C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

85 Water Pump Replace

Old Jun 10, 2022 | 09:45 AM
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Default 85 Water Pump Replace

My 85 base w/60k miles lost the water pump about a week ago. Thankfully it wasn't during the 300 mile road trip we had just gotten back from.
Shop still hasn't called me back. Really wasn't sure if I was going to use a shop.
Car runs and drives nearly perfect. I've decided to do it myself. That way I have only me to blame if something doesn't work out.
Haven't done much research and thought I would just ask here for any tips, tricks, instructions and videos you might have.
I have tools and experience so I feel more than capable of doing this repair.

TIA,
Joe K
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Old Jun 10, 2022 | 10:32 AM
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Once you get the belts, hoses, and pulley off, it's literally 4 14mm bolts to get the pump off. I would start the whole operation by breaking loose the 4 pulley bolts, before you take the belt off. Good luck and let us know how it goes!
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Old Jun 10, 2022 | 11:45 AM
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Originally Posted by vinco
Once you get the belts, hoses, and pulley off, it's literally 4 14mm bolts to get the pump off. I would start the whole operation by breaking loose the 4 pulley bolts, before you take the belt off. Good luck and let us know how it goes!
A 9/16" socket will fit tighter than a 14mm socket since that is what the head of the bolt is.

Last edited by 383vett; Jun 10, 2022 at 03:26 PM.
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Old Jul 25, 2022 | 12:14 PM
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Default Up and Running

Well I replace the pump a couple of weeks ago. Wasn't really easy, but I didn't have any serious problems. Purchased the pump
from O'Reilly's. A new Wagner standard cooling. Made in Mexico. Nice aluminum casting. About $70. Other than the anti-
freeze that was all I replaced. Car was and is well maintained so belt, hoses and clamps were all reusable.

Getting into the procedure I want to make you aware of fuel running continuously and nearly unnoticeable from the disconnected
fuel lines. I had a lot of fuel in my drain pan and soaked into the cardboard I put under the car before I noticed the fire hazard.
Couldn't find a way to plug them so I just had to reattach them to the fuel rail. I got one of my old drying towels and allowed it to
soak the fuel up when I had to disconnect them again to mount the A/C bracket. Just FYI, be cautious. I did rent a fuel pressure
test kit so I could release any pressure but there was none. Car had been sitting for a couple of weeks so I think the pressure just
bled off.

You're going to need a long nose T45 torx socket to reach the hidden bolt under the compressor. There are 3 slots in the clutch
that you can use one of to line the bolt up with to remove it. The bolt has a flat side that allows it to clear through the slot.
The bolt on the back of the compressor may or may not have a flat spot on it to clear the hoses. Mine didn't. I contemplated
using a dremil to make one but I was able to gently bend the hose out of the way, being very careful, knowing full well I could
damage the A/C hose. Attempt at your own risk.

I did remove the accumulator bracket and the belt tensioner as that was the only way I could get enough room to slide the A/C
bracket off of the studs on the water pump. You're going to need a long deep well 9/16ths socket to remove the bolts from the
water pump where the A/C bracket attaches.

Clean all of the gasket surfaces and bolt threads and holes. My 1985 FSM says 25-35 ft.lbs of torque for the bolts. The bottom on
the driver's side is tight. I did use a swivel and didn't feel there would be very much difference in the torque applied. 60 ft.lbs
for the tensioner bolt. The heater hose fitting is 15/16th. You can purchase a new one but it is going to be Corvette specific I
believe. I used my air gun to remove it and applied pipe tape to the threads when I installed it in the new pump. I put the lower
radiator and heater hose on before I tightened the A/C bracket nuts.

That about covers it. I think this is an advanced repair and only you know what your capabilities are.

Here is a video that is the only one I found that covers removal with the type of A/C compressor hose setup that I have. It's a
good video but this Corvette is a "project" and the intro to the channel is interesting in an interesting way. Didn't visit or watch
any other videos.


Hope this helps,

Joe K

Last edited by Joe K; Jul 25, 2022 at 05:35 PM.
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