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Re-use of High Pressure Injectors

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Diagnostics & Test Equipment How to 2 min read

Resource Highlights

In this article you will find out about the importance of renewing High Pressure Pipes.

Make

Model

System

Audi

All Common Rail applications

Diesel Systems

Alfa Romeo

All Common Rail applications

Diesel Systems

BMW

All Common Rail applications

Diesel Systems

Citroen

All Common Rail applications

Diesel Systems

Dacia

All Common Rail applications

Diesel Systems

Fiat

All Common Rail applications

Diesel Systems

Ford

All Common Rail applications

Diesel Systems

Honda

All Common Rail applications

Diesel Systems

Hyundai

All Common Rail applications

Diesel Systems

Jaguar

All Common Rail applications

Diesel Systems

Kia

All Common Rail applications

Diesel Systems

Land Rover

All Common Rail applications

Diesel Systems

Nissan

All Common Rail applications

Diesel Systems

Peugeot

All Common Rail applications

Diesel Systems

Skoda

All Common Rail applications

Diesel Systems

Suzuki

All Common Rail applications

Diesel Systems

Ssangyong

All Common Rail applications

Diesel Systems

Toyota

All Common Rail applications

Diesel Systems

Vauxhall

All Common Rail applications

Diesel Systems

VW

All Common Rail applications

Diesel Systems

Volvo

All Common Rail applications

Diesel Systems

Importance of Renewing High Pressure Pipes

It is important to consider renewing the high pressure pipes on Common Rail systems after any intervention on the high pressure system. This is for a number of reasons:

1. To prevent leakage.

When a pipe gland is tightened on first application, the surface of the sealing dome is deformed to provide a tight seal between the pipe and injector / rail / pump components. If the pipe is subsequently re-used the pipe further deforms but is also work hardened so a tight seal is more difficult to achieve.

2. To prevent dirt or swarf ingress.

When a screw thread is tightened, minute particles of swarf are generated and are encased within the grooves of the screw thread. When the thread is released these particles are free and subsequent re-use may dislodge these particles and contaminate the component being worked on.

3. Hydraulic performance.

When the pipe gland nut is tightened the dome of the pipe deforms. Subsequent re-use will continue to deform the sealing edge as described above. However, the other consideration is that the bore of the pipe deforms and can cause restriction of flow, which in turn affects performance of the fuel system and also the engine.

Figure 1

The pipe in figure 1 shows a cross-section of a pipe after single use and the bore is unrestricted.

Figure 2

Figure 2, however, shows a pipe after multiple uses and clearly the pipe diameter is restricted.

Safety First

When fitting pipes after repair it is imperative that the correct torque is applied to the gland nut. Exceeding the torque risks the scenario in figure 2 as the pipe will excessively deform, but also not achieving the correct torque will risk high pressure leaks.

In all cases respect health and safety when working on high pressure systems and ensure the operatives are correctly trained in the service routines for Common Rail systems.

Further Information

Read the relevant Common Rail workshop manual on Direct Evolution:

Part Number

Description

DDGX200A

Principals of CR Operation

Tools & Equipment

Part Number

Description

Operation

DS150

Diagnostic tool

Check for pressure in system

YDT339

HP pipe spanner (19 mm long)

Correct removal of HP pipe

YDT512 

HP pipe spanner (19 mm long)

Correct removal of HP pipe

YDT496

HP pipe spanner (17 mm short)

Correct removal of HP pipe


The specified form no longer exists or is currently unpublished.

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