Cracked hydraulic cylinder barrel

wdchyd · Mar 15, 2019

Your tubing is on the way

inane2 · Mar 19, 2019

Got a delivery from WDCHYD yesterday. First class service all the way!!!

Cylinder removed from machine, broke down and ready for repair.

wdchyd · Mar 19, 2019

:thumbsup:......You’ll do fine, let me know if you have trouble getting the seal kit.

wdchyd · Mar 31, 2019

You make any headway this week?

rScotty · Mar 31, 2019

wdchyd said:
View attachment 595413

Real common problem on thumb cylinders as the torque and twist of the hose does damage, the adapter welded on the tubing has no support and may be too thin of wall thickness.

The right fix is to disassemble cylinder, remove the tube assy, save and clean up the female boss tubing adapter, new heavy wall tubing (IIRC the other end has a tight 90 deg bend where welded near the gland head).

TIG weld new tube assy back on, weld other end, then weld 2 reinforcement square blocks (yellow lines in pic) on both sides of tube adapter (1/4 - 5/16 thick).

It痴 not worth trying to reweld the old tubing, it will leak again. I have plenty of that tubing in stock if you can稚 find any locally.

I must be missing something here... I can't figure out why that thumb cylinder has that piece of tubing on it in the first place? Both of mine are roughly the same size thumb (JD & Kubota) and both are plumbed like most hydraulic cylinders with standard hoses running to each end of the thumb cylinder. There's nothing like that welded piece at all.
rScotty

wdchyd · Mar 31, 2019

This exact design is very common for thumb cyls, many manufacturers use similar welded feeder tubing to minimize hoses in tight spots were they might rub on frames

rScotty · Mar 31, 2019

wdchyd said:
This exact design is very common for thumb cyls, many manufacturers use similar welded feeder tubing to minimize hoses in tight spots were they might rub on frames

Ok. I see it now. Thanks. Instead of a feeder tube, the picture below shows an example of using a standard hydraulic cylinder for the thumb and feeding it with an armored hydraulic hose. The wire wrap armor is important, otherwise my experience is that hoses exposed out there on the dipper stick will end up with some sort of physical damage that requires replacement long before the sunlight kills them. But so far I've found hoses easier to deal with than special cylinders.

My guess is that either the tube or armored hose would work the same, and the choice is up to the owner doing the repair.
rScotty

nyone · Apr 1, 2019

I have a 1990 kubota kh41 excvator that i just went through the same issue. Hydraulic tube cracked off the cylinder. It was down at the base of the boom. I spent nearly half a day welding it and testing it. Once i got it fixed i covered the area with bash plates. Its not prety but i have curled a stump against it alreaty.