xthejokerx

iTrader: (1)

Im changing out my brake pads and rotors and was wondering if bleeding the brake calipers is necessary?

terrasmak

iTrader: (8)

Probably, it sure doesn't hurt to have fresh fluid

xthejokerx

iTrader: (1)

oh ok.

at what mileage interval should i replace all of my brake fluid? since this is the first time my car's changing its brake system (30k), i will just bleed it and top off fluid instead of replacing all the fluid... sound ok?

xthejokerx

iTrader: (1)

to add to my above post, i'm only switching out brake pads and rotors. do i still need to reflush the entire brake fluid?

Buster-here

If you are careful and don't let any air into the system you can replace rotors and pads without bleeding the brakes. Remember that if the new rotors are slightly thicker and the pads are also thicker then the pistons will have to pushed back into the caliper and the brake fluid level will go up at the master cylinder.

Bleeding the brakes is so easy and cheap that I don't skimp in this area.
For normal use I would totally replace about every 2 years. Because I track the 350z a few times a year and use race fluid (which is even more hygroscopic) I put a new upopened 250ml bottle into the brake system before each meet, so over the course of a year the entire contents are totally replaced. Not hard to do while I'm changing the wheels over anyway.

terrasmak

iTrader: (8)

30k i would do a full flush, 30k or every 2 years on a normally driven car is good. My car, i bleed after every track event, and probably replace the fluid after every 3 track weekends.

DavesZ#3

iTrader: (26)

^^^ pretty much what he said. I bleed prior to every track day and do a total flush every 6 months to a year depending on how many track days.

Chris_B

If you're not tracking the car, a fluid flush is required every two years (at least) regardless of mileage. Over time, moisture gets in through the rubber lines and the master cylinder cap, lowering the fluid's boiling point and increasing the chances of internal component corrosion. If you have good quality stainless steel braided lines, moisture ingress is greatly reduced.

As mentioned by others, cars that spend time on the track need much more attention to brake fluid service.

Chris

xthejokerx

iTrader: (1)

Thanks... What about the stock brake lines and calipers? Do they need to be replaced? I've got about 30k on the car.

terrasmak

iTrader: (8)

Not at all, lines are good for 10+ years under normal conditions and calipers are too.

Chris_B

Calipers should last a very long time unless they are abused.

Rubber lines will decay over time. The most common mode of failure is internal collapse, where the fluid pressure is relieved slowly rather than quickly once the pedal is let go. This will give the same symptoms of a sticking caliper piston, but won't go away once the caliper is changed. The other (much less common) is rupture. I have changed every vehicle I've ever owned over to stainless steel lines (that is, if I could find them!). I just can't stand that mushy pedal feel that rubber lines have. Good SS lines are 99% stiffer, which can be immediately felt.

Chris

xthejokerx

iTrader: (1)

Thanks.

So what im gonna do is inspect my rotors when i take off my brake pads, and if theres substantial damage, then i will replace rotors as well.

So to flush the brake system, i just use the turkey baster at the brake reservoir and suck up all the fluid, and then pour in new brake fluid, making sure not to overflow the reservoir.

Then i head down to the brake caliper (starting from the one furthest from master cylinder), and i bleed it. To bleed, i let my partner step on the brake pedal, and i unscrew the bleeder screw. At this time, fluid will squirt out. I quickly tighten the bleeder screw. I repeat this until i see new brake fluid squirting out.. Then i go back up to brake reservoir and refill with new brake fluid. Then i move on to the 2nd caliper and repeat until all 4 calipers have been bled.

Is this correct?

prfectz

Unless you want or need to replace the fluid, you won't have to bleed them if your just installing rotors and pads. Assuming you do the job properly of course and don't disconnect or damage the brake lines or bleeder cap.

Since it looks like you are gonna bleed them anyway, I would get one of those kits that comes with the plastic hose and cup that you attach to the bleeder so you can monitor the air bubbles coming out of the system. It is a nice tool to use but not required. Sears has a couple kinds, just get the cheapest one.

Your description of bleeding is pretty much dead on, as it isn't rocket science. Make sure your friend pumps the brake pedal until he feels a lot of resistance before bleeding for best results. This may take ~10-20 pumps for the rears and only a few pumps for the fronts. The Z is actually fairly easy and quick to bleed this way compared to some other cars for some reason.

xthejokerx

iTrader: (1)

^^ can you tell me what the plastic hose + cup at sears is called?

prfectz

I can't remember the exact model I used, but there are many options, see below:

http://www.sears.com/shc/s/search_10...=brake+bleeder

I you are going to be doing the brake pump method with a friend, then you basically just need a clear hose and cup with a bleeder adapter. Whoever is monitoring the fluid coming out of the bleeder just needs to check that the hose is free of air bubbles before moving on to the next one. This one would probably be ok:

http://auto.sears.com/automotivepart...&blockType=G11

Some come with guns or something similar to replace pumping the brakes, but they aren't really worth it and are painful to use (literally!). If you are going to spend that kind of money on a cheap gun you might as well buy the mityvac and drink beer while it does the work for you.

Make sure you pick up some pb blaster while you are there (if you don't have some already). This is an absolute lifesaver if your rotor is fused to your hub, as it will save you from hours of banging your rotor with a mallet to get it off (don't ask how I know this). Spray it in the spots where your hub and rotor meet and wait ~30 minutes for it to work, as it will eat away whatever is holding the two together. Be careful not to get the fluid on anything non-metallic or painted as it is very corrosive and damaging to most other things. Only the caliper holds the rotor to the hub, so once that is off the rotor should come off easily if it isn't fused on.

Feel free to ask more questions if you want. I just installed rotors, pads, and SS lines a couple weeks ago and everything is fresh in my mind...for now that is (stupid memory!)

plumpzz

iTrader: (10)

Why do you guys flush the fluid after every track day? Ive been using endless race brake and that ***** been solid for a full year.

I switched to it from motul rbf600 and its definately worth it.

Chris_B

It's precautionary. When the fluid gets hot enough, it can offgas a bit before it starts to boil. This may or may not leave the pedal a little bit spongy, but it will lower the boiling point for the next time out. If the caliper temps aren't getting very high, it is nothing to worry about. Each track and each driver is different, so the rule of thumb doesn't cover everyone. The safe bet is to do a quick flush using enough fluid to at least displace what is in the caliper. Normally, one 500mL bottle is enough.

Chris

xthejokerx

iTrader: (1)

Wow good info here, thx. After only a day of searching around the thread and asking questions, i've gone from being completely foreign to the brake system to now understanding about half of it... I feel about 90% confident in doing my first brake pad+rotor change now!

More questions:

When bleeding, how do i know when air stops coming out? I mean i can't see air…

Is the master cylinder the same as reservoir tank under the hood?

Last question… Guide says not to let reservoir tank run dry. When i'm using the turkey baster to suck up fluid from the reservoir tank, aren't I doing it until all the fluid in the tank is empty, which means dry?

prfectz

When bleeding, how do i know when air stops coming out? I mean i can't see air…

- the entire point of the plastic tube & cup kit is to monitor the air bubbles in the clear tube as the fluid leaves the bleeder. No air bubbles = no air!!

Is the master cylinder the same as reservoir tank under the hood?

- I am not sure I fully understand what you are asking here. The reservoir is just a plastic tank that is there to allow you to easily add more fluid to the system as well as visually check the fluid level. The master cylinder converts non-hydraulic pressure (pressing the brake) into hydraulic pressure which in turn extends your brake pistons (slave cylinders) into your pads, compressing them onto the rotor.

Guide says not to let reservoir tank run dry. When i'm using the turkey baster to suck up fluid from the reservoir tank, aren't I doing it until all the fluid in the tank is empty, which means dry?

- You don't need to suck out any fluid from the reservoir before starting. Just add some new fluid and begin your pumping the brakes/bleeding cycles. Simply add more fluid to the reservoir as it begins to dip below the low limit. In the beginning you don't have to worry about filling the reservoir too much since you will be bleeding it out within a few minutes anyway. Just make sure the fluid level is between the max and min lines when you are done.

xthejokerx

iTrader: (1)

^^ so sometimes when people say "check fluid level of master cylinder", what are they referring to?

I think i know what you mean about using clear tube now... If air bubble is present in the clear tube, it will separate the brake fluid right?