rwstegne

Guys, purchased all my parts and am ready to start my front brake swap. Just had one more question concerning bolting the bracket to the spindle. Which method is better:

1. Bigbrakeupgrade.com - http://www.bigbrakeupgrade.com/LS1BracketInstall.pdf

or

2. http://lukeskaff.com/?page_id=396

The difference is bigbrakeupgrade takes and bolts the bottom of the bracket from the backside of the spindle. Wondering which method is better/stronger.

87350IROC

iTrader: (2)

For this application, given design freedom I would choose the running the fastener backwards through the back of the spindle and into the bracket. One of the bigger design issues with adapting LS1 brakes on the spindles is that the bracket is a somewhat awkward design. By running the fastener backward you eliminate the issue of the lower bolt head contacting the LS1 caliper. I am sure that is why the fastener was reversed to begin with. I am just about certain that the lower bolt on your second picture would contact that caliper. People don't realize this until they go to actually bolt the caliper on. This usually ends in in folks using a structurally insufficient button head fastener, shaving down another fastener head, grinding on the caliper, or shimming the caliper out from the bracket to clear.

Regarding which one is stronger. Well just like everything else, it depends. Strictly from geometry it does not matter the direction of the fasteners. The difference comes in the load bearing of the threads of the tapped hole. If you tap the spindle you will get more threads than if you tap the bracket However the spindles are made of iron which is weaker than steel. So the threads you have aren't as strong. Overall I would say your advantage is to tap the bracket as long as it is of decent steel and of at least reasonable thickness (3/8"). I use stainless in brackets and it taps hard and beautifully. I use 7/16" fasteners for assembling my Wilwood kit. And I have performed this exact test. I tapped the ear of the spindle (~3/4" thick) and a 3/8" section of 304 stainless with the same 7/16-20 deep 75% threads. Then I torqued the same fastener to double the torque spec (150 ft-lbs).

The iron threads held this 2 times. The first time was pretty clean with only minor powdering of the iron threads. The second time the threads were basically destroyed and only held the torque because the threads jammed. It was not a successful cycle. Once I got the fastener out, the threads were almost completely gone.

By comparison the SS threads held the torque 10 times with no visible damage to the thread or the fastener. And that is where I gave up. It was a successful test.

Another thing to consider when running the fastener backwards. The back side of the spindle is not a flat surface for the head of the fastener to sit on. It needs to be machined flat. A counterbore would work well in this situation.

Finally it may be obvious but I have seen people do some crazy stuff. If you run the fastener backwards, remember you need to drill a through hole in the spindle. I have seen folks thread both the spindle and bracket.

John

ghettocruiser

iTrader: (4)

I cant remember exactly what hits that lower bolt... but I know the clearance is tight to something. Probably the caliper. I wouldnt put them both on the same direction just to use safety wire.

I like the way BBU does it, and I thought it was the common or accepted way of bolting the bracket on. I got a set from BBU in 2006ish and they've been awesome. Still on the car. And Ive had them apart a few times. I use a little heat on the bolts to loosen up the red loctite, then I just clean the threads carefully and thoroughly and re-apply some red loctite on assembly.

Never an issue, never wished I safety wired them. Not saying its bad to safety wire, just saying I havent seen the need.

J.

rwstegne

Thanks guys