Dot5 or DOT 3/4/5.1

[Mullaney]

I am not going to get in the debate of what is better 3 or 5 but I will say I use 5 in my truck. But on to the more pertinent question that has not really been dealt with. Your wheel cylinder cups swelling 2x it’s original size is a major problem and is not related to what fluid you use as these parts are compatible with both fluids. You must have gotten a faulty part because that should not happen regardless of what fluid used. I would return them and find a different source as that is just not normal or acceptable.

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Maybe the rubber is some sort of import?
The rules are different here than other places.
Sadly, the seller and the buyer doesn't know they have a problem until it is too late.

 

[davidb56]

Rubber from China is the worse product available. Subaru timing belts use rubber from another Indonesia country such as Malaysia, (memory is bad) and is great. I used a Chinese one one time and it wore in 20K. Same with coolant hoses as they seem to swell quite a bit. So I stay away from Chinese rubber and wiring products as much as I can....which sometimes is impossible.

 

[The King Machine]

Been using DOT 3 in my truck for almost 10 years with oversize tires.

On Road, off road, loaded, and unloaded.

No issues to report, aside for the odd leaking wheel cylinder. Usually a quick fix.


My truck originally came with DOT 5, every single wheel cylinder was bypassing fluid. All new wheel cylinders and a diligent flush. I also bleed the brakes periodically and add fresh fluid. I noted pitting in all of the cylinders, which leads me to believe [B]Elijah95[/B] in post #5 may be onto something. Especially if the truck sits for long periods. The previous owner would off road the truck in very wet conditions and then park it for months.

I changed to DOT 3 because I had giant jugs of it in my shop already. If DOT 5 was readily available and cheap I would have kept it. Looking back, I'm glad I switched over to DOT 3.

MY 2 cents

 

[V8srfun]

Rubber from China is the worse product available. Subaru timing belts use rubber from another Indonesia country such as Malaysia, (memory is bad) and is great. I used a Chinese one one time and it wore in 20K. Same with coolant hoses as they seem to swell quite a bit. So I stay away from Chinese rubber and wiring products as much as I can....which sometimes is impossible.

I agree on one hand but disagree on another what I mean is that it depends on who places the production order. Some of the stuff that comes from China is acceptable quality but it must be ordered correctly. Unfortunately most that order from China are racing to the bottom and don’t care about quality. Now I am not saying that Chinese manufacturing is as good as American but in most cases they are capable of producing a decent product but most are ordering Chinese because they will build as cheap and crappy as you want.

 

[Mullaney]

I agree on one hand but disagree on another what I mean is that it depends on who places the production order. Some of the stuff that comes from China is acceptable quality but it must be ordered correctly. Unfortunately most that order from China are racing to the bottom and don’t care about quality. Now I am not saying that Chinese manufacturing is as good as American but in most cases they are capable of producing a decent product but most are ordering Chinese because they will build as cheap and crappy as you want.

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Nicely said V8srfun

There is definitely a race to the bottom in a lot of things. I may have even stated before in these forums that I am willing to pay a little more for American Made hardware - like a lot of other folks. I think what we all want is good and functional especially when lives depend on it like with brake parts.

 

[glcaines]

I stay as far from Chinese goods as possible. Sometimes it isn't possible. I was responsible for equipping a very large manufacturing facility in China with hand tools, machine tools and electronic equipment. I was under mandatory orders from the Chinese management to not purchase any Chinses tools. I was only allowed to purchase American, Swedish and German tools, regardless of cost. The Chinese know they make inferior products.

 

[Mullaney]

I stay as far from Chinese goods as possible. Sometimes it isn't possible. I was responsible for equipping a very large manufacturing facility in China with hand tools, machine tools and electronic equipment. I was under mandatory orders from the Chinese management to not purchase any Chinses tools. I was only allowed to purchase American, Swedish and German tools, regardless of cost. The Chinese know they make inferior products.

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Yeah, I know. What!?

That goofy "heart in the eyes" icon is about the best thing we have here to voice real goodness to something posted.
Really makes my day to hear that said! Maybe there are a few good Chinamen after all.

 

[Phil P]

Thanks to all of you for this information.

The only thing I have to say is I have soaked a brake cylinder cup intended to be used in Dot 3 in my Dot 5 fluid and it swelled up to a very large size.

The problem is with all of this information it is still not clear if you can just change a Dot 3 system to Dot 5 wihout doing any thing about the type of runbber used in the brake syastem.

Phil P

 

[Mullaney]

Thanks to all of you for this information.

The only thing I have to say is I have soaked a brake cylinder cup intended to be used in Dot 3 in my Dot 5 fluid and it swelled up to a very large size.

The problem is with all of this information it is still not clear if you can just change a Dot 3 system to Dot 5 wihout doing any thing about the type of runbber used in the brake syastem.

Phil P

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I had done some more reading after our thread here ran its course.

Like so many things, there are two camps. One who claims if you aren't running DOT 5 the world will end. The other is the DOT 3 camp who thinks everybody is stupid who didn't stay with what the owners manual says. As I saw and read more, it does seem that there are quality brake parts manufacturers and the rest of the "sellers". Years ago, "cheap imports" were how you could tell the difference. Now more and more folks are chasing the almighty dollar and seem to have lost their scruples.

Over a period of a week, I bought 6 sets of brake cups for a 1967 Chevrolet Impala. As they arrived I could visually see different rubber compounds. Some were rougher than others. Some seemed glossier and I even found one Genuine GM that had Made in the USA molded into the rubber. My plan is to run a test like yours with a cup in 3 and another in 5. Not very scientific though. Still will be interesting to see the results...

 

[V8srfun]

Thanks to all of you for this information.

The only thing I have to say is I have soaked a brake cylinder cup intended to be used in Dot 3 in my Dot 5 fluid and it swelled up to a very large size.

The problem is with all of this information it is still not clear if you can just change a Dot 3 system to Dot 5 wihout doing any thing about the type of runbber used in the brake syastem.

Phil P

You should be able to change any dot 3 system to dot 5 without issues. You got a bad batch that had improperly made rubber seals. Brake fluid is unique in the fact that it is engineered to be reverse compatible. What I mean by this is any system it takes dot 3 can take any higher grade as long as it is flushed properly first. The problem you experienced has nothing to do with type of fluid used.

 

[Mullaney]

You should be able to change any dot 3 system to dot 5 without issues. You got a bad batch that had improperly made rubber seals. Brake fluid is unique in the fact that it is engineered to be reverse compatible. What I mean by this is any system it takes dot 3 can take any higher grade as long as it is flushed properly first. The problem you experienced has nothing to do with type of fluid used.

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Exactly as it should be... Just like the Dextron II to Dextron III and so on.
Thinking about it, I haven't heard about that problem in transmissions.

 

[M37M35]

I switched my deuce from dot3 to dot5 about a year ago with no issues. I rebuilt the master cylinder and airpacs at the same time so they only had fresh dot 5 in them, but I didn't touch the wheel cylinders.
I think you ended up with some cheap/defective rubber parts.