Brake flush or brake bleed?
 

I am taking my car up the track soon and I want to put motul rbf 600 in brake system.

Everybody seems to be justbleeding their brakes and adding maybe adding a quart of new brake fluid. But that doesn't really replace all of the fluid in the system. Seems pointless if you are going to the track and want to upgrade to a better brake fluid.

Now to do a brake flush you need more than 3 quarts of the fluid, plus the fluid to flush the system. Way more expensive to say the least.

I would rather do the brake bleed from the money point of view but brake flush is what makes sense for me to do to bring the car towards track readiness.

Any thoughts?

What you may have read is that somebody with Motul 600 already in the system only used a quart to bleed the brakes before or after a track day or 2.

I'm not sure how much the system holds... I would think if you needed more than 2, places like Z1 would say that when buying their upgrade kit. I did 2 in mine and it seemed to do the trick. I'm not an expert... Maybe someone will chime in or you could give Z1 a call.

If it's your first track day and it's not too hot that day, you'll probably be fine with OEM fluid. I didn't have the need for brake fluid upgrade or brake upgrade until after my 2nd TD.

An oil cooler might be something to consider too. I actually was more concerned about it than the brake fluid before tracking mine the first time. The oil temp climbs pretty high on our Z's without a cooler.

My thoughts.

The brake fluid used to flush the system just needs to push all the old stuff out. Once you do that, you have a flushed system and new fluid at the same time.

If your entire system takes X amount of fluid, you only need that amount to fully flush the system. (I usually make sure I have a little more just so my power bleeder doesn't get low)

Do a complete flush, don't screw around with the the only thing between you stopping - and not stopping.

2 bottles will flush the entire system, but buy 3.

This is wrong. The fluid does not mix in the lines except for very small amounts, which is bled out. With a power bleeder, the new fluid is pushed through the system forcing the old stuff out. With a gravity bleed, the new fluid is also forcing out the old stuff, but it is working solely by gravity and takes a lot more time. Either way, there is no need to run any more brake fluid through that line once the new stuff starts bleeding out. You're just wasting good brake fluid.

I've never needed more than 2x 500mL bottles of Motul RBF600 for a full brake flush, but I always buy three and use half one to flush the clutch system :twocents:

:iagree:

If you are just refreshing your dot 4 (RBF 600 is great stuff) you are primarily trying to get the "wet" fluid out of your lines. brake fluid is super hydrophyllic (absorbent) of water (its designed to pull water out of your system), you need to fully flush your fluid as the water "travels" up the fluid column.

The primary reason to get the "wet" fluid out is that it lowers your brake fluid boiling temp from around 600 degrees down into the mid 400s. (track temps regularly are in the mid 500s)

Road and track crashed the 09 press 370 during track testing from boiling fluid (OEM DOT 3 fluid I believe)

The short answer: Use good DOT 4 fluid and FULLY bleed out your fluid to ensure its "dry" 2 bottles will get it done if your are perfect, so buy 3.

I bleed mine at least twice a year (during track season) and its very easy. Dont use a power bleeder unless you are a pro, just have a buddy pump you pedal for you. Power bleeders can damage the ABS system I've heard so are better left to pros. Manual bleeding is a quick job and very DIY easy.

Good stuff :tup:

I've only heard of problems arising with the ABS when excessive pressure is used. My research indicates that you should never go over 15 psi on any car, and some cars can't handle that. I've power bled the Z's brakes numerous times at 10 psi maximum. The power bleeder is far quicker and easier by myself than if I have a buddy to help pump the brakes :twocents:

If you want to flush you can use more than 3 qts. Just keep the valves open pour in 3 gallons if you want..or more.

I was very anal doing my first replacement at about 100 miles or so from OEM to rbf600 with my SS lines. Even being anal I still only used 750mL! I started RL, RR, FL, FR and clear as day I could see the color change and I still let it gravity bleed for a minute or two. If you get that much in I'd have to say you got it! Plus again I had brand new lines to fill up.

Stupid question: aside from the higher boiling point, is there any difference between rbf600 and regular DOT 3 or 4? To put it another way, will I sacrifice anything by switching over?

You state you were anal, but you didn't even follow the factory service manual :ugh2:

Which, for the record, states:

Thanks everyone for your replies and thoughts!

I actually ended up using on only 2 and a bit of a 3 bottle in the brake flush. When I called the Nissan dealership service place they told me I need more than 3 quarts! So I bought 7 and now I have 4 unopened ones.....ehhhh these people at the dealerships...

I had the mechanic at the dealership do it for me because I have never done this myself, and I was with him most of the time. I missed the part where he bled the master cylinder, because he said that was the first thing he has done. I know that in the future I will be doing brake flush by myself and just have someone pump the brake for me.

Does anybody know how to properly bleed the master cylinder? Just for future reference




I don't think you sacrifice anything. Only thing is that it might be a waste of money if you never plan to track your car because I doubt in normal daily city driving you will ever reach high brake fluid temperatures.

I always thought you bled from farthest from master cylinder to nearest (ie RR, RL, FR, FL)!!!

All this time doing it wrong. :0 (But it still works)

You follow the factory oil change? Factory alignment specs? Didn't think so. They don't know everything. Hell I'd at least make a car that could turn and stop and go without fuel cut, fade or over heat ;).