Water pump housing removal

[waqas]

From previous threads, it's not clear to me if it is possible to remove the water pump housing without removing the harmonic balancer. Can someone please clarify if this is necessary?  If so, how to proceed?

Thanks in advance for any pointers.

WAQAS in Austin, Texas

[Naj ✝︎]

Hello, waqas,

Its certainly possible to remove the water pump without removing the harmonic balancer. The big decision will be to remove the radiator or not?

Download Attachment: Eng3.jpg
62.59 KB

naj

68 280SL

[waqas]

Thanks for the reply, Naj.

Radiator, water pump, a/c compressor are all out already. I also had a cracked alternator housing that finally gave way (will post more details later), and needed to be replaced, so lots of stuff came out (unlike some other cars, my alternator is mounted below compressor). I decided to replace the cooling-related hoses and gaskets while everything was open and nicely accessible.

So far, I've gleaned that the housing bolts should be treated with some kind of sealant before assembly, but other folks on the board have noted having to remove the balancer anyway, for other reasons.

Any advice on housing removal without touching anything/much on the main crankshaft shall be much appreciated. Removing the pump housing shall serve two purposes: I can replace the housing-to-block gasket, and I'll be able to helicoil one of the pump-to-housing bolt holes with greater ease. (why don't people respect torque numbers clearly given in manuals??)

Thanks and kind regards,

WAQAS in Austin, Texas

[ja17]

Hello Waqas,

If I recall correctly, there is a hole in the balancer. You can turn the crankshaft so that the hole is over that one allen head bolt holding the housing on. You extract the bolt through the hole. Yes use sealer or you will have a leak, some of the bolt holes go through and into the chain gallery.

Joe Alexander
Blacklick, Ohio

[waqas]

Thanks for the info, Joe.

Any recommendations for a sealing agent? (are there different recommended agents for bolt-holes connecting to water vs. oil passages?)

Do I also need this same sealing agent when re-assembling the thermostat housing to the engine? (in other words, do those bolt-holes also connect to water or oil passages?)

Thanks again!

WAQAS in Austin, Texas

[bpossel]

Hi Wagas,

Another item to replace while you're doing the water pump is the small water passage metal pipe.  See attached pic.
 
Download Attachment: waterpumpnew.jpg
63.49 KB

Not sure if all model years has this piece, but if yours does, I would replace while all the other pieces are out.  Make sure to also buy the small washers that go on each end.  I used Permatex sealant for water pump bolts and the paper gasket.  Also used a small bit of Permatex on the passage pipe bolts.

Good Luck!
Bob



bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[waqas]

Thanks for all the replies!

By the way- does anyone know what the small cut-out (like a small bite) from the water pump flange is for? The images from Bob and Naj below apparently show the water pumps mounted with different orientations of this flange cut-out. Does it need to be oriented in any particular way?

WAQAS in Austin, Texas

[ja17]

Hello Waqas,

Yes as Bob suggests, Permatex is my choice also. The thermostat bolt holes are safe. they do not go through. You may want to use a little grease or sealer on them to keep them from siezing in the future.  The paper seals can be coated with a sealer if you want insurance. I like to use a little gasket shellac on paper gaskets.

Things like the short rubber by-pass hose (going between the therm. housing and the WP housing) should be inspected and replaced if needed. Be careful with the little metal bleeder line, the hollow bolts like to sieze and break off during removal.

the original Mercedes rubber coolant hoses will last 20 years or more. Consider this before you use some inexpensive autparts store variety.

Joe Alexander
Blacklick, Ohio

[waqas]

quote:Originally posted by bpossel

Hi Wagas,

Another item to replace while you're doing the water pump is the small water passage metal pipe.  See attached pic.
 
Download Attachment: waterpumpnew.jpg
63.49 KB

Not sure if all model years has this piece, but if yours does, I would replace while all the other pieces are out.  Make sure to also buy the small washers that go on each end.  I used Permatex sealant for water pump bolts and the paper gasket.  Also used a small bit of Permatex on the passage pipe bolts.

Good Luck!
Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

I always thought this small passage metal pipe was an oil passage for the chain tensioner. Are you saying it carries coolant? Either way, can it simply be cleaned out? (soaked in degreaser, for example)

On removal, mine was missing the washers (but I've a whole new stack of them). My question: is there supposed to be one or two on each hollow bolt? I always assumed a pair of washers "sandwiched" each pipe end (total of four washers)... is this true?

Thanks again for all the help!

WAQAS in Austin, Texas

[ja17]

Hello Waqas,

Yes the tube is for coolant and it has a total of four aluminum seals.

Joe Alexander
Blacklick, Ohio

[waqas]

Hello Joe,

Thanks for clarifying the purpose of the bypass-line! I guess it makes sense, it IS connected to the water pump housing...  :?  

The washers I was sent are copper, not aluminium (8x12x1mm). Are they equivalent for this purpose?

Thanks again for all your help.

WAQAS in Austin, Texas

[ja17]

Hello Waqas,

Copper is fine. Be carefull not to overtighten those hollow bolts they will break off. You can use a little grease or antiseeze on the seals and bolts so that the parts torque and seal easily without binding.

Joe Alexander
Blacklick, Ohio

[hands_aus]

quote:Originally posted by ja17

Hello Waqas,

Yes the tube is for coolant and it has a total of four aluminum seals.

Joe Alexander
Blacklick, Ohio

Hey Joe,
I see you say that the tube is for coolant but why is that small tube there?

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[ja17]

Hello Bob,

It is designed to help bleed the air out of the cooling system during a re-fill or change. This allows coolant to flood the water pump housing without an air block.

Joe Alexander
Blacklick, Ohio

[hands_aus]

quote:Originally posted by ja17

Hello Bob,

It is designed to help bleed the air out of the cooling system during a re-fill or change. This allows coolant to flood the water pump housing without an air block.

Joe Alexander
Blacklick, Ohio

Hey Joe,
Thanks for that info.
cheers
(wishes he was going to Blacklick 2007)

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[waqas]

So I finally got around to heli-coiling the two water-pump housing bolt holes:
http://www.sl113.org/forums/uploaded/Waqas/200742031949_waterpump-and-housing-small.jpg

Zoomed-in on the two bolt-holes:
http://www.sl113.org/forums/uploaded/Waqas/200742032123_waterpump-housing-helicoiled-small.jpg

My question is about the water pump: is there any particular orientation necessary? Do the weep-holes need to facing any particular direction? (up, down, sideways, etc)

Here's the new water pump:
http://www.sl113.org/forums/uploaded/Waqas/20074203253_waterpump-1-small.jpg

Here's what I assume are the 'weep-holes':
http://www.sl113.org/forums/uploaded/Waqas/200742032613_waterpump-2-small.jpg

Thanks in advance for any help!

WAQAS in Austin, Texas

[merrill]

waqas,
is that a new water pump? the pump I removed from my car and the replacement from K&K do not look like yours.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[waqas]

Matt,

Yes, it's a new water pump. My car uses the 'short-hub' pump, and it has a hub-extender... not quite sure why. I never went back to figure out whether the short-hub pump together with extender could be replaced with a long-hub pump. Since both short and long hub versions are readily available, I figured "if it ain't broke..."

WAQAS in Austin, Texas