A few questions about DOT 5 and what TM I need.

[tco3129]

i instead found a dealer who was selling it shipped for 65 dollars

Do you remember where? Got in a pinch and went to NAPA. A quart cost me over $40 OUCH!

 

[Heavysteven]

The use of DOT3 is debatable. Silicon brake DOT 5 is the correct fluid according to the TM's.

 

[joshs1ofakindxj]

The use of DOT3 is debatable. Silicon brake DOT 5 is the correct fluid according to the TM's.

True, but that little sticker can be removed.

 

[Goose2448]

I think that sticker is there more so because its got DOT5 in it. Its like syn oil and reg oil, cant mix them, and cant go back either.

 

[Heavysteven]

I think the decal is to ensure the operator uses the correct brake fluid. The corresponding number matches that of the silicon brake fluid container. Take a look.

 

[joshs1ofakindxj]

I think the decal is to ensure the operator uses the correct brake fluid. The corresponding number matches that of the silicon brake fluid container. Take a look.

I understand the truck was originally supplied with a DOT 5 brake fluid system.

Do you understand that a DOT 5 system can be converted to DOT 3 when the proper steps are followed?

 

[Heavysteven]

I am sceptical on the idea that the brake system can be converted to DOT 3. I have not seen this in the manuals and there are so many warnings to use silicon brake fluid only. My concern would be the associated risk if the proper procedures were not followed. I think it would be reasonable to assume brake failure is one of those risks. All of which is avoidable by using silicone brake fuild.

 

[joshs1ofakindxj]

There are enough people converting to DOT 3 without their trucks exploding that you can at least admit it can be done properly, so telling people they absolutely must use DOT 5 is not true. Yes, it was designed to use DOT 5 for military purposes. I'm modifying my truck to work for my needs now.

It is a simple conversion to do. Old fluid out. Clean or replace components. New fluid in.

There are advantages and disadvantages to both fluids: cost, availability, boiling temperature, hygroscopic characteristics, effect on painted surfaces, compatibility with seals.

In the end, a hydraulic fluid in a hydraulic system will act accordingly.

I installed a remote brake fluid reservoir in the cab of the truck next to the driver's seat. Now I can see my brake fluid level every time I get in the truck. Should I remove that because it wasn't in the TM?


For the record, I also own a 1979 Corvette that has DOT 5 brake fluid in it. That car could see higher braking temperatures that justify DOT 5 and has all stainless brake calipers and lines, so some water collecting in the system is not corrosive. I'm not some kind of anti-DOT 5 zealot.

 

[dozer1]

There are enough people converting to DOT 3 without their trucks exploding that you can at least admit it can be done properly, so telling people they absolutely must use DOT 5 is not true. Yes, it was designed to use DOT 5 for military purposes. I'm modifying my truck to work for my needs now.

I think they were actually designed for DOT 3 and converted to DOT 5 later on by the military, for their purposes. I do not know this for a fact, just seen it pointed out in other threads before.

 

[Loco_Hosa]

]I'm modifying my truck to work for my needs now.

I think they were actually designed for DOT 3 and converted to DOT 5 later on by the military, for their purposes. I do not know this for a fact, just seen it pointed out in other threads before.

I was think this same thing while reading the thread, but perhaps I have my facts wrong?

I think I have decided to go with DOT 3 for my truck, this time. Its likely that I will be back into my brakes again at a later date, I may decide to go with DOT 5 then.

The only thing left to do before I put my tires back on (A few people don't like it on jack stands, so I am being urged to hurry up and get it back on its tires) is repack the bearings and readjust the brake shoes (This time with a feeler gauge as per the TM)

 

[dozer1]

Hey Loco. Just my opinion which is based on what I was taught at a vo-tech, don't switch to DOT 3 unless you are going through everything. (MC, air pack, ALL wheel cyls, replace flex hoses, best job humanly possible to clean hard lines) I have always advocated that it would be great to do that, then be able to use much cheaper and widely available DOT 3. But if you don't intend to do it all, I would stick with DOT 5. Not trying to sound harsh, but don't switch back and forth, back and forth.

Me personally, I have always wanted to switch one to DOT 3, but have never needed to re-do the whole brake system yet on a truck. That combined with shear laziness has kept me buying surplus DOT 5.

 

[Katahdin]

The Army has compared Dot 3 to Dot 5 when issues were suspected. There's lots of hydraulic pressure data in this study:

http://www.steelsoldiers.com/conversations/77218-deuce-5-ton-brake-fluid-performance-study.html

 

[mikew]

Here's some basic info about DOT 3 and DOT 5, and how to tell which one you have:

Brake Fluid

 

[Heavysteven]

Hey Loco. Just my opinion which is based on what I was taught at a vo-tech, don't switch to DOT 3 unless you are going through everything. (MC, air pack, ALL wheel cyls, replace flex hoses, best job humanly possible to clean hard lines) I have always advocated that it would be great to do that, then be able to use much cheaper and widely available DOT 3. But if you don't intend to do it all, I would stick with DOT 5. Not trying to sound harsh, but don't switch back and forth, back and forth.

Me personally, I have always wanted to switch one to DOT 3, but have never needed to re-do the whole brake system yet on a truck. That combined with shear laziness has kept me buying surplus DOT 5.

Sounds like you would have to do a complete brake overhaul to avoid mixing. It's not as simple as filling up a pressure bleeder with DOT 3 and pumping out the Silicon Fluid.

 

[dozer1]

Sounds like you would have to do a complete brake overhaul to avoid mixing. It's not as simple as filling up a pressure bleeder with DOT 3 and pumping out the Silicon Fluid.

That would be best, without a doubt. Now could you get away with just pumping DOT 3 in the system? Maybe, and I am sure it has been done. I just know its best to start with fresh rubber seals in everything as one fluid tends to shrink rubber, while the other expands it. Also like you said, just to get all of the other fluid out would be very difficult without rebuilding all of the components.