Repair Surprise

[shortarc]

I had what I thought were just replaceable wear plates on this dozer.

Well when I got them cut off I found a big surprise, or maybe an "oh s**t". I cant believe somebody put these repair plates on without first welding up the cracks that were already there.

There is not a rush on the fix so I think I'll wait till the snow quits to start on it.

 

[Monte1255]

Looks like a sweep under the rug job. outta sight outta mind. good thing you found that! something like that will twist and distort making your repair soooo much harder. I just hate it when people just chicken sh... a patch on and call it good.
Usually that is the same sort of situation where they needed it fixed yesterday also.

 

[ETMF 58 White]

Well here is my chance to get advice and opinions on a similar crack on my 650G C-frame. The C-frame had a crack very similar to what you are showing on yours, just not nearly as long, on the bottom but only on one side and only maybe 10 or so inches long, but in the curve of the C. I ground it out clean then welded it with a 7018 rod; so far so good but that was only a few months ago. Here is my question: I would like to put angle iron or something over it for additional support and integrity, but it being in that curve has got me stumped on how to fabricate a repair plate. Any ideas? Sorry to butt in on your post, but the crack is very similar to yours.

 

[GCC]

I myself would grove it out best i could then try to weld it in 3 pass to give it best strength then add a of angle 6'x6'x1/2" and weld it on in 2-3 pass on it. i dont know what you know about fabing but i'd pre-heat my starting point then weld 6" then skip a foot or so weld another 6" just to let it cool down so your not stressing your project and then once cooled go back weld 6" and so forth atleast thats how i would do it if you heat your steel to much your only looking for trouble in the future the hotter your steel get the harder it gets and the easyer it snaps and breeaks cause it has no play in it.

 

[shortarc]

I plan on welding up the crack the best I can as it is worn pretty thin in a couple of places, then welding 1/2" x 4" plates top and bottom with an open corner where they meet and weld that full with several passes.

 

[collins_br]

SHORTARC, good catch, it could be far far worse.

ETMF 58 WHITE, as far as bending the angle goes, you could cut small "Vs" along one side, hammer them closed and weld them up again. It may take time but it will work.

 

[koldsteele]

Got something similar in the shop an angle frame off a ..well it dont matter ...But for the love of God where do theses snot stickin welders come from ??
If that left my shop I would be embarrased to the 5th degree....

I think its more like solderion ??? just stickin on the outside ha ha ..

 

[koldsteele]

I'm sorry didn't mean to ge bent out shape in my earlier post ..its just people bring me iron thats wore down and want magicto put it back together with what they got...

Its been in the dirt for a long time !!! fix it right ...

 

[1080 bobcat]

Koldsteele Like i tell them when l get hold of something like that "CAN'T PERFORM A MARICLE ON SOMETHING THAT AIN'T THERE" When you got a AMMATURE with a welder you got a DANGEROUS thing. Like the saying says "THERE'S NEVER TIME TO FIX IT RIGTH THE FIRST TIME BUT THERE ALLWAY'S TIME TO FIX IT AGAIN"

 

[ttazzman]

If it were mine (having much experience as a welder and fabricator) i would bevel the crack with your prefered method ..grinding,airarcing, etc i would lay down with the appropriate number of passes weld with a minimum of a 7018 electrode rod or stronger or a equal wire........then i would grind it back to flush and fit a appropriate sized angle back on since this is obviously a weak and wear spot and be prepared to change the angle out again....as posted by others something like a 6x6x1/2 angle would be perfectly appropriate..........i doubt i would do a contineous weld on the angle i would probably do 2-3inches of the appropriate weld for every foot around the angle....if you decide to go with your method of welding plates on i would do something heavyier on the bottom where i assume it gets the most wear

 

[Mccahilldozing]

When you get the metal for the angle I would use T-1 strips due to the tensile strenth involved. I've had really good sucess with 91k2-t1 dual shield wire in high strength stuff like T-1 metals. I run 1/16th wire with 75/25 gas mix. The welds are clean and the slag is easy to remove. It goes alot faster than using a 7018 rod.

 

[shortarc]

Thanks for the comments and advice. I plan on getting back at this thing tomorrow or Friday and will try to get pictures.

I will probably use flat plates although the angle is a good idea, but I am afraid there is to much curvature to use angle.

T-1 was what we were thinking about using, but in this rural area it would take a while to get it here and they are wanting to get it back in service. You know how that goes! This a farm use dozer so it won't get the hours on it that one in commercial use will get.
They called me today and said they had four strips A36 5" x 7' so hopefully will get it done before the weekend.

 

[ttazzman]

it would be good to keep in mind long heavy welds can create a lot of wharping and stresses

 

[bulldozer phil]

How many hours on the machine? I've got an elderly D6H-bought it new- that we plated the sides of the pusharms with mild steel. I have not had any visible cracks in the pusharms to this point. My machine has moved a LOT of dirt-topsoil stripping -and has been used, but not abused. If had to do over would use T-1 or something else that would polish better and would have plated the bottoms of the pusharms as shown by your photos!!

 

[shortarc]

Update

Holes and crack welded up.

Plates installed, and a few more passes to be welded.

Don't look to close at the weld beads, the old body ain't as steady as it once was.

Pictures out of order, don't know how to move them around without redoing the whole post.

 

[ETMF 58 White]

Good looking job; that should last a long time. It occured to me that using two pieces of flat steel like you did is better than a single piece of angle iron to repair my cracked C-frame on the 650G. Why can't I weld a flat plate on the bottom of the C-frame in the curve, leaving it sticking out in the curved portion. Then I could use the curve of the C-frame itself as a torch guide to trim it close. Then take the second flat piece for the side and heat and bend it around the curve as I go. Make the fillet weld to tie them together like you did as the final step. Will that work?

 

[shortarc]

That's exactly what I did. It's upside down right now but I laid the bottom piece on and tacked it in place with it an even margin along the inside edge, then clamped the outside plate in place and scribed the bottom plate and cut the curve and when I put the side plate back on I had my open corner. Well with a little trimming.

 

[koldsteele]

Good lookin repair ...sorry for my earlier rant on your thread...

 

[Scrub Puller]

Yair...you did a neat repair job shortarc. What some folks don't realise though is that you can't stiffen up a "C" frame TOO much because it HAS TO FLEX, that's why they crack.

The trunnions are forward of the outboard bearing/dead axle pivot so, on level ground if one track runs over an obstruction and maxes out the equalizer travel it will apply a twisting moment to the "C" frame.

I have seen frames "beefed up" with heavy plate and whatall and it only makes things worse...they crack again untill they reach a state of equalibrium. From the pictures I would say thats's what's happened here...that original crack is quite extensive and didn't happen overnight. When they eventualy welded on the "cosmetic" angle it made it look decent and stopped it from getting any worse...best practice though is to gouge and weld the crack as you have done and as folks here have pointed out.

Depending on what the tractor is doing a thousand hours or so will probably see the weld crack at the intersection of the ninety degree plates and for that reason I reckon the angle suggestion may have been a little better.

I'm just say'in thats all, my two cents worth...and I've been around the block.

 

[shortarc]

Scrub Puller. I understand what you are saying. On this particular problem it was obvious that the metal on both the original frame wore down paper thin before it cracked, kinda hard to tell from the picture. Also the plates they welded on had worn through on the outside bottom edge.

The reason we didn't use angle is because the arms are tapered.