Hi, I'm working on a "new" 1960 420 b Case. Previous owner tampered with the valves trying to cure a blown boom lift packing. Wondering if anyone can tell me the hoe system relief pressure and as a bonus question, the setting of the special relief valve added to the boom down line. I'm planning to get a service manual but they're weeks out and I need to test this now. Thanks. Mac in Missouri
Answer for hoe and shovel relief valve settings for 420b Case This from the Case 420B operators manual. Front shovel system main relief valve pressure: 1450 PSI. Rear hoe hydraulics main relief valve pressure 1650 psi. It has also two relief valves on the hoe swing spool outlets for left and right swing cylinder: 1350 psi. Corey (Mac) in KC:usa
Lift packing now ok. Tested hoe relief pressure. Main relief valve popped at 500 psi. Adjusted with screw it to max. 1200 psi and the hoe will jump through the roof now. Needs to be at 1600-spring must be sacked out or wrong. My 1500$ hoe is lookiing better by the minute.