dingolfing

I replaced my water pump on my E60 550i this weekend and was successful in completing the operation without having to remove the vibration damper. Also, since I wasn't replacing the radiator, I saved myself the trouble of not having to remove that or the fan assembly. I assume the service manuals state to remove the fan assembly for extra clearance to the damper. Even with everything in place, there is still plenty of room to remove the water pump.

Now everyone knows how the bottom water pump bolt is hidden right behind the damper, prohibiting use of a socket wrench. Because of the extremely confined space and low visibility, it is almost impossible to even use a regular wrench... almost.

I won't document the typical procedure for replacing the water pump, as there are already many well-documented threads on this forum that have helped me tackle mine. Here is how I got access to that bottom water pump bolt in case others want to follow...

First, if you are lucky enough to have a 10mm crowfoot wrench like this, then it will make this job a little easier...


Since I'm not lucky, myself and every other garage mechanic will have to make do with the most common car tool:



You'll want the 10mm combination wrench, as both the open slide-on end and the closed 12-point box end are important here.

CONTINUED IN THE NEXT POST...

dingolfing

You do not want to attempt this without being able to see the bolt, so find a good, bright tiny flashlight. So here is the bolt in question, with flashlight resting on the AC belt, pointing at the "tight squeeze":



To get to that bolt, you have two options. What I first did was use the 12-point box end and maneuver it onto the bolt head from the right side like this:





You will really need small hands for this. Skinny, dexterous hands... so go find your wife or kids and ask them for this favor.

Or, you can remove the thermostat and the smaller bottom expansion tank hose and attack the bolt from the left side, like this:





I initially found it hard to remove the clip on that bottom hose when the water pump was still in place, because it was impossible to see, so I used the "right side" method above.

These bolts aren't on too tight, so just a good push on the wrench will unseat the bolt. Once that's done, you can twist the bolt loose with a finger, which you will be doing by feel only, enjoy!

Now, you won't be able to remove the bolt all the way, because it is as long as the space between the vibration damper and the water pump mounting face plus the length of the non-threaded water pump mounting hole, so you will remove the pump with the bolt still in it.

Be warned, it will take some wiggling of the water pump to free it from the engine, because that bolt still has a millimeter or two still sticking in the threaded hole and you don't want to damage it.

CONTINUED IN THE NEXT POST...

dingolfing

Before installing the new water pump, remember to place the bolt through the bottom hole of the pump before positioning the pump onto the engine. Again, you will have to wiggle and maneuver the pump to align the bottom bolt with the hole. It can be a little tricky.

And once you're past that, you may find that you can't get enough forward force to initially hand thread the bolt into the hole. It took me quite awhile to figure out how to overcome this, as there is just not enough room to squeeze my fingers down there to both push in and twist the bolt on the right side.

So, I noticed the vibration damper has a cutout that coincidentally lines up nearly perfectly with the bolt. After a little cranking on the damper using a 27mm socket wrench, it lines up like this:





Too bad a ratchet with extension couldn't be used through that cutout. Life would be so easy... And don't mind that bolt, it is just the longer one that is used at the top hole. In place of that bolt, I used a flathead screwdriver to push against the head of the bottom bolt with my right hand while using my left hand to tighten the bolt:



Obviously, I don't have a picture of that, so I'm re-running my previous pic... And you only need to apply screwdriver pressure until the bolt starts threading into the hole. After that, the screwdriver isn't needed anymore.

Back to the importance of that combination wrench, which you better double check is an offset open-end head combination wrench. The open-end head needs to be tilted to one side, like this:



There is only enough room to crank the wrench about 1/8 of a full clockwise turn. So, you will be performing many dozens of 1/8 clockwise turns by hand, each time flipping the open-end wrench so that it can slide itself on the hex bolt head. I don't think any combination wrenches are made with a centered open-end head, but if so, those won't work here. And you can't initially use the box end either, since the bolt head is touching the damper face AND the box end is itself offset on a perpendicular plane, making it impossible to use in this situation. Good thing the left side gives you plenty of space to work with your hands.

After some time of "wrenching away", the bolt should be ready for torquing down. Move the wrench to the right side and use the 12-point box end to give it one good push down. By the way, the right side is so tight, you really only want to use this side for one turn of the wrench, because it takes some time to reposition the wrench onto the bolt head. That is why it is best to do the final torque down from the right, because it also allows use of the box end to lessen the chance of stripping the bolt head.



The spaces here are so tight that if any of those clearances were just a hair smaller, the wrench or my hands wouldn't fit, and the damper would have to come off. But no need here, and I just enjoy the fact that there is always a different way to approach things.

Well, now you're done! With that bottom bolt anyway.