72 250c head removal help needed. - PeachParts Mercedes-Benz Forum

72-250c · #1 05-05-2007, 07:28 PM

72 250c head removal help needed.

i have a m130v type gas engine in need of a head gasket. at this point i have a few questions. i am following along in the haynes manual step by step and need further advice.

1. how do you pull out the chain tensioner sprocket once the shaft is removed? is there a special trick i have yet to find out? the chain tensioner sprocket and pivot bracket are free from the extracted shaft but it seems to bind against the cam sprocket and chain as i try to pull it out.

2. what size are the two socket head screws that hold the chain guide in? from what i see there are no distinguishable surfaces in the holes to get any tool on to.

3. cam sprocket bolt. leftie loosie, standard bolt right? as i turn the bolt with a breaker bar, the whole engine turns. should i brace the cam sprocket by jamming a bar in one of the holes to stop it from turning?

i am going back under the hood tomorrow.

thanks

MunichTaxi · #2 05-06-2007, 02:17 AM

1. If you need a head gasket, you probably need a new chain. Alwats start at TDC, then measure chain stretch. Cut the old chain with a Dremel, use the master link with the new chain to create a continuous chain.

2. Why do you need to remove the tensioner sprocket? Are you replacing the tensioner rails? It takes a special puller.

3. Why are you removing the cam sprocket? Remember, you are getting a new chain. If you "jam" the sprocket, it will be expensive.

4. Mercedes and Haynes manuals are a contradiction of terms.

t walgamuth · #3 05-06-2007, 07:51 AM

on #2, i suspect you are talking about the pins that hold in the guide rail. these have a threaded center which can be pulled with one of the bolts in the thermostat housing which takes a 10 mm wrench.

using this bolt or one similar and a stack of washers and or nuts you can pull the pin. just take your time and it will come right out. replacement is by tapping it back in with a hammer.

good luck

tom w

Mike D · #4 05-06-2007, 09:14 AM

To clarify Tom's procedure. By using a stack of washers he means; the washers against the head need to be large enough for the pin to slide inside. You are trying to create a cylinder. About a 3/8" washer if I remember correctly. Use 3 or 4 of these stacked with two or three 1/4" washers between the larger stack and the head of the bolt you are using to provide the pulling force.

I wouldn't use one of the thermostat bolts. I'm not saying it won't work but those are some pretty low-grade bolts. Disgusting sound, that dull snap. Take one of the thermostat bolts down to the local hardware store and get a 10.9 HARDENED bolt to use.

Usually, when you get the pin to slide it comes out smoothly. Make sure you have the washers centered over the pin.

Alternatively, and the method I prefer, pull the radiator and use a slide hammer.

Before I would use a hammer handle (nothing metal!) through the cam sprocket, and I have used that method with success, I would use an impact wrench to loosen the cam gear bolt.

wbain5280 · #5 05-06-2007, 01:00 PM

This is what I used on my 420SEL M116.

http://i19.photobucket.com/albums/b177/wb300se/MB_420SEL/DSC_0035.jpg

Pretty simple.

Mike D · #6 05-06-2007, 03:22 PM

Those responses pretty much covered the Continental U.S.!

72-250c · #7 05-06-2007, 07:36 PM

thanks for the info.

head is now off. ordering gaskets, valve oil seals and possibly valve guides. sending the head to the shop to be checked out. oil and coolant were mixing causing hesitation, fouled plugs and occasional white smoke. there is evidence of the white creamy mayonaise like substance in the upper portion of the block.