cooling pump shaft

[lufc]

gday fellow gasers ,i own an 06 ec300 and the cooling pump shaft has brocken in two ,has anyone else had this problem ,i am at a loss as to how it has happened

 

[GMP]

Thats a new one. Even if the bearing seized I would think the gear would break first. Post a photo of the broken parts I would be interested to see them.

 

[lufc]

as you can see in the photo it has snaped were the locating pin goes. also you can see how the counter weight has come into contact with the plastic gear.
when the shaft is in one peice the gear cant! come into contact with the counter weight so the shaft must have broken first then the gear has moved back and come into contact with the counter weight (this is my therory) so how did the shaft break its not under any load the impeller has no marks on it to sugest that it may have been jamed.
i hav orderd the parts and there very inexpensive but i dont want it to happen again.

 

[GMP]

You are absolutely right. I'd say the shaft was damaged when the pin was pressed in. This is a very, very rare case. I'd put it back together and not worry about it.

 

[sprocket74]

lufc

My 06 de300 did the exact same thing, except when my shaft broke it took out the internal water pump bearing as well.

 

[lufc]

sprocket how do you reckon it happened ,i am thinking that the bearing has worked its way out of the seating which has allowed the shaft to move around and eventually snap

 

[GMP]

From the GGs I've rebuilt, those bearings are a pretty tight press fit in the side cover. I had to grind special "fingers" for my slde hammer puller and use heat to extract them. I see the bearing outer race is cracked. Was it seized? Its tough to say what damage came first.

 

[gasgasman]

If I was to guess.
I'd say , when the shaft broke the drive gear was smacked by the counterbalancer causing the bearing to crack.

 

[lufc]

From the GGs I've rebuilt, those bearings are a pretty tight press fit in the side cover. I had to grind special "fingers" for my slde hammer puller and use heat to extract them. I see the bearing outer race is cracked. Was it seized? Its tough to say what damage came first.

it wasnt the bearing in the side cover but the bearing pressed into the engine side and no it wasnt seized.

 

[lufc]

If I was to guess.
I'd say , when the shaft broke the drive gear was smacked by the counterbalancer causing the bearing to crack.

yep sounds good, so how did the shaft break!

 

[sprocket74]

the failure on my model occured where the water pump shaft was machined down from 10mm to 8mm this same area is where the pin is pressed through for the plastic drive gear. Although I am sure it was a fluke occurance I think that leaving the water pump shaft 10mm right through would have helped the situation.

 

[gasgasman]

yep sounds good, so how did the shaft break!

The shaft may have not been heat treated properly,or the case is misaligned.
If the shaft wobbles-eventually it will fail from fatigue.