Water pump and what else?

[BHap]

My water pump decided to leak this spring....  My car is a 70 280SL with manual trans and Frigiking A/C.  Does the compressor have to be removed to replace the pump?  I'm still running R-12 so I'd rather not open the system.  My front crank seal is also leaking so I'm thinking of doing this at the same time.  I've read a few of the posts in the archives, but does anyone have a suggestion on how to hold the crank to remove the center bolt? (no impact gun)  While I am in there, I was thinking I should replace the fan clutch out of general principal - it is original to the car but only 55k miles... any thoughts on this?  Finally, should I buy Mercedes parts - or are there quality aftermarket parts available?  Thanks for your help..

Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed

[al_lieffring]

Bob

The compressor bracket can be unbolted from the engine and pulled far enough to the side to remove the water pump, without having to remove the refrigerant hoses. When changing the waterpump I always change the bypass hose to the thermostat housing too. It is only accesable with the A/C bracket removed.
I can't think of any reason to change the fan clutch unless you suspect it is causing a overheating problem (fan turns on the shaft with no resistance), Usualy they only need to be replaced if damaged in an accident.
 
The easiest way to hold the crank is to remove the starter motor and have a helper wedge a prybar through the starter hole against the ring gear teeth as you remove the front crankshaft bolt.

Al

66 230sl
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[waqas]

Bob,

The suggestion by Al is spot-on. Simply disconnect the a/c bracket without disconnecting any a/c hoses. Remember to place it somewhere securely (so it doesn't scratch your paint!)

You might want to make sure the leak is just from the water pump. Sometimes, the gaskets between the water pump housing and the block begin to leak soon after a water pump is replaced. This is cheap insurance, and is very easy to do once the a/c bracket and water pump are off. Another one to check is the gasket between the thermostat housing and the head. Your thermostat seal might need to be renewed (no need to mess with the thermostat if it works).

Remember to use thread sealant on all bolts connecting to the water pump housing, as most of them screw into water jackets. (water pump bolts, pump housing to head bolts, etc). You might consider changing your belts and hoses while you have them out.

Lastly, take pictures before you take something apart (belt and hose arrangements)-- you might need to refer back to them later.... much MUCH later!  

WAQAS in Austin, Texas