Changing the water pump on my '91 300CE with the M104 motor. I have everything out of the way, and I think 3 of the bolts are fairly accessible (There are 4 bolts, right??), but I can not figure out how to get to the top rear bolt. It's a 13 mm bolt and I have a 1/4 & a 3/8 13 mm flex socket, but I cant get to it. It sits right under the intake manifold (which I really don't want to remove!). I can't even see the thing w/o a mirror!

Any help?

Thanks, Ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

You have completely removed the belt tensioner, and you have removed the power steering pump with lines attached & positioned it to the side?

Yes, there are four bolts, and a long time ago we were able to loosen & remove all four without taking the intake manifold off. We used a long extension I think.

Take out the Air Idle Valve bolts so it's loose and moveable and push towards the firewall. This should allow you to get the extension in at the right angle. I put some electrical tape on the neck of the flex socket to keep it stiff until I get it lined up then push it on. It should come right off after that. It's easier to put back in although it may not look like it.

PeachPartsWiki: Replacing the Water Pump

If you can find the Snap-on FLX-M13 it will be much easier.

Rob

GOT IT - #@^^&&&^%%$##$^&&*****!!!

It really helped moving the idle air control valve out of the way - at least then I could see what I was aiming at and had a little bit of room to help guide the socket on to the head of the bolt.

I used a 1/4" 13mm flex head socket on the bolt, attached to a 6" extension, which was attached to a 1/4" universal just underneath the front side of the intake manifold. Then I attached another 1/4", 6" extension to this universal and SUCCESS! Once you know where the bolts are etc. I can see this job taking half the time the next time around!

Thanks for the help! Any advice in putting things back together (which doesn't look nearly as difficult now)? I am a little concerned bout the tensioner assembly...

ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

can't find it anywhere

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)

If you are in a sizeable metropolitan area - find out where the local Snap-On HQ is.

In my area - it's not unusual for the operators of the tool trucks to gather from time to time at HQ during the work week.

In this case - you'll have bucu tool truck doors to knock on. They don't all carry the exact same thing - at least that's been my experience.

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

The tensioner is pretty easy but sometime the little plastic arrow indicator doesn't go back on accurately if it accidentally slipped off while out but not a big worry. You put on the brass adjustment assembly first and then the tensioner pulley next. You'll have to fiddle with it a little. IIRC the long arm goes on the side nearest the engine. Once you get everything back on, adjust it tight using the 13mm brass adjustment nut and then lock it down with the big bolt that is in between the waterpump and steering pulley. If you have to do the job again, you can probably knock it out in 3 hours. Glad the Idle Control Valve trick worked. It only takes a little more room.