The timing guide rail assists timing belts and chains by keeping them stretched out, by guiding them into the appropriate gears, and by making them less prone to engine vibrations. Such a harsh working environment eventually takes its toll on the guide rails. They eventually wear down, go brittle and break off into pieces. Replacing the timing guide rails is a must in such instances. The process is long, hard and complex, and will require you to take apart most of the components of your engine compartment.
Difficulty level: Difficult
Tools that you'll need:
- Timing guide rails
- Ratchet and socket set
- Wrench set
- Breaker bar
- 6mm, 1.00 pitch hex head bolt
- Hex nut
- Penetrating oil spray
- 13mm socket
- Brass hammer
- Tool 10
The following steps for replacing the timing guide rail are for the 1984 Mercedes-Benze 380SL
Step 1: Remove the valve cover of the engines.
Step 2: Remove every component in the engine bay blocking access to the engine and its cylinders. They include the engine covers, power steering pumps, cruise control modules, alternators, and the distributor.
Step 3: Remove the timing chain tensioner.
Step 4: Look for the pins securing the guide rails around the chain. Use a penetrating oil spray to clean the pins and make them easier for extraction.
Step 5: Thread in the hex nut all the way into the hex head bolts.
Step 6: Insert the hex head bolt through the 13 mm socket before screwing it into the pins.
Step 7: Turn the hex nut to jack the pins outs. Secure the hex head screw with a wrench to prevent it from over tightening into the pins. With this setup, the socket is placed upon the cylinder head while the nut is screwed against the socket.
Step 8: Remove the pins from the guide rail.
Step 9: Carefully lift the guide rails out.
Step 10: Place the new guide rails into place and secure them with the pins. Make sure the pins are all the way in by tapping them with a brass hammer.