Brake upgrade

[TomoHawk]

Originally posted by Bambikiller240

... I would assume that anyone considering doing this job had a certain level of mechanical competance and understanding as to what was needed and why. It is really just common sense where to put the spacer. Same reason I wouldn't bother to explain how to bleed the brakes after the install.

I put a bandaid on my brakes the last time they were bleeding.

It makes no difference how competent you are, when you inquire where to put the spacer in question. According to your statement, you would assume one also knows the thickness of the spacer, which is impossible to determine without either trying it yourself, or asking someone else.

Have you considered that the caliper might interfere with the wheel, regardless of the backspacing, just because it extends past the face of the rotor?

That makes 3 reasons to use the spacer. In that case, An explanation of bleeding the brakes is irrelevent to the reason for having the spacer, and would also be covered in any general service text, so I personally wouldn't bother asking about that.

Chill out, man.

[Bambikiller240]

Originally posted by TomoHawk

It makes no difference how competent you are, when you inquire where to put the spacer in question.

Au Contrare. A little thought on the subject goes a long way to answering questions like this.

Originally posted by TomoHawk

According to your statement, you would assume one also knows the thickness of the spacer, which is impossible to determine without either trying it yourself, or asking someone else.

No, not true. I WOULD (if I were the author) post the thickness that *I* used , though the thickness required is easily measured when one installs them on their own car. (see below)

Originally posted by TomoHawk

Have you considered that the caliper might interfere with the wheel, regardless of the backspacing, just because it extends past the face of the rotor?

Yes I have, but spacer needed to correct for this will vary based on the offset of the wheels on YOUR car. Impossible for the author to tell the world in general, and would NOT be corrected by the same spacer that would center the rotor within the caliper. If you have a problem with the Wheel hitting the caliper, you would need a different spacer between the wheel and the hub to correct that. Again common sense.

Understand it's not like these instructions are for a comprehensive kit PURCHASED from the author, IMO it is unreasonable to expect, and impossible for the author to hold someone's hand though the entire process. They have no obligation to do so, and have no idea of the size of wheels on anyones car but their own. They are doing a service to the community by posting ANYTHING on the subject.

Originally posted by TomoHawk

Chill out, man.

Dude, I'm chilled, you are the one who should relax.. I just gave you an explanation. I also asked you to not take offense at the statement as none was meant. Guess you don't read BOLD very well

[71_240Z]

my spacer needs to be about 5/8" to make my 300zx vented rotors line up with the caliper. I put 6 washers on each bolt to create the space between the hub and the rotor. This setup doesn't seem safe to me. ]!!!!!![

] = hub

[ = rotor

! = washer

the washers are hardened steel and the bolts are #8's, but something about this setup makes me uncomfortable.

What is wrong with using washers as spacers? I have visions of bolts shearing and my rotors free wheeling while I wrap my car around a tree.

I talked to a machine shop today that can make the spacer that I need, but I am still uncomfortable with this set up.

The rotor does not touch the hub axle when the spacer is in place. There is about 1/8" gap. When the rotor is not very snug against the hub axle, the four bolts that hold the rotor to the hub are subject to intense sheering forces. Normally when you apply the brakes, all the forward force is applied to the hub due to the fact that the big hole in the rotor is machined to fit exactly on the hub. When the spacer is in place and the rotor hole is bigger than the hub axle, all braking force is borne by the four little bolts. That scares me to death.

These bolts can only withstand a few thousand pounds of sheering force. I don't know how much a 240z weighs, but the force = mass X decelleration. The faster you slow down, the more force is applied to those bolts. Even at 1g, I'll bet you exceed the sheering force ratings of these bolts.

I haven't seen anyone mention it before, but has anyone had any bolts break with this set up?

My solution is to machine a thin ring to put around the hub axle so that the inside diameter of my rotor contacts the hub. This takes all the force off the bolts and transfers it to the hub axle as the engineers originally intended. Without that ring, it is my humble opinion, that you are driving a death trap.