M103 water pump reseal
 

Anyone ever reseal a water pump or know if it can be done? I was just thinking that since it has a weep hole there is probably some internal seal that can be replaced.

It's not just a simple seal, and the shaft is pressed together. Its not worth the effort to even try. 103 pumps are cheap enough.

Ok, thanks. I guess I'll get a new pump when the time comes and just experiment with the old one to see what makes it tick.

Ismalley, best to buy a reconditioned water pump at your local MB dealer. Turn in your old water pump to avoid paying the core charge.

I bought a reconditioned pump from Mercedes. The casting was badly corroded before the re-build. The pits were filled with a compound that came out after a year in service. The corrosion was not adequately removed so it continued to corrode.
A recon is OK if you are lucky enough to get one made from a good core but I will no longer buy anything but 100% new from a reputable manufacturer.

MB likely contracts with an outside supplier for rebuilt parts. ( in fact very little of a car is made directly by any car maker. ) In the US the rebuilder is likely Cardone as few rebuilders exist these days.

I've rebuilt water pumps on industrial engines, not hard. The only real tools you need is a small shop press and a measuring device. Obtaining parts to rebuild an automotive pump could prove more difficult.

Water pumps can come apart two ways, bearing out the front ( drive side ) or bearing out the rear ( seal side ) Sometimes the seal is a smaller diameter than the bearing so pressing in that direction won't work. In that case, the bearing must exit from the front, this can damage the impeller.

Haven't tried it - but looks like MB sells the seals (items 8 and 20 in attached image) for rebuild - atleast for the M103 engine and the rebuild instructions are in the shop manual. See attachments.

The hard part would probably be getting the impeller pulled off without damaging it. Instructions show a specialized puller.
Chances are that you would get the seal changed and the bearing would go next. Best to replace the entire pump.

The procedure neglects changing the bearing. When the seal leaks, water can enter the bearing even with a weep hole.

For this pump, the bearing is pressed out towards the front. For water pumps in general, many times the impeller is damaged in the process since special tools are not available or even possible.

I bought a reman pump from the dealer for my 190D 2.5 NA. I guess because of the rarity of the part, the casting was completely new, only used bit was the pulley face. My water pump wasn't leaking but was starting to make some noise so I replaced it. Not bad for a 320k mile part.

Buy a good German brand for the pump, should last a long time if you do.

The last water pump I installed was a Graf brand on July 24, 2010 about 120,000 ago.My pump is still going strong, but when it goes I'll try to find that same brand.

Perhaps the quality of reconditioned MB water pumps has diminished over the years. Thinking back it was 15 years ago that I last purchased a reconditioned MB water pump, but it is still going strong.

How many miles are on that car?

381057 miles.

381059.....just got to work :D