Dot 5 Fluid and CSSB Warning

[Owen L.]

I realize this is an old issue/topic and I felt my comments would be best connected to the following thread:
https://www.forums.ncrs.org/showthre...+Delco+Moraine

It appears that Lonestar does not have any DOT 5 warnings on their warranty or installation instructions for either the lip seal or O-ring calipers. Does anyone have info that shows otherwise? Additionally, I recently received lip seal caliper rebuild kits made by Raybestos and there is no notice whatsoever about using DOT 5 fluid. I would think that if it were a problem with their products they'd certainly make it known.

As an aside, I find it humorous that Corvette Stainless Steel Brakes Inc. put Will Void Warranty in quotation marks. Who are they quoting? (As a teacher for elementary school literacy, I'd have to ding my kids if they used quotation marks inappropriately.) The link they offer as back up proof of problems with DOT 5 contains not one reference to any DOT spec and appears a misdirection for their justification.

Here's the background of why this came up for me: I am in the process of rebuilding/replacing my '72s brake system. After about 28 years of storage the fluid had evaporated/jelled/dried to powder in all of the components -- probably DOT 3 or 4 but I don't recall. I have changed out the brake lines and rebuilt the master cylinder. The front calipers were changed to sleeved SS from Vette Brakes and Products 30 years ago; other than a couple of dark stains there is no indication the liners have suffered. I plan on having the caliper halves' mating surfaces machined because they seem a tad rusted and I want to be sure they mate well. I believe the rear calipers are original to the car, the bores are pitted and must be replaced.

I also have a '67 which has had sleeved lip seal calipers since the mid-80s-ish. Since day one they have had DOT 5 fluid and show no signs of leaking or any sort of spongy pedal. I'd like the same performance with the '72. Which brings me to my research on what's out there. I realize there is quite the contingent of O-ring believers, but it's hard to argue against 35 years of positive lip seal experience.

No real question here, just yakking.

[Stephen L.]

Re: Dot 5 Fluid and CSSB Warning

I've had DOT 5 silicone in my 67 since about 1983. I've also had DOT 5 in my Mopar since the 1980's. NO problems in either car. Fluid is as clean as when initially installed. No spongy pedal either..... one is standard brakes, the other is power. I'm a firm believer in DOT 5. Another advantage; a spill will NOT remove paint!!!!!

[Gary B.]

Re: Dot 5 Fluid and CSSB Warning

Almost hate to reply to this thread and get my poor typing skills and grammar graded. But what the hell.

Lonestar does indeed put stickers on there boxes. Attached is a picture from a few weeks ago. One on each box and the mater cylinder.

I have quit using DOT 5 on any car I work, or still do maintenance work on, except for two cars. One is a 71 that the owner refuses to convert, so like clock work, every 12-months it gets new caliper rebuilt after dripping on the new floor. The other car, it's probably been in there for 30 or 40 years and still don't leak. Why? Who know. Somewhere the seal material changed, the brake fluid changed, or both. If a brake manufacturer tells me not to use DOT 5, I'll listen to them. I don't like the sound of breaking fiberglass.

I have recycled all my DOT 5 (Safety Kleen oil drum), except for a little STP metal can I keep for nostalgia. All I use is Dot 3 or Dot 4. Non of the Corvettes I work on get driven hard enough to boil Dot 4.

Attached is Lonestar decal on all four boxes....

20200511_181603.jpg

Gb

[Patrick H.]

Re: Dot 5 Fluid and CSSB Warning

The 77 here had DOT5 in it for years, but eventually the fronts leaked. The back ones did not. They had all been sleeved many, many years ago.

I wet through 3 sets of Raybestos seals in the fronts before I threw in the towel and bought new calipers from Lonestar.
Guess what? Leaked with DOT5 which the owner insisted I use despite the warning shown by Gary.
Tried Raybestos seals in the new caliper. Leaked.
Converted the whole system to DOT3...and the right front leaks twice again despite new Raybestos seals.

I have a new set of O-ring pistons that will go in both front calipers soon. It will be my last ditch effort to get these to stop leaking.
The back ones? Still don't leak and never have. I don't know why.
I've serviced calipers on other cars and never had recurrent leaks like I do with this one.

Even though the Cartel DOT5 fluid says it will work with modern seals, and Raybestos seals say they will work with DOT5... apparently they don't.

Oh, and the Raybestos seals are better than what came in the Lonestar calipers.

I have plenty of new Cartel DOT5 fluid if you want to buy it from me.

Patrick

[Owen L.]

Re: Dot 5 Fluid and CSSB Warning

<snip>
I wet through 3 sets of Raybestos seals in the fronts before I threw in the towel and bought new calipers from Lonestar.
Guess what? Leaked with DOT5 which the owner insisted I use despite the warning shown by Gary.
Tried Raybestos seals in the new caliper. Leaked.
Converted the whole system to DOT3...and the right front leaks twice again despite new Raybestos seals.

Seems like no fluid will stay inside long term with the calipers and seals on that car, not just DOT 5...

Are other antique and collector car marques having the same issues with brake systems and suppliers?

[Owen L.]

Re: Dot 5 Fluid and CSSB Warning

Almost hate to reply to this thread and get my poor typing skills and grammar graded. But what the hell.

Attached is Lonestar decal on all four boxes....

[ATTACH=CONFIG]98830[/ATTACH]

Gb

No worries on grammar or typing - I generally don't correct folks, just companies and advertising.

Huh. Isn't that the exact sticker CSSB uses? I find that a tad odd.

Does anyone know the molecular size of DOT 3, 4, 5.1 vs. DOT 5? Could it be that DOT 5 is much smaller, leading to leaks? Is there a chemical measure of slippery-ness?

[Tom M.]

Re: Dot 5 Fluid and CSSB Warning

After 15 years with DOT5 my front calipers started leaking. I attributed it to the car sitting way too much. For replacements (received in February) Muskegon drop shipped calipers that had been built by Lone Star and that exact yellow sticker and LR,RR,LF,RF stamp was on the box.
The project of flushing the DOT5 for DOT4 was completely un-fun. It looks like there are caliper rebuilding kits with silicone o-rings and seals available for our cars so I'm already planning on caliper service within the next couple of years.
Silicone fluid has been in my '42 jeep for 22 years. When using Castrol LMA in the jeep I had rusty frozen wheel cylinders within 5 years of a rebuild because of the humidity.

[Patrick H.]

Re: Dot 5 Fluid and CSSB Warning

Seems like no fluid will stay inside long term with the calipers and seals on that car, not just DOT 5...

This car had the previously sleeved calipers, those same calipers that I honed, and now the Lonestar calipers.
I have no idea why they continue to leak even though I am beyond picky about installing seals. Will the O-rings fix it? I dunno, stay tuned.
It doesn't make sense.

[Joe L.]

Re: Dot 5 Fluid and CSSB Warning

Another advantage; a spill will NOT remove paint!!!!!

Steve------

I think that's the biggest advantage. If anyone has a spill happen to them with DOT 3 or 4, they'll think so, too.

[William F.]

Re: Dot 5 Fluid and CSSB Warning

O rings much less likely to leak. BUT, if your rotors have excessive runout, even o ringed calipers will leak.

[Jim L.]

Re: Dot 5 Fluid and CSSB Warning

I think that's the biggest advantage. If anyone has a spill happen to them with DOT 3 or 4, they'll think so, too.

Joe,

I put DOT 5 fluid in the brake systems of our track cars because of its lack of affinity for water and its extremely high boiling point. Those two properties have meant that I don't have to obsessively bleed the brakes before each track event. Being a lazy individual, I consider that a huge win.

Jim

[Patrick B.]

[Owen L.]

Re: Dot 5 Fluid and CSSB Warning

One of the DOT 5 criticisms I've come across is that water can form pockets of moisture in the low spots, since the water is the denser of the two liquids, causing rust point failures. The thought process is that since #3 and 4 are hygroscopic / hydrophilic the water is entrained and regular system flushes clear it out. How would moisture enter the DOT 5 system since silicone is hydrophobic?

[Patrick B.]

Re: Dot 5 Fluid and CSSB Warning

One of the DOT 5 criticisms I've come across is that water can form pockets of moisture in the low spots, since the water is the denser of the two liquids, causing rust point failures. The thought process is that since #3 and 4 are hygroscopic / hydrophilic the water is entrained and regular system flushes clear it out. How would moisture enter the DOT 5 system since silicone is hydrophobic?

[Owen L.]

Re: Dot 5 Fluid and CSSB Warning

Thank you Patrick. I didn't realize the rule change proposal was withdrawn. I found it somewhat difficult to decipher what that rule document was getting at, so thank you for the clarification that it was focusing on rubber compounds and not fluid compositions. I read something about the EPDM compound being evaluated but wasn't clear on what became of anything.

I assume that brake component manufacturers as well as those offering rebuilding, like Lonestar and CSSB, must have some sort of testing and safety assurance evaluations in place, yes? For example, do stainless sleeved calipers meet or exceed SAE/NHTSA/etc. braking requirements? Do the assembled components also have to pass any sort of evaluation?

I would be more worried about brake fluid that removes paint degrading your Chinese seals than silicone fluid that you can polish your car with and probably ingest in small amounts without harm.

I presume the comment about silicone fluid as polish is a bit tongue in cheek. How difficult is it to repaint a surface that had silicone fluid exposure? Will a standard fish-eye eliminator eliminate any problems? If I do get a spill, is it probably good practice to wipe the area with a silicone solvent like naphtha or paint thinner?