Service Information Document Title: Hydraulic dieseling
Function Group: cylinders, 091
Information Type: Service Information
Date: 10/10/2024
Profile: EC210D Volvo
Hydraulic cylinders, dieseling Showing Selected Profile Valid for serial numbers Model
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EC210D Volvo If air enters the hydraulic cylinders during work on the hydraulic system, this can lead to spontaneous ignition, an effect known as dieseling. This occurs if a favourable mixture of air and hydraulic oil is compressed when the piston approaches its end position in the cylinder. A sufficiently high temperature can be reached for the mixture to spontaneously ignite.
NOTICE The dieseling effect may result in burnt piston seals and bushings. In order to prevent dieseling, the lines for the hydraulic cylinders must be bled after work is completed, as follows: 1. 2.
No load and keep the lowest engine rpm Operate the piston slowly up to the middle of cylinder in order to remove air from inner chamber of cylinder. Repeat over 5 times. After that, operate the piston up to the end of cylinder in order to remove residual air from cylinder, pipe and hose gradually. Repeat over 5 times.
NOTICE If the cylinders are pressurized either through lifting of the machine or lifting of a load in the bucket, without first performing the mentioned bleeding movements, the seals will likely be damaged. If a cylinder is to be pressure-tested after a repair, the piston rod should be run in and out a few times before increasing the pressure to testing pressure.