RKnight

Dave Z. ,I have read the tech paper from StopTech that explains how there is really no such thing as a warped rotor. Is there ever a real reason to turn a rotor or is it just a money maker for auto shops?

DZeckhausen

If you're experiencing a judder problem that won't go away with repeated bedding attempts (see: http://www.zeckhausen.com/bedding_in_brakes.htm), then you might try having the rotors turned to remove whatever excess, uneven pad deposits are causing the symptoms.

It's still a judgement call. Depending on the car, new rotors can be inexpensive. So if the rotors giving you trouble have less than 50% of their remaining life, it may be a better idea to grab a replacement set from Tire Rack or some other discount vendor. (Not eBay, since branded rotors there are often counterfeit and unbranded rotors are virtually always from boutique foundaries in Mainland China with no process control and are of poor quality.)

There is no compelling reason to turn rotors when changing pads if the car does not have any judder problems under braking. Many shops just do it anyway and it's a total waste of time, money, and iron.

HokieZ

iTrader: (1)

Exactly what he said. Shops make a killing doing unnecessary work.

Huh, small world, my wife grew up in Maplewood, very close to the Maplewood Country Club.

Wired 24/7

iTrader: (2)

Even if you change the rear rotor, you won't be affecting the e-brake.

kardan350z

Is there any chance of damaging the Master Cylinder when you compress the piston on the calipers? Is it better to open bleeders, compress, then bleed?

SS350Z

I think there is minimal chance of damage. You might want to open the resevoir and possibly remove some fluid prior to compressing the piston, so the fluid doesn't overflow, or build up pressure.

DZeckhausen

It's always a good idea to open the bleed screw when retracting the caliper pistons for exactly the reason you surmised.

The brake fluid in the calipers is the most stressed, moisture saturated, heat cycled fluid in the system and may even contain rust particles if the calipers are cast iron. Sending all that crap back to the master cylinder is not a good idea. If someone has topped off the brake fluid reservoir recently, you may even overflow the reservoir when pushing the piston back in. Fluid can spray out the vent hole and make a mess under your hood. Remember, brake fluid dissolves paint. Finally, it is easier to push the piston into the caliper when the bleed screw is open and fluid is allowed to escape into a catch bottle. You're not fighting fluid pressure in the system. Thus, you are less likely to damage the caliper piston bore when retracting the piston, since you'll be using less force.

I always bleed the brakes when changing pads, since it takes so little extra effort. The wheel's already off and you're right there. Why not just do a complete job?

MyZ4U2C

I did this change today and it was super easy!! Took about 45 minutes per wheel and most of the time was jacking up the car and taking the lugs off and reassymbly. Do this yourself...a very easy job and great instructions!!!

DZeckhausen

Don't forget to bed the brakes: http://www.zeckhausen.com/bedding_in_brakes.htm

HokieZ

iTrader: (1)

Excellent point. I'm going to do the brakes on the G within the next few weeks and will add this to the list and incorporate it in the write-up. I don't need to as I have only 1400 miles but as you said, why not?

1badv

bump

SS350Z

What is the process for bleeding the brakes? In general, I know the procedure, but specifics would be helpful, along with any tricks.

Wired 24/7

iTrader: (2)

The smallest bolt on your brake caliper is the bleeder valve.

You hook up a tube to it, and the tube should drain into a container (bag, jug, etc).

Have one person sit in the drivers seat, and pump the brake pedal HARD 3 times, then hold. This person should say something like "holding".

Then the person at the brake caliper loosens the bolt until fluid starts to flow, then closes the valve quickly.

Repeat this process until no more air comes out of the lines. You can bang the caliper with a rubber mallet a little bit to release any trapped bubbles.

Start from rear right, then rear left, then front right, then front left.

Happy bleeding!

-Mike (again thanks Chebosto for all his help with the stoptech stage 2 kit)

rodH

iTrader: (2)

why isn't this a STICKY????

DavesZ#3

iTrader: (26)

It was at one time. Not sure why it got un-stuck but it's back to Sticky again.

goshdarnitsa

I got my 7500 mile service today and they checked my break pads to see how much of it was left. I have 7mm left on the front ones and 5mm on the back ones. Shouldn't my front ones wear out faster than my back break pads? And the service lady told me that 350Z uses rear breaks more for stopping from high rate of speed and stop-and-go's. Then why do I get more break dust on front wheels than I do on the back ones? Thanks for your help. And this is a great thread!!

HokieZ

iTrader: (1)

That is strange. The only logical reason I could think of is that the back pads are smaller, but they are doing less of the work unless Nissan has dialed in some pretty severe rear brake bias which would just be unsafe (think rear of the car swapping ends with the front when you brake hard).

My fronts definitely wore faster than the rears.

DZeckhausen

That depends. On the 350Z (non-track) the rear brake pads are the size of postage stamps. With such a small pad, it's no surprise they wear out so quickly.

She's making stuff up. Under heavy braking, there's much more forward weight transfer and the front brakes do even more of the overall total of braking. Under light braking, the fronts still do the lion's share, but as a percentage, the rears do more than they would under heavy braking.

For example (and these numbers are totally made up - just to make my point) your front brakes might be doing 90 percent of the total work under heavy braking, but just 75 percent of the total work during gentle braking. Under gentle braking, there's less forward weight transfer, thus there's enough weight on the rear wheels for them to contribute a more significant portion of the overall braking. But under heavy braking, when the car is practically standing on its nose, the rear wheels have far less weight on them, and too much rear braking would result in premature rear wheel lockup.

This article on proportioning helps explain how car makers design rear brakes that can contribute more (as a percentage) during light braking than they can under heavy braking: http://stoptech.com/tech_info/wp_pro...g_valves.shtml

mikeg8r

iTrader: (2)

First off excellent How-to HokieZ. Thanks to you and your write-up I was able to change my brake pads with no problems.

I also wanted to add a few tips of my own:

According to my '05 service manual, for the front calipers you remove the lower bolt, in the rear you remove the upper bolt.

Here's a pic with my custom caliper hanger:

If you can't tell from the pic, it's just a wire hanger.

Also having one of these is very handy:

I picked one up from sears for $10.

Here's a pic of it in action:

#1 is an old brake pad, #2 is the spreader's backing plate, #3 is the caliper body.

This is the only thing I was confused about. I bought some brake quiet and used it on the inner shim cover like so:

Hopefully it is the right place for it.

Also according to my manual to specs for torquing down the sliding pin bolts are:

Front calipers: 17-22 ft-lbs
Rear calipers: 28-36 ft-lbs

basam350z

iTrader: (1)

Do I have to bleed all four if I am only changing the front pads?