Yanmar water pump replacement

[Thedigger]

I've stripped the pump of the 1G and removed the 2 seals. But trying to fit the water seal in the grove on the pump is impossible. There seems to be too big a gap between the lip on the seal and the back of the impeller. The lip on the pump is only about 2 or 3mm deep getting the seal to stay in place is impossible. I'm wondering if I need to get a new pump. Looking through the hole from the impeller side the housing is very rusty. I banged in the water seal and it only just enters the hole and there is a gap of about 3 or 4mm between the seal and the back of the impeller. According to practical boat owner article on this the seal should meet the back of the impeller. The problem is either I have the wrong size water seal or the grove that fits the seal is so badly corroded there is no room for the lip - anyone help as buying a new pump is expensive - I did notice the invoice for the seal said there was an earlier edition model so perhaps I have the right oil seal but the wrong water one.

 

[VicS]

The diagram in the workshop manual shows that the water seal does not meet the back of the impeller


Clean off all the rust and compare the new seal with the old one if you think you have the wrong seal

 

[Thedigger]

The old seal was destroyed so no way of knowing. When I try to fit the seal in it doesn't like going in and just falls out even when I give a few strong hammers using a socket and a hammer. I've scraped as much as I can from the grove in the pump and it doesn't look deep enough to hold the seal in place.

 

[VicS]

The old seal was destroyed so no way of knowing. When I try to fit the seal in it doesn't like going in and just falls out even when I give a few strong hammers using a socket and a hammer. I've scraped as much as I can from the grove in the pump and it doesn't look deep enough to hold the seal in place.

Are you sure you've got all the old seal out?

 

[Thedigger]

It is hard to tell. It looks like it's all out. Bit it feels like the seal lip is too big for the grove to hold it in place. I've gone through 2 new seals trying to solve this. Is it possible there are 2 different seals which are different sizes? I will try cleaning it again I did put a blow torch in the hole hoping I'd melt any remaining rubber.

 

[VicS]

This website lists spares for a number of 1GM versions GM Series

They all seem to use the same water pump and all have the same oil side oil seal listed but there is some variation the the waterside oil seal
for some 128170-42120 is the only seal listed while others list this one and 124240-91450 as well.

I dont know why this is but it maybe worth investigating the difference.

 

[Sidestep]

I had the same type of issue and started a new thread yesterday (didn't see this one). I too destroyed a seal in the process. I kept looking at the pump body and just couldn't work it out. Then I realized in the mangled remains of the old seal I didn't have any steel. The new seal is a round of steel covered in a rubber type coating. So I got the pliers in again and removed what I thought was part of the pump body. It was in fact the steel ring of the old seal! So I now have the body ready for the new seal when it arrives. Next time I'll remember this.....! Might be your issue too?

 

[Thedigger]

I had the same type of issue and started a new thread yesterday (didn't see this one). I too destroyed a seal in the process. I kept looking at the pump body and just couldn't work it out. Then I realized in the mangled remains of the old seal I didn't have any steel. The new seal is a round of steel covered in a rubber type coating. So I got the pliers in again and removed what I thought was part of the pump body. It was in fact the steel ring of the old seal! So I now have the body ready for the new seal when it arrives. Next time I'll remember this.....! Might be your issue too?

It looks like it thanks