fabchef

Hi everyone, so one of the last fluid that hasn't been changed out yet, is the brake fluid. Usually once a year i'll remove what's in the reservoir and put in fresh fluid. I have not "bleed" the system at all. I've had the car 6 years now and not sure if it's ever been done before (it's a 2009 rx350. The brakes seem to work well and no signs of leaking anywhere. I do live in a colder climate with salted roads in winter. I know the fluid is hydroscopic and attracts moisture.
i've brought it up twice (about bleeding system), with my indi. Garage. The guys there told me that you don't really have to do it, unless there is a form of air leak, and the system gets compromised.
is this true? I know it's best to bleed it out, but can it be left as is? I've tried to carefully open a bleeder but didn't want to move and i'm afraid of snapping the screw and then i have to change the calliper.
thanks
fab

Leeper

Brake fluid breaks down as well as draws water (hygroscopic not hydroscopic) breaking it down even more. The end result is slowly rusting internal parts in the master cylinder and other parts within the brake system, if enough water gets into the system it can make the pedal feel mushy but rust and damage is more the consideration. Topping off or simply replacing the visual fluid at the reservoir does nothing the the contaminated fluid within the system. Brake fluid is extremely inexpensive ($10 at Wallymart) and the process is quite simple why would you NOT replace (flush) the whole system? If you don't have a second person to pump the brakes when needed there are a couple awesome tools that will help - Mitivac brake bleder or "Motiv"... I have both and love them! "Speedbleeders" are also an awesome and not expensive alternative.

As for your issue with them not wanting to move, sounds like someone ham-fisted them as they should not be nearly that tight. I would highly recommend flushing all the old fluid out, if you break a bleeder screw they are cheap and easy to replace.

fabchef

Leeper, i think i'm just worried about snapping the bleeder while trying to loosen it. As i said i don't know if/when the bleeders where cracked open. I've bled brakes before on other cars and they undid themselves easily. Also, if i managed to loosen them, I wonder if there's a chance of fluid not coming out (the bleeder passage is clogged)?
Another question...if i manage to crack them open, can i simply remove the bleeder and install a new one?
thanks
fab

Leeper

yes, if you wind up damaging the bleeder you can simply replace it (been there done that on another car). Don't use the open end of an open-end wrench getting on two sides of contact on the bleeder, use the other 6pt end or a socket if possible perhaps even put some masking tape on the head to reduce tolerances. Tighten them only until slightly tight no need to crank them down sounds like someone did that prior, I think I had to use Vicegrips on one years ago saved it using it afterwards

XRX

Brake Fluid Change - ClubLexus - Lexus Forum Discussion

Oro

If you are swapping the res. fluid annually, you really don’t need to bleed from the screws. I’ve been doing this about 10/12 years and it works fine. I’m also in (very wet) western WA and an avid motorcyclist. If it did not work, I would not be doing it.

The reservoir fluid does communicate fully with the system and caliper fluid over time (a few days worth of driving). This is simple physics as well as design (look at the mechanical diagram of a master cylinder). It is a very persistent misunderstanding that reservoir fluid and system fluid do not mix. That is false.

Swapping just the reservoir fluid will drop the fluid H20 content about 50% (you can test this with hygrometer strips, but no need to, it’s been shown to be true and you can Google that). If you do it annually you will keep the fluid pretty dry and have no issues, and it is EZPZ.

fabchef

Oro... thanks for the reply. I have always heard that just simply changing fluid is not enough as the fluid needs to get by the seals in order for it to changed.
How does the old fluid in the lines, lets say, get exchanged from the fluid in reservoir?
maybe your point does work, as i've seen videos of people sucking out old oil from the reservoir that is dark or black...maybe it does make its way to reservoir again?
fab

Felix

Replacing the old brake fluid in the m/c is a start to keeping the old fluid from flowing thru ,bleeding the whole system. Best to bleed the whole system w/ dot 3 every 3-4 yrs......Really not that many ppl do it....Brake fluid does break down as does coolant, p/s fluild, a/t fluid.......Basically common sense maintenance......

Leeper

It costs @$7 - $10 for a quart of fluid to do it and very little time, I'm surprised this is even a conversation on the RX, motorcycles take less than a pint and is even easier/quicker

fabchef

Leeper... i've done this job before on other cars, no issues. I don't know if it was ever done on my 15 year old car! Bleeders are rusty (salted winter roads here). I'm just afraid of trying too hard to open them and they snap!
fab

Leeper

I get it Fabchef, this thread seemed to wonder into whether it is a sensible choice for others to just replace the reservior rather tha a full bleed and IMHO to save $7-10 seems hardly reasonable. In your case I understand your dilema/quandry

MattRX

I was able to get some really rusty bleeders out (2004 Camry) by just hitting them with MAP gas for a minute after using a wire wheel on a drill where the bleeder meets the caliper and letting penetrating fluid soak in for an hour. I was able to get them out without damaging the seals in the calipers. If I hadn't used a torch, they would have 100% snapped off.

fabchef

Mattrx.... so if i get this right...you brushed around the bleeder with wire wheel, then penetrating spray. After that you torched the bleeder? Did you Shock it with cold water after torching?
also...did you remove the bleeder completely and install a new one right away, or you kept old bleeders?
thanks
fab

Oro

When sitting still, seals keep them separated. But NOT when activated. Think about it - if they were fully sealed off, what would be the point of a reserve reservoir, and how would the reservoir fluid get into the system in the event of a leak? A quick look at an MC diagram will make this apparent.

When you activate the brake, orifices line up and let them mix. After a bit of driving, they fully mix, and through the system 100% after a short while. In fact the active system even mixes while sitting still because of Brownian motion.

So bleeding is really a waste of time to get water out, but necessary to get air or solid contaminants out in older or compromised systems.