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Water pump leak. Why and how.

Posted: Mon Jul 02, 2007 2:07 am
by octane
Oil leaking from pump weep hole ?
Water leaking from pump leak hole ?

Why ?...how does it happen ?



Oil can find it's way to the weep-hole this way:

This is the pump assembly see from the engine/OIL side:
Image
..the only thing that keeps the oil out are
the aluminum washers.

If they are defective (or the bolts not tightened sufficiently)
the oil will pass through the holes for the bolts, (3 holes on pic)
(there's plenty of room around the bolts for that)
and into the the where the pump sits, and out the weep hole
(that's the hole on the side of the 'cylinder' on the pic)
Image


Schematically it goes like this:
Image
Green stuff is the oil
Red lines is the weep hole



Strangely the washers in the rebuild set are not to the same
dimensions as the originals.
The hole is a bit larger than 6.5mm
and originals has a hole a bit smaller than 6.5mm
The outer diameter is bigger on the ones from the rebuild set
It's the original one on the right:
Image


..or oil could enter
IF it's somehow able to pass this O-ring on the pump:
Image

witch sits like this,
see from inside the pump-body (shown without the pump installed)
Image


and schematically it goes like this:
Image
The O-ring is marked with a yellow dot.

Be sure to use the right O-ring.
Dimensions 37.2 x 2.3 mm



On the other hand water can only enter if it's
somehow able to pass the big O-ring (56 x 2.4mm)
Seen here on the pump:
Image

and it would go like this:
Image
Blue stuff is water.
O-ring marked with a yellow dot.


Throughout all this I take it that the pump itself
is fresh and new and not to blame for the weeping.

if the pump (the pump seals rather) were to blame it would look like this
Image
Yellow lines: internal 'weep-hole' inside the pump
Red lines: weep hole
Blue stuff: water
Green stuff: oil

and all you can do is to replace the pump.


The internal weep hole inside the pump
starts from here (red ring)
Image

Thanks Lars

Posted: Mon Jul 02, 2007 11:07 am
by Rat
Just followed your step by step to fix the Fat Rat.
With long distance help from Darwin (RR) and Frenchy (Susan) :twisted:

Thanks for the help all of you.

And Oldewing too of course.

Gord (I did do a BIT myself) Jones :P

Posted: Mon Jul 16, 2007 10:18 pm
by Whiskerfish
Octane is there a torque value for the 3 bolts with the alum washers?? I could not find one so I used 80 inch lbs??
Steve

Posted: Tue Jul 17, 2007 5:10 am
by octane
Hi Steve. No I can't find any.
Strange ! ...Honda is usually very meticulous telling
torque values.

(They any state
6 mm case bolts 87 to 122 in-lb
8 mm case bolts 157 to 191 in-lb)

Donno; them being 6mm, I guess 80 or a bit more
sounds right.

Posted: Tue Jul 17, 2007 6:58 am
by Whiskerfish
The case bolts are what I based the 80 guess on. Not knowing the material composition I figured a bit lower would be ok. I know those washers are very soft and it should not take much to make them seal. I am going out to install it shortly so I will think about it a bit more after my coffee and may bump it up to 90.

Thanks for the thoughts and response.

Steve

Posted: Sun Mar 30, 2008 9:40 pm
by heraldhamster
hey, hey.

this all makes good sense to me. thanks again, octane.

my current problem is something else. I gotta start a new thread.

Posted: Sun May 25, 2008 11:34 pm
by LakerV4
Is the reseal kit worth the effort or should a new pump be bought?

Posted: Sun May 25, 2008 11:44 pm
by Cookie
There will be some debate on this but my opinion is that it is 30 years old.
Even with low mileage it is still 30 years old. This came up with me on fuel pumps as I have a few wing owning friends around here and folks on the board also echoed that fuel pumps rarely go bad.
I've had four out of four that are defective. I just ordered a new one from Frenchy as I am personally tired of 30 year old fuel pumps.
M water pump just gets the chance to seep once.

Posted: Mon May 26, 2008 6:59 am
by Whiskerfish
LakerV4 wrote:Is the reseal kit worth the effort or should a new pump be bought?
If you take off the housing that the lower hose attaches to you can reach in and get your fingers on the pump fins. Try wiggling it. If there is more than a hair's worth of movement order a new pump.

Posted: Tue May 27, 2008 10:55 pm
by LakerV4
Right, If the bearings are good then new seals should work..
otherwise a new one is pretty cheap compaired to a hurt motor. :-? :)

Coolant leak

Posted: Sun Jul 13, 2008 11:26 am
by Howard Halasz
Thanks for the link and advice, Randakk. My '77 Wing "Mirandy" was stored for about 26 years before I brought it back to life. "Mirandy" still has the original pump with the bakelite impeller. I'll replace it with the new metal impeller pump when the heat wave here in Houston eases up a bit. We'll see you again at the 2009 Randakks Customer Appreciation Rally.

Howard

Posted: Sun Jul 13, 2008 2:51 pm
by LakerV4
I have taken my pump out and upon Physical inspection my assessment is.
Their should be NO detectable movement in the bearings of the pump shaft.
If any movement is present then a new pump will need to be installed. If the bearings are solid then new seals will do the job nicely as long as care is taken during the instillation.

Posted: Sun Jul 13, 2008 9:16 pm
by Q
While replacing the hoses on my 79 I discovered that I could wiggle the water pump impeller side to side close to 1/4 inch. The bearings were toast. Took out the old pump and pressed it apart with a vise and some sockets. Bought a couple bearings at the local bearing supply shop and pressed it back together using the original ceramic seal. Put it back in with a front cover gasket/O ring set. Works great and I saved a bunch of money by not buying a new pump.

Q

Posted: Sat Aug 16, 2008 9:45 am
by backyardbob
I replaced the bearings on an old (stored for 19 years) pump, still using the original seal, about 3 years ago, so far so good.

Posted: Tue Nov 25, 2008 11:43 am
by 6adan
Octane, from your drawing it looks like the only thing that stops the oil is the seal in the bearings. Is this correct?
Dannie