13 53 158 Removing and Installing/Replacing Rail

13 53 158 - Removing and installing/replacing high-pressure rail (N54, N53)





Special tools required:
- 37 1 151





Warning!
Observe warning on cylinder head cover.

Disconnect battery negative terminal 61 20 900 Disconnecting and Connecting Battery Negative Lead (risk of fire due to short-circuiting on removal).

Electric fuel pump starts up automatically each time door is opened!

Carry out installation work on fuel system only with coolant temperature below 40 °C.





Important!
Wear full face guard and protective gloves.

Fuel can emerge spontaneously at high velocity when the high-pressure line is released!





Important!
Adhere to conditions of absolute cleanliness when working on the high-pressure fuel system.

Introduced contaminants can cause malfunctions in the system!

- Do not allow any dirt particles or foreign bodies to get into the system.
- Remove all traces of dirt before removing pipes or individual components.
- Use only fluff-free cloths.
- Seal all fuel system openings with protective caps or plugs.





Important!
When working on the oil, coolant or fuel circuit, you must protect the alternator against contamination.

Cover alternator with suitable materials.

Failure to comply with this procedure may result in an alternator malfunction.





Necessary preliminary tasks:
- Remove pressure lines 13 53 192 Removing and Installing/Replacing A High-Pressure Line
- N54 only: Remove intake filter housing





Recycling:
Fuel escapes when fuel lines are detached.

Catch and dispose of escaping fuel.

Observe country-specific waste-disposal regulations.





Unlock plug (1) and remove.

Pull connector holder off high-pressure rail.

Remove all holders for wiring harness from high-pressure rail.





Unlock plug (1) and remove.

Slacken nut (2).

Release screws (3) and remove high-pressure rail (4).





Installing high-pressure rail:

Installation of high-pressure rail is described separately from removal.





Install high-pressure rail (4); in so doing, tighten screws (3) and nut (2) hand-tight only.

Note:
- It must still be possible for the high-pressure rail to slide on the cylinder head.
- Nut (2) must be able to be screwed on easily by hand.

Push on plug for high-pressure sensor (1).





Fitting pressure lines:

(Same procedure for all pressure lines)

Connect pressure line (1), tightening nuts hand-tight only in the process.

Important!
Connect pressure line (1) without tension only.

To ensure distortion-free installation of the pressure line and to avoid damaging the thread, it must be possible for both nuts to be screwed on easily by hand!

If the nuts cannot be easily screwed on by hand, the injector must be turned into the installation position.

Note:
Description of "Turning injector into installation location" in the following work step.





Only if one injector has to be turned into installation position:

- Release screw a few turns until holding-down element (1) is slackened.
- Turn injector (2) in direction of arrow until nuts on pressure line can be easily screwed on by hand.
- To do so, engage wrench on hexagon head of injector (2) if necessary.
- Tighten nuts on pressure line hand-tight.

Important!
Do not under any circumstances pull injector out of bore!

If the injector is pulled out of the bore hole, the PTFE sealing ring must be replaced!

Replacing PTFE sealing ring, refer to 13 53 310 [1][2]13 53 310 Removing and Installing/Replacing A Fuel Injector.





Tighten down screws (1).

Tightening torque 13 53 1AZ 13 53 Fuel Injection Nozzles and Pipes.

Tighten nut (2).

Tightening torque 13 53 7AZ 13 53 Fuel Injection Nozzles and Pipes.





Tighten down screw for holding-down element (1).

Tightening torque 13 53 5AZ 13 53 Fuel Injection Nozzles and Pipes.

Note:
This work step is only necessary if one of the holding-down elements has been slackened beforehand.





Adhere to tightening sequence:

- First tighten down nut (1) on injector.
- Then tighten down nut (2) on high-pressure rail.
When tightening nut (1) on injector, grip hexagon head of injector with wrench (3).

Tighten down nuts with special tool 37 1 151.

Tightening torque 13 53 8AZ 13 53 Fuel Injection Nozzles and Pipes.





Assemble engine.

Check fuel system for leaks.

Check function of DME.