Break Fluid

[avensis_man]

Hi,

Just a Quick question.......

When do you know when your break fluid needs changing?

Thanks

[scionic]

The change interval should be in your owners manual. It's part of scheduled maintenance. It's not something that gets depleted the way motor oil does, per se. Why do you ask? Brake problems?

If your braking has become somewhat 'spongey' then it's possible the system needs to be purged and refilled to get rid of air bubbles.

[jdbecks]

the fluid should also be clear...not misty too

[Karma Supra]

Yup.. if it is cloudy of black it needs changing... Same goes ffor clutch fluid, as its the same stuff!

[mad welshman]

slam dot 5 into her. baz

[nrgizerbunny]

slam dot 5 into her.  baz

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Don't do this unless your seals can take this, i think dot 5 is the silicone based fluid and it will eat your seals.

Dot 4 or if you need the ultra high boiling point dot 5.1 will be okay.

I personally change brake fluid once a year. it only costs £4 and that does 1.5 cars!

hope this helps

[Karma Supra]

I agree with 5.1 as opposed to 5

Its what I run in my supras.

[rickers]

It's not something that gets depleted the way motor oil does, per se.

have to disagree with you

Brake fluid is made to attract water, so it stops your brakepipes rusting. hence it needs to be replaced on a regular basis. normally 2 years, but as said before your service book will advice when and what.

rickers

[nrgizerbunny]

I think scionic meant that the brake fluid doesn't get burned like engine oil which ends up getting burned in the cylinders as a result of getting past the piston rings. hence the level goes down

Brake fluid does go off by absorbing moisture but does leave the system unless you've got a leak. Although i suppose you may get a bit of loss through the seals in the slave cylinders - albeit hardly anything.

[Karma Supra]

I need a new master cylinder :'(

[nrgizerbunny]

karma, how often are you topping the level up? i hope you haven't got any on your paintwork as it eats paint :(

also if you can get the thing apart, might be worthwhile changing the seals before you go out and fork out money on a new master cylinder

[Karma Supra]

I don't actually have to top it up.... but it feels constatly spongey, and the brakes are crap :P

I rebuilt all 4 calipers, fitted 4 Brembo 20 groove disks and new pads... bled the system throughly on dot 5.1..... things are still spongey....

I'll look into rebuild seals when I go to toyota next...

[sotal]

Have you tried braided brake lines they're supposed to take the last bit of spongyness out.

I had the problem of spongy brakes on my motorbike, turned out to be a leaky seal on the caliper (easy to diagnose as it p1sses all over the disc!!) I rebuilt the caliper put the system back together, reverse bled the system, cleaned the discs and put new pads in.

Went for a test drive and they felt spongy, bled the system again checked everything, went for another test drive - still felt spongy. Gave up trying to do anything else as a friend convinced me that seeing as I could do an endo they would be good enough.

Went for the MOT in October, still felt spongy to me. So I asked the Bloke at the MOT place to give it a test drive - he almost flipped over the handle bars! He said they were the best brakes he had ever used!! Just goes to show how you can think they are spongy even when they aren't really!

(they still feel spongy to me!)

[avensis_man]

hi,

thanks for all your reply.....to bleed the brakes do u need a brake bleeding kit or can you just unscrew the bleed nipple and press on the brake pedal untill it all empty's?

Thanks

[nrgizerbunny]

you can unscrew the bleed nipple. but you need to keep pouring fresh fluid into the resevoir.

As the fluid depletes in the resevoir you end up with air in the system and air unlike brake fluid is compressible so you won't end up getting the crappy fluid out.

just keep pressing the pedal (with an assistant to prevent air getting in the nippled end) until the fluid coming out the caliper is clean.

*Remember to bleed your brakes in a diagonal formation. ie left front, right rear then right front and left rear*

Karma,

I reckon its your seals, as the pressure builds up the seals (probably master cylinder) are leaking (internally) this causes fluid to flow back round the piston and you end up with spongey feeling - although this is all relative and your brakes might be great like sotal said

[Karma Supra]

I'll be getting braided lines when I have some spare cash... as the rest is all rebuilt I think it can only be the master cylinder seals!!!

I had a breif moment when after some heavy braking around thd nurburgring my brakes went mega effective.. then they went soft and cack again

right now my pads are nearly to the metal, so I'll replace them before I investigate any further!

[b1nda]

Hi,

Im going to bleed the brakes on my car, can anybody recomend a good bit of kit?

Thanks

[nrgizerbunny]

karma, do you have fast pads? if so they may not work until your brakes get really hot!? I still reckon its the master cylinder piston seal though, the symptoms suggest that fluid is going escaping round - hence spongeyness Its a right fiddly job to change the seals and good luck for when you get round to it!

b1nda, If you haven't got a friend to help you, then Gunson make a pressure blead kit which will bleed the system, be careful when you use this as you can end up with no fluid at all in the system. This isn't a problem if your car doesn't have ABS but on VW's (not sure about toyota ABS- starlet doesn't have it), the pump has to be bled by sticking a computer into the ECU. If I were you i'd enlist the help of a mate!

[Karma Supra]

they were Pagid fast road pads.... but they got even worse when hot!!! Maybe I just got a duff set???

The only bit that worrys me about chaning the seals on the master cylinder is, etc, is removing all the brake lines to get it off...... they seem to be notorious for seizing, and rounding off nuts!

I had the same problem on my old manual turbo supra, after toyota didn't put the slave cylinder on properly (held it on with one nut) the other nut sheered, the clylinder fell off, and the piston popped out.. I re asssebmled it, and had to bleed it every day to drive it

This was the basis for my dislike of maindaler mechanics!

[b1nda]

hi,

can anybody recomend a decent brake bleeding kit?

Thanks

[System~G]

hi,

can anybody recomend a decent brake bleeding kit?

Thanks

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The ones Halfords sell are OK.

[nrgizerbunny]

hi,

can anybody recomend a decent brake bleeding kit?

Thanks

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sykes pickavant

[b1nda]

hi,

can anybody recomend a decent brake bleeding kit?

Thanks

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sykes pickavant

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Hi,

Thanks......are the ones you have mentioned above "one man" operated and are they easy to use?

Thanks