Saturn ION RedLine Forums banner

1 - 20 of 48 Posts

·
Superd00d
Joined
·
22,040 Posts
Discussion Starter #1
Anyone have any tips on changing your brake fluid? I mean totally purging it out and refilling the system. I've never had to do that before, that I can think of. Should I assume it's just like bleeding them for a long time, or is it something that would be 'shop-worthy'? If I can have a brake shop do it for $30 and 30 min, I'll go that route.

Also, anyone know anything about the different levels of brake fluid? I'm looking for a high-temp, racing quality fluid, but the DOT3, DOT4, etc... have me a little confused. Is that just so you don't mix different types together, or do certain brake setups require certain brake fluids, like engine oil.
 

·
Registered
Joined
·
2,143 Posts
I have done my brake fluid once before and will be doing it again this weekend. When I went to autozone I had them look up the type of fluid for our cars and they came up with DOT 3, so that what I used. I bought the sythetic fluid. I also bought a one person bleeding kit and I didnt have much luck with it. It was ten times easier for me to have someone pump the pedal as I bled each caliper. The difference in the colors between the OEM fluid and the Prestone stuff I bought was significant enough that I just bled each caliper until new fluid came out. You gotta top off the master cylinder every now and then while doing this. Once I got the second person to pump the pedal it only took about 15 min. to do.

I hope I didnt give you any bad info. There are a lot of people that know more that me about this stuff. This what worked for me though.

I think the difference between fluids is the lubrication qualities between DOT 3, DOT4, ect.....
 

·
Superd00d
Joined
·
22,040 Posts
Discussion Starter #3
It seems the higher temp brake fluid is a higher DOT rating, I also noticed that the silicone fluid seems to be the best. Not totally sure.
 

·
Registered
Joined
·
2,233 Posts
DOT3 non-silicone type for your ION Sp00ner.
Many internal parts not compatible with DOT4
Also when bleeding brakes, the recommended method is a pressure bleed (master cyl pressurized to 25-30 psi) FOLLOWED BY AN ABS AUTO-BLEED. This is an automated bleed of the ABS modulator using a scan tool, and is very important as air can get trapped in the ABS hydraulic unit during bleeding or service. This air can go undetected (pedal feels OK) until the first ABS event where it can both disrupt ABS performance and/or result in a spongy pedal afterwards.
HTH
WOT
 

·
Superd00d
Joined
·
22,040 Posts
Discussion Starter #5
So, just head to a brake shop there Wop? Or Saturn? I'm not one that like to play with the brakes, at least not that aspect of the brakes. I'm getting steel lines as well. So any DOT3 (non-silicone) fluid? Is the DOT4+ all silicone based or something?
 

·
Registered
Joined
·
283 Posts
Here at the shop we use DOT4 for all of our brake flushes. We have been doing that for a few years now with no problems in any vehicle. The DOT4 has a higher heat tolerance than DOT3. We use a machine that attaches to the top of the master cyl and pressurizes the system and runs about a full quart of fluid through the system. We have not ever had to do a bleed of the ABS system afterwards since there is always fluid present with no chance of air getting into the system.
 

·
Registered
Joined
·
2,233 Posts
Sp00ner said:
So, just head to a brake shop there Wop? Or Saturn? I'm not one that like to play with the brakes, at least not that aspect of the brakes. I'm getting steel lines as well. So any DOT3 (non-silicone) fluid? Is the DOT4+ all silicone based or something?
I recommend your dealer of course.
But look in your owners manual under
'"Recommended Fluids and Lubricants"
GM recommends ONLY DOT3 brake fluid in all of their products and train thier dealers to do the same. DOT4 and 5 fluids cannot be guaranteed to be compatible with all of the materials it may come in contact with ,in a modern brake system.

As far as brake system "flushing" goes, GMs position is stated in TSB# 04-06-01-029
In normal usage, GM vehicles do not require additional procedures or additives beyond what’s presented in the former Vehicle Maintenance Schedules and the current Simplified Maintenance Schedules. Maintenance schedules do not call for flushing of engine crankcases, fuel injectors, A/C lines, radiators, transmission coolers, brake systems, or power steering systems as a part of regular scheduled maintenance.
If there's been some sort of "contamination", that's another story and GM has an FSM process to deal in with that event.
WOT
 

·
Registered
Joined
·
283 Posts
From my understanding of it, you can go to DOT4 from DOT3, but you can't go down from a DOT4 system to a dot3. From what we were told from BG when we started using this system is that you can flush the entire system and put DOT4 in it, but you shouldnt just top off the DOT3 with DOT4. We have used DOT4 in all makes and models when we flush them with no problems.
 

·
Registered
Joined
·
2,233 Posts
racenpilot said:
From my understanding of it, you can go to DOT4 from DOT3, but you can't go down from a DOT4 system to a dot3. From what we were told from BG when we started using this system is that you can flush the entire system and put DOT4 in it, but you shouldnt just top off the DOT3 with DOT4. We have used DOT4 in all makes and models when we flush them with no problems.
As with anything like this the best course of action in general is to go with the manufacturer's recommendations. For instance, if a repair facility chose to use a DOT4 or 5 fluid in a GM car or truck AND that vehicle was involved in litigation (for an accident maybe?) then that repair facility can be found negligent for not performing service as the manufacturer recommends.
Quite simply GM does not recommend ANYTHING but DOT3 (even in a C6 Corvette!) so doing anything otherwise opens you up to potential lawsuits.

JMO
WOT
 

·
Registered
Joined
·
2,012 Posts
You can by a syringe from the parts store to suck up all of the old fluid from the master cyliner. Then put the new stuff in and bleed the brakes. Do it yourself, it's so simple.
 

·
Registered
Joined
·
1,444 Posts
racenpilot said:
From my understanding of it, you can go to DOT4 from DOT3, but you can't go down from a DOT4 system to a dot3. From what we were told from BG when we started using this system is that you can flush the entire system and put DOT4 in it, but you shouldnt just top off the DOT3 with DOT4. We have used DOT4 in all makes and models when we flush them with no problems.
What that basicly means is if something goes wrong with a braking system and someone gets dead or hurt, say a seal leaked. Then you are on the hook for it and all GM has to say is " we recommend DOT3 just for this reason" Bang, huge insurance settlement and maybe out of business.... wow....


Mark
 

·
Registered
Joined
·
2,233 Posts
mailmars said:
What that basicly means is if something goes wrong with a braking system and someone gets dead or hurt, say a seal leaked. Then you are on the hook for it and all GM has to say is " we recommend DOT3 just for this reason" Bang, huge insurance settlement and maybe out of business.... wow....


Mark
Trust me, it happens- and more than people realize. Maybe not as prevalent as medical malpractice suits but getting there. In a LARGE SUIT (multiple fatalities, heavy loss) the big insurance companies will even pay for "auto autopsies" on the wreck/s and attempt to determine if any sort of defect, modification or incorrect service/repair could have been a contributing factor.
Not something to mess around with IMO
WOT
 

·
Registered
Joined
·
1,444 Posts
matt said:
You can by a syringe from the parts store to suck up all of the old fluid from the master cyliner. Then put the new stuff in and bleed the brakes. Do it yourself, it's so simple.
And you are going to bleed the ABS circuit how?


Mark
 

·
Registered
Joined
·
283 Posts
Battle of the DOTs
DOT 3-4 Verses DOT 5. Which brake fluid should I use?

From Oak Okleshen #35 "With regards to the DOT 3-4 verses DOT 5 brake fluid controversy, here is an article sent to me by Mr. Steve Wall. It is one of the most professional treatments I have seen on the subject".

[I had to condense this article from 6 pages to 1 due to space limitations -ed]

Brake Fluid Facts
by Steve Wall

As a former materials engineering supervisor at a major automotive brake system supplier, I feel both qualified and obligated to inject some material science facts into the murky debate about DOT 5 verses DOT 3-4 brake fluids. The important technical issues governing the use of a particular specification brake fluid are as follows:

1. Fluid compatibility with the brake system rubber, plastic and metal components.
2. Water absorption and corrosion.
3. Fluid boiling point and other physical characteristics.
4. Brake system contamination and sludging.

Additionally, some technical comments will be made about the new brake fluid formulations appearing on the scene.

First of all, it's important to understand the chemical nature of brake fluid. DOT 3 brake fluids are mixtures of glycols and glycol ethers. DOT 4 contains borate esters in addition to what is contained in DOT 3. These brake fluids are somewhat similar to automotive anti-freeze (ethylene glycol) and are not, as Dr. Curve implies, a petroleum fluid. DOT 5 is silicone chemistry.
Fluid Compatibility

Brake system materials must be compatible with the system fluid. Compatibility is determined by chemistry, and no amount of advertising, wishful thinking or rationalizing can change the science of chemical compatibility. Both DOT 3-4 and DOT 5 fluids are compatible with most brake system materials except in the case some silicone rubber external components such as caliper piston boots, which are attacked by silicon fluids and greases.
Water absorption and corrosion

The big bugaboo with DOT 3-4 fluids always cited by silicone fluid advocates is water absorption. DOT 3-4 glycol based fluids, just like ethylene glycol antifreezes, are readily miscible with water. Long term brake system water content tends to reach a maximum of about 3%, which is readily handled by the corrosion inhibitors in the brake fluid formulation. Since the inhibitors are gradually depleted as they do their job, glycol brake fluid, just like anti-freeze, needs to be changed periodically. Follow BMW's recommendations. DOT 5 fluids, not being water miscible, must rely on the silicone (with some corrosion inhibitors) as a barrier film to control corrosion. Water is not absorbed by silicone as in the case of DOT 3-4 fluids, and will remain as a separate globule sinking to the lowest point in the brake system, since it is more dense.
Fluid boiling point

DOT 4 glycol based fluid has a higher boiling point (446F) than DOT 3 (401F), and both fluids will exhibit a reduced boiling point as water content increases. DOT 5 in its pure state offers a higher boiling point (500F) however if water got into the system, and a big globule found its way into a caliper, the water would start to boil at 212F causing a vapor lock condition [possible brake failure -ed.]. By contrast, DOT 3 fluid with 3% water content would still exhibit a boiling point of 300F. Silicone fluids also exhibit a 3 times greater propensity to dissolve air and other gasses which can lead to a "spongy pedal" and reduced braking at high altitudes.

DOT 3 and DOT 4 fluids are mutually compatible, the major disadvantage of such a mix being a lowered boiling point. In an emergency, it'll do. Silicone fluid will not mix, but will float on top. From a lubricity standpoint, neither fluids are outstanding, though silicones will exhibit a more stable viscosity index in extreme temperatures, which is why the US Army likes silicone fluids. Since few of us ride at temperatures very much below freezing, let alone at 40 below zero, silicone's low temperature advantage won't be apparent. Neither fluids will reduce stopping distances.

With the advent of ABS systems, the limitations of existing brake fluids have been recognized and the brake fluid manufacturers have been working on formulations with enhanced properties. However, the chosen direction has not been silicone. The only major user of silicone is the US Army. It has recently asked the SAE about a procedure for converting from silicon back to DOT 3-4. If they ever decide to switch, silicone brake fluid will go the way of leaded gas.
Brake system contamination

The single most common brake system failure caused by a contaminant is swelling of the rubber components (piston seals etc.) due to the introduction of petroleum based products (motor oil, power steering fluid, mineral oil etc.) A small amount is enough to do major damage. Flushing with mineral spirits is enough to cause a complete system failure in a short time. I suspect this is what has happened when some BMW owners changed to DOT 5 (and then assumed that silicone caused the problem). Flushing with alcohol also causes problems. BMW brake systems should be flushed only with DOT 3 or 4.

If silicone is introduced into an older brake system, the silicone will latch unto the sludge generated by gradual component deterioration and create a gelatin like goop which will attract more crud and eventually plug up metering orifices or cause pistons to stick. If you have already changed to DOT 5, don't compound your initial mistake and change back. Silicone is very tenacious stuff and you will never get it all out of your system. Just change the fluid regularly. For those who race using silicone fluid, I recommend that you crack the bleed screws before each racing session to insure that there is no water in the calipers.
New developments

Since DOT 4 fluids were developed, it was recognized that borate ester based fluids offered the potential for boiling points beyond the 446F requirement, thus came the Super DOT 4 fluids - some covered by the DOT 5.1 designation - which exhibit a minimum dry boiling point of 500F (same as silicone, but different chemistry).

Additionally, a new fluid type based on silicon ester chemistry (not the same as silicon) has been developed that exhibits a minimum dry boiling point of 590F. It is miscible with DOT 3-4 fluids but has yet to see commercial usage.
 

·
Superd00d
Joined
·
22,040 Posts
Discussion Starter #16
Ok, so the GM suggestion is DOT3, and I assume there must be SOME reason for that.

It SEEMS from this article that you could also use DOT4, IF you disregard the manufacturer's suggestion. Thanks guys. Good stuff.

What do you personally think about the DOT4 idea Wop? Would you do it if you racing, and only racing, rather than also driving on the street?

Any idea of the boiling point of the standard brake fluid? That's sorta what I'm looking for in a new fluid, is one with a higher boiling point.

Is there a difference between synthetic and regular fluids, or is that the difference between DOT3-4 and DOT5?
 

·
Registered
Joined
·
283 Posts
Just a little tidbit of info I found on the different types of fluids.
 

·
Registered
Joined
·
283 Posts
DOT 4 glycol based fluid has a higher boiling point (446F) than DOT 3 (401F).
 

·
Registered
Joined
·
2,233 Posts
Nice article and all (there are over 700 SAE papers related to "brake fluids")
but it doesnt change the fact that GM recommends "DOT3 ONLY" in ALL of their passenger cars and trucks. I'm not disputing the performance advantages that might exist in the DOT4+ fluids. And an owner can do whatever he/she wants of course (syphon it with a garden hose and replace it with SuperDuper DOT7+++) and may even get great results, but that wont change what the manufacturer recommended procedures or fluids.
Fortunately (UN?) on a safety system such as brakes, these recommendations take precident.
WOT
 

·
Registered
Joined
·
2,233 Posts
Sp00ner said:
Ok, so the GM suggestion is DOT3, and I assume there must be SOME reason for that.

It SEEMS from this article that you could also use DOT4, IF you disregard the manufacturer's suggestion. Thanks guys. Good stuff.

What do you personally think about the DOT4 idea Wop? Would you do it if you racing, and only racing, rather than also driving on the street?

Any idea of the boiling point of the standard brake fluid? That's sorta what I'm looking for in a new fluid, is one with a higher boiling point.

Is there a difference between synthetic and regular fluids, or is that the difference between DOT3-4 and DOT5?
Spooner, in an off-road race car OF COURSE! But I would never recommend a brake fluid that a manufacturer specifically says NOT to use on a vehicle used on public roadways. You need only tread into the FSM "Brakes" section to observe the GM recommendations of: "fluids labled DOT-3 ONLY"

Like I said IT'S YOUR CAR and if you wanted to change it to DOT4 to rasie the BP slightly for weekend competition, you certainly can. Providing you were willing to assume responsibility for ANYTHING that MIGHT occur as a result. I would also make sure when you sold the car you either switched it back, or made sure your included full disclosure of this modification at time of sale.

I may sound a bit paranoid, but having been involved with some of these cases (and our current SUE EVERYONE legal climate) and you really cant be too careful. I recently heard of a case where a guy sold a car that included a baby car seat, that got sued when the installation turned out to be sub-standard and there was an unfortunate accident. Even though it's the operators responsibility to insure the baby seat was secure correctly, the original owner was found negligent and held partially responsible in the settlement.

WOT
 
1 - 20 of 48 Posts
Top