Cast iron repair?

[Arc weld]

There's a lot of smart guys on this forum so maybe they can help with my repair. I have a Cat track loader with a 3204 engine. I just put new check valves in the transfer pump but had to remove the bolts holding the oil cooler on so I could get the bottom bolt for the transfer pump out. I got it all back together and everything seemed fine, no leaks. I was going to go try it out and drove about 100 yds. I thought I'd check again for any leaks. No fuel leaks but oil was leaking. Closer examination showed that the top mounting tab for the oil cooler had pulled right off. About 3/8" thick. It looks like a spacer because it was such a clean break. I think it's a 5/16" bolt that goes into it. I need to fix it and it's cast iron. I don't know if I can tap it deeper into the housing or not. I read on the welding web about a guy doing a similar repair using nickel rods and just doing very quick welds so it doesn't get hot. I can take the transfer pump off but the injection pump is above that and I don't want to take that off. Looking for some good ideas on the easiest way to fix it. Thanks in advance!

 

[jwmorris]

Can you show a photo of the problem area?

There are several thread solutions but if the fix demands a weld that can get a little more complicated. I have had the most success with silicon bronze rod and TIG welding. Wouldn't want to try and tap it though.

 

[Arc weld]

Sorry can't show a pic. It's like a raised boss that's threaded for mounting the oil cooler and the bolt pulled the threaded section off. It's out at my property and I don't have a shop. I have a welder and a torch but because it's not too far from the injection pump, I don't want to get it too hot.

 

[the old grind]

I wonder if you could back the injector pump bolts out a few turns and just break contact where heat would otherwise conduct from the casting ... and/or without tearing a gasket. (injector lines too stiff? can you loosen a nearby bracket/'loom' then too??) 1/16" would be plenty far away if the job went quick enough. (strategic toothpick spacers?)

Cooling the welded casting gradually enough could be as important to minimize stress around the weld as getting however hot you might preheat locally with the torch, and an extra pair of hands on scene could be most helpful when you're ready to strike. btw: Our tool & die welders would use the 'nickel' rods on cast Iron. There may be ones that require the least preheat or would 'stitch' the best if you don't do much of that.

I'm thinking you might not have to tap anything. Can you: 1) reach to weld/stitch all the way around the boss? 2) Thread the boss onto a bolt and into a remaining deep thread or two and snug it down nice with/vs clamping? If not so easily aligned perfectly you could still chase-out with a tap to assure clean threads to the most depth.

 

[whistlepig]

I can't weld a lick but have supervised welding and maintenance groups for decades. The welders and maintenance people prefer brazing over Ni-Rod for cast iron. Ni-Rod makes the cast iron brittle around the weld and it breaks easily. Brazing to them is a better long time fix. Again, I am not an expert. Just sharing an observation.

 

[Arc weld]

I need to find out if the part that the oil cooler bolts to is separate or part of the engine block. It's a kind of complicated. The oil cooler attaches to it and so does the injection pump. There's a drain plug in one end. I think maybe oil comes from the injection pump into it or from the oil cooler to the injection pump. If it is a separate part, it might be best to just replace it. If it is separate I hope I can get it aftermarket or a good used one. Cat parts are NOT cheap.

 

[Shield Arc]

WOW! Not being in a position where you can use heat really limits the options. Only thing I can think of is some type of epoxy. Years ago before I ever bought my first aluminum Tig welder I had to repair an aluminum engine case that went on a motorcycle. I used a 2-part epoxy that worked great. Have no idea what is on the market now, that would work in this situation.:confused3:

 

[the old grind]

.... welders and maintenance people prefer brazing over Ni-Rod for cast iron. Ni-Rod makes the cast iron brittle around the weld and it breaks easily. Brazing to them is a better long time fix.... Just sharing an observation.

Shield Arc, I worked in leak test/repair in the transmission plant before I went into the trade (Toolmaker). We'd use an epoxy to repair 'case' leaks (aluminum) between testing and the shipping dock. Porosity in pressure areas meant a teardown, but with 'trichlor' to clean/prep the area & a dab of silver paint on top for looks it worked for the rest. None of this was structural but it seems logical that brazing would adhere to CI well and provide some resilience for heat expansion at the repair site, so +1 on that. (I have seen CI brazed outside the toolroom)

btw: I wonder if too long a bolt (a replacement of yore) had bottomed out in the hole and pushed/snapped the boss off when fully tightened. I'd rather hear that it was a spacer and that too short a bolt didn't get a good purchase in threads below. (How thick or thin the 'parent' material is could demand some understanding/finesse, too.)

Can we help the OP post pics to tempt more welding guys into this exchange? (... if I didn't 'wonder'/ask so often I'd never learn much ....)

 

[flusher]

Cast iron or cast steel? Makes a difference in welding/brazing. My engine guy repaired a broken water pump casting on my Minneapolis Moline BF tractor using braze rod. He said it was cast steel.

 

[yomax4]

Should be an easy fix. If you are not sure what the base metal is, Use MG600 or Missle Weld or Versalloy. 2 second tack welds all the way around. Silicon Bronze will work as well. All come in stick or tig. Make sure you have the bolt in there before you weld. After, Just snug it up with lock-tite so you don't need to reef down on it. Or I think someone mentioned welding a nut on in place of the boss. Same filler metals will work. Good Luck.

 

[Arc weld]

I thought about epoxy too. I'm pretty sure it's cast iron. I don't think cast steel would pull apart like that. I'd much prefer if the threads had just stripped. I don't think the bolt bottom out. I'm not going back to look at it today but I think the part that pulled off, while still threaded on the bolt, is loose. By loose I mean the bolt with the broken piece will turn while still on the oil cooler. You would think it would be sucked tight on the oil cooler unless it vibrated loose after it broke?

yomax4, your post didn't come up right away when I opened the thread but where I work we have some specialty rod that I think is 312 stainless based. It says it's for welding difficult to weld steel and unknown types of steel. It's called EZWELD ALS sold by FSH.

• Superstrength electrode for the welding of all high alloy steels, cast steel
and unknown steels,between themselves or for dissimilar assemblies
• Outstanding mechanical properties(120 000 PSI)
• Easy to use
• Corrosion, heat and oxidation resistant
• Machinable, crack-free deposit
• Can be used for build-up
Applications: Repair of chains,spring steel, axles,parts of ATV,
gear teeth and splines,wear plate,small farm machinery,
stainless steel, extracting bolts and studs, and
where there is a need for high
tensile strength
in the joint.

 

[Gaemes]

Just a thought from the new guy. If you gave a thought to being able to tap deeper, did you consider Heli-Coil? I have drilled and tapped for Heli-Coils in cast and they worked great.

 

[Arc weld]

Another guy who's familiar with my engine said not to drill it deeper because it go into something it shouldn't. I wish I could have installed a heli-coil.

 

[muddstopper]

Its hard to make repair suggestions without seeing what needs to be repaired. With that said, on something as important as the engine I wouldnt want to take short cuts. If it runs, load it up and take it to somebody with the proper equipment to fix it right the first time. If you cant take to a shop, find someone with a well equipped welding truck to go to the field and do the work. While epoxy might hold and be an easier fix, braze or welding would be more permanate.

 

[CliffordK]

Here is an interesting YouTube video that was posted here on tractorbynet.com not too long ago. I haven't tried it myself.

"No-PreHeat" Cast Iron Repair Technique

In the video, he suggests hitting your piece with an angle grinder. If it sparks, it is cast steel. If it doesn't, it is cast iron.

Even if you repair it, you may consider changing your mount to alleviate some of the strain on the repaired piece.

 

[Arc weld]

I am a welder but haven't done a lot of cast. The problem is the injection pump is about 8" above where it has to be repaired. Also it needs to be a good repair or I could lose all the oil and have a major repair bill. Taking it somewhere is a bit of a problem. It weighs about 22,000 lbs. and I don't have a truck to move it. I'm pretty sure it's cast iron and part of the block but I'm going to check with a Cat parts book. Nothing against Chucks video but anybody can make a video of welding cast. I was looking for suggestions from someone with experience that has had their repairs hold after being put back in service over a length of time.

 

[george md]

Arc weld,
You and I have had some of this discussion before, I sent you to the web site of one of the biggest and best cast iron repair shops in the
country. Your comment was a sales pitch for his plugs and wasn't really accurate.You know that I have very little use for any form of arc weld
on cast.I see that you are looking at a high tensile rod for repair WRONG , cast is normally 30 to 50,000 pounds tensile ,why would you want
120,000 weld ,when it cools and contracts it will pull the cast apart or pull away from the cast. There is no such thing as welding it and it
staying cool, the arc is several thousand degrees and so is the weld metal,and when it cools it has to shrink and there in lies your problem.
To weld that with arc , you will need the softest and most ductile material you can find ,and by the way nickel is about 90,000 tensile. I think
I would look for some arc weld bronze, I have used it on meonite ( sp) castings and it worked well , the other thought is fusible powder
torch with the most ductile powder, eutectics 10224 or 10225 ,I have had better luck with 10225 . It has more iron and the 224 has more
nickel.

If that turns out to be a piece that is removable , send it down and I'll O/A weld it . Also clean the gasket off better next time and it
won't break the ear off.

george

 

[jwmorris]

I would bet 100:1 its cast iron. Cast steel is for other parts, like drive line and you don't need to braze cast steel, just weld it like normal.

 

[Danno1]

I was looking for suggestions from someone with experience that has had their repairs hold after being put back in service over a length of time.

I've had exhaust manifolds brazed and stay together for long lengths of time. I was told by the weldor that did this that welding is the wrong process for such a fix.


.

 

[muddstopper]

With cast, preheat is as important as the welding material. I have seen engine blocks welded with mig and regular wire and the engine is still running today. Guy ran a mig in one hand and a o/a torch in the other with lots of taps with a ball pien hammer. I have tried tig on a cast iorn fruit press and made a mess of it. I have also brazed cast water pumps using O/A and as far as i know its still running for the last twenty years. The water pump was laid on top of a wood heater until it got hot and then brazed while setting on the heater and allowed to cool over night as the stove burnt out. I dont know if one of those mapp/butane/propane torches will get the cast hot enought to use as a preheater, but If that was all I could carry into the field, I would use it. Which makes me think, how about trying some silver solder. It doesnt need to get as hot as the brass I dont think, and it holds like heck.