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post #1 of (permalink) Old 07-19-2002, 08:29 PM Thread Starter
 
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Spring Center Pins

Ok, can I use a grade 8 bolt for the spring center pin on my rear springs or do I have to get the pin?

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post #2 of (permalink) Old 07-19-2002, 09:58 PM
 
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Re: Spring Center Pins

i think i read an old tech article of shawn spicklers once and he said you could use a bolt, and double nut it, and grind the sides of the nuts to make them roundish..i think he said to do this if your centering pin wasn't long enough or something..might work both ways
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post #3 of (permalink) Old 07-19-2002, 10:53 PM
tjayandlisa
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Re: Spring Center Pins

You are going to want Grade 5 bolts...They have much higher impact strength then grade 8...They are not as brittle

Most spring shops can get you long spring pins that you cut to length...

You have spent this much money and time already... Id get pins...
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post #4 of (permalink) Old 07-20-2002, 03:36 AM
 
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Re: Spring Center Pins

I got an allen head cap screw - I think its called this...had a round head that fits perfectly in the perch
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post #5 of (permalink) Old 07-20-2002, 10:52 PM
 
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Re: Spring Center Pins

Grade 5 bolt do not have a higher shear strength than grade 8.

Shear strenght is normally taken to be about 60% of your tensile yeild strenght (correct me if I'm wrong). The advantage of grade 5 bolts is they will bend before breaking, grade 8 are so brittle they will shear before bending.

IMHO use grade 8 bolts if you can not find AN botls and make sure your u-bolts are torqued tight, and then tight again after driving for a while.

Grade 8 will always be stronger than Grade 5 in a PURE shear application.

Grade 8 is like 130ksi tensile strength
Grade 6 is like 90ksi tensile strength
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post #6 of (permalink) Old 07-21-2002, 12:44 AM
tjayandlisa
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Re: Spring Center Pins

Yes you are correct the actual shear strength is stronger in numbers on a grade 8...Im sorry maybe worded it wrong "impact strength" is what I was refering to ....Here is where to be cautious...High strength steels are heat treated in order to get the higher strength, and this correlates to hardness. Hardness in turn correlates to brittleness...IMHO I would go with grade 5 for they give(bend)more, instead of breaking...In a clamping type situation a grade 8 is much stronger...And I agree with beaterchevy the key to any bolt is to be torqed correctly
post #7 of (permalink) Old 07-21-2002, 07:14 AM
 
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Re: Spring Center Pins

Yep, allen head cap screws are what they are called. They are all grade 8. I used them in my rear spring packs and have had no troubles at all with them. The head of the cap screw fits the hole in the axle nicely. With all the clamping force being exerted on them, I wouldnt worry too much about having one break.
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post #8 of (permalink) Old 07-21-2002, 11:26 AM
 
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Re: Spring Center Pins

FYI allen head cap screws should be a bit stronger than regular grade 8 bolts. I'd use them for sure.
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post #9 of (permalink) Old 07-22-2002, 06:18 PM
tjayandlisa
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Re: Spring Center Pins

I through a quick email to bds suspension and one to alcan spring to see what they use here is what they had to say:

-----Original Message-----
From: Tjayandlisa [mailto:[email protected]]
Sent: Sunday, July 21, 2002 2:12 PM
To: [email protected]
Subject: Rear spring pin



I need to replace the center pin in the rear leaf spring, can you tell me what is the best grade bolt to use? I have herd mixed opions about grade 8 bolts being to brittle, because of the hardening process? Which do you use? Thank you very much... Tjay



Tjay

You may find this hard to believe, but ours and Original Equipment and almost everyone in the spring business uses grade 2 center pins. You won’t be able to find a grade 5 or 8 anywhere. The softer metal is used so if there is a problem the center pin will stretch a lot before breaking.

Thanks

Posie

BDS



Visit BDS on the internet at www.bds-suspension.com


Alcan spring said:


Tjay The center pin is just for locating the spring and the axle at the right point , after that the u-bolts take over . Weather you use a grade 8 or grade 2 if the U-bolts are not tight you will shear center bolts .
Charles


Hope this helps ya out....
post #10 of (permalink) Old 07-22-2002, 06:45 PM Thread Starter
 
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Re: Spring Center Pins

Ok then, I'll either go with a allen head cap screw or an actual center pin. Now for the next question. As far as the clamps, can I just buy some 1/8"x3/4" steel and bend it and make my own and then just run a bolt through the top? Possibly? Maybe?

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