Hey sixto (and everyone else that replaced their water pump).
First, thanks for the thread and DIY article. You mention how to remove three bolts, but the one that's the biggest PITA is the lower front bolt. Do you have any suggestions on how to get that one off?
I'm replacing the O-ring seal from pump to cylinder head.
Thanks guys.

__________________
1987 300e W124 M103 My baby.

Camohall, your 124 must have a slightly different accessory layout than the 300SE. On the '91 SE the two forward bolts are very easy to reach.

DG

nice work

that job is more of pia on a 201 since theres so little room to fit an 8mm allen in front

__________________
1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

Did this job myself last week on my W124 M103 260e. Water pump was O.K. just a leak from the bottom.
What a barsteward of a job to replace a $ 3.00 O ring. The Aircon hoses are in the way of the rear bolts of the pump.
While removing the components to get at the pump I rocked the water pump pulley back and forwards to determine whether or not the pump front bearing was O.K. The rocking backwards and forwards of the pump exacerbated the O ring leak and it was quite easy to see coolant dripping out from the bottom area of the pump and not the bearing assemblies. The rubber O ring between block and pump body flat, hard and leaking


Items removed to facilitate job: Fan shroud, fan and clutch, fan and power steering pulleys, Dipstick and tube removed, belt tensioner, power steering moved out of the way, removed distributor to get at bolt holding heating tube to block, first two injectors and lines, moved IACV out of the way, radiator hoses.
Time taken to complete entire job 8 hours - including time to look for dropped bolts hidden in inaccessible locations

New items: O ring for pump body, O ring for heater tube, new bypass hose between block and thermostat housing, lower radiator hose.

Ivanerrol recommends purchasing a flexible extension - extremely handy.

Ivanerrol

Hats off to you !!

That is the way to post great comprehensive info for our informative website !!

Mega

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

on the same topic, my 90 300se 6 cyl 's fan clutch is slipping, it has viscous coupling.
Looks like it has no room to remove her either, any suggestion from the best & brightest?
TIA

Looks like the rad has to come out.

__________________

The fan clutch can be removed by just removing the fan shrouds.
there is an allen-head bolt in the middle of the clutch - 6mm if I remember correctly. Just enough room behind the rad to get the allen in and turn it.
hold the pulley from turning with a smaller allen wrench, or a bent rod about the size of a coathanger wire. The rod goes into one of the pulley holes from the rear, and jams between two humps on the bearing housing on the upper-driver's side. Kinda hard to see; do a search here and there are some photos and explanations.

DG

I just finished replacing my water pump and tensioner. I went to sears and bought a flex socket in 1/4" drive and the job went real smooth. I removed my radiator to give me more room, that is what i would recommend. Removing the radiator only took a few minutes and really gave me more room. The tensioner is a simple item to change when you have everything open. I would sure look long and hard at this item. If it has not gone bad it will and when you are so close why not change it also.

I just need to replace the bypass hose. Do I need to take of the water pump just for that? This is for my 1990 300 SEL.

__________________
1990 Mercedes 300 SEL (320,000 miles)
1994 Mercedes E420 (140,000 miles)

Yes.

If you're creative, you can trim the hose, set it in boiling water to soften it then twist and contort it into place.

Sixto
87 300D

Thanks, how much to trim and have you heard of anyone doin that?

I also was thinking of taking a hacksaw and cutting the pipe from the block. Any harm to that? Looks like it should not be that long to begin with

__________________
1990 Mercedes 300 SEL (320,000 miles)
1994 Mercedes E420 (140,000 miles)

Oops, yes. You have to trim the pipe too. It's all in the archives but basically you eyeball how much pipe you feel comfortable having the hose and clamp contacting keeping in mind there's no undo button for this shortcut.

Sixto
87 300D

As per another similar thread. You are risking getting metal filings through the cooling doing this.

Use a torch or plasma cutter

Sixto
87 300D