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Pelican Technical Article:

Camshaft Removal

Steve Vernon

Time:

3 hours3 hrs

Tab:

$6 to $500

Talent:

***

Tools:

Mercedes-Benz tool #103-0040, 12mm 12 point 1/2 inch drive, 140mm long, Mercedes-Benz slide hammer (impact extractor), 27mm, 19mm, 13mm socket, 5mm Allen, 8mm wrench

Applicable Models:

Mercedes-Benz W123 (1977-85)

Parts Required:

Camshaft and support parts as needed

Hot Tip:

Keep the hardware in order

Performance Gain:

Proper working valve train

Complementary Modification:

Valve adjustment

The camshaft controls the opening and closing of the valves on the cylinder head. The W123's have one overhead cam that controls both the intake and exhaust valves and is driven by a double chain at the front of the motor off the crankshaft. You will need to remove the camshaft to replace the head gasket and while this may seem intimidating for the beginning DIY mechanic, if you have the right tools, give yourself enough time and follow these directions you will be fine. Just make sure that you are working in a weather safe area as you will have the top of the motor partially open and you do not want it rained on.

Over the years your car may have been serviced by multiple people including previous owners and this can lead to parts replaced with different size fasteners and hardware. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches. If something is different on your vehicle please let us know and share your info to help other users. If you have any questions or comments or even a different procedure you would like to share please leave it below and please leave your vehicle information.

Begin by disconnecting the ground strap from the battery and placing it somewhere where it cannot accidentally make contact with the battery post while you are working (red arrow).
Figure 1

Begin by disconnecting the ground strap from the battery and placing it somewhere where it cannot accidentally make contact with the battery post while you are working (red arrow).

Remove the four 8mm bolts from the heat shield (red arrows) and remove it from the vehicle.
Figure 2

Remove the four 8mm bolts from the heat shield (red arrows) and remove it from the vehicle.

You will need to remove the valve cover; please see our article on valve cover gasket replacement for additional assistance and remember that you will need to replace the gasket when installing it.
Figure 3

You will need to remove the valve cover; please see our article on valve cover gasket replacement for additional assistance and remember that you will need to replace the gasket when installing it.

Next remove the EGR valve; please see our article on EGR valve removal for further information.
Figure 4

Next remove the EGR valve; please see our article on EGR valve removal for further information.

Use a 19mm socket and remove the chain tensioner from the front right side of the motor and see our article on chain tensioner replacement if you need additional assistance.
Figure 5

Use a 19mm socket and remove the chain tensioner from the front right side of the motor and see our article on chain tensioner replacement if you need additional assistance.

Next the rocker assemblies need to be removed; please see our article on rocker removal for more instructions.
Figure 6

Next the rocker assemblies need to be removed; please see our article on rocker removal for more instructions.

With the rockers removed use a 27mm wrench and turn the motor clockwise by the nut on the crankshaft dampener until the marks line up at Top Dead Center on the camshaft chain sprocket and tower housing (red arrow).
Figure 7

With the rockers removed use a 27mm wrench and turn the motor clockwise by the nut on the crankshaft dampener until the marks line up at Top Dead Center on the camshaft chain sprocket and tower housing (red arrow).

If your vehicle is equipped with a self-leveling system you will need to move the pump on the front of the motor.
Figure 8

If your vehicle is equipped with a self-leveling system you will need to move the pump on the front of the motor. Use a 5mm Allen and remove only the four bolts (red arrows) that hold the pump to the motor. Do NOT remove the bolts that hold the pump together.

While removing the pump make sure not to lose the gear (red arrow) on the rear of the pump and replace the gasket (yellow arrow) when installing.
Figure 9

While removing the pump make sure not to lose the gear (red arrow) on the rear of the pump and replace the gasket (yellow arrow) when installing.

Use a 13mm wrench and remove the slide rail retaining bolt (red arrow).
Figure 10

Use a 13mm wrench and remove the slide rail retaining bolt (red arrow).

Remove the slide rail bearing bolt (red arrow) by using a small slide hammer.
Figure 11

Remove the slide rail bearing bolt (red arrow) by using a small slide hammer.

Lift the slide rail out from the chain area.
Figure 12

Lift the slide rail out from the chain area.

Use some white paint and mark the relation between the chain sprocket and chain (red arrow).
Figure 13

Use some white paint and mark the relation between the chain sprocket and chain (red arrow). Do not use something like tape or a mark that can wear off as using this to check how everything lines up later is important.

Slide a bar between the chain sprocket (red arrow) to keep it from moving and remove the 22mm nut on the front of the cam.
Figure 14

Slide a bar between the chain sprocket (red arrow) to keep it from moving and remove the 22mm nut on the front of the cam.

Make sure to keep the both the bolt and two washers in the correct order when installing.
Figure 15

Make sure to keep the both the bolt and two washers in the correct order when installing.

You are going to remove the sprocket from the camshaft but while doing this you need to keep constant tension on the chain; you do not want it to slip or drop down into the motor or you will be spending a lot of time taking the front of the motor apart to get the chain and line everything up again.
Figure 16

You are going to remove the sprocket from the camshaft but while doing this you need to keep constant tension on the chain; you do not want it to slip or drop down into the motor or you will be spending a lot of time taking the front of the motor apart to get the chain and line everything up again. With the sprocket off move the chain off to one side and keep it under tension.

Use a 13mm socket and remove the nuts on the base of the camshaft bearing towers (red arrow).
Figure 17

Use a 13mm socket and remove the nuts on the base of the camshaft bearing towers (red arrow). Keep these nuts in the same order for re-installing later.

You are going to need to use the proper tool to remove the camshaft bearing tower bolts; Mercedes makes one but a 12mm 12 point 1/2 inch drive, 140mm long will work.
Figure 18

You are going to need to use the proper tool to remove the camshaft bearing tower bolts; Mercedes makes one but a 12mm 12 point 1/2 inch drive, 140mm long will work. Do not try and remove the bolts with the wrong tool; if you strip these out you are going to be in for a very long job removing them.

Make sure that you clean out the heads of the camshaft bearing tower bolts before trying to remove them.
Figure 19

Make sure that you clean out the heads of the camshaft bearing tower bolts before trying to remove them. Start in the center of the head and working outward loosen all of the bolts first before removing them (red arrow).

Get a cardboard box or some other way to keep everything in order.
Figure 20

Get a cardboard box or some other way to keep everything in order. You want to reinstall the bolts and nuts in the same place that you removed them from.

Gently wiggle and rock the bearing housing towers and camshaft to free it from the head and then once free remove it from the engine.
Figure 21

Gently wiggle and rock the bearing housing towers and camshaft to free it from the head and then once free remove it from the engine.

Installation is the reverse of removal.
Figure 22

Installation is the reverse of removal. If you have removed the camshaft from the bearing towers make sure to lubricate it before installation. The bearing tower bolts are part of the torqueing of the head and must be carefully re-torqued to the proper tension working from the inside out. Once everything is back together check that when the TDC marking on the camshaft are lined up that the marking on the CPS on the dampener is also at TDC; if these line up along with your paint marks you are good to go. You will need to check the valve clearances once everything is back together so please see our article on valve adjustment for assistance.

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Page last updated: Mon 7/24/2017 03:15:12 AM