Maintenance and Repairs

Bearing Removal on a MET SE83 Turbocharger

 
 

 

INTRODUCTION

The Mitsubishi MET SE83 turbocharger has an axial flow turbine driving an aluminium radial compressor.

The journal bearings which support the shaft are located between the compressor and turbine, with the thrust bearings located at the compressor end.

There are air and gas labyrinths at the back of the compressor and turbine wheel and oil labyrinths situated at the ends of the bearing housing to prevent leakage of oil into the gas and air side.

Oil to lubricate and cool is supplied by an external pump.

 

STEP 1

Disconnect the tachometer.

Attach sling to the silencer. Remove the nuts securing the silencer to the air casing and remove and land silencer, securing if necessary.

 

STEP 2

Using feeler gauges, measure the clearance between compressor impeller and air inlet casing. Measure at top and bottom and both sides. Record the readings and compare with manufacturers data.

 

 

STEP 3

Undo the socket bolts holding the inner scroll air casing, Attach lifting gear and jack off casing using jacking bolts. Remove and land safely taking care not to damage the diffuser.

 

STEP 4

Remove top securing nuts from the gas casing, attach lifting tool, and remove remaining nuts. jack off casing using bolts, land gas casing and secure taking care not to damage nozzle ring

 

STEP 5

Using feeler gauges, measure the clearance between the turbine blade tips and the gas casing. Record the readings and compare with manufacturers data.

 

 

STEP 6

Place a clock gauge on the shaft end on the gas side. Spin the rotor several times to break the lub oil adhesion and then pull and push the rotor to gauge the total thrust clearance (about 0.3mm)

 

 

STEP 7

Remove the cap from the end of the shaft on the impeller end. Using a micrometer, measure the depth  from the end of the shaft to the top of the nut. Record this reading. This is so that  a reference can be made when refitting impeller. Next, use a clock gauge to measure the shaft run out. This should be less than 0.01mm.

 

STEP 8

Screw the support shaft on to the end of the shaft at the turbine end and mount the support stay and guide roller to the end of the gas casing.

 

 

STEP 9

Screw the hydraulic jack supplied on to the thread on the impeller end of the shaft, and back off 1 turn. After using a jacking pump to raise the pressure to 675 bar, loosen the nut with a tommy bar.. Remove jack and nut. Bolt on tool and free impeller from seating

 

STEP 10

Bolt on lifting tool, slide impeller off shaft and land safely.

 

STEP 11

Remove the impeller drive sleeve from the splined shaft by screwing two rods into the threaded holes provided and pulling off.

 

 

STEP 12

Undo bolts, screw in two support rods and remove oil labyrinth and thrust bearing housing.

 

STEP 13

Screw two threaded rods into the holes in the thrust collar and remove.

 

 

STEP 14

Screw rotor guide tube onto the rotor shaft, lubricate with oil and bolt on the guide tube support stay as shown.

 

 

STEP 15

Lift rotor shaft slightly by raising the roller on the guide tube support at the turbine end. Attach strop to rotor shaft, support with chain block and slide rotor out of casing

 

STEP 16

Attach second strop to other side of rotor, remove support stay and slide rotor out of casing. Land in cradle so as not to damage turbine blades.

 

 

STEP 17

Undo bolts and remove gas labyrinth from casing.

 

 

STEP 18

Remove turbine end oil labyrinth from casing.

 

 

STEP 19

Remove turbine journal bearing from casing.

 

 

STEP 20

At the compressor end, unscrew allen bolts and remove turbine side thrust bearing.

 

 

STEP 21

Lastly, remove the compressor end journal bearing.

 

 

In Members section: Bearing examination and rebuild

 

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