Cat D5C C- Frame Trunnion Mount

[Dave303223]

1993 D5C Sn 6PJ00785

I pulled my Eyebolts from the C- Frame (oh what fun that was!), and it doesn't seem right. The eye bolt has a machined face all the way around but the trunnion mount has two raised index points. You can see it has deformed the eyebolt face, is there something missing like an index spacer? Maybe the wrong eyebolts were installed at one point? The SIS doesn't show any other parts other than the eyebolt, washer and nut. I cant find anything on the trunnion side in SIS.

 

[Nige]

With everything as badly worn as that it's hard to tell what should be there and what shouldn't. Certainly SIS doesn't show any sort of thrust washer on the eye end of the eyebolt, but then again why should it because the eyebolt should not move. The relative movement between it and the C-frame is catered for by the spherical bearing in the end of the eyebolt.

 

[Nige]

Here's a question. Were the eyebolts free to rotate, or at least loose, in the machine frame when you came to remove them.?

 

[Dave303223]

I had a long conversation with my Cat dealer and they can't find any drawing showing how the trunnion face should look and the mech's don't remember doing one in a long time. The eyebolts were very loose in the trunnion from wear and one bearing was broken, the other had welded itself to the mount pin. Someone had just welded a small plate to the C-frame to hold the pins in the eyebolts since all 4 retaining bolts were snapped off. It let the pins slide around back and forth in and out a good bit.
My dealer agreed I'll be doing some Farm Yard Engineering. I'll get everything back to as original as I can.

 

[Dave303223]

Here's a question. Were the eyebolts free to rotate, or at least loose, in the machine frame when you came to remove them.?

After looking at Undercarriage GP, part 8Y-6578, I think my support is just worn that much to make the nubs or lugs. I'll have to weld it up around the Eyebolt support and machine face it back to standard. Oh well, good thing I like this stuff! What else does a retired aircraft mechanic have to do, LOL.
Dave

 

[Nige]

Make sure that you preheat that casting well before cranking up the welder.
It's obvious how much wear has taken place by the mark on the lower web of the casting caused by the eye of the eyebolt rubbing on it. That burr will need grinding off while you're in there.

 

[Welder Dave]

Stoody Build Up rods or equivelant might be a good idea. They have good fusion and higher hardness so they have much longer wear and don't mushroom like 7018 and they don't gall like hardfacing sometimes does. You can use them for multiple layers if required too. They are good for metal to metal wear and often used to build up parts prior to hardfacing. They're also used on idlers and track rollers. At least on heavy equipment you can get away with trying to salvage and repair components unlike aircraft where they have to be replaced and be certified.

 

[Dave303223]

Make sure that you preheat that casting well before cranking up the welder.
It's obvious how much wear has taken place by the mark on the lower web of the casting caused by the eye of the eyebolt rubbing on it. That burr will need grinding off while you're in there.

Good point, I'll have to get a rosebud on it, that's a big one piece casting!

 

[Dave303223]

Stoody Build Up rods or equivelant might be a good idea. They have good fusion and higher hardness so they have much longer wear and don't mushroom like 7018 and they don't gall like hardfacing sometimes does. You can use them for multiple layers if required too. They are good for metal to metal wear and often used to build up parts prior to hardfacing. They're also used on idlers and track rollers. At least on heavy equipment you can get away with trying to salvage and repair components unlike aircraft where they have to be replaced and be certified.

I'll look into those, I was concerned about quick wear and even thought of just having a machined piece made up for a repair. Welding would still be the best at home repair for me though.

 

[Welder Dave]

A propane weed burner torch is much more economical than a rosebud and better because it spreads the heat out a lot wider. It only needs to be preheated to about 300F.

 

[Nige]

and even thought of just having a machined piece made up for a repair.

Another option is that you could grind the existing wear face to remove the flats, have a steel "thrust washer" manufactured with an I/D to suit the diameter of the eyebolt and an O/D to suit the "groove" (red arrow) in the casting. Slot it in place and tighten the eyebolt then weld it around the outside and Bob's your father's brother.