What Kind of Steel for My Water Pump Bolts?

[minuteman62-64]

Have '82 30 HP Mariner, Japanese made. Water pump housing has an extension to accommodate the long-shaft configuration. Rebuilding the water pump and noted, on re-assembly, that the bolts that hold down the pump housing only have 1/8" purchase on the threads. Looks like the bolts that were on there were for the short-shaft model. I need to get some longer bolts.

Are these bolts SS or some other alloy? The existing ones don't rust, but are magnetic. Could I use hardware store SS (probably 18-8 stuff), or would the SS tend to seize in the aluminum LU housing?

 

[gm280]

You have a few options as I see it. You could either research the factory type bolts and buy them, OR purchase stainless steel bolts of the proper thread and diameters and apply some anti-seize before installing them to help with any corrosion or dissimilar metal issues. I would go with either situation on my own engine... But I am no professional and that is just my opinion. Others will certainly chime in and give you their answer shortly I'm sure...

Oh, one other thing. Being manufactured in Japan, there is a chance that those bolts could be metric and not SAE. So verify that the threads are one or the other...

 

[racerone]

???------Long shaft or short shaft should not make a difference on the pump / bolts.-------verify that you have the correct parts here,----Pictures ?

 

[minuteman62-64]

Yes, they are metric. My local hardware store has metric fittings in SS.

See attached photo. Brown(ish) component is water pump housing. Black component is extension used on long shaft models. You can see bolt protruding from base of pump housing. When the gasket and base are in place there's just a little over 1/8" (since it's metric, maybe I should say 3 mm ) of thread protruding. It doesn't help that the top few threads on one of the holes have been mangled by parties unknown

 

[Fun Times]

Looks like your looking for merc part number 10-83285M. There's not much info about the material of the bolt but I did find where they're 1- 3/8" long. http://www.ebay.co.uk/itm/Mercury-Qu...item20f3fff748

http://fsg-53-screws-bolts-studs.par...10-84058M.html

Item numbers 9 for short and 12 for long. Also take note the washers 10 and 13 are different sizes.
http://www.mercruiserparts.com/Show_...sc=GEARHOUSING

Your best bet is to go OEM.....See my signature line below.

Good luck.

 

[minuteman62-64]

The bolts I have are 1-3/8" long and just don't seem to penetrate far enough into the threaded holes in the LU.

The bolts are 6mm. I found some 6mm metric bolts in my local hardware store that are about 1/4" longer. I may try those (there's plenty of thread depth to receive the extra length) with some anti-seize (or Locktite or maybe even Napa Aviation Gasket Sealer) to prevent seizure.

 

[Georgesalmon]

I would not use locktite,, anti-seize is best. If you don't have any just get one of those little packets they sell for spark plugs at the auto parts store.

 

[gm280]

Certainly don't use Locktite. Unless you never plan of taking them out again, especially in that area, or there is some type of anti-seize Locktite product you're talking about. DO use the anti-seize being how the bolts are steel (stainless or otherwise) and the thread part is probably aluminum.

 

[dingbat]

Never arbitrary use "anti-seize" on any connection, especially in the presence of dissimilar metals. Locktite blue or red, depending on the need.

Hardened austenistic stainless steel is slightly magnetic. Common material for fasteners requiring higher torque values

 

[minuteman62-64]

The Mariner factory repair manual specifies "Loctite Type A". Based on a couple of threads on here, consensus seems to be that the modern day equivalent of Type A is Red - which makes no sense at all for the water pump bolts. If I use Locktite I'll use the Blue.

 

[oldman570]

The best sealer to use is the newer silicon thread sealer made by Loctite and manufactures when needed. Never Seize and the standard red or blue liquid thread locker will cause the aluminum to seize to the bolt and act as a wielding agent. The red or blue silicon sealer will work fine after it has time to setup. The use of longer stainless bolts without any sealer as long as there is room for them, and they are not over a 1/4" longer. JMO
Oldman570

 

[minuteman62-64]

Update: The longer bolts don't hit good thread in one of the holes. Looks like next step is Helicoil. Here comes a new thread w/Helicoil questions

My one hour impeller replacement job has now extended over a week, with more to come. Oh well. That's why I'm retired