DarrenSTI

iTrader: (3)

About to fit new disc's & pads front and rear, along with new brake fluid, but was wondering the best way to remove the old fluid?

whats the technique?

also how easy is it to change the braided lines too?

scooby1929

iTrader: (1)

I think the best way is to open a bleed nipple, hold a container over it and get a mate to operate the brake pedal and pump it all out

DarrenSTI

iTrader: (3)

That was the only way i thought of doing it, just wondered if there was a quick was, like sucking it out from the res tank?

scooby1929

iTrader: (1)

I am not sure mate!! I have never done it on a Subaru but on other cars thats the way I have done it.

If your front pads are worn down your rears might well be okay

Godspeed Brakes

iTrader: (259)

If I had a car in to fit everything you had off me , I would fit a corner at a time , discs pads , then the hose , the hose , I would clamp the standard hose , remove it from the caliper , then off the strut fixing , fit the new hose to the caliper , then connect it to the strut , then remove it from the inner wing bracket then fit the new hose , where its fitted on the inner wing , the steel pipe fitted into the standard rubber hose is very tight , I think they have a sumo wrestler tightening them up in the factory ! I crack them loose with mole grips being carefull not to damage the pipe end , if you use a small spanner it will end up slipping off and damaging the pipe end , if you crack it loose first you can then use a spanner.
Fit the braided hose to the inner wing bracket and screw the steel pipe into it , and tighten it up
Do the same to all corners , then bleed the system last , when I bleed them , I always do the drivers side front first , then the passenger side front , passenger side rear , then drivers side rear , I pump the brake pedal to get all the pistons out tight onto the discs , then check the pedal , If I thhink it needs bleeding more , I go round and do them all again.
Its quite time consuming but easy enough

Hope this helps
Cheers Ian

djandyg

iTrader: (2)

you cant do this because you can only remove a small amount of brake fluid before you will get air into the system, which will then compress when you brake - giving you a spongy pedal.

brake fluid is hygroscopic so will absorb moisture from the atmosphere, meaning over time the fluid will have water/moisture in it - which will compress the same as air in the system, so make sure you use fresh brake fluid that been sealed.

You'll need some sort of tubing that will fit tightly over the caliper bleed nipple, and then run this tubing into some sort of pot. You can buy this bleeding kits quite cheaply or make your own.

Starting on the caliper that is the furthest away from the master cylinder first (this is important), stick the tubing on the nipple, and undo it slightly - will probs only need 1/4 of a turn after being cracked off.

Get some one else to pump the brake pedal - the fluid will flow thru the tubing and into your container/pot. Watch the fluid flowing through the tubing and look for bubbles of air or dirty fluid passing through - get your assistant to keep pumping until neither of these are present in the tube - it should start coming through clean and free of air bubbles. Make sure you do a minimum of 10 pedal pumps per corner regardless to ensure a decent amount of fluid has come out.

When your satisfied, tell your assistant to stop pumping and keep the brake pedal down to the ground, until you have tightened the bleed nipple back up.

Top the brake fluid reservoir up the max mark with new fluid.

Repeat this process for all four corners, going in order from the corner which is furthest away from the master cylinder, with the corner closest being the last caliper to bleed.

When you have done all 4 corners, pump the brake pedal and it should go hard and feel firm, with no spongy-ness. If the pedal is spongy, then you havent done it correctly and will need to start again.

Make sure at no point the reservoir level reaches below the minimum mark as you will allow air to enter the system and you will need to start again.

Hope that helps

DarrenSTI

iTrader: (3)

Thanks Ian, again.
The order you bleed is different to what I found.

REAR PASS
REAR DRIVER
FRONT PASS
FRONT DRIVER

is that the wrong way????

Bleeding wise I may get what they describe as a one man bleeding kit, basically has a one way valve in it, so in theory i can pump the pedal letting the fluid go through come out of car and close the bleeding valve, with no air going back due to the one-way valve.......
wonder if it works as well as that lol

DarrenSTI

iTrader: (3)

how can i get all the old fluid out first?

can bleeding be done on my Brembo calipers with the wheels on and car is on the floor?

djandyg

iTrader: (2)

using mole grips on the bleed nipples is a bit risky - wouldnt advise it personally! the best option is to use some brake pipe spanners as they offer more grip and torque over a standard 12 point - not very expensive to buy and your less likely to round the nipple off - which is gonna give u a major headache if u do lol
Also the correct order to bleed them is furthest away from the master cylinder, working your way nearer - so should start at the rear first.

djandyg

iTrader: (2)

The brake fluid will be replenished as you pump the brake pedal and force the old fluid out through the bleed nipple - you dont drain the system first. Make sure you dont get any brake fluid on any paint work though as it will melt your paint right through! Id advise getting some brake cleaner as well to wash everything down with afterwards.

You can do it with the wheels on, but if your doing this DIY on axle stands then its going to be far easier doing it with the wheels off.

Godspeed Brakes

iTrader: (259)

Read my advise again , I haven't said to use mole grips on the bleed nipple ??

Why is bleeding the rears correct compared to my way , I have been doing this over 20 years with never a problem/
Cheers Ian

360ste

iTrader: (1)

Iain reading through these posts does bleeding the rears first originate from before the diagonally split brake system was introduced? Which like many things was laid in stone and not re-assesed as things changed.
With regards to brake fluid with fitting braided brake lines so unless they rub on something, mine did, won't need replacing. Why not pay a bit more and use Silicon fluid, it does not absorb water so never needs changing and won't screw the paintwork if spilt. I have this in my brakes and all I do is when I replace a set of pads expel the old fluid out through the bleed nipple as I retract the pistons.

djandyg

iTrader: (2)

i apologise i misread your post about the molegrips.

With regards to the bleeding order, iv always been told that thats correct way to do it - altho i appreciate that on a lot of cars nowadays the braking circuit is split front/rear so wouldnt make any difference.

stockcar

would heavily advise against silicone fluid (dot5) as it only really has a place in specific military applications where life is more important than outright performance..........

use a good quality dot4, dot5.1, etc...............

alyn

p.s. if your fitting new lines you have automatically pretty much drained the old system, just flush/bleed the new fluid through no need to drain first even if not changing lines

360ste

iTrader: (1)

Why? Had silicon fluid in for 4 years and brakes are great!!

stockcar

(generally speaking)

it does not absorb water, therefore any moisture that builds up in the system stays seperate and turns to water vapour with heat build up in the brake system/calipers - as water is totally compressible then you can at best lose pedal efficiency (at worst you lose the brakes completely)
it can also cause corrosion and seal damage as a side effect

alyn

Setright

Erm..the biggest worry with Silicone is that is less dense than water, meaing that moisture will tend to collect in the calipers! Doesn't sound like good plan to me


Of course, the water is expelled when 360ste replaces pads

Slystav

iTrader: (1)

hi guys

sorry to be a pain in the rear but for all intents and purposes water is not compressible. i'm a hydraulic design engineer and deal with this stuff all the time. i think apart from corrosion in the lines (probably unlikely as stainless steel, copper or copper nickel brake lines, and rubber, are very good with water) the main reason you could end up with spongy brakes is that the pressure goes up when you press the pedal, raising the fluid temperature and turning any water to steam. this steam is compressible, so as long as the fluid is over 100 degrees c (i would guess this is possible while braking repeatedly) the system will be spongy.

stockcar

thats exactly what i said above although maybe not as clear as i stated it turned to water vapour.............

either way i would rather use anything than dot5 in a road/track vehicle

alyn