Why flush brake system?

They tell me that I need to flush my brake system and coolant system. Both of these systems are closed! Why would you need to flush a closed system. They are not under the same pressure and abuse as oil, I change my oil every 3000 miles. Those other "flushes" sound like a way for Subaru to get more money?

Any advice. Is Subaru different from ALL the other different cars in the world.

Nick

Reply to
nrs2001
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Brake fluid is hygroscopic...it absorbs water and must be changed at the recommended intervals. Sludge builds up in cooling systems and must be flushed as per the book. Neither system is 'closed' All cars are the same....and if you disregard the book you'll learn the hard way when you run out of brakes and the cooling system blows up. C

Reply to
Clive - Selectron

It's necessary for ALL cars! Brake fluid attracts water - and the system is NOT closed - there is a necessary little hole in the cap of the brake fluid beholder. Water vaporises when heated - but the vapor is strongly pressable - with too much water in your brake fluid braking is even impoosible. And then there is the question of corrosion - and I have had a brake piston corroded in its cylinder - I was driving at 130 km/hr on a German motorway when the rear brake of my car (a Renault) slammed shut .... not nice!

Your coolant liquid deteriorates because of the combustion system and aging - there's no need for a head gasket to blow up to get your coolant liquid contaminated with oil and smear over a number of years. My advice: Renew braking fluid and coolant every two years on ANY car make, or every 60,000 miles.

George

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Reply to
G.J.H. Jørgensen

Hi,

At the risk of offending someone, Subaru is just like all the cars on the market in the "flush brake fluid" and "flush coolant" departments. The other guys already explained why.

Rick

Reply to
Rick Courtright

All you have to do is watch someone flush your brake fluid to be a believer. It starts coming out of the system the color of dark pancake syrup and ends up clear as the new fluid gets to the calipers.

One of the few maintenance procedures that I actually find rewarding at the time.

Reply to
Jim Stewart

Flushing of brakes was not common in the old days, but flushing of radiators was. Much greater chance of rust/gunk causing trouble in the radiator. On thing that I take exception to is the interval. There are 5 year antifreeze products out there. Radiators have more non rustable plastic parts. Antifreeze has better rust inhibitors. A flush when the coolent is replaced should be sufficient.

If your Subaru book has a recommended flush interval, I'd go with that. Note that your dealer is likely to have a much shorter recommended interval.

And ... I used to never flush brake fluid. That concept didn't exist in the 1970 when I started driving. Never ran out of brakes. But I paid attention ... small leaks would appear and that was the old way to know that something needed replacement. Usually at the same time the shoes/pads were replaced.

My personal opinion ... flushing brake fluid isn't a bad idea. But it's also a good profit center for the dealer. And they like to use scare tactics. Use your good judgement as to how often.

Reply to
Kurt Krueger

Yes, and I remember fighting leaky slave cylinders in the 70's and leaky calipers in the 80's. Haven't had any problems with them since I started bleeding the brakes after each pad change.

Reply to
Jim Stewart

Was your 1970's car a high performance model with discs with suberb (think 'heat') brakes?

1970 and 2006 cars are different in every technical respect and what was OK then sure ain't now and clearly the poster does not possess good judgement in this area. Any other approach except by the book is dangerous penny-pinching.

-C-

Reply to
Clive

Hi,

Don't forget back in the '60s amd '70s how much more frequently we rebuilt or replaced cylinders, both master and slave. You didn't think about "flushing" the brakes as a separate drill cuz there was usually enough frequency of "other" brake service to keep things cleaned out and "fresh" reasonably well.

Rick

Reply to
Rick Courtright

Reply to
mike

I think intelligent people would read their owner mantancence manual. Most manufactures recommend 3years/36,000 miles for most brake & cooling system service.

Reply to
Edward Hayes

I agree:

Newer systems are almost closed. Cylinder tanks now have rubber bellows under the caps that allow for expansion or brake pad/shoes wear compensation of the brake fluid level, keeping the air on the outer side of the bellows. The thing is that there is always wear due to the rubbing parts inside the cylinders. That wear results in microscopic particles being in the brake fluid and it does not get any better with time. Flushing guarantees that the system will last as long as possible.

For the cooling system I recommend replacing the coolant with water and Zerex antifreeze (the green one that comes in a white container). I did that when my 94 maxima had 10k miles on it. Recently at 114k miles, i replaced the water pump because it began dripping. The coolant that came out when draining the system was perfect in color, smell and consistency. When I removed the pump, there were no rust traces anywhere in the system, not even slight deposits in the radiator. I never flushed the system since the initial change.

Reply to
AS

Hi,

No recommendation for antifreeze brand here (I don't buy into the "Brand A is so much better than Brand B" arguments since I'd not be surprised to find all of 'em come from the same vat!), but I DO recommend (as do many) that you use DISTILLED water (some sources recommend "de-ionized" which I believe is what they claim to use in the "pre-mix" stuff you can buy at the auto parts store for way too much money!)

Rick

Reply to
Rick Courtright

What applies to Nissan does not apply to Subaru. Standard antifreeze should not be used, and you can't go by color. The correct coolant for Subarus is silicate and phospate free, many generic coolants do not meet this requirement. Safe to use are the OEM stuff from the dealer, Peak Global, and Prestone "All Makes All Models" (not their regular stuff). The Peak and Prestone are both available in 50-50 premix form so you don't have to worry about sourcing or adding water.

Reply to
mulder

Reply to
nrs2001

If you don't believe us, do it yourself and compare the two fluids. You will see how brown the brake fluid coming out of the calipers is compared to the new stuff... and old coolant can be plain nasty looking.

As for coolant, if you have a 1998-02 Subaru with a 2.5 liter engine, you might have to put in the Subaru coolant conditioner to help prevent head gasket problems and get a free repair if they do happen.

You will find people on here recommending OEM stuff a lot because, with a few exceptions, Subaru OEM is just better quality and performance than the stuff you can get at Autozone or Walmart.

And no, I don't work for Subaru.

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Reply to
Dmitriy

Reply to
mulder

While you are at it, to do a complete job, don't forget the power steering fluid. Although I wasn't prepared to flush the entire system (not prepared technically), I did use a turkey baster to remove all the old fluid from the reservoir, and refilled it with new. The old stuff was really nasty looking. It probably would have been better to drain the PS Cylinder, but I had no idea how to do so, and didn't want to mess around with a high pressure side.

Does anyone know if using a silicon based brake fluid would be a better idea if you plan to keep the car for years and years? Silicon fluids are not hydroscopic. They cost more, but are they worth it?

Reply to
QX

Silicone fluid (DOT 5) is not compatible with systems that have already had glycol based fluid in them. The two do not mix and all the seals in the system will be ruined if DOT 5 is used to replace DOT 3 or 4. In addition, DOT 5 cannot be used in systems with ABS due to foaming.

Reply to
mulder

The ONLY real advantage of DOT5 fluid over the previous DOT's is that it does not dissolve paint. I believe that the fact that they are no hydroscopic (don't absorb water) makes them even worse, because instead of having the moisture evenly spread out, you have pockets form in the brake system - not good.

Go with DOT3... you can get it for like $1.50 at Walmart for some good synthetic stuff... you'll probably need 3 of the little bottles or so for a complete bleed.

Reply to
Dmitriy

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