[mr_saab]

I'm planning on bleeding my brakes since I bought the car back in October and I don't know when the previous owner had them done, but I always like to bleed them at least twice a year. On the reservoir cap it says to use DOT4. I'm wondering if these cars need a special brand of fluid like the PS system does (Pentosin CHF) or can I just buy any DOT4 brand of fluid and it will work fine?

Thanks

 

[Cosmicflash]

Any type DOT should be good.

ATE Blue is a good fluid if you want something a bit better.
And why change twice a year? That seems like overkill. Makers say every 2-4 years, Saab says 4.

 

[aerojon]

don't use DOT 5.0 though..twice a year is more than over kill imo..

 

[A10GAC]

I just changed my fluid this weekend and used Napa's Dot 4 (P/N 40-032) and it worked fine. It took just under a quart and about an hour (including time to get the car on the jack stands) to do the whole car. I've used Napa's house brand fluids in a few vehicles and on the motorcycle and I've always been pretty pleased with them.

Could be the placebo effect, but the brake pedal feels much better now.

 

[mr_saab]

And why change twice a year? That seems like overkill. Makers say every 2-4 years, Saab says 4.

I'm not flushing the entire brake system I'm simply bleeding the calipers on each wheel. I do this up to twice a year, and I find it keeps the pedal firm and responsive. Every mechanic I've dealt with for my hondas and volkswagons religiously do it once a year on their vehicles. I hope you're referring to flushing the system every 2-4 years...because yeah that would be overkill twice a year. Bleeding the calipers should be an annual thing if you want to keep your system in good working order.

 

[Cosmicflash]

I'm not flushing the entire brake system I'm simply bleeding the calipers on each wheel. I do this up to twice a year, and I find it keeps the pedal firm and responsive. Every mechanic I've dealt with for my hondas and volkswagons religiously do it once a year on their vehicles. I hope you're referring to flushing the system every 2-4 years...because yeah that would be overkill twice a year. Bleeding the calipers should be an annual thing if you want to keep your system in good working order.

Isn't bleeding the calipers part of a flush? You bleed them until the new fluid from the master cylinder works it way thru. Going to a colored fluid like ATE Blue makes it easier.

So what do you think you are doing here I guess?

 

[Saabohème]

Isn't bleeding the calipers part of a flush? You bleed them until the new fluid from the master cylinder works it way thru. Going to a colored fluid like ATE Blue makes it easier.

So what do you think you are doing here I guess?

The brake fluid at the calipers is the most likely to have air bubbles or a concentration of contaminants in it. So my guess is that the OP is opening the bleed screw and letting gravity do the work. In this manner he can, in a few minutes, essentially empty each caliper and the short section of flexible rubber hose from the hard line to the caliper and then replace that small amount of fluid in the reservoir. The OP is very likely letting the fluid drain until he sees the cleaner fluid (cleaner than what was in the calipers) draining and then he tightens the screw. Next he will replace that little amount of fluid in the reservoir and then move on to the next corner. The result will be a firmer pedal and less likelihood of developing corrosion within the caliper.

For $60.00ish bucks one can get a Motive Products pressure bleeder and flush the entire system every two years. If one is irredeemably anal, he may then take it out and force the ABS system to actuate three or four times and then flush it again.

Ate Super Blue Racing fluid (and its un-dyed product companion in the Ate line, Ate Typ (not a typo, it is spelled "Typ") 200, has a much higher than average (for DOT requirements) wet boiling point (390+ deg F) than quite a few out there. It is pretty cheap at an average online price of around $13.00 per litre and if you look hard you can even find it on the net for a little under $11.00/litre.

A little less than twice expensive is Motul RBF 600 with a higher yet WBP (410+ deg F). It is sold in half litre bottles and you can get 2 online, to make your full litre, for around $18.00.

And for the wealthy purist we have Castrol SRF (synthetic racing fluid) at a little over $50.00/litre with an eye-poppingly high WBP.

 

[heliskiier]

Why bleed the brakes if you don't have air in the system? This is the way a dealer rapes you on a pad change. They say it has to be done. It doesn't ever need to be done unless you have air in the system. A pad change rarely puts any air into the system.

 

[Saabohème]

Why bleed the brakes if you don't have air in the system? . . . It doesn't ever need to be done unless you have air in the system.

Brake fluid is hygroscopic. It absorbs moisture over time. It can, and does, absorb moisture through the rubber brake hoses. After only a year in service, the brake fluid may contain as much as 2 percent H2O. After 18 months, the level of contamination can be as high as 3 percent. And after several years of service, it is not unusual to find brake fluid that contains as much as 7 to 8 percent H2O. As the H2O is absorbed, the boiling point of the brake fluid drops dramatically.

Only 1 percent H2O in the fluid can lower the boiling point of a typical DOT 3 fluid to 369 deg F. 2 percent H2O can push the boiling point down to around 320 deg, and 3 percent will drop it to 293 deg, which is getting dangerously close to the minimum DOT and OEM requirements. DOT 4 fluid, which has a higher minimum boiling temperature requirement (446 deg F dry and 311 deg wet) soaks up moisture at a slower rate but suffers an even sharper drop in boiling temperature as moisture accumulates. 3 percent H2O can lower the boiling point as much as 50%!

As well, H2O, the universal solvent, causes corrosion. Brake fluid left inside a closed hydraulic system over extended periods of time will cause corrosion to interior components, including your very expensive ABS unit.

 

[heliskiier]

Brake fluid is hygroscopic. It absorbs moisture over time. It can, and does, absorb moisture through the rubber brake hoses. After only a year in service, the brake fluid may contain as much as 2 percent H2O. After 18 months, the level of contamination can be as high as 3 percent. And after several years of service, it is not unusual to find brake fluid that contains as much as 7 to 8 percent H2O. As the H2O is absorbed, the boiling point of the brake fluid drops dramatically.

Only 1 percent H2O in the fluid can lower the boiling point of a typical DOT 3 fluid to 369 deg F. 2 percent H2O can push the boiling point down to around 320 deg, and 3 percent will drop it to 293 deg, which is getting dangerously close to the minimum DOT and OEM requirements. DOT 4 fluid, which has a higher minimum boiling temperature requirement (446 deg F dry and 311 deg wet) soaks up moisture at a slower rate but suffers an even sharper drop in boiling temperature as moisture accumulates. 3 percent H2O can lower the boiling point as much as 50%!

As well, H2O, the universal solvent, causes corrosion. Brake fluid left inside a closed hydraulic system over extended periods of time will cause corrosion to interior components, including your very expensive ABS unit.

You sound like your writing straight from a dealer's tech manual...

Yeah, great science lesson. Scary sort of. However, in real life, unless you drive the living crap out of your car, you will likely never ever have to bleed brakes, and you will almost certainly never have a failure unless true O2 get's in the lines. Stop trying to sell us stuff we don't need. I'm a wrench too. Not just any idiot posting. Yeah, scare the people and make 100/hour for having done it. People need to know what they are capable of doing themselves, what's really serious and what's not and what their real problem is. I'm sick of folks coming on here and saying they should go pay a wrench hundreds of dollars for something that they can do without a wrench's help.

That's why these sites are on the web. So we can learn.

 

[Saabohème]

You are free to believe what you want. I am not selling anything. Likewise, please do what you want.

I have a pressure bleeder. Every two years I bleed the brakes and it costs me about $30.00 for the litre of Motul RBF 600 I use.

As for your assertions: regardless of how you drive, H2O absorption occurs as a simple function of time. That is it. Nothing more to say about that. I have seen a few ABS modulators that were so corroded due to H2O contamination in the brake fluid that the pistons had frozen completely. I have also seen some caliper pistons corroded badly enough to abrade the seals. Rebuild or replacement are the only solutions for these failures.

And true air rarely gets into the system, absent an improper repair of some sort. What usually happens is that the old brake fluid, with the now inadequate wet boiling point, will boil at the calipers where the heat is transferred, and the boiling brake fluid VAPORIZES, leaving behind bubbles of FLUID VAPOR. Admittedly, boiling at the calipers would be otherwise rare absent hard driving and repeated heavy braking, or when towing, or when descending a sustained downgrade.

I may not agree with your opinion but I respect your right to have it and express it. Please continue to do so with passion and vigor. I would appreciate it if you could refrain from the derogatory "thumbs-down" nonsense and the baseless assumptions that I am shilling for car repairs that are unnecessary. This is not true. Believe me, I am a lawyer.

 

[jimmy154]

I may not agree with your opinion but I respect your right to have it and express it. Please continue to do so with passion and vigor. I would appreciate it if you could refrain from the derogatory "thumbs-down" nonsense and the baseless assumptions that I am shilling for car repairs that are unnecessary. This is not true. Believe me, I am a lawyer.

In lieu of extenuating circumstances; I don't know who to believe :lol:

 

[1stsaab99]

At 11 years possibly on your brake fluid.

Flush it out and get 11 years more.

Simple.

 

[LS1 SAAB]

How many back yard mechanics just push back the caliper pistons and push all that nasty fluid back through the hoses, anti lock modules, seals and back into the master cylinder.

Always open the bleed screw then push the nasty fluid on the ground then wash it away with water. When done with the brake job open the bleeder and let it just gravity bleed.

 

[aerojon]

this thread is 5yrs old..


Closed..