Hi: I have a 1985 380SE. I'm trying to replace the water pump but encountered some difficulty. Seems like the bolt at the bottom of the water pump will not come out unless I remove the main pulley. Am I corrrect? If so, I'm not sure if the bolt thread on the main pulley off the crankshart is left or right hand. THE BOLT IS VERY TIGHT, SO I DON'T WANT TO MESS IT UP.
Any help here will be much appreciated.
Thanks.

do not undo centre bolt on main pulley.undo all the small bolts 13mm [6] in the outer circle and your obstruction will be gone.taking off the pulley and hub with the main crankshaft bolt will give lots of problems when going back because of keyway on crankshaft that you cannot see.david poole european performance dallas tx.

If memory serves me correct, then you dont have to remove the pully at all, there is a recess in the pully, just turn the engine by hand till the recess in the pully coincides with the bolt of the waterpump, use a socet and undo the bolt. that is why there is a recess molded in the pully.

Hi Pilot Man:
I have to remove and replace the water pump on the 1985 380SE. The crankshaft pulley seems to be in the way of the bottom bolt of the water pump. I have already tried aligning the water pump bolt with the recess on the crankshaft pulley but still not enough room to remove it. Are there any other tricks to replacing the water pump without removing the crankshaft pulley? Thanks.

I got the waterpump bolt out on my 380sl, same motor, by aligning the recess and using a thin wall socet by wurth.

IIRC on the 380 you may be able to access the bolt but the bolt won't clear the balancer. On the big block (500/560), IIRC you can remove the water pump without removing the balancer (longer stroke=greater distance between balancer and water pump). Mark

Hi hookedon210s:

Can you tell me if the bolt on the crankshaft pulley is LEFT or RIGHT hand thread? Thanks.

As David Poole said above, you don't need to and should not remove the large (27mm socket) bolt holding the hub---you just need to remove the 6, 13mm headed bolts which hold the pulley and the balancer to the hub. The pulley and balancer will pull off by hand separately once those bolts are removed (you will have to wiggle the balancer back and forth to get it past the accumulated crud on the hub). IIRC, the bolt circle is not uniform (balancing reasons) so it is best to mark the pulley and balancer for later installation (avoids having to try possibly 6 difft. orientations to reinstall the balancer and pulley) Mark
PS. The large bolt is a normal ccw to loosen bolt but it is torqued to about 200 ft. lbs. No need to remove this unless you will be replacing the front crank seal.

I drive the 420 SEL and ran into the exact same problem last week. You are correct, the bottom bolt will not come out by any means without removing the balancer or pulley.

The 27MM bolt on the crank is right hand threaded like normal. I first attempted to remove the pulley and balancer by themselves when I did the work, but the balancer would not come off and of course it doesn't have any way of pulling or prying loose without damaging the oil pan.

When I went to remove the entire hub assembly I removed the radiator and put an impact gun on the 27MM bolt. I didn't manage to remove the bolt as my gun is rather weak but instead managed to vibrate the balancer loose with it. You might try this if you have access to air tools.

If you don't have any other way to work around this and really want to remove that 27MM bolt I suggest putting a socket on one end of a breaker bar and the other end on the ground and bumping the starter. There isn't any way I'm aware of that will get you more torque than that. I'm assuming you've already removed the distributor so no need to worry about the engine starting. When you go to replace the hub assembly put the whole thing in the oven and heat it to around 200 degrees F and then quickly take it from the oven and slip it onto the crankshaft. This should make life a little easier.

The first time I did this on a 380 I thought that a puller would be necessary to remove the harmonic balancer from the hub so I went to borrow a universal type puller from a neighbor (I was on a trip to PA and was conscripted into replacing a leaking water pump on my father-in-law's car). After trying to attach the puller by all possible means I was surprised to feel that the harmonic balancer had begun to wobble free without using the puller so I continued to wiggle the harmonic balancer back and forth from top to bottom and side to side until it came free. Almost an interference fit with the accumulated crud on the hub. Much easier to reinstall the whole assembly provided the balancer and pulley were marked before removal. If you remove the entire hub be sure to heat it as 15289577 says because the keyway is recessed down the crankshaft (stupid IMO) so lining up the hub can be problematic. Mark