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6.9 water pump and crank front main seAL

Started by s class, 27 August 2018, 07:51 AM

s class

During 2014, I was using the red 6.9 as a daily, until I suddenly started having cooling issues.  I decided to replace the thermostat, and see if that improved things.  MY assistant then managed to break the thermostat housing in the process. 

I moved the car under the steel carport, and parked it there intending to get on with it as time allowed.  The broken thermostat housing was then duly removed, and I noticed a weep from the water pump.  I went through the not-so-easy task of removing the water pump and water manifold.  I pressed the pump apart with some measure of difficulty, and then discovered it uses an NLA cartridge bearing.  I have on and off been looking for a solution, and eventually procured a NOS pump earlier this year. 

THat reminded me that I still needed to draw the flange off the front of the crank shaft in order to change the front main seal.


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

SO this weekend, picking up from years ago, I started by removing the crank pulley cone.  Of course, two bolts had to be drilled out.

Next was the crown nut.  On the 4.5's, this is a bolt with a 27mm head, on the 6.9 its a shaped nut with a 50mm head...



On a 4.5 engine, the damper is installed in front of the flange, whilst on the 6.9 its installed behind the flange, so the damper and flange must be removed as one unit.  I optimistically tried a very large puller, which turned out to be no match for how tight the flange was.

Eventually I made a makeshift tool :



It worked, but it did this to the 5mm plating :




[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

Removed :



I then cleaned up the front of the block, and installed the new seal, without much difficulty.



After some time spend figuring out where all the hardware belongs, I fitted the water manifold :



There was a changeover in hardware used in early 1979.  Earlier cars had hex head bolts, whereas later engines use cap screws for the manifold.


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

daantjie

Nice work there Ryan, wow this looks like a prick of a job...Praying to the 6.9 gods that I would not have to do this anytime soon :-\
Daniel
1977 450 SEL 6.9 - Astralsilber

raueda1

Great work, looks like a bear of a job.  I'm amplifying Daniel's prayers to the 6.9 gods that your sacrifice will appease her, sparing us the same fate.
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Harv

Just trying to pull a waterpump off one of these is a massive job. I can't imagine trying to put one back on.
1980 300SD
1983 240D
2000 E55 AMG
2002 G500

daantjie

Ryan what is your trick to get the 50mm nut torqued back to 400nm :o?  Big effing torque wrench I'm guessing?
Daniel
1977 450 SEL 6.9 - Astralsilber

TJ 450

Nice job! Yes you need a massive torque wrench for that indeed.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

robertd

Ryan, you are the man!
This is a mongrel of a job, My Goldie had a weeping water pump a few years ago,  I ended up taking it to my valued Merc mechanic and I watched him struggle  to remove it. although once it was out we had no trouble finding replacement bearings and seals from a cooling specialist in Melbourne Vic.
I remember posting this event back then.
116   1978 450SEL 6.9 #  4848
116   1979 450SEL  6.9 # 5884
116   1979 450SEL  6.9 # 6225  SOLD
116   1978 450SEL  6.9 # 5128  SOLD
116   1979 450SEL  6.9 # 5884  SOLD
116   1974 450SEL  DJet

s class

Thanks guys. 

Tonight we hope to try and refit the damper/flange assembly.  I can see that being a challenge, to get the alignment of the keyways absolutely spot on.  Once that is done though, the rest is just routine assembly work.

For the crank crown nut, we will torque to 200Nm, and then give it a bit extra with a pipe on a breaker bar. 



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

damper painted and ready for baking in the oven...



I baked it for 30 mins as recommended by the WSM, my thermocouple indicated it was at 57 degrees C.  The first attempt to refit was a resounding failure, as it seized hard onto the crank immediately, after only getting it about 2mm on.

I tried again, at 75 degrees C, and had some more happiness.  It was a huge amount of effort to pull it onto the crank, requiring a massive pull on the breaker bar to advance it 1/6 of a turn at a time.  After hundreds of pulls on the breaker bar, we actually managed to get it correctly seated, with the dowels lined up perfectly.



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

While-I-was-in-there, I discovered that the alternator bearings were rather poor, so I decided to strip the unit completely for rebuild :





[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

I painted the alternator stator with red oxide :



Alternator casing components cleaned up :





[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

robertd

116   1978 450SEL 6.9 #  4848
116   1979 450SEL  6.9 # 5884
116   1979 450SEL  6.9 # 6225  SOLD
116   1978 450SEL  6.9 # 5128  SOLD
116   1979 450SEL  6.9 # 5884  SOLD
116   1974 450SEL  DJet