed the hole.  Blend smooth to finish.  I've seen engine blocks repaired with this method.  The aluminum doesnt weld to the copper obviously.  Then you remove the backing plate and you're set.
Reply:Hi again,these are really great ideas and I really like the fact that we can share our experiences via this medium.  Its like collective knowledge, like the borg (for you star trek fans, ha ha).I've used the copper backing for anything and everything that requires filling in as described by anickode.  It is a good trick for welding real thing stainless edges, etc.  I use it all the time for rebuilding rims that have missing pieces broken out.For steel I learned from an old timer decades ago using carbon rods or pieces for building up missing areas as well.  I will remember next such repair to make patches symmetrical.  I think it would give a more professional look to the job.  Good one.I found out a few hours ago that my client got an emergency call from his family in Florida that his brother is gravely injured from an accident so he called me to say he would not be picking it up, was leaving for Florida right away and didn't know when he would be back.  Oh well....I wished him luck.  I hope I don't get stuck with the part but under the circumstances I can't say I blame him.  He was calling me from the airport.Thanks again,Tony
Reply:That looks like it came out really well even with the odd shaped patch (was probably easier to pull off the way you did it)! I suggested 4043 as its very soft, in this case that would be good for preventing cracks. This is a repair where tensile strength isn't really important at all. Amazed with how little contamination you got, had I done this it would have been a lot uglier. -Chris
Reply:Nice fix. Any pictures of your rig?IW Local 580 NY, NY
Reply:i generally turn oil pan repairs down, not worth the time, or the hassle.  I tell people to buy a replacement or find a good used one.If you warp the mating surface, and it leaks oil, whose responsible? If the repair fails, who is respnsible?  Welding cast aluminum thats been holding all just plain sucks (ive done it, and had no returns) but for what? id just rather not put myself in that position if possible, just my 2 cents.PS  Your repair looks about as good as they get.
Reply:Hi again,I've done quite a few oil pans over the years.  I've never had a problem with any leaking or warping with the exception of one I did last year that was the oil pan from hell.  However I did it in place, did not do it slowly, did not take precautions to control heat.  So I set myself up for a rough job.  I started a thread about it.  It came out real rough looking but in the end it didn't leak and is still in service.I kept chasing cracks and was hitting probably every gas pocket the pan had so I was blowing holes all over the place.  That job I should have walked away from but oh well.....you live and learn.  It had a hole in it that I put a patch over that was probably about 7" in diameter!!!I am starting to shy away from doing them in position as the oil that is left in them seeps out and what would normally be a half hour fix on the bench turns into a three or four hour job as it has to be repeatedly heated and cleaned to burn all the oil out of the area before it will weld decently.Thanks for all the ideas, they will go into my brain's database and I'll whip them out like the right tool for the right job.Tony
Reply:For Blue Arc,here are a few pics.  My truck is an old Mercedes Unimog model 404.1 TLF.  It used to be a military firetruck complete with power take off pump, water tank, siren and blue flashing light.  I stripped all the guts out and put my gear in it. It is a true mobile welding shop.I put a Ford straight six in her when I first got her as she was too underpowered as the stock engine only had 80 horses. Now I have 150 and it made the world of difference, especially with all the weight I carry in it.I have on board air, air assisted brakes, swing out work bench, drill press and what have you to get the job done.For technical support for it I belong to a list of Unimog owners who help with practically any problem that arises, a good bunch of guys.  There are also a network of dealers who import them from Germany as they go up for auction and stock parts for them.For anyone thinking of getting one, you should know:1) they are gas hogs (7 mpg).2) they are noisy as hell, you can't hold a conversation in them when their running.3) no conveniences (radio, air conditioning, power steering, etc.)4) slow as hell, top speed may be 50mph with the wind at my back and going downhill.On the plus side:1) they are fun to drive.2) they get a lot of looks and guys wanting to touch her (like a fine woman) and check her out.3) they are high with good visibility and will never get stuck.  I was once up to my axles in mud and she just churned her way out of it.TonyTonyTony Attached ImagesLast edited by therrera; 05-23-2012 at 11:22 PM.Reason: to add more pictures
Reply:That's one sweet rig, I have always liked the unimogs.Next question I have is ehat is the oil pan off of, it's not relevant to the fix, but I'm wondering what this rare pan came from as I just gotta know it appears to be a factory pan. ThanksOffering CNC Plasma cutting and welding projects.Follow me on facebook https://www.facebook.com/nobigdeal.fabSupport those that support WW.
Reply:Hi again,The client told me but I can't remember.  He just said he had been trying to locate a used one but were not available at any of the wrecking yards here in Phoenix (and there are plenty of them).  He also said the dealer would have to order it and they were expensive.  So he opted to see if it could be repaired.I let it go at that.  Now he had to take off to Florida on a family emergency before picking it up so I can't even ask him about it.The way I took it was that he did want to (or couldn't) pay the dealer's price for a new one.Tony
Reply:That's cool. I only ask because I have sources for hard to find items. And have access to salvage yards that are not open to the public. The yards are not advertised, or even known outside Thier customer base. I was going to see if it was avaliable if so I thought about getting one for you for your customers return. Just trying to help out when and where I can.Offering CNC Plasma cutting and welding projects.Follow me on facebook https://www.facebook.com/nobigdeal.fabSupport those that support WW.
Reply:That's good to know cause there are times when it is better to replace than repair.  If you don't mind sending me a private message with your contact info I will keep it handy for when that situation comes up.  Its just a matter of time.I appreciate your offer.Thanks,Tony
Reply:Is that a sheet rock toggle bolt holding the drain plug?-IanMiller Dynasty 350Miller XMT 304
Reply:How did you clean off the oil pan while preparing it?  Was there any contamination while you were welding or were you able to get all the oil and contaminants removed?
Reply:Originally Posted by crab fishermanIs that a sheet rock toggle bolt holding the drain plug?-Ian
Reply:A unimog welding rig is all sorts of awesome, thanks for posting.What kind of work do you do where you can compromise so much (speed, mpg, comfort) for the added capability?IW Local 580 NY, NY
Reply:Originally Posted by zapsterI would have used 5356 myself but what do I know......zap!
Reply:Hello gentlemen (and any ladies present or lurking),Here are some answers:1. You are right, that is a sheet rock toggle bolt looking contraption.  I didn't even pay attention to it until it was brought up.  Apparently a leaky drain plug was shored up with some silicone and pressed into place with the toggle bolt.  What can I say??2. I got the Unimog when I lived in Arizona's White Mountains in a rural area of the state.  I had a welding service and the truck could go anywhere it was needed regardless of terrain.  The economy couldn't support us up there so we left our place with friends and migrated to Phoenix where work was.  I don't mind the creature discomforts though lately I have given thought to selling her and replacing her with a more modern version with the niceties.It becomes a major hassle to travel to one of the outlying cities like Mesa or Chandler as these are one hour trips for me whereas in a freeway speed truck it would be half that time.  I am getting older too and at some point I may not be able to climb into the cab.3. Oil pans, transmission cases, engine blocks all have one thing in common, dirt, grease and oil on top of aluminum's oxide layer.  The technique I use is to pass the tig torch over the break or crack to burn and clean the area.  This is after I've cleaned it squeaky clean with gas or some other solvent first and wire brushed the **** out of it.I've assembled a nice selection of cleaning tools such as a roto-zip, dremel, carbide aluminum bits both 1/4" and 1/8" to fit both including wire brushes for them.  Not to mention stainless steel hand brushes both large and small, assorted 3m type scouring pads and so on.  I have also got drill chuck type wire wheels so that before I run the torch over the repair it is shiny clean.  These cleaning passes burn the junk out of the cracks or metal in general and leaves a black soot which must be cleaned again and again until it no longer seeps out of the metal or the crack in question.  Finally the metal is ready to weld when you can form the nice shiny aluminum puddle we are all used to seeing when working with clean stuff.Once you have that, then it will weld without a problem.  It may still leave behind some impurities which will get caught up in the puddle but they will not prevent the puddle and metal from flowing nicely, just leave a "dirty" look to the finished weld as the junk rises to the surface of the weld as it cools.  It can be brushed off. This is why I am reluctant now to do them in position as the burning / cleaning action must be done sometimes a dozen times or more as the oil that is in the pores of the metal or the moist oil slick still inside the pan or block oozes out and into the puddle.  That's why I say that a simple 1/2 hour repair on the bench can easily take 3 or 4 hours in position.  I use an oxy-acetelyene torch in those cases to boil out the oil and grease too until it forms a hard soot that can be brushed or scraped off.Finally I will look into the use of 4043 for these types of repairs as it makes sense that a softer aluminum will "give" more when subject to shrinkage than the harder stuff.  The idea of making the patch flexible by putting a slight flange or bow in it is a great idea and I will incorporate that into future repairs.  Thanks for that one too.Attached are pictures of that toggle bolt.  It seems to be an off the shelf repair plug as the head of it is not a screw head but some type of solid coin type plug pushing agains the outside of the plug and being squeezed by the toggle in the back end.Tony Attached Images
Reply:Nice fix Tony, do you know the make of the car? Originally Posted by dave powelsonAs I recall, I had a pan in that resembled the above--and it would consistentlycrack outside the weld and in other areas-despite keeping the castingtemp, very low. Very thin casting, highly restrained--it was a no go.(Do 100 repairs and bomb on one--then 'the guy can't weld AL')Tony:I recently had to replace the aluminum oil pan in my wife's Mazda Tribute. The clowns at the local oil change placed first stripped the damn threads on the drain plug and put in one of those toggle thingy's as their "fix" for it. Then when I complained the put in an oversize self threading bolt. Then the next time it went for an oil change ( I was out of town and she went anyway to them) the knobs cracked the oil pan casting around the drain hole in such a way that it was cheaper to replace the whole bloody pan. The damn thing had to be towed home as it was leaking oil all over the place. Took me almost a full day to do it, and they wouldn't pay for it.She'll never return there and I will do all the oil changes from now on.....I already was doing them on my Ford diesel.I mention how much I hate these dumba$$ oil change places.......One thing I forgot to add was: Did you see the episode of Pawn Stars where they bought a UniMog? It was completely restored and I think they paid something like $17,000 for it. They said that UniMog started out as a farm "tractor" thing. It also has the offset axle design like the HMV for added ground clearance. I've always thought they were an awesome vehicle.GlennLast edited by Stampeder; 05-25-2012 at 10:13 AM.Sign on East Texas payphone: Calls to God 40 cents......it's a local call...