Which brake fluid should be used? DOT 3, DOT 4, or DOT 5.1?

[Lukas2009]

I've read a lot about this. Some say, DOT 4 is only a newer version of DOT 3 and can be used.
But a few years ago, a friend told me that his garage used the wrong brake fluid and damaged the seals and hoses of his Explorers brake system.
Can you tell me your experience?

 

[CDW6212R]

You can use any DOT 3 or DOT 4 brake fluid, and evidently the newest 5.1 fluid.

The old DOT 5 is a silicone kind that cannot be mixed with any of the other brake fluids. It's typically for show cars or vehicles which don't get driven basically at all. That is safe for paint, but it must not be mixed with the other types, and it is very difficult to flush out a system to use that DOT 5. So simply avoid the DOT 5 silicone fluid unless you have a big need for that and are ready for the trouble to remove the other.

 

[94Eddie]

I just went through looking at brake fluid types since I am flushing the fluid in all our vehicles soon. CDW is right about DOT 5 and I decided DOT 4 is what I am using. IMO, DOT 5.1 is only for someone who races and stresses their brakes to the max. DOT 4 is a nice upgrade from DOT 3 that many vehicles are spec'ed to use. The main difference is that DOT 4 has a higher boiling point and might go longer between flushes. Everthing I have seen doing reaesrch shows DOT 4 is compatible with DOT 3 and can replace it.

 

[CDW6212R]

I have used a lot of DOT 4 brake fluid, and rarely have ever considered buying DOT 3. The parts stores carry a small amount of DOT 3 and DOT 4, some have a small selection of higher end brands. I have tried several brands not typical at parts stores, basically everything works about the same.

It's best to choose it based on your driving needs. I'm very hard on brakes so I have had good reason to try better brands etc. I settled on preferring Ate brake fluid, which is an old major brake system maker company. Since it is available in liter cans and larger quantities, I get about seven liters at a time;
Amazon product ASIN B003VXRPL0
They used to make it in two colors, clear and blue, which made it very nice to bleed the entire system. They stopped that before the last time I needed fluid about 6-8 years ago.

 

[Rick]

I've been running this for years in everything I have...

Amazon product ASIN B00AN1X4UE

 

[CDW6212R]

I've been running this for years in everything I have...

Amazon product ASIN B00AN1X4UE

That's a great lower cost choice. Valvoline is one of my favorite old brands, they make the TC fluid that I prefer, about $6 a quart from Amazon years ago.

 

[94Eddie]

That's a great lower cost choice. Valvoline is one of my favorite old brands, they make the TC fluid that I prefer, about $6 a quart from Amazon years ago.

I went with Prestone for $4.06 per 12 oz. On Amazon it is far less expensive to buy several individual bottles of it than a case for some reason.

Amazon -Prestone

 

[CDW6212R]

I read some more and saw how much the 5.1 fluid is being used, and mixed with DOT 3/4 in everything. I compared some of those linked here, and saw another one on the same pages, Bosch has a quart of the 5.1 or what they claim is better than(extended interval), for $14.42, which is almost three times as large as the common 12oz bottles. I think I like that one a lot for the future;

Amazon product ASIN B07338GQM8

 

[FATK]

I've read a lot about this. Some say, DOT 4 is only a newer version of DOT 3 and can be used.
But a few years ago, a friend told me that his garage used the wrong brake fluid and damaged the seals and hoses of his Explorers brake system.
Can you tell me your experience?

Hi There, FATK here. I just did a full brake job and flush on my Dad's 96 Ford Explorer with the 5.0 V8. I looked it up and the book said DOT-3. When I looked at the brake fluid I had in my shop I found DOT-3 (2), DOT-3-4(1) and one big bottle of DOT-4. I used the DOT-3s and the DOT-3-4 bottles up to completely flush and bleed the entire system. The 3-4 bottle said it would work fine with either type. I would have to expect that they are probably compatible with each other. It may be as simple as a slight difference in the additive package that is blended to call it a DOT-4. (Probably for marketing purposes or maybe they discovered they could add something else to make it a little better or less Hydroscopic. (water absorbent). Anyway it seems to work just fine. Brake fluid is not compatible with Buna-N seals or Viton which are very common. EPR, EPDM and Butyl are usually recommended with brake fluid and some specific fire resistant fluids. If you ever install a "Line Lock Valve" make sure it has one of those recommended O-Ring seals on the cartridge of the valve. I hope this helps anyone that is looking for this answer.

 

[94Eddie]

The main difference between DOT 3 and DOT 4 is the boiling point of the fluid. Other than this the differences are not all that substantial. I think the minimum standardized boiling point for DOT 3 is 401 degrees and 446 degrees for DOT 4. DOT 4 typically has a longer service interval than DOT 3. Individual brands usually have different claimed boiling point and service intervals but to use a particular rating they have to meet the minimum DOT standard for that rating.

 

[Lukas2009]

I settled on preferring Ate brake fluid, which is an old major brake system maker company.

There is a video on the german ATE website, where a specialist explains, why not to use DOT 4 in a DOT 3 brake system.
He says, it's because of boric acid ester in DOT 4 and 5.1 brake fluids, which is able to destroy rubber parts in DOT 3 brake systems and could so lead to a complete brake failure.

 

[CDW6212R]

That is very useful information. For older cars that could have those older system seals etc, made of rubber and materials not compatible with the later fluids, DOT 3 would be the only choice unless the system parts were upgraded. I wonder what models that would apply to, which years those changed going along.

 

[fastpakr]

I'm a little curious about that too. It's not like DOT4 is particularly new, and I've never heard any manufacturer warnings before about compatibility issues, or horror stories from owners after switching.

 

[CDW6212R]

I will bet that the DOT 3 system materials issue was from the late 70's, that in the 80's the brake systems did upgrade those materials so DOT 4 is okay for them. But which manufacturers changed their brake systems, and which cars, when did they do it.

I went from 1972 and 1973 Fords to a 1986 Ford at one time, and I'm sure I used DOT 4 in that 86 Crown Vic many times. I put 245,000 miles on that car, and it had 85k on it when I got it at auction. The friend I sold it to fairly cheap, he got two years out of it before he wrecked it. I'm sure DOT 4 is fine for a 1986 CV.

 

[Blackhawkxx]

There is a video on the german ATE website, where a specialist explains, why not to use DOT 4 in a DOT 3 brake system.
He says, it's because of boric acid ester in DOT 4 and 5.1 brake fluids, which is able to destroy rubber parts in DOT 3 brake systems and could so lead to a complete brake failure.

All my motorcycles starting in 1978 always have said to use dot 4, my oldest currently is a 94 that I bought new still has all the factory hoses, seals, etc. I have also used dot 4 in 1970s cars with no issues.

 

[Pinout]

I've read a lot about this. Some say, DOT 4 is only a newer version of DOT 3 and can be used.
But a few years ago, a friend told me that his garage used the wrong brake fluid and damaged the seals and hoses of his Explorers brake system.
Can you tell me your experience?

Dot 3 heavy duty is spec and will absorb less moisture than dot 4. But the most important thing to do, is to flush the system regularly. The new fluid will dissolve varnish out of the system, making it last much longer. I just do a basic flush yearly, and I never have problems with any components.

 

[94Eddie]

I have a question. How many here compress the pistons in the calipers to squeeze out every bit of brake fluid from the system during a flush?

 

[Lukas2009]

How much brake fluid will I need to do a change on a 2006 - 2010 Ford Explorer V6?
The user manual does not contain such information.

 

[Bazz270]

according to my experience

Full change quantity including bleeding procedures on all four calipers approx.: 1.2L.

if ABS pump bleeding procedure involved :1.5L

 

[CDW6212R]

I have a question. How many here compress the pistons in the calipers to squeeze out every bit of brake fluid from the system during a flush?

Flushing all brake fluid is not normal or at all easy. To change to the silicone DOT 5 would be very difficult.

For practical purposes, not changing to DOT 5, it isn't needed to be pushing all the pistons back completely, or cycling the ABS module. Just make a point to fully bleed all four corners at least every couple of years.

When changing pads, it is not proper procedure to compress the pistons without the bleed screws open, that pushes old fluid back into the ABS module, which is the most fragile part of the brakes, and most expensive. The right way to do it is to attach a bleeding hose to the bleed screw, before compressing the caliper pistons. That lets the oldest fluid inside the caliper out first. Then bleeding the brakes after the pads are in gets new fluid through there and any air out that got in by opening the bleed screw.

I gather on another forum about brakes that the Ate fluid is possible to buy the blue fluid version of still, from an international seller. I liked that along with their clear fluid, to help with bleeding. The USA regulations made the blue fluid unapproved many years ago, racers love it for bleeding brakes as I point out, regulations are excessive here.