PorscheDoc

That is correct, you need a fine thread 7/16 (20) bolt, not a 14.

LC MotorSports

And I must make a full appology for that mistake... I went out and checked my stock of hardware and it was 7/16-20... Talk about Egg on my face!

philooo

no worry, one need to learn ... the hard way.
I did not own a set to check thread, now I do
I'll go check ace hardware tomorrow as it seems the blot cost like $50 as an oem part.
I only have one bolt that is pretty badly injured, the other three are decent but I need to clean them up.
today I bought a inch tap and die set, but unfortunately the 7/16x20 die is too small.. the bolt doesn't fit in.

LC MotorSports

How bad are the threads on the OEM bolt damaged? If they just have some dings in them... you can take a thread file and clean them up or if you have a any jewelers files... Take one that is tapered and carefully file the damaged areas (blend into the thread form). I would do this over chasing the thread with a die... these tend to remove much more material then needed and changes the thread class (makes it much looser by thinning out the thread shape).

logray

Why not just go to a hardware store that has a bigger bolt selection. For example there are two ACE hardware stores within about 30 miles of me that have literally every fastener known to man - two massive isles from floor to head height filled with bolts and nuts and stuff. They've even had stuff that Fastenal didn't.

Or order one for about $5 from fastenal?

(assuming yours is the 3.5" long one...)

http://www.fastenal.com/web/products...ex?sku=0172414

99704480019 - 7/16"x90 - $50
90007549402 - 7/16"x45 - $8.76
90007549302 - 7/16"x70 - $8.76

philooo

thanks for the link, but it seems grade 18-8 is not as strong as grade 8 though.

I am going to ace hardware now, we'll see If not fastenal, I'll keep you posted if I find what I need.

My bolts are in pretty good shape but with all the drama about the threads being very fragile on the car, I want to have my bolt as clean as possible to avoid damaging the car threads, which would be a major pain.

logray

At least you will have owned your AB (associates in "boltology") when you are through with this ... LOL.

LC MotorSports

The Grade 18-8 is for Stainless steel fasteners and only has a Tensile strength of 100 - 125 k psi... while grade 8 is for all other materials of fasterners that meet a min of 150 k psi tensile strength (also the yield strengths are much different.... 18-8 ~ 80 k - 90 k psi vs 130k psi).

More advacned course work towards that AB

logray

Here's a grade 9 bolt for $2.53.

http://www.fastenal.com/web/products...l.ex?sku=20853

LC MotorSports

You can use a grade 9 bolt... But, you need to keep in mind as the bolt strength goes up, you also risk potential failure in a different mode. Most of the time the L9 bolts (specialty bolts) are used only in HIGH Load applications where the bolt is subjected to extreme Tensile Loads and not typically high Shear loads.

logray

Tough to please huh?

http://www.fastenal.com/web/products...l.ex?sku=18884

7/16"-20 x 3-1/2" Yellow Zinc Finish SAE J429 Grade 8 Hex Cap Screw

philooo

I went to ace hardware and they do have some choice in grade 8 and they have similar size as what I needed.

they guy at the store thought I was nuts when I was trying each single bolts in that size to make sure the thread was as soft as silk, he came back twice, certainly thinking I was...nuts

Installing this weekend is wife is undertanding.. if not will check back here on monday