Fuel Tank Selector Valve mounting bolt size

[SilveradoDude]

I am trying to swap out the Fuel Tank Selector Valve on my 85 Silverado and I cannot seem to get the size of the bolt heads. They are in an unbelievably hard to get to place between the frame and the cab (Thanks GM!!), It seems to be larger than a 7/16 inch but smaller than a half inch. Any ideas on the size and how to get these things out?? Any assistance is appreciated.

[sweetk30]

1/2" hex for the socket / wrench size . bolt has american grading markings on it not metric .
5/16" x 18 fine thread just under 1" full length but pointed end with 3/4 threads usable . has a built in cone shaped locking teeth edge flat washer with a o.d. of about 3/4" that cant be removed from the bolt .

i have 2 switcher valve here in the shop . the bolt threads in both the 83 and 87 c-10 trucks . 83 was 6.2 diesel 87 was tbi 305 gas . both switcher valves have captured nuts of threaded body's on them .

i love ratchet wrenches for tight areas .

[SilveradoDude]

Originally Posted by sweetk30

1/2" hex for the socket / wrench size . bolt has american grading markings on it not metric .
5/16" x 18 fine thread just under 1" full length but pointed end with 3/4 threads usable . has a built in cone shaped locking teeth edge flat washer with a o.d. of about 3/4" that cant be removed from the bolt .

i have 2 switcher valve here in the shop . the bolt threads in both the 83 and 87 c-10 trucks . 83 was 6.2 diesel 87 was tbi 305 gas . both switcher valves have captured nuts of threaded body's on them .

i love ratchet wrenches for tight areas .

wow thanks!!! I sometimes use a 13mm for 1/2" bolts like this but it seems way loose any ideas? I also would use a ratchet wrench but at the ones i have in 1/2 are straight I think I need more of an angle....

[Nickelcharlie]

I just finished doing mine and this is the wrench, I used, a 1/2 Snap On. Finally found something I could use this wrench on! The only wrench that I had that I could get in there with. The bolts are a PIA to remove! I also had the bed off. I have done it both ways bed on and bed off and for me it is much easier with the bed off.

With this wrench it didn't take but just a few minutes to remove the bolts. Replacing the valve I got my wife to start the bolts on top while I held the valve from the bottom. Works fairly easy this way.

[sweetk30]

not to be the mean guy here but i di it this way . no body on at all .

[100%Chevy]

Having removed a bunch of those valves,I don't see how anyone can get a box end wrench on the bolt heads!You might break it loose,but you will have to go to an open end to finish!
You can bend the valve down a little for more room.But still plan about 30 minutes per bolt!
I won't tell my trick to get them back in!
Mike.

[gmachinz]

Originally Posted by sweetk30

not to be the mean guy here but i di it this way . no body on at all .

I love the new “see-thru” sheetmetal offered for these squares now! Guess I gotta start wearing pants now when I wanna hit a drive thru early in the morning huh?

[sweetk30]

Originally Posted by gmachinz

I love the new “see-thru” sheetmetal offered for these squares now! Guess I gotta start wearing pants now when I wanna hit a drive thru early in the morning huh?

just dont sit on the shifter handle

and no they dont offer it . i fixed the problem and put the body on .