Backhoe Pin/Bushing replacement in Woods 750 Backhoe

[TMGT]

The 1144 is holding up extremely well on my BH so far, spring bushings hold up way better then a lot of bronze bushings in BH due to shock loads. Only place I used bronze was in the pivots for the trunions on the swing cylinders. Didn't want the pins wearing first.

 

[Dataway]

Just ordered some of the early model Woods bushings to compare with the McMaster spring bushings .... Woods refers to them as "Tension Bushings" .... which, pretty sure is the same as spring bushing.

 

[TMGT]

Most likely, Wallenstein uses the same bushings as I used on my BH on theirs.

 

[Dataway]

Any idea how the swivel bearing comes off? They are the two bearings at the top and bottom of the king pin on the main housing. I can see how I might be able to get a puller on the top bearing, but there is no way on the bottom. I'd have to try to jack up the tractor by the housing until it pulled the bearing out of the frame. The bottom bearing might just be stuck in the housing ... the outer race is supposed to freely rotate in the housing ... at least it does in the top and they are both the same part number, and have a grease passage to the outside of the outer race.

 

[Dataway]

Got the first pin made from the 1144 ... was somewhat taken aback by how easy it cut and machined. Behaves like it's soft, but it isn't. Compared to the 1045 I can just feel it trying to grab the surface of the 1045 .. so it is a bit harder. And in the reverse the 1045 just skitters off the surface of the 1144. The 1144 cut way faster than the original OEM pin .... I'm hoping that's just an example of Woods not wanting to pay the extra money for "easy to machine" alloys. The original pin didn't appear to substantially harder than the 1144 though.

This is the pin that connects the boom ram to the main housing. Obviously the old one is bent badly, a couple of years ago it broke the ears off the main housing and in the process bent the pin, it had been repaired once before poorly. This time I rebuilt the whole area, bent the ears into alignment, welded on additional 1/4" plates to reinforce the area. Poor design from the get go, the main housing should be 1/2" plate, not 3/8". New pin is 1/2" longer to compensate for the additional 1/4" plates.

New pin slides in nicely. Going to make a couple of the bucket pins next ... they are about $90 each .... cause they have a washer welded to them. The plain pins are cheap from Woods, but any pin with any machine work on it is like 3 times more expensive.

 

[TMGT]

I love working with 1144, almost fun to machine it's soo nice!

 

[Dataway]

Got a set of the McMaster spring bushings today .... they aren't kidding when they call them "tension" bushings. Those things take some force to compress. No worries about them spinning in the housings unless they were rusted solid to a pin.

 

[TMGT]

They are nice, I did a lot of research when I was building my BH and decided to go with them.

Here's some of the over 20 pins I had to make, a lot of them have grease passages, took a little while to make!

 

[Dataway]

Did your experience building it give you any insights into the hole size for the spring bushings. I notice the typical min/max hole size for a 1.25" OD, 1.00" ID bushing is 1.250 min, 1.2513 max. that's a .0013 spread ... pretty tight tolerance to maintain. I'm shooting for around .002" pin/bushing clearance. Haven't mic'ed the 1144 yet ... typically rods run about .001-.002 undersize.

I'd like to avoid much "experimentation" .. don't want to bore the holes, insert the bushings and find the pin is too loose or too tight. Any advice appreciated as I've never used spring bushings before.

 

[TMGT]

.001-2 on a 1" pin in this application might be a little tight, I usually run at about .005 per 1" of diameter for grease clearance.
The .0013 doesn't sound right, the spring has more working range then that.