| Flex plate bolts [message #330253] |
Fri, 23 March 2018 17:17  |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma:
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Senior Member |
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So, a looong while back the following exchange was part of a "knocking noise" thread. Jim Hupy told me the bolts could be too long on the flexplate, and I finally went in there to check today and voila! Threaded to the head, and marks like it bottomed in the converter lug. I am hopeful.
Now, what is the right bolt?
Does the shoulder part really matter, or can I just add a lock washer to this one I have to shorten it up?
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Tyler, the noise a loose flexplate makes sounds like a broken crankshaft.
Heavy knocking. Diagnose by removing the starter, then the sheet metal
shield. This exposes the attachment bolts. Turn engine by the large nut on
the fan end of the crankshaft, and check the dampener while you are there.
They can mimic this noise. Turn crank until torque converter bolt is
exposed. Remove one and carefully inspect it. It should NOT BE THREADED
upon its full length. The correct bolts will have a large shouldered head,
and the upper portion will have a precision shoulder that is slightly
shorter than the thickness of the flexplate. Check also that the bolts DO
NOT bottom in the converter lug. Look carefully for any signs of bottoming.
Use a strong light source and look in the hole in the torque converter lug.
If it is shiny in the bottom of the hole, the bolts are bottoming before
the flexplate is tightly against the lugs. It will knock like mad if you
find this condition.
Jim Hupy ( aka. the taller brother)
Salem, Oregon
On May 5, 2015 10:39 AM, "Tyler" wrote:
> Asking more on the whole thread, and specifically Dwayne's comment about
> flex plates:
>
> I took my coach to an experienced truck mechanic friend just last week for
> a noise that only happens after driving coach to full operating temp, then
> turning it off, and then restart it from two to maybe twelve minutes later
> (hot restart).
>
> He said he had only ever heard a noise like that one time, a guy had a
> Buick that they eventually found a cracked flexplate.
>
> So, if this is a correct direction for me - does the hot re-start tell me
> anything? And can I see potential cracks or loose bolts from an access panel
> or anything, or is tearing it down the only way to know? I have debated an
> engine oil analysis to learn more engine internal scenario, but then this
> thread came up!
>
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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