harmonic balancer bolt size ... help!

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Nov 21, 2019 | 10:59 AM

xtal_01

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harmonic balancer bolt size ... help!

So, I am trying to use my only good day (already had 12" of snow here in VT) to put the engine back into my 1986 F-150

Before I do, I am putting in new timing gears, oil pump and gasket set.

The bolts on the harmonic balancer are completely rusted over (what can I expect for 33 years old).

I can't figure out what size they are? I have taps and can run one down it if I know the size.

The puller comes with coarse and fine bolts. I "almost" got a 5/16 - 18 started (I think that is what it was) but I didn't want to force it till I knew for sure want size.

Thanks ..... Mike

Nov 21, 2019 | 11:35 AM

xtal_01

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got it ... cleaned the hole with a dremel till I could see the threads ... 3/8 - 16

Nov 21, 2019 | 11:35 AM

FuzzFace2

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From: Angier, NC

You have the old bolts you pulled out?
If so take 1 and a tap, lay them together and see if the thread pitch is the same.
That is what do with my metric set, my SAE set has a thread pitch Guage I use.
Dave ----

Nov 21, 2019 | 01:31 PM

xtal_01

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Sorry, maybe didn't explain well ... running in and out of the house ... I have a puller but didn't know what size the bolts are that go from the puller to the balancer.

Looks like I need a new balancer anyway.

The rubber is rotted ... all cracked. I almost left it but I can actually see where the rubber is pushing out from between the two.

Thanks ... Mike

Nov 21, 2019 | 04:03 PM

FuzzFace2

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From: Angier, NC

Quote:

Originally Posted by xtal_01

No I understood.
You use the tap as a thread gauge on the bolt that came out.
If the threads on the tap fall into the threads on the bolt they are the same pitch.
Then all you need to do is find the size but I am pretty sure if the threads don't fit the size will be wrong.

Dave ----

Nov 21, 2019 | 05:08 PM

xtal_01

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The problem was, these three holes don't have bolts in them. They are only there for pulling.

They are empty and thus full of rust after 33 years.

I could only just start a bolt into them. I didn't want to try forcing a metric or fine thread bolt into a hole with UNC threads (or vice versa).

I finally just made the assumption they had to be UNC threads and put a tap into them .... it went in easy so I know I must be right and not trying to re-tap the hole.

Thanks .... Mike