Penta MD Water Pump Leaking

[dje67]

Looking for any experience the forumites can offer on this one, please. My Penta MD11 water pump is dripping from the tell-tale hole between the engine and the impeller. My immediate thought is to replace the seals, but this is the second pump to leak like this in 6 months; the previous pump leaked in exactly the same manner. So:-

1) Has anyone replaced the seals on their MD pump and did it cure the problem permanently? If not, how long did the repair last?

2) There seems to be a couple of options for repair kits; a "seals-only" kit and a more extensive kit containing a new shaft. WHich should I buy?

3) Where could I get a non-Penta equivalent seal, as the volvo parts are dear?

4) Given that 2 pumps (neither new) have failed in the same way, could there be any other underlying fault that is causing them to fail?

Thanks all,

David.

 

[VicS]

Yes replaced the seals, at least helped a friend replace the seals.

Seemed to be an effective repair I think maybe they were only replaced two or three times in 30 years.

Inspect the shaft and renew it if scored/worn where the seals run.

If the bearing, just a plain bush, is worn then that will probably lead to premature failure of the seals.

A bearing stockist may be able to match the seals from the number on them.

 

[Kurrawong_Kid]

Have you put the seals in the correct way round? Can't remember which way they go but believe they are back to back. Very important that you get the seals ove the forked ends without damaging them.

 

[OGITD]

The tell-tale on the pump on my Bukh was spurting water every cycle when I first bought the boat.
Certain people in the club said that this was OK, and that this showed that a good supply of sea water was getting to the pump.
I happened to phone Bukh at Poole and once they had literally picked themselves up off the floor from falling off their seats with laughter, they explained that this was the indication of imminent seal failure, which would result in water passing into the engine oil an causing a serious problem.
So I purchaser a full set of seals, impeller and gasket, replaced everything. And for the last 18 months normal running temperature with lots of water out of the exhaust and no water from said tell-tale.
In hindsight I would replace the shaft, as mine had an indication of a little wear / play, but that will be done on its next service.

Also for something as critical as you engines water pump I would never use a generic part. Not quite the same but the previous owner of one of my outboards used a generic impeller which fragmented and went into every channel possible.

 

[Dyak]

Just replaced the seals on my MD 2030 for the first time since new (nearly 7 years) and found that the original seals were incorrectly fitted I.E not back to back. There is also a spacer to hold the seals apart that was the wrong way round.
There was some wear on the shaft but I left it as it was but expect to change the seals a lot sooner than 7 years the next time round. For the cost of the shaft I'd replace the whole lot next time round.

 

[grafozz]

see my previous reply to recent similar thread, its all there .

 

[Bilgediver]

You can get new seals from any local bearing supplier. Ensure if a seal with a spring that the spring is stainless. Take the worn seal with you as it is also possible to get either double lipped seals or seals with lips in different positions which would help if there is wear on the shaft from the old seal.

The seals could be worn if you sail and dry out in a sandy area and maybe the bump body bore is also worn.

The seals are just a pound or two each from a supplier however a lot more from Volvo and you need a mortgage to buy the shaft.

If drying out is the problem then some folk shut the sea cock before leaving the boat so that sand and mud is kept out of the works,.

In som small volvos it is possible to adjust the location of the seal so it bears on unworn bits of the shaft.

Make sure the seals are fitted correctly with the recess side of the seal towards the fluid ie the seals sit in the housing back to back with the one nearest the engine keeping the oil in the crankcase and the one nearest the pump keeping water in the pump.

 

[RAI]

It was more or less that problem that was the last straw for my old MD21A. New seals were easy to fit but didn't work because the shaft was scored. The new shaft set comes with new bearings, now fitting the new bearings is not so easy. That, and Volvo taking the MD21A off their spare parts list, led my to buy a Yanmar.

 

[dje67]

Thanks all. I kept the original pump, so will take it apart first to see what state it is in and whether the shaft is badly scored. I'm not aware of any local bearing/seal manufacturers, so will probably get the (rapidly emptying) wallet out and buy the volvo parts so that at least I know I've got the right parts. The boat is kept in the marina, so don;t think sand/dirt is the issue. Both the original pump and the recent replacement are probably a fair old age, so expecting to have to buy the shaft as well.