Hydraulic fluid leak and the brake fluid trick. Who has done it?
- Thread starter ng8264723
- Start date
Firebrick43
Well-known member
It’s not wise to do.
Hydraulic oils is usually a 20 weight oil unless it’s in fire prone applications. Most systems use NBR/ Buna N seals
DOT 3 Brake fluid is a glycol derivative. Glycol based systems use EPDM
It will make all the seals in a system swell including things you don’t want to. I also can dissolve NBR, and it’s very likely that the seals or rod glands are cracked/torn anyways. Swell a cracked gland doesn’t solve the problem and destroys every seal in the system.
Hydraulic oils is usually a 20 weight oil unless it’s in fire prone applications. Most systems use NBR/ Buna N seals
DOT 3 Brake fluid is a glycol derivative. Glycol based systems use EPDM
It will make all the seals in a system swell including things you don’t want to. I also can dissolve NBR, and it’s very likely that the seals or rod glands are cracked/torn anyways. Swell a cracked gland doesn’t solve the problem and destroys every seal in the system.
All of a sudden three of the rams starting leaking. UGH. I need it for another month and then I will pull the rams and have them rebuilt over the winter. The strange one is the side to side. I do not know how this one works. It is not a ram but a pivot
Firebrick43
Well-known member
Never had a Grove apart but the JLG is a short stroke vertical concentric cylinder.
The rod has an helical lead (coarse thread) that engages a sliding nut that has its own helical lead that engages the housing on the outer perimeter and rod helical on the inside. When the concentric piston push or pulls on the nut it causes the shaft to rotate but not extend/retract.
Since the the basket is bolted to the rod on top it’s forced to rotate.
The rod has an helical lead (coarse thread) that engages a sliding nut that has its own helical lead that engages the housing on the outer perimeter and rod helical on the inside. When the concentric piston push or pulls on the nut it causes the shaft to rotate but not extend/retract.
Since the the basket is bolted to the rod on top it’s forced to rotate.
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Retired dozer fixer
Well-known member
You put brake fluid in that system you will rebuild the whole system. Guaranteed 
Rockable
Well-known member
This is a rotary actuator made by Helac. https://www.parker.com/us/en/divisi...DRo4-Jj0K7n8yQ8zlCvFQ-PE8613od_BoCAPgQAvD_BwENever had a Grove apart but the JLG is a short stroke vertical concentric cylinder.
The rod has an helical lead (coarse thread) that engages a sliding nut that has its own helical lead that engages the housing on the outer perimeter and rod helical on the inside. When the concentric piston push or pulls on the nut it causes the shaft to rotate but not extend/retract.
Since the the basket is bolted to the rod on top it’s forced to rotate.