Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 25-01-2015, 16:50   #1
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,947
Quick Raw Water Pump Sea Water Seal Replacement

Thought this little trick might be handy to others:

Had a water pump">raw water pump start leaking a little sea water out of the weep slot today. Wasn't really a good time to pull and rebuild the whole thing (and I was out of spare seals). Often it is just the metal tensioning spring on the sea water side seal that has failed anyway and the other components are good.

No problem. On many pumps, like the Johnson pump on my Volvos, you can pop out the seal and replace it with a bit more time and effort than it takes to replace an impeller.

All you need is an appropiately sized 90 pick or bent piece of heavy wire. Close the sea cock, remove the face plate from the pump, remove the impeller, carefully pass the tip of the 90 pick into the weep slot on the sea water side and gently rotate he tip toward the seal. With just gentle pressure the seal should start to come out. Repeat on the opposite side of the seal and it should come out or at least be far enough out to easily remove.

Press a new seal back into place. Reassemble and you're good to go. Way quicker and easier than pulling the raw water pump.

This is handy too because it does not destroy the seal, as picking it out from the front does, so you can inspect it to confirm the source of the problem (usually a failed spring)...or repair it with an o-ring if you are out of spare seals (see below).

You can avoid the failed spring scenario to begin with by replacing the spring with an o-ring. This will work as a field repair too...it may not entirely stop the leak on an old seal, but it should be much less than it was with a failed spring.

A deep socket can be used to press the seal back in. I've made my own seal press from PVC.

Picture of pick, seal press, and the offending seal repaired with an o-ring.
Attached Thumbnails
Click image for larger version

Name:	1422230026055.jpg
Views:	287
Size:	55.8 KB
ID:	96047   Click image for larger version

Name:	1422230075430.jpg
Views:	259
Size:	55.7 KB
ID:	96048  

__________________

__________________
belizesailor is offline   Reply With Quote
Old 26-01-2015, 01:38   #2
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,454
re: Quick Raw Water Pump Sea Water Seal Replacement

Good one, BS (hmmm, perhaps a poor choice of initials!)

I've rebuilt lots of these pumps, but never thought of getting the seal out like that. Wouldn't be easy to get at on my engine, but just might be able to do it in a pinch.

We always replace the springs with o-rings... sure helps in seal life expectancy!

Jim
__________________

__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is offline   Reply With Quote
Old 26-01-2015, 04:48   #3
Registered User

Join Date: Jun 2010
Posts: 392
Re: Quick Raw Water Pump Sea Water Seal Replacement

How do you size the O ring?
Is it just a standard rubber ring from an auto parts shop?
I have a similar type of Volvo pump.
__________________
olaf hart is offline   Reply With Quote
Old 26-01-2015, 05:40   #4
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,947
Re: Quick Raw Water Pump Sea Water Seal Replacement

Quote:
Originally Posted by olaf hart View Post
How do you size the O ring?
Is it just a standard rubber ring from an auto parts shop?
I have a similar type of Volvo pump.
Most have the dimensions coded on the front. This one is a 12x24x7 mm. Take the old one into the shop with you. Calipers are handy for confirming dimensions (good tool to have aboard). It is a standard seal, commonly available at many suppliers/auto parts stores world wide (ditto for the bearings, but you really need a press to remove/install those...fortunaltely they last much longer than seals). You can buy a handful of seals at normal retail prices for what Volvo charges for one.

Rear oil side seal is the same, but you must remove the pump to change....which is a PITA on the MD2020 I have because you have to partially remove the motor mount behind the pump to get some of the bolts out. WTF? I have modified my pump flanges so I can remove all the bolts without messing with the motor mount.

Pump is a Johnson F4B9, but has a flange specific to Volvo. I have not been able to find an F4B9 with this square flange except from Volvo.

Impeller is a Johnson 1026 B-1 available from other retailers (like Defender) for about half of what Volvo charges.
__________________
belizesailor is offline   Reply With Quote
Old 26-01-2015, 05:48   #5
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,947
Re: Quick Raw Water Pump Sea Water Seal Replacement

Another raw water pump tip: if replacing a slightly damaged impeller, for example just one damaged blade, then trim the damaged blade off cleanly and keep the impeller. Its still serviceable, will only move slightly less water (not enough to matter) and sure beats the crap out of no impeller in a pinch.
__________________
belizesailor is offline   Reply With Quote
Old 26-01-2015, 06:03   #6
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,947
Re: Quick Raw Water Pump Sea Water Seal Replacement

Good article on rebuilding these pumps at link below. Its for a Westerbeke, but its the same pump (different water side seal though).

http://www.pbase.com/mainecruising/raw_water_pump
__________________
belizesailor is offline   Reply With Quote
Old 26-01-2015, 07:12   #7
cruiser

Join Date: Feb 2008
Location: North Charleston, SC
Boat: Camano Troll
Posts: 4,669
Re: Quick Raw Water Pump Sea Water Seal Replacement

I was planning on rebuilding mine but the shaft was scored. I know there's a rebuild kit with a new shaft but the easiest thing for me was to replace the pump so that's what I did. I replaced the hoses and clamps at the same time.
__________________
rwidman is offline   Reply With Quote
Old 26-01-2015, 07:31   #8
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,947
Re: Quick Raw Water Pump Sea Water Seal Replacement

Quote:
Originally Posted by rwidman View Post
I was planning on rebuilding mine but the shaft was scored. I know there's a rebuild kit with a new shaft but the easiest thing for me was to replace the pump so that's what I did. I replaced the hoses and clamps at the same time.
Yep, that's full rebuild time. My spare needs a new shaft now too so that's on my todo list. I keep a spare rebuilt so if I do have a problem I can just swap out pumps and rebuild as I have the time/motivation.
__________________
belizesailor is offline   Reply With Quote
Old 26-01-2015, 07:37   #9
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,947
Re: Quick Raw Water Pump Sea Water Seal Replacement

Updated pic of my DIY seal press. The center hole should be slightly larger than the shaft and the OD just larger than the OD of the seal...this way it stops the press level with the inside body of the pump so you can't press the seal in too far. A level sufarce on the end of the press is important too so the seal is seated true and flush.
Attached Thumbnails
Click image for larger version

Name:	1422283304480.jpg
Views:	179
Size:	43.0 KB
ID:	96084  
__________________
belizesailor is offline   Reply With Quote
Old 26-01-2015, 08:03   #10
cruiser

Join Date: Feb 2008
Location: North Charleston, SC
Boat: Camano Troll
Posts: 4,669
Re: Quick Raw Water Pump Sea Water Seal Replacement

Quote:
Originally Posted by belizesailor View Post
Yep, that's full rebuild time. My spare needs a new shaft now too so that's on my todo list. I keep a spare rebuilt so if I do have a problem I can just swap out pumps and rebuild as I have the time/motivation.
The typical rebuild instructions show replacing the cam but on my pump, this is part of the casting so that's another reason to replace the pump. As far as I know, the existing pump was the original so if I get another 3800 hours and fifteen years out of the replacement, I'll be fine.
__________________
rwidman is offline   Reply With Quote
Old 26-01-2015, 15:39   #11
Registered User
 
jldunn86's Avatar

Join Date: Oct 2014
Location: Texas
Boat: C&C 121
Posts: 45
Re: Quick Raw Water Pump Sea Water Seal Replacement

Good stuff...
Thanks..
__________________
PopArcher
jldunn86 is offline   Reply With Quote
Old 26-01-2015, 16:11   #12
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,947
Re: Quick Raw Water Pump Sea Water Seal Replacement

Quote:
Originally Posted by rwidman View Post
The typical rebuild instructions show replacing the cam but on my pump, this is part of the casting so that's another reason to replace the pump. As far as I know, the existing pump was the original so if I get another 3800 hours and fifteen years out of the replacement, I'll be fine.
Fortunately the pump bodies are very long lived...mine are about 15 yo too.

Cam is held in place with a screw in this version, so is replaceable, but by the time its due to be replaced the rest of the body probably has enough wear on it to be due to be retired too.
__________________
belizesailor is offline   Reply With Quote
Old 26-01-2015, 17:36   #13
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: Quick Raw Water Pump Sea Water Seal Replacement

Quote:
Originally Posted by belizesailor View Post
My spare needs a new shaft now too so that's on my todo list.
I think the shaft is a Volvo-specific thing if yours is also the taper one with gear, so most likely a whole new pump will be about the same price as a shaft.

If the shaft is scored on the seal surface, usually there is enough play on the seal seat to change the riding point of the lip.

Mark
__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 26-01-2015, 18:58   #14
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,454
Re: Quick Raw Water Pump Sea Water Seal Replacement

Quote:
Originally Posted by colemj View Post
I think the shaft is a Volvo-specific thing if yours is also the taper one with gear, so most likely a whole new pump will be about the same price as a shaft.

If the shaft is scored on the seal surface, usually there is enough play on the seal seat to change the riding point of the lip.

Mark
There are also repair items called "Speed-sleeve" or such like for fixing scored shafts. These are very thin s/s shells that slip over the shaft in wayof the scored area. Commonly used in industrial applications, and they will extend the life of the very expensive water pump shafts nearly indefinitely (via successive applications). Should be available from any bearing supply house.

Jim
__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is offline   Reply With Quote
Old 26-01-2015, 20:31   #15
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,947
Re: Quick Raw Water Pump Sea Water Seal Replacement

Quote:
Originally Posted by colemj View Post
I think the shaft is a Volvo-specific thing if yours is also the taper one with gear, so most likely a whole new pump will be about the same price as a shaft.

If the shaft is scored on the seal surface, usually there is enough play on the seal seat to change the riding point of the lip.

Mark
I think so too. Other versions of the pump I've found have different end fittings than the gear.
__________________

__________________
belizesailor is offline   Reply With Quote
Reply

Tags
men, raw water, raw water pump, water

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
MD2020 Raw Water Pump Seal Replacement belizesailor Engines and Propulsion Systems 4 16-09-2012 20:13
Jabsco Raw Water Impeller Pump Shaft Seal Leaks sdowney717 Engines and Propulsion Systems 27 04-02-2012 14:26
Raw Water Pump vs Fresh Water Pump Cheechako Engines and Propulsion Systems 44 01-02-2012 15:31
Universal M12 Raw Water Pump Replacement bmiller Engines and Propulsion Systems 5 15-10-2009 18:57



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 22:26.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.