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1999 ML320
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Discussion Starter · #1 · (Edited)
I'm in the midst of replacing water pump. It didn't go well, head of one of the long bolts broke, rusted out, pump must have been leaking. With help of PB Blaster, somehow able to remove the water pump out.

I have a few questions as I'm having some difficulty, please help.

1) GRAF water pump(said to be OEM) came with two gaskets, one flat one rubber, which one should I use? Original gasket just removed was rubber with some trace of sealant, should I use sealant with rubber gasket? What I read in DIY section on this forum shows to use FLAT one, different year but still confused.
Here's the DIY link mentioned above;
http://www.benzworld.org/forums/w163-m-class/1597370-diy-coolant-water-pump.html

2) Once I removed water pump and gasket, I noticed what looks like a groove / slot as shown in photo #1 below, is this normal, no need to worry about?

3) I'm soaking the broken piece with PB Blaster overnight and then try to turn with vice grip, what's my best option if this doesn't work?

Any and all help is always be appreciated.
 

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1999 Benz ML430, 1997 Benz E320, 2006 Toyota Avalon, 2002 Jag. S-Type (sold), 1985 Benz 380-S
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I'm in the midst of replacing water pump. It didn't go well, head of one of the long bolts broke, rusted out, pump must have been leaking. With help of PB Blaster, somehow able to remove the water pump out.

I have a few questions as I'm having some difficulty, please help.

1) GRAF water pump(said to be OEM) came with two gaskets, one flat one rubber, which one should I use? Original gasket just removed was rubber with some trace of sealant, should I use sealant with rubber gasket? What I read in DIY section on this forum shows to use FLAT one, different year but still confused.
Here's the DIY link mentioned above;
http://www.benzworld.org/forums/w163-m-class/1597370-diy-coolant-water-pump.html

2) Once I removed water pump and gasket, I noticed what looks like a groove / slot as shown in photo #1 below, is this normal, no need to worry about?

3) I'm soaking the broken piece with PB Blaster overnight and then try to turn with vice grip, what's my best option if this doesn't work?

Any and all help is always be appreciated.
I don't believe the groove is anything to be concerned about, especially if you're using the round rubber gasket...just make sure you get all the debris out of the track that the old gasket may have left behind, it may not be very visible. Hope you're successful with the bolt.
 

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2000 ML55 sold? 2013 ML500,? 2017 C43 AMG,1929 Victory 6 roadster, 1927 Dodge 4 sedan, 1929 Dodge
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You definitely need the rubber gasket with that one. Try get a 6 or 8mm flat punch and give the area around the bolt some light but firm taps. It will spread the alloy slightly to help free up the rusted bolt. Do not deform the alloy.



Give it about 5or 6 light taps in each position. Repeat if necessary
 

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ML55 2003, ML63 2007
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You don't have to use sealant , but you can use a bit to keep the gasket/rubber in place.
Don't worry about groove. Just clean everything gently with gasket remover spray or something. Don't use abrasive stuff. Your another option is to carefully use a blow torch. Don't damage hoses & electrical wires with the torch.......
 

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99 ML430, 00 ML320, 05 E500 4matic Wagon
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When I did the WP on the 2000 ML320 I got the Graf pump also. The engine as put together with the gasket that went in the groove so that is the one I used. Been holding tight for over a year. Once the pump is tightened into place it pushes hard enough on the groove gasket to make a strong seal.
 

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Discussion Starter · #7 ·
broken piece is out finally

Thanks noodles, for confirmation to go with rubber gasket.

Soaked overnight with PB blaster and liquid wrench(yes, I used both), with periodic re-spray, broken piece is finally out. Initially I got freaked out when the rusted bolt gave away without much force at all. A few other bolts are showing some degree of rust, it was pretty obvious the water pump was on its way out. Preventative maintenance is the way to go.

Matt, I gave light but firm taps around the bolt housing area a few times with large punch as in your instruction, I think it helped out a lot. Thanks for the great tip. Now, off to store to buy some replacement bolts, gasket remover and anti-seize.

You guys are great! :thumbsup:


Photo below - one or two more turns to go.
 

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Discussion Starter · #9 ·
Thanks for the concern. I went to town to get one in exact size M16 1.0 42mm long. No torx screw available but regular w/washer in same size but in 43mm long, should I file it down to the same length?.
 

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Discussion Starter · #11 · (Edited)
Matt, there are 3 of the same length bolt, right?
These are #4c in the pic below. I took one of the 4c to a fastener shop in town, the lady measured it as 42mm. You got me concerned.

Now, looking at the picture, I counted there 6 different length of bolts, not 6, I'm worried now. I thought bolts marked as #4d(one), 4e(one) and 4g(two) are all the same length. I'mgoing to undo all #4d, 4e and 4g out and make sure they're the right length.

Do you have the length of these? Thanks.
 

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I'm actually sitting at an MB shop now. I'll have to check when I get home.


Wind it in by hand without the pump on until it bottoms out. Then measure the corresponding hole on the water pump. If the bolt is shorter than the W/P housing then it will be ok.
 

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Discussion Starter · #14 ·
Here's the measurement I just did.

#4d (only 1) - 80mm
#4e (only 1) - 90mm
#4g (2 of the same) - 110mm
I had placed all the bolts removed onto corresponding hole on cardbord box I made (those shown on many DIY) as soon as I remove each bolt, but now I'm worried that I may have mixed a few, especially #4d, 4e and 4g.
Someone please confirm above size, I'm waiting so I can wrap up the work.



#4c (three of same size) - Replacement bolt filed down to 42mm(with double washer) is on LEFT
Original bolt is almost 43mm long on RIGHT
 

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Discussion Starter · #15 ·
Oh, one more . . . this isn't going well at all.

Temp senor housing got busted completely while trying to turn it to its original position. Naturally, I tried to plug in to bare poles, broke those as well, new sensor is needed.

I'm going to MB dealer in Portland(80 miles away) tomorrow, but doesn't know how to replace it. Looks like air pump need to be removed so the clip holding the sensor in place can be lifted out, then just pull the sensor out, is this correct way? If not, please help. Thanks!
 

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2000 ML55 sold? 2013 ML500,? 2017 C43 AMG,1929 Victory 6 roadster, 1927 Dodge 4 sedan, 1929 Dodge
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Yes mate you will find they are very brittle. I just touched mine the other day doing my water pump and it snapped off with no force at all. Removing the air pump will give good access.


Sent from my iPhone using Tapatalk
 

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Discussion Starter · #17 · (Edited)
Thanks Matt.

Can anyone confirm these bolts are the correct length?

Here's the measurement I just did.

#4d (only 1) - 80mm
#4e (only 1) - 90mm
#4g (2 of the same) - 110mm
I had placed all the bolts removed onto corresponding hole on cardbord box I made (those shown on many DIY) as soon as I remove each bolt, but now I'm worried that I may have mixed a few, especially #4d, 4e and 4g.
Someone please confirm above size, I'm waiting so I can wrap up the work.

Thanks!
 

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2000 ML55 sold? 2013 ML500,? 2017 C43 AMG,1929 Victory 6 roadster, 1927 Dodge 4 sedan, 1929 Dodge
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Sorry mate I have thrown all my spare bolts into a tray so they are all mixed up.


Sent from my iPhone using Tapatalk
 

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Sparky, Matt gave you a good advice in post 13.
Also buy bolts which are fully threaded. Not like the one in the picture you posted.
After trying post 13 advice if you are still unsure, use a washer to reduce the size of the bolt.
 

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The cardboard thing is a waste of time. Use the new pump as a template.

What everyone should do is, after removing each bolt, place in the corresponding hole in the new pump. Then when finished with all the bolts, transpose those bolts back to the old water pump.

Here are the confirmations.
 

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