Water pump bolts
Instructor
Joined: Jan 2014
Posts: 128
Likes: 3
Had to take one bolt off from the right hand side of the water pump last night to mount the smog pump bracket for my 69 L71. It was 3/8" x 1.75" with TR head mark.
I measured it with a metric caliper in mm as per photos. With the smog pump bracket over the water pump, 1.75" bolt is just a touch too short with barely 2 threads engaged. That's why I measured it.
I measured it with a metric caliper in mm as per photos. With the smog pump bracket over the water pump, 1.75" bolt is just a touch too short with barely 2 threads engaged. That's why I measured it.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
I believe that all the bolts are 3/8"-16. Measure the depth of all the holes and size bolts so that they are at least 1/8" shorter than the hole depths. It's also a good idea to put a little sealant on the bottom few threads of each bolt to get a leak-free pump assembly.
Thread Starter
Melting Slicks
Joined: May 2006
Posts: 3,438
Likes: 41
From: Raleigh NC
St. Jude Donor '13-'14
I believe that all the bolts are 3/8"-16. Measure the depth of all the holes and size bolts so that they are at least 1/8" shorter than the hole depths. It's also a good idea to put a little sealant on the bottom few threads of each bolt to get a leak-free pump assembly.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Just stick an ice pick into the hole and mark the top of the hole with your thumbnail. Then measure that length. Close enough.
Every car will be different due to casting differences, tap wear, etc, etc.
If your bolts have thread engagement that is more than 2 times the bolt diameter (3/4" plus pump casting flange thickness), they are long enough. But, longer is always better...unless they are TOO long.
Every car will be different due to casting differences, tap wear, etc, etc.
If your bolts have thread engagement that is more than 2 times the bolt diameter (3/4" plus pump casting flange thickness), they are long enough. But, longer is always better...unless they are TOO long.
