1989 560 Sel Water Pump Need Help

[TOPGUN]

Is It Necessary To Remove The Entire Hub And Balancer Sheave Assembly To Get At Bolts Behind The Balancer? It Looks Like The Bolts Holding The Balancer And Pulley Could Be Removed From Hub. If It Was Done This Way Is There Anything That Could Get Out Of Specs Like The Crank Sensor Etc.? The Factory Used A Sealant On The Pump Gasket. Does Anyone Know What To Use If Any?

[mbdoc]

Yes, you must remove the damper to reach those bolts..

No sealant is required....however I always use aviation Permatex.

[TOPGUN]

Thank You Mbdoc. Can I Simply Unbolt The Balancer From The From The Hub Assembly? There Are Six Bolts Holding The Balancer To The Hub. I Wanted To Know If I Had To Remove The Entire Assembly Held By The 27mm Crankbolt. Btw Thanks For Your Previous Advice About Using Only The Original Mb Chain Tensioner.

[emerydc8]

I just went through this to change the water pump on my 1993 400E. The shop forum at the dealer suggested that I could "walk" the balancer off once I took the 6 bolts out. But it turned out that I had to take the 27 mm center bolt out in order to get the damper off.

In order to loosen the bolt, though, I had to figure out how to lock the crank up so it wouldn't turn counter clockwise when I turned the bolt. The forman showed me how they did it at the dealer. They didn't use the crank lock tool that is specified in the manual. They simply opened the access plate on the bottom of the bell housing and turned the crank clockwise (while facing the engine) until they could see one of the three torque converter bolts. Then, they pulled out one of the bolts and replaced it with a longer bolt that had a sleeve on it. See the picture. You can get the bolt and sleeve at Ace hardware, but make sure you get the hardest bolt they have.

Also, the torque required to get that bolt off is very high. In fact, the forman told me that the shop's torque wrench only went up to 250 lbs, so when they reinstalled it, they would go to the 250 lbs then add a quarter turn to it. He said the MB shop manual used to have that procedure in it but they took it out. I used a floor jack under the breaker bar to loosen the bolt and it nearly lifted the engine off the mounts.

The forman suggested that if I disturb the crank bolt that I should also replace the front main seal. They loaned me the tools to pull off the hub that goes around the crank. There is also a two-sided tool for installing the seal (one side pushes the seal back further than the other side, in case there are running scores where the main seal sits.

Be careful that you don't turn the engine counter clockwise. At least on the 119 engine, the forman said the timing chain tensioner only works in one direction and you might kink the chain if you're not careful.

Hope this helps. I'm sure there are others who are real mechanics that can add to this.

[david s poole]

just unbolt the damper from the hub.DO NOT remove 27mm bolt or you will need to make sure that it engages the keyway on the crank as it goes back on[which you can't see] i have had several cars come into my shop where someone who didn;t know any better took off the hub and then hammered thehub back on.it lasts for a while and then all the belt driven accessories dont work.at that point if we are lucky we can save the crankshaft.by the way when you take out the six or seven bolts from the damper assembly make sure that you mark position as they only go back one way.[that's how timing mark stays correct].

[emerydc8]

I agree. If you don't have to take the crank bolt off, then don't. I guess some of the cars have dampers that can be "walked" off with the six bolts removed. Unfortunately, my 400E wasn't one of them. Once I loosened all but two of the water pump bolts, I realized that I was in too far to close it back up. By the way, if you are forced to do the main seal, the hub slid right back in the slot after I heated it for a few minutes with a blow torch to expand the aluminum.

[Andras]

I'm happy to report that on the 1994 E420 the harmonic balancer can be walked off the hub with the 27mm bolt + 4 washers on, no need to remove in order to change the water pump. You do need to hold the 27mm bolt in place while loosening the 6 13mm bolts holding the pulley and harmonic balancer in place, but only to prevent the crankshaft from turning counter-clockwise. Also, the pulley and harmonic balancer only bolts onto the hub one way, because one of the 6 bolts is a little off center.

[emerydc8]

That's good to know since I have two E420's now. I don't know why my old 400E required removal of the crank bolt to get the damper off, but it did.