High-Pressure Pump Replace (M276)

Index

Mercedes-Benz

Model

Chassis

Engine

Transmission

E350

R350

S550

W251

W212

W221

M276

722.9

M278

As the request of a friend, due to time constraints, the relevant content of "Benz Maintenance Manual WIS" was temporarily posted below. The specific steps will be listed later. If you have replaced the ATF according to these documents, I'll appreciate it if you make some videos or photos of the process and post them to Forum to help more people to perform this work.

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Notice: Replace the high-pressure pump is one of repairing project. There are several steps to reach the position of high-pressure pump. and there also have some sealing part should be replace, preparing before you start the work.

Main Steps of replace the high-pressure pump

Drain in coolant

Disconnect the ground line from the battery

Remove air filter housing

Take off and remove the insulation from rail

Remove resonance intake manifold

Detach engine wiring harness on crash plate. (reference  document)

Place engine on cylinder 1 at 40° after top dead center

Relieve fuel pressure over diagnostic socket

Relieve fuel pressure in fuel high-pressure circuit

Tightening procedure for housing of fuel system high pressure pump

Check high-pressure lines

Attach union nuts for fuel lines to rails and High-pressure pump

Inspect cooling system for leaks

Check fuel high-pressure circuit with diagnostic system

Additional Word

The repair program is written according to the repairing booklet of Mercedes and the operation by myself. There will definitely be some incorrect or immature. I appreciate it if you might leave a comment of suggestions to improve the above program, in order to benefit the DIY hobby Needs, thank you!