question about lower filter bolt (426)

4 replies to this topic
  • gbalias

Posted March 12, 2010 - 01:53 PM


im aware of the ball bearing mod, oil change procedure, etc.

my question is about a note made by Gray about having the hole thats frilled into the threads covered.

gray said:
"It MUST be AT LEAST long enough to completely close off the drain hole that is drilled across the threads, or a loss of oil pressure will result."

is this the reason for the allen bolt to be shouldered? if i were to replace the bolt with a hex head, it HAS to be shouldered correct? not just the full length threaded???

or is it ok to have a fully threaded replacement?

thanks guys! :banana:

  • grayracer513

Posted March 12, 2010 - 03:09 PM


No, the shoulder doesn't intersect the drain port. The threaded portion of the bolt does that, which is why it's so subject to damage from the junk that settles there. Look in the picture below and you'll see the drain hole (arrow). I'm not sure what they had in mind with the shoulder, but I know that the cover aligns better with it than without. When using a Time-Sert, be sure the counterbored hole is cut deep enough to clear the base of the shouldered section of the bolt once the insert is in place.

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  • gbalias

Posted March 12, 2010 - 03:43 PM


ok cool..

my concern was that my shouldered OEM bolt's threads are less than stellar. however, the threads on the cover are fine. (dont ask how this occured...i have no idea. youd think the AL would go before the bolt, but i dont know the history of the biolt either... :banana: )....i just got through doint the whole WP shaft replacement and what not, and i wanted to just replace that bolt with an equal length fully threaded hex head.

if this wont affect the oil pressure, ill run that for the next couple days until i get the ball bearing in there as you did in your fix, gray.

any objections to running a full length thread bolt?

  • grayracer513

Posted March 12, 2010 - 03:48 PM


Not as long as the cover gets lined up right, and the bolt reaches in past the drain hole.

  • gbalias

Posted March 12, 2010 - 04:48 PM


yep. bolt is same length as the allen head, and cover aligned properly.

i dunno why they wouldnt just use a shouldered hex like all the rest of the clutch cover fasteners. ugh. sometimes i wonder what they were thinking.


thanks gray!

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