Stripped screw on water pump mounting bolt

[StephenGwyn]

Just a flat washer.

I've thought of a stud, but it's the same problem, only a different thread count. Getting a tap handle in there is going to be tricky. Then you have the problem of lining the pump up with the studs while at the same time getting the slot on the pump shaft to engage with the bar inside the accessory drive.

There are various solutions involved JBWeld or similar, but it seems a bit oily back there.

[Surcouf]

Just a flat washer.


There are various solutions involved JBWeld or similar, but it seems a bit oily back there.

I have been recommended to burn the oil with a torch before applying JB weld.

[ndutton]

This was a while ago, but I find myself with a similarly stripped hole. Can you describe in a bit more detail how you did that? There is not a lot of room back there for a drill and a tap handle.

Have you considered replacing the aft housing?

https://moyermarine.com/product/aft-housing-late-model-engine-used-ocas_01_258/

It will give you a first class result compared to a glued bolt remedy, especially on a component with rotational stresses.

Do it right, cry once ($).

[ronstory]

@Stephen

You are talking about the stripped hole in the block side and not the accessory drive, correct?

[StephenGwyn]

I am talking about the holes that mount the water pump to the aft housing.

I considered replacing the aft housing (I have two A4s sitting in my shed and both aft housings are relatively rust free and have nice, tight holes) but it looks like a lot of work getting that thing off, with a lot of potentially seized bolts. Doesn't the rear seal have to come off? Doesn't that mean pulling the prop?

The other thought I had is to try to get access to the inside by removing the accessory drive.

[ndutton]

I considered replacing the aft housing (I have two A4s sitting in my shed and both aft housings are relatively rust free and have nice, tight holes) but it looks like a lot of work getting that thing off, with a lot of potentially seized bolts. Doesn't the rear seal have to come off? Doesn't that mean pulling the prop?

Pages P3-1 and P3-2 of your Moyer Marine Service and Overhaul Manual, steps 1-4.

[ronstory]

I am talking about the holes that mount the water pump to the aft housing.

Thanks... for some reason I got confused with a through bolt on a accessory drive. Could be the fumes from painting the engine.

Ok, I pretty sure i'm going to get flamed for this, but we could start a sub-forum for "Confessionals"

I was a similar situation with a tranny housing in a *very* confined location. The size was the same 5/16x18 and the mating flange didn't have a lot of meat in it so I really didn't want to drill to 3/8". So my toyota buddy said 'let try M8x1.25 bolt, what have you got to lose?". I replied "Just my dignity".

After I finished coughing and sputtering about "crossing the streams" of the SAE and Metric universes, jokes about metric crescent wrenches.... and my impending confirmation of dignity loss... he handed me a M8 tap which i stuffed it in my ratcheting tap holder. I packed the hole with heavy grease to catch the shavings, carefully started the tap to line the threads up as best possible and did the deed. When all was done, it worked fine, a small of enough increase in diameter that I didn't need to enlarge the thru-hole it he flange... and is still there 20+ years later.

The M8x1.25 is about 0.040" larger than 5/16" and about 20 TPI vs the std 18.

I painted the head of bolt 'pink' to remind me that I did an ugly hack that offends my OCD gene everytime I see it. But again, the practical engineer in me said "nice workaround". YMMV.

... i'll go stand in the corner now...

[Administrator]

we could start a sub-forum for "Confessionals"

Check this out.

Bill

[ronstory]

Ahh! Thank-you! A support group for the "things we are not proud of" folks.

[StephenGwyn]

The current alternatives are:

(1) epoxy to rebuild the threads
(2) enlarge the hole and cut new threads

I'm not optimistic about option (1), but if someone has done it, I'd love to hear from them.

At least one person (back several years ago now) has done option (2), but I'd really like to know about how they did it, given the poor access. Going from 3/8" to M10 is annoying, but acceptable. 7/16" is a bit of a big jump.

[ronstory]

Stephen--

Is the bolt for the water pump housing 5/16" or 3/8"? I thought it was 5/16", but I may be mistaken.

[ronstory]

Ok, looks like I may have answered my own question. (red below)

OBERDORFER TYPE - STARTING LATE 1969
CODE DESCRIPTION NO. USED PART NOTE
Water pump assy. early 1 290660 use 295625
Water pump assy. late style 1 295625 M202-3
1. Screws, cover 4 296580
2. Cover 1 296578
3. Gasket 1 295626
4. Snap Ring 1 295629
5. Impeller 1 295628
6. Shaft 1 296575
7A. Cam - M202 1 296578
7B. Cam - M202-3 AR
8. Screw, cam 1 296580
9A. Body - M202 AR
9B. Body - M202-3 AR
10. Seals 2 295627
11. Plug 1 296576
12. Grease Cup 1 296577
13. Gasket, pump mounting 1 261044 use 300253
14. Kit, impeller (includes 295628 1 200209
& 295626)
Water inlet elbow - V drive 1 241019 ½"x3/8"
Water outlet elbow 1 289770 ½"x3/8"
Mounting screws 2 231080 3/8-16x1
Mounting lock washers 2 260704 3/8"
15. Kit, repair kit, water pump, 1 200210
Contains 296580, 295628, 295626,
295627, 295629, 296575, 296578,
296579, 296580, 300253