Water Pump Replacement
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Cruising
Joined: Mar 2015
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Water Pump Replacement
Hello all! I'm about to replace the water pump on my ’73 convertible and need to know if I can do that without removing the lower radiator hose. The hose is fairly new and in good shape, and I recall it was a giant PITA to get it onto the radiator when I put it on, so would like to avoid removing it if at all possible. All of the step by step instructions I’ve been able to find for water pump replacement simply say “drain coolant”. What’s the easiest way to do that? Any help/advice on this would be greatly appreciated.
Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
The lower radiator hose is attached to the water pump - you can't remove the pump without removing the hose from the pump. You can leave it attached to the radiator.
Drain the coolant by opening the drain **** on the radiator and loosening the radiator cap.
Before buying a new water pump, verify which pump you have installed on your engine: Most of the Corvette water pumps had the fat 3/4" diameter shafts, whereas other pumps have 5/8" diameter shafts. Measure your pump shaft diameter, and check the hole size in your water pump pulley, before buying a new pump. There are "long" pumps and "short" pumps - all Vettes use the "short" pump regardless of shaft diameter.
Lars
Drain the coolant by opening the drain **** on the radiator and loosening the radiator cap.
Before buying a new water pump, verify which pump you have installed on your engine: Most of the Corvette water pumps had the fat 3/4" diameter shafts, whereas other pumps have 5/8" diameter shafts. Measure your pump shaft diameter, and check the hole size in your water pump pulley, before buying a new pump. There are "long" pumps and "short" pumps - all Vettes use the "short" pump regardless of shaft diameter.
Lars
Last edited by lars; Mar 27, 2020 at 11:48 AM.
Thread Starter
Cruising
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Thanks, but my radiator doesn't have a drain **** so that's why I removed the lower end of the hose from the radiator last time I did this. There's not enough room at the bottom of the radiator to get a good grip on the hose and there's also a brake line near there that's in the way. I used soapy water to help slide it on, but I remember it was really, really difficult to get that thing on far enough to clamp down. Haven't looked at it yet but I think I ended up putting two clamps around it to keep from leaking. So, was hoping to avoid removing it but if that's not an option I will just go through the misery again. I will try antifreeze instead of soapy water this time. Thinking this water pump should be an exact fit: https://www.jegs.com/i/JEGS/555/5103...791+4294828856
Thanks again for your response.
Thanks again for your response.
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,328
From: At my Bar drinking and wrenching in Lafayette Colorado
If you're going to drain it by yanking the hose, you don't need to pull the hose at the radiator. Pull the heater hose off the water pump first to get a somewhat controlled leak that you can capture under the car. Once pulled, slowly remove the lower radiator hose from the water pump and leave it attached at the radiator. By pulling the hose slowly and at an angle, you can somewhat control the resulting coolant leak. No need to remove the hose from the radiator.
Lars
Lars
Last edited by lars; Mar 27, 2020 at 12:44 PM.
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Thread Starter
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Good idea. I drained my gas tank once with my air compressor using a small hose with a slit in it a few inches from the end that you put an air gun into. Worked like a champ. Might give that a try first. Thanks for the tip!