941 Upper & Lower Bucket Pin Internal Threads

[Metalman 55]

I am replacing some pins & bushings on the General Purpose bucket of my 941 (80H298X) & plan to pull the 4- pins out where the loader frame & linkage connect to the bucket. Some of them are seized in the pin bosses & I will have to push or pull them out. I see one end of the pins has a bore part way in & it is threaded with a fine thread. Upper pins are #6K3937 & the lowers are #7K9360. Anyone know if the tread is 1-#12 NF thread? It measures about that tap drill size, but it has lots of paint on it, so hard to tell. If I know what thread it is I can get a tap & clean the threads. Perhaps the internal thread on the one end pins can be used as a puller of sorts to assist in getting the pins out?

 

[Metalman 55]

Here is the internal thread in the pins that I was asking about. As mentioned on the earlier post some of the pins are seized & I thought I could make up a puller by using the blind threaded holes. Anyone know what thread it is?

 

[DB2]

TCT Tony will know for sure but likely some one will else as well. Seems to me they are a fine thread. You could always use a drift from the other side with a BFH.

 

[RayF]

Cat have a habit of using UNS in pins. 14 tpi. It would pay to check before tooling up

 

[kshansen]

I see one end of the pins has a bore part way in & it is threaded with a fine thread. Upper pins are #6K3937 & the lowers are #7K9360. Anyone know if the tread is 1-#12 NF thread? It measures about that tap drill size, but it has lots of paint on it, so hard to tell. If I know what thread it is I can get a tap & clean the threads. Perhaps the internal thread on the one end pins can be used as a puller of sorts to assist in getting the pins out?

Metalman. close! according to SIS similar parts info. the threaded holes are 1"-14 threads. From the picture the ends with the threads have grease working out from the bushings so you may not have a bad time pulling them. Maybe hook up a good hydraulic puller to them and then apply some heat to the area around the end with the retaining bolt.

 

[Metalman 55]

Metalman. close! according to SIS similar parts info. the threaded holes are 1"-14 threads. From the picture the ends with the threads have grease working out from the bushings so you may not have a bad time pulling them. Maybe hook up a good hydraulic puller to them and then apply some heat to the area around the end with the retaining bolt.

Actually, the upper pin on the other side is seized, no grease coming out around that one.

I do have new pins ordered for the bottom, so perhaps when they come in I can check the internal thread size off of the new ones.

 

[Metalman 55]

Re the top pin that was seized in the pin boss, we put heat on the inner pin boss & then used a 30 ton pancake jack from inside to try to force it out & all it did was start to twist the ears on the bucket. So, for plan B I took my torch with a large tip & started blowing away at the inside of the pin, chewing out a ragged hole a couple of inches deep, let it cool a bit then put some oil on & gave it a hard whack with a sledge & got it moving; then out she came! Just got 2 new bushings & pins for the bottom from Cat where it attaches to the loader arms & hope to put them in now. The lower bushings are shot & the pins wore bad too........

 

[Metalman 55]

Got the bucket off this morning.....found the 2 bushings at the bottom of the loader arms were "homemade", just some pipe to act as bushings & were loose in there.

I have 2 each of new Cat lower bushings, pins & 4-seals to replace with. The Cat bushings are loose (sort of expected that they would be) in the loader arms, so am going to carefully weld the holes to reduce the play, then grind with an internal grinder & fit the bushings to suit the best I can. Want to avoid the cost of line boring for a machine that old. Have a long straight bar that fits the ID of bushings to help with getting the alignment as close as I can.

Will clean up the upper pin bosses with a flap wheel to shine the ID's back up..........

 

[Metalman 55]

I got the lower bucket bushings installed in the loader arms & everything back together. Had to do a fair bit of build up weld around where the OD of the bushing went, then ground it smooth the best I could with an internal grinder.

I then end welded the bushing in place, as there were still gaps here & there, just to make sure the bushings did not shift or start turning. With the weld at the ends of the bushings I could not put the seals in.

Still have some build up work to do on the pin lower pin bosses on the bucket, as there is some play there, but nothing rotates there, just moves around a bit. It should be easier from here on in, as the pins are all free now.

 

[Metalman 55]

Well, we decided this morning to take it one step further, so pulled the bucket off again & carefully added some weld to the lower pin bosses on the bucket ears, then ground n fit, ground n fit, ground n fit some more, using an internal grinder to shave off the high points................. The end result after a few more hours of labor is the bottom hinge point has no movement at all. Given the fact that it was all done by hand, there will be high points where the new pins shoulder against the built up areas, so it won't be long until it has a bit of play again, but the end result I am very please with. The upper pins are relatively tight yet & everything takes grease once again.