Repairing a dripping yanmar 1GM10 water pump

[ShipsWoofy]

A common fault on Yanmar 1GM10 engines is a dripping from the tell-tale hole on the water-pump. Left alone this will cause corrosion around the pump and will almost certainly corrode the oil pipes which are directly below the pump.

New seals for the pump will fix the problem and are a lot cheaper than buying new oil pipes. Though these can be manufactured from rubber hose by a hydraulic specialist, mine cost £9.00 for the two pipes. Yanmar will remove £70+ from your wallet for genuine parts.

Left leaking for long enough, water might breach the oil seal. Sea water will not only destroy the pump bearings but could theoretically enter the engine. If your pump is dripping, <u>fix it now.</u>

I have recently repaired one of my pumps and photographed the method I used; this can be carried out by any competent diy’er. Tools required,

10mm spanner to remove pump.
7mm spanner to remove impeller cover.
Long nose pliers or proper tool to remove bearing retaining clip
11mm, 3/4in sockets and hammer to drift new seals.

Bearing grease
Sharp blade to remove gasket
Cleaning materials (wire or brass brushes)
Spray paint

128170-42120 Water pump seal (This is the one which has failed)
128170-42110 Water pump oil seal (You WILL damage this to get the other one out)
128170-42090 Water pump cover gasket (you may use gasket seal if you must!)


The first thing we must do is remove the retaining clip, careful with this I had to find it by a plant pot on my patio as it got away.

Now remove the impeller cover by removing the 3 retaining bolts. This allows you to remove and inspect the impeller and then gently drift the shaft and bearings out of the pump.

Here is the shaft and bearing races. When I removed this I found a small amount of melted rubber on the shaft which had come of the water seal and was the reason for the leak. I scraped off the rubber with a scalpel and used a little wet and dry to ensure the shaft was clean.

I can’t give chapter and verse on removing the old seals, it isn’t easy. Lots of tapping with screwdrivers and tugging with pliers is required. Do try not to damage the pump, it is bronze and there for not as strong as your screwdriver.

Fitting the new water seal with an 11mm socket as a drift.

Gently (gently means gently) drift the new seal home.

The water seal home and sealed.

The oil seal home and fitted.

The bearings were cleaned and re-greased. I used the ¾ socket to tap them home.

All openings and unpainted areas masked off for spraying

Finished and ready to go to the boat

EDIT>> I tried to find alternate parts (seals) from auto parts specialists and a well known marine hydraulic engineers in Warrington. After a day driving around I gave up and resorted to genuine parts.

I went to a place called Alec Martin Marine on the Wirral. Not only was he the only place holding stock, he was also the cheapest. A proper old fashioned marine engineers, do not be put off by the website. For most marine stuff, give them a call, he knows his stuff! They will mail order.

**usual disclaimers apply**

 

[Rick]

Whenever I replace a waterpump seal, I remove the plain steel spring that is visible in the photo below "The oil seal home and fitted" and replace it with an o-ring, especially on the one facing the impellor, as this then prevents that spring rusting and causing the failure even before the lips of the seal have worn.

 

[Ships_Cat]

Seals with ss springs are readily available (so there should not be a "plain steel spring" in the first place, if exposed to sea water) - they last no problem.

John

 

[Rick]

[ QUOTE ]
Seals with ss springs are readily available (so there should not be a "plain steel spring" in the first place, if exposed to sea water) - they last no problem.

John

[/ QUOTE ]
Must be using the wrong bearing suppliers, but have been unable to get them with SS springs, hence use of o-rings here in Aus. Supplier actually gives them (the o-rings) away whenever he smells it's a marine application.

 

[Ships_Cat]

Hi Rick

I am just across the Tasman - my prop shaft seal, as one example, uses ss sprung lip seals and are not a special - but don't recall what make when I have bought them.

However, I have had a look in the NAK Technical Reference and they list two stainless steel options for springs in their seals, one of which is 316 stated for salt water and other services. NAK have an office in Brisbane (as well as in Melbourne, Sydney and Perth) so if you ever want some seals may be worth giving them a call.

I would also expect any of the other big seal manufacturers such as James Walker would be able to help no problem at all.

John

 

[fastjedi]

Rebuilt mine about 60 engine hours ago. Guess what, it's just started to leak again! When I rebuild mine I replaced a shaft that was in significantly better condition than the one in the photo ...... given the cost of the shaft and the fact that it only lasted 50 hours anyway, i'm thinking i should only replace the seals this time! Opinions please?

 

[charles_reed]

An excellent exposition

nm

 

[charles_reed]

My experience of a 2GM20 raw-water pump

is that once it's started to leak it needs more than the superficial replacement of seals.

I always carry a spare raw-water pump, and when it gets to the leaking point, I strip, have the body and backplate machined and rebuild including a new bearing as well as the seals.

 

[Guest]

We had the same problem in Brisbane. No one would sell us bronze or stainless springs for the engine or stern tube seals. Everyone just said put on rubber o-rings. They were not even oil resistant ones. Ended up ordering them from the UK. "Flow seal Ltd" in Hampshire. They make any seal up with any spring type and, of course, Golden Arrow.

 

[cindersailor]

Water pumps can leak due to the grooving of the shaft by the water seal especially in areas wher the water contains silt. Your shaft shows evidence for this. Replacing the seal, whose lip is also worn by this process, may solve the problem, but it is still running in the groove so it is likely to start to leak again rather sooner than it should. When I rebuilt my 1GM pump to get around this issue I also put a spacer (cut from cork gasket material aboit 1mm thick) behind the water seal so that the lip bears on a slightly different and ungrooved part of the shaft. It apppeared to work well.

 

[ShipsWoofy]

I agree.

Although not a great engineering check, I did have a good feel of the shaft and the marks you see are more polished than grooved. The photograph does make it look worse than it actually is. But if it does leak again I will take your advice and push the water seal back a mm. I bought a few spares when I bought the seals.

So far about 20hrs and still dry, but it will be a good while before I fully trust it anyway. Like I said, when I first took the shaft out, there was lump of plastic/rubber welded to the shaft under the seal collar. Every time the shaft rotated this would have opened a gap and let water in.

I did pull a lot of grit out of the pump, in fact, the inlet pipe on the pump was half blocked with solid grit. I must have gone a bit shallow! My fault too as I still do not have a strainer on the starboard engine. Only because I am having trouble finding the type I want.

The scratches on the shaft were my heavy handed scalpel removing the welded plastic, I gave the shaft a gentle wet and dry before replacing and it looked and felt fine, we'll see I guess.