Water pump backing plate gasket

[Patrick H.]

Does anyone happen to have a part number or source for a water pump backing plate gasket? I can find them under Mercury Marine engines (27-35380, which are likely the same) but you'd think that there would be some available from auto parts vendors. Pump-to-block gaskets are easy to find, but it's the backing plate that is leaking on a 72 and needs a fix.

Thanks for any sources you can provide.

Patrick

[Edward J.]

Re: Water pump backing plate gasket

Patrick, I am pretty sure that Fel Pro makes a water pump backing plate gasket. Just call your local parts store.

[Patrick H.]

Re: Water pump backing plate gasket

Ed,

Yes, they make them. I should have mentioned that. However, bright blue won't work on a judged car.
I'm looking for one that is brown/black or similar. The rebuilders use them, so they must be out there somewhere.

Patrick

[Joe L.]

Re: Water pump backing plate gasket

Does anyone happen to have a part number or source for a water pump backing plate gasket? I can find them under Mercury Marine engines (27-35380, which are likely the same) but you'd think that there would be some available from auto parts vendors. Pump-to-block gaskets are easy to find, but it's the backing plate that is leaking on a 72 and needs a fix.

Thanks for any sources you can provide.

Patrick

Patrick------


The gasket was originally GM #3782611. Later it became GM #10204452 and currently it's known as GM #12555493. Orderable by you local GM dealer.

However, you can also obtain a suitable replacement under Victor-Reinz #K27091 or Fel-Pro #13032 (in fact, the GM gasket is likely one of these).

[Patrick H.]

Re: Water pump backing plate gasket

Thanks Joe. The Victor-Reinz shows up as black, the Fel-Pro as blue. So I will try to find some of the V-R gaskets.

Patrick

[Joe L.]

Re: Water pump backing plate gasket

Thanks Joe. The Victor-Reinz shows up as black, the Fel-Pro as blue. So I will try to find some of the V-R gaskets.

Patrick

Patrick------


Yes, the Fel-Pro gasket is blue. The original gaskets were either black, gray, or tan. I expect that's because GM had multiple suppliers of this gasket which was used by the millions. In fact, even the same supplier might have used different colored gasket materials, all meeting GM specs.

[Edward J.]

Re: Water pump backing plate gasket

Pat, maybe a light dusting of flat black paint before you install??

[Patrick H.]

Re: Water pump backing plate gasket

Pat, maybe a light dusting of flat black paint before you install??

It's tough to get these to accept orange paint. I'd wonder if black would also be difficult.

I might check locally, else Rock Auto has them too.

[Joe L.]

Re: Water pump backing plate gasket

It's tough to get these to accept orange paint. I'd wonder if black would also be difficult.

I might check locally, else Rock Auto has them too.

Patrick------


Make it easy on yourself:

http://www.ebay.com/itm/12555493-GASKET-WATER-PUMP-GM-CARS-AND-TRUCKS-1987-2010-FACTORY-/370823548633?hash=item5656ce4ed9:g:W2IAAOxyOalTbDPs&vxp=mtr

[Mark E.]

Re: Water pump backing plate gasket

Is this gasket installed dry, or with some sort of sealant?

I paid a nice sum to one of the advertisers in the Restorer for a restored pump with the "correct" PN and date for my '70 LS5. It leaked immediately from the back plate gasket. Not much- maybe a drop every 10 minutes, but enough to be a problem.

Now I have the pleasant task of taking apart the carefully restored pulley and belt system to fix the water pump. Rework due to poor part quality! Argh.

[Patrick H.]

Re: Water pump backing plate gasket

Is this gasket installed dry, or with some sort of sealant?

I paid a nice sum to one of the advertisers in the Restorer for a restored pump with the "correct" PN and date for my '70 LS5. It leaked immediately from the back plate gasket. Not much- maybe a drop every 10 minutes, but enough to be a problem.

Now I have the pleasant task of taking apart the carefully restored pulley and belt system to fix the water pump. Rework due to poor part quality! Argh.

Mark,

Originally dry. I had the exact same issue. Replaced the gasket with a free replacement one sent by the vendor, and used a bit of UltraCopper sealant. I suspect the teeny bit of leaking now is due to the pitting of the plate. I've been told to try the Right Stuff gasket sealer, as it will work even better. However, I have no other replacement gaskets from the vendor so I need to buy one. I think it will wait until after judging events are done, though.

Patrick

[Joe L.]

Re: Water pump backing plate gasket

Mark,

Originally dry. I had the exact same issue. Replaced the gasket with a free replacement one sent by the vendor, and used a bit of UltraCopper sealant. I suspect the teeny bit of leaking now is due to the pitting of the plate. I've been told to try the Right Stuff gasket sealer, as it will work even better. However, I have no other replacement gaskets from the vendor so I need to buy one. I think it will wait until after judging events are done, though.

Patrick

Patrick-------


A VERY common problem. Make sure of the following:

1) The backing plate you use should be the type that has a slight "raised ridge" between the bolt holes. If yours is original to the car it will have this feature. The type backing plates that do not have the ridge will almost always leak;

2) The backing plate must not be warped in any way. Place it on a flat surface and observe carefully;

3) The area around the bolt holes must be flat. Flatten the same way you flatten the area around the holes on the rails of an oil pan.

4) As you mention, no sealer was originally used. However, I use a thin coat of Ultra Copper or Ultra Black;

5) It may be necessary to tighten the backing plate bolts a bit tighter than the torque specs.

The backing plate can be installed so as to be leak free. Millions were originally manufactured that were leak free.

[Joe L.]

Re: Water pump backing plate gasket

Does anyone happen to have a part number or source for a water pump backing plate gasket? I can find them under Mercury Marine engines (27-35380, which are likely the same) but you'd think that there would be some available from auto parts vendors. Pump-to-block gaskets are easy to find, but it's the backing plate that is leaking on a 72 and needs a fix.

Thanks for any sources you can provide.

Patrick

Patrick------


Here's the definitive answer to the backing plate problem. This backing plate is an exact reproduction of the original backing plate but it's made from a high quality stainless steel (either 304 or 316, I believe). Thus, it's harder and stiffer than the originals and it will never suffer corrosion damage. For my money, the ONLY way to go.

You can get them from a fellow on eBay known as "h20pumpman1" His name is Michael Scott from Bloomfield, Michigan. He sells these with a gasket that looks just like the current GM gasket for about 13 bucks. Wonderful! I wish these had been available 30 years ago.

[Patrick H.]

Re: Water pump backing plate gasket

You can get them from a fellow on eBay known as "h20pumpman1" His name is Michael Scott from Bloomfield, Michigan. He sells these with a gasket that looks just like the current GM gasket for about 13 bucks. Wonderful! I wish these had been available 30 years ago.

Joe,

Ebay says that no one exists with that name, but I did find him:

http://www.ebay.com/itm/CHEVROLET-GM-STAINLESS-STEEL-BACK-PLATE-SMALL-BLOCK-NEW-/252430280903

Apparently their seller search function is quite poor.

Patrick

[Joe L.]

Re: Water pump backing plate gasket

Joe,

Ebay says that no one exists with that name, but I did find him:

http://www.ebay.com/itm/CHEVROLET-GM-STAINLESS-STEEL-BACK-PLATE-SMALL-BLOCK-NEW-/252430280903

Apparently their seller search function is quite poor.

Patrick

Patrick-------


I think I see the problem. I typed "h20pumpman1" but it's actually h2opumpman1". A "0" instead of an "o" makes a difference.