replacing raw water pump?

[pjcomeau]

I ordered a new Oberdorfer raw water pump as the old one looked like it was leaking at the mount and at the cover.

I have not installed it yet, because I'm worried of how much time I'm going to take. The old one leaked long enough to completely rust the mounting bolts. Even if I can put the new pump using the old bolts (which I doubt), it would not make sense to leave those rusted bolts on.

What is involved in removing those bolts, where would I get replacements?

Thanks,

Pierre

[Ken Juul]

If you are asking about the bolts that mount the pump to the engine, they are a standard metric size.  Most hardware stores should have them.  Unless you run into difficulties removing the old pump, it should take 30-45 minutes to put the new one on.

[Stu Jackson]

I used nylock nuts to replace the originals on the studs.  It took me two days, with old Liquid Wrench, to get the old ones off (in 1999).  I've since learned about PB Blaster, a much better solution than liquid wrench.  Don't use WD40 - I've taken that OFF our boat, as it's relatively useless.

As I recall, the bolts are actually studs into the block.  Check at www.marinedieseldirect.com or our manuals website section for the parts.  If you get the nuts off the studs, you may be able to clean the studs enough to reuse them.

Once the nuts are off, Ken's right, it's a simple replacement.

As mentioned on a recent thread and other's painful experiences, if you've had that saltwater leaking for any amount of time, be SURE to check the oil pan below as well as the engine mount, for damage from rusting.  If the saltwater's gone down to the pan, clean it up and repaint it to avoid the pan and its seal to the bottom of the engine from deteriorating.

[Stu Jackson]

Pierre, I just checked the marine diesel website and I can't find the parts number for the studs for the raw water pumps; can't even find anything on all the parts drawings that even shows the studs!  They show three pumps: the Oberdorfer, the old Sherwood and the new Sherwood, none of them show the studs.  Therefore, if you need to find them (because, or if, yours are goners), I suggest giving MDD or Torrensen a phone call to get the right ones.

When I redid the alternator bracket on our M25 in 1998, new studs came with the upgrade kit but our studs were in good shape and I was able to reuse them.  On a friend's Ericson 32 with his M25, when I redid their bracket for them (good friends, I didn't want them to have that mess and they weren't mechanically inclined) I had to back their studs out and install the new ones because theirs weren't long enough.  Since they were "goners" I used penetrating oil (well before I knew about PB Blaster) and big vise grips (I "shaved" the sides of the studs to flatten them out to "get a grip"!), which killed the old threads, but they were going into the waste anyway.  Took a few hours for the five or so studs to come out and it was the worst part of the job.

[cwbrownjr101]

Replaced my Oberdorfer raw water pump this weekend.  When removing the old one, I had no problem (with some help of PB Blaster) getting the nuts off the top two studs, but the bottom two nuts were corroded badly and fused to the studs. Luckily the bottom two studs came out cleanly -- they couldn't be re-used, though.  Replaced them with M6 bolts (10.9 grade) that I had cut the heads off. Used some Permatex to make sure the new homemade studs stayed in place.  Tested the new pump and it seems to have done the trick.

[MarkT]

Obtaining a replacement raw water pump is on my list for the immediate future. What part did you buy and how much did it cost? My engine has the sherwood pump which looks ok but I don't much care for the design. Add to that my recent experience with a failed circulating pump and I'm eager to get a replacement.

I'm sure the info is in the history somewhere but I can't find something to hang my hat on and say this is the part for my engine.

Mark Tamblyn
1987 C34 #326 Alena

[Ron Hill]

CWB : I believe that you should have replaced those studs using some #1 Locktite.  That would insure they will not back out. 

Mark : If you already have a Sherwood, I'd recommend that you stick with Sherwood and just get another one.  That way you can rebuild the old one and have a spare ready to go.  I'd call DEPCO @ (800)445-1656.  Describe your Sherwood (or give them the model # if you know it) and they'll give you a price for a new one. 

[cwbrownjr101]

Ron, I used #1 Permatex. Is there something I should be worried about re: Permatex vs. Locktite?

[Ron Hill]

CWB : #1 Permatex is a harding gasket type material.  #1 Locktite is a metal to metal thread sealant.
I wouldn't worry about it now, but if the studs loosen I'd clean out the threaded hole and use #1 Locktite.
A thought