O6 FJR Water pump re build

Hi,

Getting ready to perform a re build on my water pump due to a leak at the weep hole. I understand that at a minimum only the mechanical seal need be replaced but since I've not yet disassembled the pump I ordered all of the needed parts "just in case" O ring, Bearings, oil seal, mechanical seal and impeller.

Is any prep required to the casing bore or OD of the bearings/oil seal before pressing? Should they be pressed dry or is lubrication needed? Should the impeller shaft be inserted into the oil seal dry?

If any of the old oil seal material remains in the bore whats the safest way to remove it?

I'm probably over thinking it but I'd like to get it right the first time without damage. Any helpful advice or recommended procedures are welcomed.

Thank you in advance, Uenjoy

I cannot answer your technical questions, my apologies. But I do have the old water pump from Patriot's grenade motor. It was a gen 1 (90% sure it's compatible), with 90K miles on it, and no evidence of leaking. As a fall back, you are welcome to that pump for only the cost of shipping.

Good luck.

hppants said:

I cannot answer your technical questions, my apologies. But I do have the old water pump from Patriot's grenade motor. It was a gen 1 (90% sure it's compatible), with 90K miles on it, and no evidence of leaking. As a fall back, you are welcome to that pump for only the cost of shipping.
Good luck.

Click to expand...

Thank you for the generous offer hp!

Looking at parts lists for gen 1 and gen 2 everything matches up but the casing. (different part #'s) A call to my local dealers service department confirms the gen 1 pump wont mate to the gen 2 motor.

Thanks for the encouragement, Uenjoy

Anytime I am installing bearings I like to put the bearing in the freezer overnight to very slightly shrink the bearing so that it is not quite the interference fit it would be at room temperature.

I also like to use a o-ring lube on the seal lip to help with assembly. It's probably not necessary but it was the way I was taught by a very good mechanic who has built a number of successful race motors.

The 'mechanical seal' is likely to be fragile, so use care.

Different bike, but Rotax used to sell the parts separately, but installation damage to the mechanical seal was common.

Now the Rotax part comes as a shaft in mechanical seal assy.

This part I pressed in easily using a drill press and socket.

yamafitter said:

Anytime I am installing bearings I like to put the bearing in the freezer overnight to very slightly shrink the bearing so that it is not quite the interference fit it would be at room temperature.I also like to use a o-ring lube on the seal lip to help with assembly. It's probably not necessary but it was the way I was taught by a very good mechanic who has built a number of successful race motors.

Click to expand...

Lube the seal lip for the impeller shaft or the OD of the seal before pressing?

Got the easy part done tonight, pulled the pump and it now sits on the bench awaiting further clarification on specifics such as heating the casing which was recommended by the Yamaha tech at my dealership.

I have heard of freezing the bearings and the tech said heating the casing and freezing the bearings will often times allow the bearing to "fall" right into the bore with little effort. He recommends heating with a blow torch but I've also heard of dropping the casing into boiling water. I would prefer the latter as I'm not comfortable with a blow torch. I don't want to heat it it too much for fear of warping or other imagined damage.

EDIT: Hmm... On second thought, dropping it into boiling water doesn't sound so great either. seems it should be heated slowly.

Thoughts?

SunRider said:

The 'mechanical seal' is likely to be fragile, so use care.Different bike, but Rotax used to sell the parts separately, but installation damage to the mechanical seal was common.

Now the Rotax part comes as a shaft plus mechanical seal assy.

This part I pressed in easily using a drill press and socket.

Click to expand...

The mechanical seal is indeed very fragile and easily destroyed if care is not taken. It cannot come in contact with any surface other than its ceramic counterpart.

I work on swimming pool pumps and change out failed shaft seals all the time. I have the perfect drift that does not damage the mechanical seal and fits the Yamaha seal perfectly.

Thanks for the input guys!

Thanks,Uenjoy

"Dropping the casing into boiling water " will only get you to 100 degrees C (212 F).

We always used oil to heat bearings or casings, think cooking oil..........

Donal said:

"Dropping the casing into boiling water " will only get you to 100 degrees C (212 F).
We always used oil to heat bearings or casings, think cooking oil..........

Click to expand...

Have you ever used a blow torch and if so what is the procedure and drawbacks if any??

Thanks for the advice!

I would be very wary about using a blowtorch on anything with a painted finish.

If you don't have another option apply heat (from the torch) from the inside of the housing only and keep the flame moving.

I had my waterpump fixed by Yamaha dealer this summer for exactly the same reason as OP states -coolant leaking from the weep hole. Although I was not there when they did it, I am sure they did not use any heat or freeze. We discussed the process when I picked the bike up. When I look at the bill I see they replaced the mechanical seal (30€) and the waterpump body seal (4€). That did the job...

How about Put your casing in the kitchen oven. Turn on heat to 300 degrees?. Thats hot enough coupled with a frozen bearing to get that part of the job done. This is how we did wheel bearings with no tires on the wheels.

As for the seal, for me a socket that fits it perfect to use as a drift.

hppants said:

How about Put your casing in the kitchen oven. Turn on heat to 300 degrees?. Thats hot enough coupled with a frozen bearing to get that part of the job done. This is how we did wheel bearings with no tires on the wheels.
As for the seal, for me a socket that fits it perfect to use as a drift.

Click to expand...

That's the trick! Heat is your friend. After struggling with removal of the mechanical seal with a blind bearing puller slide hammer I put the casing in the oven and heated it to 350 degrees for 30 minutes after which the mech seal popped out on the first pull, same with the oil seal. The bearings were easily tapped out with a punch.

Scotch brite to the bore to remove residue from the oil seal and crust from the leaking mech seal then back in the oven for a half an hour to heat to 350 degrees while the bearings chilled in the freezer. Both bearings, OD wiped with fresh oil, needed little persuasion with a 20 mm socket and rubber mallet and fell into their seats straight and true.

After cool down, a small amount of o ring lube to the OD of the oil seal and using a 20mm socket the seal was pressed in by hand... almost, again a tap from the rubber mallet was required. For mech seal installation I used a 3/4" PVC Coupling with an inside diameter of 1 and 1/16" and an OD of 1' and 5/16" (a perfect fit) and drove it home with three or four good whacks. The ceramic half of the mech seal, after carefully lubricating the rubber bit, was finger pressed onto the new impeller using a thin piece of cardboard to prevent transfer of skin oils to the ceramic surface.

A small bit of o ring lube to the oil seal lip and the impeller was inserted and cir clip mounted.

VOILA' good as new water pump!

Thanks to all, Uenjoy

Well done, although sounds pretty complicated bit of work.

Good I could rely on the pros, I would definitely have screwed it up myself ...

Enn said:

Well done, although sounds pretty complicated bit of work.Good I could rely on the pros, I would definitely have screwed it up myself ...

Click to expand...

I don't know. The "pro's" were going to use a torch to heat the casing and charge me an exorbitant amount of $ to do the build, not to mention more than a week to finish the job. I found some valuable how to's and info as to why a torch is a bad idea here

One thing I may have done differently is read the service manual first. While there is no recommended procedure regarding removal and installation of the bearings, it is suggested to use water or coolant as a lubricant on the oil seal and the ceramic/rubber half of the shaft seal. I learned this looking for torque specs pre installation of the water pump.

I rode 200+ miles today with no issues, so apparently o ring lube works just as well and was also recommended by the "pro's"

Cheer's, Uenjoy

Oop's link didn't post. Here you go https://www.microbluebearings.com/bearing-removal/