Cat 257B undercarriage

[estatevm]

Hi There,

I recently purchased a Cat 257B track loader used. I noticed today that the left rail (holds the rollers and idlers) is cracked pretty bad. I wanted to see 1) if this is something I can weld myself (until I can afford to have it replaced) 2) how hard is it to take apart the undercarriage to get access to weld it. 3) General advice on what to do at this point.
Please help!

 

[Nige]

I'm sure some of the CTL specialists will be along soon with advice but I'll take a bet right here and now that the crack was started by that snot of weld on the plate that's tacked on to the top of the structure. Any idea what it is..?

 

[estatevm]

Thanks Nige, Im not sure what that plate is. I cleaned it off and theres nothing on it. The crack is almost all the way though the rail. I have a felling its not going to be cheap to replace it. IM crossing my fingers its weldable for now.
Thanks!

 

[movindirt]

Well, how good of a welder are you? You'll need to remove the 2 idler wheels, to do this loosen the track with the screw tensioner just in front of the crack there. Once the track is loose remove the dust caps on those 2 wheels, behind them you'll find a 1-1/8" nut, take that off and the slotted washer behind it as well. After those have been taken off you can now tap the back of the wheel with a hammer to pop the bearing loose, the front bearing will pop out and the rear bearing will stay in the wheel. Be careful where you ground your welder when you weld, and be sure to unhook the ground cable off the battery. I'll let someone who is better at welding comment on how to go about welding it

 

[Nige]

I'm working blind here because I'm off line as far as getting technical info goes, also I'm working from a tablet instead of my home computer so that makes things doubly difficult. However if you can get the wheels off it and let the dog see the rabbit so to speak I'm sure I can come up with some suggestions.

As a suggestion have a trawl through the grader section and on Page 3 you will find a thread regarding welding a ball on to a 16 grader, funnily enough also titled "welding question ". There is a lot of welding technique info in that thread you can also use for this repair.

Also post a Serial Number to help locate any technical information that might be available.

 

[estatevm]

the serial # is slk01521

Im a mediocre welder at best. If it is Cast steel I think I can weld it, but if it's cast iron I will have to find someone for sure. Does anyone know what the rail is made of? Also is that what the part is called? Left rail?

Thanks all

I will pop the wheels off an send more pictures soon.

 

[movindirt]

the serial # is slk01521

Im a mediocre welder at best. If it is Cast steel I think I can weld it, but if it's cast iron I will have to find someone for sure. Does anyone know what the rail is made of? Also is that what the part is called? Left rail?

Thanks all

I will pop the wheels off an send more pictures soon.

It should be a piece of rectangle tube steel, I've swapped some axles on one before and it was just 1/4" or 3/8" wall tube steel. Looking on Cat Parts it looks like the part number is 252-0440 which was replaced by # 305-9300, shows price is about $1,600. Again don't quote me on that. That also means you have to swap all of the wheels over to the new frame. I think if I was going that route I would just get all new wheels for it as well. just depends on how much you want to spend. Personally, If it was my machine, I would just weld it. If you don't feel comfortable doing it a local machine shop should be able to for not a whole lot. I am honestly surprised it broke in the first place, how long have you had the machine?

 

[estatevm]

Well thats great news that its just tube steel! I should be able to weld that no problem as long as I can access it. I just got the machine a few days ago and cant really put any more money into it at this point. So welding it could be my only option.
When I purchased it you couldn't see the crack because it was filled with dirt, and I got it on an online auction so all I saw were pictures of it and a guarantee that it ran and nothing was wrong with it.

Im not sure how it broke like that. It seems like you would really have to beat it up good to get that to crack.

Thanks!

 

[seatwarmer]

Nige
Do you think this is applicable ?

PROBLEM
In certain applications, the undercarriage frame on the 247/247B/257/257B multi-terrain loaders may crack where the track adjuster is mounted to the frame. This crack can not be weld repaired and must be replaced. See the following graphic for the location of the cracks.

 

[Nige]

Nige
Do you think this is applicable ?

PROBLEM
In certain applications, the undercarriage frame on the 247/247B/257/257B multi-terrain loaders may crack where the track adjuster is mounted to the frame. This crack can not be weld repaired and must be replaced. See the following graphic for the location of the cracks.

View attachment 147337

That looks exactly where the OP's crack is. Bad news in that case but remember to read between the lines "cannot be weld repaired" can simply mean that a weld repair will not survive long-term. If this repair is attempted it needs sh1t-hot welder to do it because he'll only get one shot at it. Meantime the OP needs to start saving his pennies for a new replacement frame.

 

[Tracklayer]

Who is making that statement in the bulletin on the possible cracking? Is this a known defect? It sounds like it is describing a known defect and that the cracking is abnormal rather than normal wear and tear effect. When it says the crack cannot be welded, and the part must be replaced, it is possible that there reimbursement from the factory for the repair?

I wonder what type of steel it is and if that is the reason why it cannot be welded. If the part is known to break, I wonder if it is known why it breaks.

 

[Tones]

I'm only a mediocer welder but I would have a go at welding it and also plate over the crack along the side wall. It may last long enough till you can afford a new frame. Nothing ventured nothing gained.

 

[Nige]

Who is making that statement in the bulletin on the possible cracking? Is this a known defect? It sounds like it is describing a known defect and that the cracking is abnormal rather than normal wear and tear effect. When it says the crack cannot be welded, and the part must be replaced, it is possible that there reimbursement from the factory for the repair?

I wonder what type of steel it is and if that is the reason why it cannot be welded. If the part is known to break, I wonder if it is known why it breaks.

The statement is from the factory. In view of the statement one would assume it's a known defect. If it wasn't known then obviously the factory wouldn't know about it and therefore couldn't make the statement - a bit like D1ck Cheney's "known unknowns and unknown unknowns" really.
There could well be some factory participation, it would depend on the age of the machine, hours, and previous service history. Possibly also how good a customer the owner is and how loud he shouts.

It will be nothing special as regards steel, probably a 29Mpa structural steel that you would normally repair with low-hydrogen electrodes. However what makes things difficult in this case is the square hollow tubing from which the frame is made. It's likely to be such a thin wall that it would be extremely difficult to get any thickness of weld and/or penetration on to it without blowing right through it and making things worsecin a heartbeat. As I said before, IMHO it's not that it CANNOT be weld-repaired, simply that it's unlikely that a repair would be sufficiently durable long-term to be regarded as a permanent repair. However a repair might well last long enough for the owner to come up with the coin to replace the frame, so by that criteria it would be judged as a successful repair.

 

[seatwarmer]

Its Service letter SEBE9059-03 date last updated 14/01/2007

PS50883

NOTE: This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS50883" as the Part number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
NOTE: Although this Program is to be administered as described above on the Affected Product, parts should be removed from parts stock as soon as possible.

***** Affected Product *****

Reference RENR4859 Dissassembly and Assembly Manual for replacing the undercarriage frame on the 247 or 257 machines. Reference RENR4874 Dissassembly and Assembly Manual for replacing the undercarriage frame on the 247B or 257B machines.

NOTE: Inspect opposite undercarriage frame for cracks where the track adjuster mounts and replace if cracked. Loctite all fasteners and torque the 8T4910 bolts to 105Nm +/- 20Nm.

 

[estatevm]

I was quoted about $4900 from caterpillar to replace the part. I then found someone to weld it for me instead. It was plated on 3 sides and welded and so far seems to be holding fine. I sent a picture of the crack to the company that sold it to me and they are reimbursing me $3700 for the crack, or so they say. Still no check, but I was surprised they would even consider paying for the repair. I'll use it until it cracks again and then replace the part in time. For now seems like the weld is holding! Thanks everyone for your help

 

[Nige]

Get on to your local Cat dealer ASAP and inform them of the failure and show them the photos. Mention that you know about "Service Letter PS50883" regarding cracked frame replacement, that should be enough to put the frighteners on the dealer and get you a replacement frame at little or no cost to you. Whether the factory pays all the cost a lot will depend on the age of the machine and how many hours are on it. Be sure about one thing, you will get something......

 

[KSSS]

I would not count on getting any help regardless of what TB's are out on the issue. The Perkins motors that have been prematurely blowing for years in these machines, and owners have not received any "reliable level" of help on the matter from CAT.

 

[Cmark]

I wouldn't get your hopes up. The program for the frame replacement ended in Feb 2008.

 

[Nige]

I give you one word my learned friend - goodwill......... Even when a program has passed its termination date by a few years there's always scope to apply it, maybe not 100% coverage but anything's better than nothing at all.

 

[Cmark]

Fair comment Nige, you never know 'till you try but around my neck of the woods, "people" are more interested in chasing the multi billion dollar miners and you sometimes get the feeling that small gear is just an inconvenience.