M127 water pump

[MarkCan]

I’m slowly coming to the point of installing the cooling system components on the engine. I’ve restored the pump housing and tested the fit with the old pump. I’ll be replacing it anyway and therefore I got the question,
Would it be wise to use the long body pump instead of the short one with the spacers?

[Shvegel]

In theory having the bearings farther apart should reduce the load on them but I can't honestly see that it would make a measurable difference considering the average miles traveled in a year.

[mdsalemi]

What would be wise is not putting an old pump back on to your engine…my OEM lasted about 9 years before it started leaking after it was replaced during restoration.

The bearings eventually start to fail, and will cause coolant leaks. It happens when a car sits for a while, such as during a Toronto winter…each year.

Sounds like you’re doing the work yourself. Consider saving yourself the effort of replacing once it’s all back together. The pumps are not that expensive and are readily available.

[MarkCan]

Work in progress;
https://youtu.be/qy4dsAc8-bQ

[MarkCan]

Part 2, installation
https://youtu.be/R7E3t5HYweQ

[mdsalemi]

Curious as to why you chose stainless steel bolts. Did you have a problem with rust and corrosion on the OEM?

I've used plenty of SS fasteners on external and non-structural things such as mounting bumpers, where the originals got very rusted and corroded, and replacements would do the same.
Personally I would not choose them on anything on the engine. SS bolts are much weaker than Grade 5 or Grade 8 (or whatever the DIN equivalent is) steel bolts and it's pretty easy to torque the head off on a stubborn one--on both insertion and removal. It's happened to me. Unless you know the origin and testing specs of the bolts you are buying, they may very well be of "import quality" which means the actual specifications are suspect. I've had the occasional "bad bolt"(generally on SS fasteners) that had a weakness in it and it snapped easily. Again, on both insertion and removal.

But to each their own.

[Tomnistuff]

What would be wise is not putting an old pump back on to your engine…my OEM lasted about 9 years before it started leaking after it was replaced during restoration.

When I restored my car, I took a chance and did not replace the waterpump.  I now have an additional one year and 2700 km on that pump and new restoration and I now have all winter to change the water pump because two weeks ago it screamed at me, "Change me, Change me, Change me" until I got the car stopped, turned off and restarted.  I drove it straight home and have spent the last two weeks looking for a non-composite impeller, non-stamped steel impeller or any waterpump that is made like OE.

I finally found a German-made GEBA water pump for the 230SL made just like the GRAF water pump (probably sitting on a freighter in the port waiting to be unloaded and the MBZ water pump (made by ?, and 5 times the price when available).

If it's accessible and old, even if it looks perfect, replace it, is my advice.

I'm waiting for my GEBA to be delivered by the end of today by UPS.

Tom Kizer

[mdsalemi]

...If it's accessible and old, even if it looks perfect, replace it, is my advice.

That's called sage advice...

Sage means wise and knowledgeable, especially as the result of [a lot of] experience...