Kuhan

iTrader: (17)

Not sure if I want to get the hats anodized since the fronts are aluminum and the rears are steel.

As far as the hardware, I am getting new steel washers and allen socket bolts. But I will use the pins since I don't even know where to get them. Unless someone can help me out.

My plan is to clean the surface between the rotors and hats and around the bolts. Also I will torque all the bolts to 10 ft-lbs and use wicking Loctite (type 290).
And after a 100 miles, I will re-torque all the bolts again.

If everything fails, I have no choice to buy new rotors and hats.

Thanks for all the help so far.

lgear080

iTrader: (21)

Trust me. Strip and anodize the Fronts.

Take the rear hat to a machine shop and get a quote
For aluminum replacements.

Do this right the first time and you'll never worry.

Every other path will not yield optimal results.
Every other path also costs more in the long run.

This coming from one of the few with legit experience
In a high end debacle.

Kuhan

iTrader: (17)

This is possible?

Chris_B

If you use Loctite 290, you will not be re-torquing them -- nor would you want to. Get it right the first time and then leave them alone. If you over-torque them, they will break the first time they see real heat. Aluminum will expand more than steel with temperature, which will overstretch the bolts. This can be a big problem, especially with the fully threaded screws in that picture you posted.

And, it is best to use reasonably high strength steel bolts on brake hats, not the lower strength and hardness stainless fasteners.

Chris

lgear080

iTrader: (21)

Khu - thats Why god made mAchine shops. Just make sure the
Aluminum grade is identical. You're looking at $500-$1000 ballpark
...

But it'll be done right. If you were down here we'd help.

Kuhan

iTrader: (17)

Thanks for the tip. Then I won't use loctite. I bought class 12.9 alloy steel zinc-plated bolts and washers. Those should do job, correct?

I'll play safe and torque them to 8 ft-lbs. And then at 100 miles or so, I'll check the bolts again.

Sorry man. I'm just a noob. I never thought about that.
But for that price, I might as well get new hats.

I already requested a quote for new rotors and hats to Z1 Performance.



I also bought this Craftsman torque wrench today at local Sears store.
Torque range: 25-250 in-lbs.
Craftsman Microtork® Torque Wrench, 25-250 in. lbs., 3/8 in. Drive

Chris_B

I prefer 8.8 due to their higher toughness (less brittle), but 12.9 should work fine unless you are building an F1 car!

Chris

Kuhan

iTrader: (17)

I thought class 12.9 steel has higher strength? That's why I bought class 12.9 instead of class 8.8 or 10.9.

http://www.boltdepot.com/fastener-in...ade-chart.aspx

Kuhan

iTrader: (17)

Recommended Torque (N*m)
Diameter(mm) Class 8.8 Class 10.9 Class 12.9
5 --------------7 ---------- 9 -------------11?
6 --------------12----------16
8---------------30 -------- 40
10 -------------55 ---------75
12 -------------100---------135
14 -------------160---------215
16 -------------245---------335
20 -------------480---------650

9-11 N-M => 80 - 100 in-lbs => 6 - 8 ft-lbs.

So torquing these class 12.9 zinc-plated alloy steel bolts to 8 ft-lbs should work.

http://www.boltdepot.com/fastener-in...ed-Torque.aspx

Chris_B

Strength and toughness are inversely proportional (generally). Stronger bolts are more brittle -- they yield at a higher percentage of their ultimate tensile strength. In other words, they will take a higher load, but will fail catastrophically as opposed to slightly yielding. Many times stronger is better, but not always.

Chris

Chris_B

Do NOT use maximum recommended torque values that the bolt manufacturers provide! Only use what is recommended by the particular brake manufacturer. Sometimes they may be the same, but most often rotor hat hardware needs to be torqued at a slightly lower value to allow for thermal growth. Generic bolt specifications do not take expansion into account. I've seen this error made many times and, if lucky, it only resulted in a few ruined parts. The more unlucky ones got to choose their next track car.

Chris

Kuhan

iTrader: (17)

Thanks a lot, Chris B!

Since I'm not getting any help from Endless Usa regarding recommended torque.
Is it safe for me to use Stoptech recommended torque of their 2 piece rotors of 6 ft-lbs?

Chris_B

You should really get the info from them, but I use the recommended 62 lb-in (5.2 lb-ft) for 5mm fasteners on AP Racing and Brembo discs.

Chris

plumpzz

iTrader: (10)

yes. many shops even sell their own rear 2 piece in aluminium hats. check out arizonazcar.com for example. their website sucks but dave knows his ****.

lgear080

iTrader: (21)

try to get a price from a machinist or dave @ arizona.... does endless sell an alum
rear hat.

take your time... mine took only 14 mos or so

Kuhan

iTrader: (17)

I finally got a reply from Endless Usa.

Conversion:
1.3KGF-M = 12.75 N-m = 113 in-lbs = 9.4 ft-lbs

So if I torque each bolt to 113 in-lbs, then what does this mean?

Kwame

iTrader: (78)

Kuhan, I got your PM and I will send you a reply shortly.