So the three way tee fitting on the right rear of the intake manifold was seized into the old intake and was broken while trying to remove. Satan no longer can get this fitting i have tried junk yards but have failed to locate one. So I orderd a golden egale vaccum box so i can run a vaccum line from a hose barb at the back of the intake to this box and tee off from there.

I was wondering if any one knows the correct thread pitch and size to this hole. i have also tried to find some bolts about that size but there too big. i have atempted to home depot and lowes but they only cary 1/4 & 1/2 hose barb fittings. any help is appreciated i will be tring some other hardware stores around town.

Thanks Dirk

The Vacuum tree is 3/8" NPT if I recall. Lowes/Depot should stock 3/8 ->hose barb fittings. Otherwise I bought some from McMaster recently.

Dirk,

You need a barb fitting that has a 5/8-18 thread on it. Here is one:

Originally posted by DirtMegirt
Dirk, You need a barb fitting that has a 5/8-18 thread on it.

Negative. How would a vacuum port seal without taper threads & sealant or some form of o-ring/crush washer?

Originally posted by CODE4

Originally posted by DirtMegirt Dirk, You need a barb fitting that has a 5/8-18 thread on it.

Negative. How would a vacuum port seal without taper threads & sealant or some form of o-ring/crush washer?

I am speaking from experience here. I purchased the oem 3-way vac. fitting (I agree Dirk, a bitch to find) and put it where my egr pipe used to attach to the back of the plenum. I drilled the hole out with a 37/64" bit and tapped the hole with a 5/8"-18NF plug tap. The oem fitting came with sealant already on it. Now I have a few extra vac ports at my disposal. No problems yet.

Ok I see what you did.

A 3/8 NPT fitting has a nominal O.D. is 0.670" - 18 threads per inch. Appropriate drill size for tapping a 3/8 NPT hole is 37/64".

Using a 5/8x18 tap would create a non tapered hole with a diameter of 0.625" - close enough for it to work.

I've got a spare 3 way I'd sell ya.

Originally posted by irregular defect
I've got a spare 3 way I'd sell ya.

Thanks but no thanks, it would defeat the purpose of the vacuum box i bought i apreciate it though.

Thanks guys i got that tap and i got the drill bit. so now all i gotta do is remove my upper intake and il drill it out and hope fully put up some pics of it so if some one else comes across it they got some idea on how to fix it.

we will see how well this goes this weekend.

Thanks,
Dirk