B/L4520B repairs/maintenance

[shootem604]

Pulled the bucket and dipper cylinders off the backhoe. Local hydraulic shop recommends against straitening the one rod since it is bent at the very end, and the other because it is so badly bent. They can make new rods, but it will cost as much as buying a new one. New ones aren't available from Kubota, but thankfully Messick's could get me the rod and seals from Woods (the B/L4520B is a Kubota branded Woods 650-2). Also ordered new pivot pins (from my Kubota dealer, cheaper than Messicks or Woods by almost 50%?) and brought my bucket into the local machine shop to have new ears fabbed up and welded on - they were worn excessively. Going to have the new ears made from 1/2" instead of 3/8" as I have room for the extra width and it should last longer. The pins had grooves at least 1/4" deep all the way around, and the pin holes in the bucket ears were oval and at least 1/4" oversize all the way around. I knew the bucket had too much play, but I didn't know it was this bad. Put this up if anyone else out there is running this backhoe or the Woods equivalent, and has any other tips to add. I will be changing the filter and fluid at the same time - any ideas on purging all the old hydraulic fluid from the cylinders, etc?

 

[shootem604]

For anyone else trying to find the parts for a similar rebuild (especially if you are in Canada), here's the weird way pricing worked out: pivot pins are cheaper from Kubota Canada, the rods are cheaper from Woods USA, and the seals/seal kits are cheaper from Kubota USA.

The cylinders are simple to tear down: a pipe wrench unscrews the end cap, pull out the rod, unthread the nut, use a mallet to slide the seals off, and that's it. Now waiting for the parts.

Going to repaint the hoe while I have some pieces apart, and Princess Auto has plastic spiral hose wrap on sale, so the hoses will get some love too. Also replacing some of the grease zerks.

 

[shootem604]

Update: The backhoe is back at work with a fresh coat of old Kubota orange paint and some new decals. I had the "ears" on the bucket replaced with 1/2" and bought some new pivot pins too. The dipper and bucket cylinders have new custom made induction hardened rods and Kubota seal kits, and the backhoe has a new filter and new fluid too. Almost as good as new - just need a new seat sometime.

I was worried about how difficult it would be to repair the cylinders, but installing the new seals and rods took under 15 mins per. Hot water helps soften the hard seals, and some hydraulic fluid helps slide them into place.