I can definitely, positively assure anyone that it is IMPOSSIBLE to get off a water pump on a 560SL without removing the balancer. The notches will entice you (perhaps what they were designed for...). Even if you DO (as I did) manage to get the bottom bolt threads out of the water pump, you will never be able to actually remove it far enough to remove the pump.

This thread is mentions "sedan" 560's; could anyone verify for me that an '86 560SL has a harmonic balancer that comes off as mentioned above (without removing the center bolt). I've liquid wrenched the heck out of the inside hub of the balancer and am going to allow it to sit overnight. How much rapping (with a hard plastic mallet) should it take to come off? A lot? Any advice on how to pull / knock it off (hopefully, without using the radiator as a backstop). Thanks in advance.

PS: a strap wrench saved me on this. Wife is out of town, and I wanted to do major work. Used a strap wrench to hold the pulley, didn't have to hold two wrenches (one on the center bolt, one on the pulley bolt) at the same time. I tried this and it was impossible for me to do alone.

To answer my own question: It is capable of coming off. I suppose that my CD didn't really cover 86+ very well. It does, however, take a lot of Liquid Wrench (and time, overnight) and some persistent knocking at 12:00, 6,3,and 9:00 positions to persuade it to loosen. And it didn't go through my radiator!!!

You can make things easier for next time by substituting the problem bolt with a piece of threaded rod screwed into the engine block then use a nut to hold the water pump on. Keep the rod as short as possible. Pump removal will not require you to remove the harmonic balancer the next time around.

water pump replacement on 420 sel
 

I've got the spare pump in the mail. It took me about 4 hours to take the old one off. I found a lot of residue, like white pouder, perhaps aluminum rust on the old pump. Should I be concern?. I followed the directions given by Mike and they were very useful. The only thing I did not take out was the air filter. It acts like a big table to place nuts, tools, lunch etc.

82 380sl
 

Help. Is there a way to wiggle the harmonic balancer away from the water pump WITHOUT having to remove the crankshaft pulley via the 6 bolts inside the pulley? I think the balancer sits on a crankshaft hub. Is the balancer friction fit onto the hub? If I tap tap here and there, I only need enough space to clear the last remaining bolt on the water pump. TIA.

82 380sl
 

If I had to remove the 6 small bolts inside the crankshaft pulley so that I can remove the balancer thereafter, how do I remove the pulley if there is a large washer underneath the 27mm bolt? Will the pulley come off?

When I had my engine apart, I had the center bolt out, as well as the surrounding ones. It had the washers stacked there, but I don't remember off the top of my head if they would have held everything together without the surrounding bolts, or if they would have allowed the pulley and harmonic ballancer to come off.

If you do pull the center bolt, make sure you have the ability to reinstall it.
It required torquing to ~230 ft/lbs. With my engine on a stand, and locked on the rear, I was still hard pressed to reach the rated torque, with a 3' long 1/2" drive torque wrench!

If you can wait until after this weekend, I'll let you know how mine goes back together, though. I'm about to tear into the water pump myself. (Seemingly the only part I didn't change! )

Looking at the EPC exploded view, it seems to me that the previous mechanic placed the big washer incorrectly. The big washer should have been placed BEHIND the balancer. Instead, he placed it in front of the balancer.

Removing the 6 13mm bolts will be challenging. I have little or no clearance to insert my 13mm socket......:mad:

Even if I removed the 6 13mm bolts, I will not be able to remove the pulley/balancer because that big washer is preventing me from removing it unless I also remove the 27mm bolt. That's the last thing I want to do.:eek:

The big washer is not holding the pulley to the balancer. It is smaller then the hole in the pulley. It only looks like it is holding the pulley onto the balancer. As mentioned above make sure you mark the pulley to the balancer. The six bolt pattern is not symetrical. Do not remove the 27mm bolt. Good luck.

On my 560SL engine, I was able to remove all the bolts holding the water pump, but had to pull the harmonic balancer out about a half inch to actually get the water pump off. I don't know if this is specific to the SL setup. I loosened the center bolt and was able to move the harmonic balancer quite easily on the crankshaft. Guess I was just lucky.

380sl
 

Thanks to all those who replied.

I removed the 6 13mm bolts and the pulley fell right off..... I didn't even have to apply pressure to the pulley to remove it.

At first, I was concern about the large washer underneath the 27mm bolt. It turns out that the big washer in the photo above had no significant meaning.

The entire project to remove the water pump on my 380SL took about 5 hours. 1/2 of the time was reading the forum and staring at the engine.

I now consider myself a "PRO" at replacing water pump. LOL Can you believe my mechanic wants to charge me 6 hours book time to replace the water pump? That's about $540 that I just saved. Whoohoo!!

After reading all the information supplied by everybody before attempting this job, I decided it was much easier to just remove the one center Bolt, 27mm, the complete assembly came off beautifully without any trouble at all, I really don,t know why they say to remove the six pulley Bolts, as you still need to remove the 27mm Bolt !!

I hope this helps somebody

Regards Michael

The reason we don't want to remove the center 27mm bolt is that it requires approximately 240 ft-lb of torque to install correctly, whereas the 6 smaller bolts require much less, and are nowhere near as difficult to keep from spinning the engine when doing so.

I found that when I was working on my engine and replacing the front main seal, that there was enough dirt stuck around the nose of the crank inside the pulley, that it kept it from coming off easily. After cleaning out that area, things worked much easier, and it went back together with no issues.

That being said, when you actually do have to remove the main bolt, there is a tool designed to lock the flex plate starter gear, through the bottom of the bell housing.

I took the easy way out when my 380 water pump leaked. I removed the pulley the backed the bottom bolt out enough to get at it with a hack saw. I cut it off close to the water pump's ear and took the pump off.

I like the idea of using a piece of all thread and a nut for reassembly but I didn't think of that. I notched the bottom ear of the water pump and slid it down on a new bolt.

That was seven or eight years ago. No leaks yet.

In reply to what hey-allen said about the torque setting of the 27 mm Bolt, I overcame the problem with a small piece of hard wood 10"x 1.5"x 3/4", by turning the harmonic balance clockwise, and fitting the end of the piece of wood into one of the cut out sections on the down side of the harmonic balancer, and the other end against the cross member, it allows you to torque the bolt to 200 to 240 ft-lbs much easier than removing the starter motor, but I will admit, you do need a good Torque Wrench !!
I think anybody attempting to do there own mechanical work at home, should have a good Torque Wrench, this is very critical if you a going to try and do the job right !!

I don,t claim to be a mechanic, I'm actually a Chef, but I have been working on my own cars all my life, and I actually found it much easier doing it this way !!

My Car is a 1986 420SL, the size of the piece of wood might vary a little bit in length, for a 420SEL but it,s basically the same engine !!

Regards Michael