# Brake Fluid, Rotors & Pads



## h00pslayer90 (Dec 10, 2006)

Ok so I drive a MK4 04 GTI and I recently did a brake Pads & Rotor job on my girlfriends 03 Saab pretty easily other than having to run to the parts store multiple times looking for dumb proprietary sockets and other tools & lacking a good community and info like on Vortex. Anyway now my brakes are worn to the point I need to replace mine. I have done most of my research on the forums and in the bentley manual but my question unanswered still is why and do I have to siphon my brake fluid. If anyone could please answer this for me and also it would be nice to get a outline from anyone else on the things I need and steps I have to take to do this job. Please don't flame on this Post I.E. telling me the purpose of the search button and Bently manual, plus this job is very difficult because I live 20 miles from Boston and if anyone else knows this New England weather we have about 15 inches of snow on the ground and I'm doing this all outside. Ok Thanks in advanced everyone!


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## spitpilot (Feb 14, 2000)

*Re: Brake Fluid, Rotors & Pads (h00pslayer90)*

As your pads wear, the caliper pistons come farther out from the cylinders...creating more volume which must be filled with brake fluid....That's why fluid level in master cylinder drops slightly over time...when you go to retract pistons to allow for thicker new pads...that fluid in the caliper cylinders has to go somewhere....and its back to the MC...so if you don't take a "turkey baster" and suck some out of the MC tank B4 retracting your caliper pistons...it can overflow...and brake fluid eats paint for lunch..so you can get some nasty damage to your firewall/booster paint job!...I use an old turkey baster to suck out old fluid from MC during fluid flush....you suck fluid down to bottom then wipe up the black crud that builds up in old brake fluid..refill with fresh fluid and start your flush...you'll get clean fluid flowin thru the system faster and use a bit less new fluid to do a good flush...Dont forget to clean and lube (synthetic caliper grease) the slide pins when doin your brake job...folks tend to forget this on rears, since the pins are hidden from view under the dust boots and all you have to do is remove lock bolts to change pads..but dirty/dry pins can cause caliper hang up and brake drag...bad!


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## h00pslayer90 (Dec 10, 2006)

*Re: Brake Fluid, Rotors & Pads (spitpilot)*

Thank you this was very helpful and explains why this needs to be done but two more thing, where is the master cylinder? and Do I pull from the MC and somewhere else? I am going to get a sipon at autozone. Thank you.


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## GTijoejoe (Oct 6, 2001)

*Re: Brake Fluid, Rotors & Pads (spitpilot)*


_Quote, originally posted by *spitpilot* »_As your pads wear, the caliper pistons come farther out from the cylinders...creating more volume which must be filled with brake fluid....That's why fluid level in master cylinder drops slightly over time...when you go to retract pistons to allow for thicker new pads...that fluid in the caliper cylinders has to go somewhere....and its back to the MC...so if you don't take a "turkey baster" and suck some out of the MC tank B4 retracting your caliper pistons...it can overflow...and brake fluid eats paint for lunch..so you can get some nasty damage to your firewall/booster paint job!...I use an old turkey baster to suck out old fluid from MC during fluid flush....you suck fluid down to bottom then wipe up the black crud that builds up in old brake fluid..refill with fresh fluid and start your flush...you'll get clean fluid flowin thru the system faster and use a bit less new fluid to do a good flush...Dont forget to clean and lube (synthetic caliper grease) the slide pins when doin your brake job...folks tend to forget this on rears, since the pins are hidden from view under the dust boots and all you have to do is remove lock bolts to change pads..but dirty/dry pins can cause caliper hang up and brake drag...bad!









^^^ this guy's pretty smart


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## spitpilot (Feb 14, 2000)

*Re: Brake Fluid, Rotors & Pads (GTijoejoe)*


_Quote, originally posted by *GTijoejoe* »_
^^^ this guy's pretty smart









I'd better know something...I stayed awake in Physics classes for years...and I've been wrenchin (on everything from Alfa's thru Opels & Toyotas..to VW's...had about 9-10 under my care over the years) for decades!


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## GTijoejoe (Oct 6, 2001)

*Re: Brake Fluid, Rotors & Pads (spitpilot)*


_Quote, originally posted by *spitpilot* »_
I'd better know something...I stayed awake in Physics classes for years...and I've been wrenchin (on everything from Alfa's thru Opels & Toyotas..to VW's...had about 9-10 under my care over the years) for decades!























Spit, are you trying to tell me you made every mistake in the book?








That's where your 'not to do' experience comes from


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## .je (Feb 8, 2003)

How about this question - I've got old brake pads. They were on the car when new, in 2000. Brake pads changed (only 1/2 worn), but those ones are finished, and I want to put the old ones back on to even F/R, for a couple of years (since there's still 1/2 remaining).
Is there some kind of age limit for brake pads? I have seen lots of people use someone's old setup after they'd upgraded, but it wasn't 10 years old!


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## GTijoejoe (Oct 6, 2001)

*Re: (.je)*

There is no expiration date on friction material to my knowledge, of course it would vary upon what's in it.... For example, cashew nut dust is popular ingredient, how would that differ with age








Other than that sometimes the friction will delaminate from the backing plate as they get older (especially if adherd with glues.


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