How tight should the water pump be attached?

[LordGothington]

Ahoy!

I am replacing the ancient sherwood water pump with a MMI water pump. How tight should the bolts be that attach the pump to the engine? The old bolts were not very tight at all. But, I also strongly suspected the water pump was leaking oil. (Something in that area definitely is). Initially I assumed it was due to the internal oil seal failing and leaking out of the weep hole. But now I am also considering the possibility that it was just not bolted on tight enough. I do have a torque wrench -- but it is probably too big to fit in the work area.

Also, does it matter which way the gasket faces? One side has writing, the other side does not.

In case it is not obvious, I am new to engine repair

[zellerj]

They should be tight. Use your calibrated elbow, tighten until tight, then go 1/8th turn more.

[JOHN COOKSON]

Tighten both bolts evenly in progressive stages. Do not tighten one bolt max then tighten the other bolt max. Tighten them alternately and in evenly steps to max torque.This could have been the original problem that caused one bolt to be looser than the other.
Be sure you have a correct gasket - one that can withstand oil.
What do the pump and accessory drive mating surfaces look like? Are they parallel?
Be sure the threads on the bolts and the accessory drive are not a.....screwed up. While you have the pump off be sure the bolts twist in far enough and easy to secure the pump. Maybe the loose bolt cross threaded bit?


TRUE GRIT

[lat 64]

I don't recall what the thread size is for those water pump bolts, but I would not exceed these specs.:

GRADE 5
Coarse Thread
5/16-18 - 13 ft lbs.
3/8-16 - 23 ft lbs.
7/16-14 - 37 ft lbs.

[ndutton]

The water pump mounting bolts are 3/8"-16. Lat's spec is right in the neighborhood of what I was guessing (25 ft-lbs.).

[thatch]

And one last bit of installation instructions, "do not use split lock washers on those bolts". If you do, oil will follow the thread gaps and leak out through the slot.

[tenders]

And one last bit of installation instructions, "do not use split lock washers on those bolts". If you do, oil will follow the thread gaps and leak out through the slot.

Great Scott, it is entirely possible I’ve been doing this across multiple pumps over decades, and suffered the resulting consequences. I’m going to check that this weekend.

[Al Schober]

This problem of the fluid following the root/crest of the threads is also an issue for the water jacket cover plate and the fasteners for the aft end of the reversing gear. With the water jacket, the use of studs vs bolts is a known solution. What do folks think about using studs for the water pump? Might actually make it easier to undo the lower fastener as the threads on the nut can be clean and back off easily. Using a bolt, we're always fighting the sealant.

[ndutton]

What do folks think about using studs for the water pump?

That's how mine is (spare engine pictured for clarity)

[thatch]

It would appear that a combination of a stud in the top hole and an "extendo-bolt" in the bottom hole might be the easiest installation approach.

[lat 64]

This problem of the fluid following the root/crest of the threads is also an issue for the water jacket cover plate and the fasteners for the aft end of the reversing gear. With the water jacket, the use of studs vs bolts is a known solution. What do folks think about using studs for the water pump? Might actually make it easier to undo the lower fastener as the threads on the nut can be clean and back off easily. Using a bolt, we're always fighting the sealant.

We used to use Ford brand weatherstrip adhesive for head bolts(and others) that were set in threads that went into the water jacket.
It was a gooey rubber-cement-like product that set up in the threads and sealed them. The bolts would still be removable without much trouble.
However, we did have to clean the old glue from the bolt threads before putting them back.
I don't see it for sale anymore but I bet the black stuff from 3M would work the same.