Page 40 - Foton Workshop Manual - Auman EST-M

IN - 34 Introduction - Cleaning regulations

the blasting cabinet, such dust is difficult to control in the workshop (it’s possible to remove the large deposits
but all the media can’t be removed in case of blowing the parts in the cabinet).
The blast cleaning is the best method to remove the stubborn dirt/carbon deposit, which can’t be removed by
steam/higher-pressure cleaning and hot water cleaning in the cleaning cabinet. It’s particularly so for piston.
The carbon deposits remaining in the ring groove shall be safely removed by steam cleaning & piston soaking
and then plastic blasting method (don’t use any wire wheel, otherwise it will lead to damages of ring groove
surface layer or fracture of piston ring). Ensure that the part is dry and oil-free, and then blast-cleaned, so as to
avoid the blockage of blasting machine circuit. Make the nozzle of blasting machine always towards the part
“sideways” and not straight to the part, which can make the blasting beads enter under the substance to be
removed. Keep the nozzle moving and not aligned to one position. It can cause metal overheating and
movement around to make the nozzle towards one position for too long time. Don’t blast only the dirt or
carbon deposits. If the machined mark of piston groove or edge is ground off, it’s caused by insufficient
nozzle movement or overhigh air pressure.
Don’t clean the valve stem via blasting. During blast cleaning, protect the valve stem with a tape or bushing.
Make the nozzle towards the surface and radius of valve seat sideways, and not straight to them. Its purpose is
to remove any carbon deposit, because it’s a waste of time to remove the stain via continual blasting method.
7. Fuel system
Before repairing any fuel system part, it’s required to clean the pipe joints, mounting parts and surrounding
areas around the parts to be removed, because these parts may be polluted before the removal. If the
surrounding areas can’t be cleaned, the fuel system may have dirt in it or may be polluted.
Some inner fuel ducts in fuel injectors are very tiny, and easy to block by pollutants. Some fuel injection
systems can work under the high pressure. High-pressure fuel can make single-component dirt and rust
particles turn into abrasive pollutants, which can damage the high-pressure pumping parts and fuel injector.
If no steam cleaning tools are available, apply the electric contact detergent. In case of cleaning the dirt and
chippings on the joint of fuel system pipe, apply the electric contact detergent, and don’t apply the compressed
air. The diesel exposed on fuel system parts can absorb the air pollutants.
Select the non-dust cloth for operation of fuel system.
Once the fuel system is opened, it’s required to cover or plug the fuel pipe, joint and oil port. Once the fuel
pipe or other parts are loosened or removed from the engine, the rust, dirt and paint may enter into the fuel
system. Among many examples, it’s a good method to loosen the pipe or pipe joint for dropping the rust and
paint, and then remove these dropped materials.
In case of removing the fuel pipe or pipe joint from newly painted engine, ensure that the peeled paint
fragments/chippings are removed. These fragments/chippings are formed when the wrench contacts a painted
pipe nut or pipe joint, and the quick-break joint is removed.
The size of fuel filter shall be calculated in micrometer. The word “micron” is an abbreviation of micrometer,
or part per million of one meter. The micron size is that of the smallest particle captured by the filter
medium.The filtrated pollutant is much smaller than the one, which can be seen with eyes, magnifying glass
or low-power microscope.
It’s required to clean the tools of fuel system for fault judgement and removal to avoid pollution. Like the part
of fuel system, if the tool surfaces are covered with oil or fuel, they will absorb the air pollutants. Please
remember the following points related to fuel system tools:
● Try to keep the repair tools of fuel system clean.
● Clean and dry the tools before placing the tools back into a toolkit.
● If possible, store the fuel system tools in the closed container.
● Ensure the cleanness of fuel system tools before the use.

IN-034