Geez I miss going for a drive.

[Hazdaz]

Howdy gents.  My Riv has been hibernating for some 8 months.  Longest I've gone without driving her since I got her.  Took her out for a very short drive yesterday and today.  Definitely need to change out the fluids and get some things checked out.  Hate to say it that she's got the cancer - behind the rear quarter panel, there's rust.  Looking for ways to keep it from spreading now and thinking about a solution moving forward.

 

For now, I am thinking about brake fluid and coolant.  Any reason not to go with the latest DOT brake fluid 4 or 5.1?  Websites say they are all backward compatible if they are glycol based (as opposed to 5 which is silicone based and not compatible).  Similar deal with coolant? 

 

And to be clear, I do have the manual, but with chemistry advances, figured I would see if the newer stuff is better than more period-correct fluids.

[Seafoam65]

You need to flush out all the old brake fluid and install silicone DOT 5 fluid. If you do that,

your brake hydraulics will last longer than your human life span. I run DOT 5 in all my older cars

that don't have antilock brakes, and I have old cars with the same wheel cylinders, calipers, and master cylinder for decades and decades......plus if you do have to work on the brake system, DOT 5 won't damage your paint if you spill it on the car......it's a no-brainer. As an example of what I'm talking about......my 69 GTO which has had DOT 5 in the brakes for 47 years still has it's original 55 year old front calipers and the master cylinder and wheel cylinders are 47 years old........never any leaks or problems with the hydraulics.  This is why I have no interest in converting to a dual  system on my 65 Riviera, as the master cylinder isn't going to go bad with DOT 5 in it during my lifespan. 

Edited July 7 by Seafoam65 (see edit history)

[Hazdaz]

Seafoam:  I had watched a bunch of videos explaining the difference after I posted and I was ready to pull the trigger on 5 ...until two issues came up. 

 

DOT5 is more compressible than the glycol-based fluids (3, 4, 5.1).  That's a pretty big no-no for a hydraulic system.  The other big negative would normally seem like a big positive - 5 doesn't absorb water.  You'd think that was a good thing, but the way it was described in the videos I watched is that because 3, 4 and 5.1 absorb the water and take it out of your brake system - there will always be some level of moisture in there so if the liquid doesn't absorb it, it will eventually work it's way into the extremities of your braking system and cause corrosion problems there.  I rather flush my brake system every couple of years which will get rid of that moisture that has been absorbed into the fluid, than start replacing parts because they've rusted because the silicone-based fluid of DOT 5 isn't absorbing it - similar to oil and water not mixing. 

 

I like the other benefits of 5 such as not worrying about contact with paint!

 

I'm sure in the real world the compressibility of 5 isn't a major issue and I can only hope that the fact that it doesn't absorb water isn't a huge negative either, but it does cost like 3x as much too.  I think I will stick with 3 or 4 for now, but consider 5 in the future - thanks for posting your experience with it.  It is definitely something to consider.

[Seafoam65]

People who claim there is something wrong with DOT 5 don't know what they are talking

about.......I have 47 years of proof that it works, and the brakes on my cars that use it will stop on a dime and give you nine cents change. I used it in my customer's classic cars for 45 years with never one complaint or one hydraulic failure. It is worth every penny that it costs and then some.....as I said it is an absolute no-brainer.

Edited July 7 by Seafoam65 (see edit history)

[Frank DuVal]

I too run DOT 5 in my antique cars. I first started using it in the early 80s. I usually do a rebuild of the brake system and then fill it with DOT 5, not just flush it through an existing system.

 

Two reasons not to use DOT5:

 

1. People who rapidly slam the pedal to the floor during brake bleeding ( YES, I've seen them do it!) like it needs machine gun action, they induce bubbles into DOT 5. Just a normal push the pedal, open the bleeder or power bleeder or vacuum bleeder will be perfect.

 

2. If you live up in the mountains between 8,000 feet and 14,000 (Pike's Peak) you might experience compressibility issues. I have no issues here in the east where we might get up to 5,000 feet. I have a mechanic friend in Denver area who will not use it for that reason. He claims to have experienced it.😮 Going to do Pike's Peak?

 

I LOVE not having to flush the system every few years (who actually does that if they own more than two antique cars and several daily drivers?) and never seeing that white corrosion crap of the DOT 3,4,etc.  in wheel and master cylinders.

 

I've never seen a steel brake line rust out (wait, of course I have had lines rust out, let me finish😉) from the inside! I live in the rusty east where they all rust out from salt on the outside of the steel line. If DOT 5 collected moisture form the air (and it is humid here) and made the steel line rust through form the inside I would have experienced brake line failure in my antiques like I do on my daily drivers (salt). I say a NON-ISSUE!🚗🚗🏎️

[Bloo]

 

2 hours ago, Seafoam65 said:

People who claim there is something wrong with DOT 5 don't know what they are talking

about

They aren't getting all the air out. It really is that simple. They conclude it must be "compressible".

 

4 hours ago, Hazdaz said:

The other big negative would normally seem like a big positive - 5 doesn't absorb water.  You'd think that was a good thing,

It is a good thing.

 

4 hours ago, Hazdaz said:

but the way it was described in the videos I watched is that because 3, 4 and 5.1 absorb the water and take it out of your brake system - there will always be some level of moisture in there so if the liquid doesn't absorb it, it will eventually work it's way into the extremities of your braking system and cause corrosion problems there. 

This is ridiculous because it is EXACTLY the problem caused by DOT 3, 4, 5.1 glycol fluid. It doesn't "absorb the water and take it out of your brake system". It absorbs water out of the air, 24/7, which then reacts with the glycol and becomes corrosive. This corrosive by-product is heavier, and sinks to the bottom of the cylinders, where it remains basically forever and eats away at the bore. Even bleeding won't get rid of much of it, because it is heavier than the glycol, and the bleeders are at the top of the cylinders to let air out. Take apart a used wheel cylinder and look at the bore. If the whole thing is rusty, hone it a little and look again. See that huge deep rusty pit at the bottom of the bore? See how much metal is missing? See how it is only on the part of the bore that is at the bottom?

 

4 hours ago, Hazdaz said:

I rather flush my brake system every couple of years which will get rid of that moisture that has been absorbed into the fluid, than start replacing parts because they've rusted

Take some old cylinders apart that had glycol in them. It's an eye opener.

 

For full disclosure, I am not advocating everyone use DOT5. I don't use it anymore, but probably will in the future. The system should be completely clean and new, or you lose the benefits and gain the downsides of DOT5 silicone, the main downside being that it is tougher to bleed. 

 

 

Edited July 7 by Bloo (see edit history)

[EmTee]

I converted my daily driver to DOT5 35 years ago and never had an issue.  I even went so far as to convert the hydraulic clutch.  Any car with ABS should NOT use DOT5, as the rapidly cycling pump will whip the fluid into a froth.  That said, I'm currently running DOT3/4 in all of my cars, but try to flush each of them every 2 ~ 3 years.  The good thing about that is it forces me to take a close look at the system and keeps the bleeders free...

[Wayne R]

Have used dot 4  for years in all my classics, but for the cars i keep for  many years re hone my cylinders in 

stainless steel, and them i flush the brakes about every 5 years.

Example the 1965 Riviera i owned in 1991, i did the cylinders in stainless steel in CA, and the present owner i sold it to

here in Australia has never had to touch  them.

[XframeFX]

On 7/6/2024 at 7:15 PM, Hazdaz said:

I had watched a bunch of videos explaining the difference after I posted and I was ready to pull the trigger on 5 ...until two issues came up. 

DOT-5: NEVER AGAIN for me!

After a complete brake job on my 1963 Riviera in 1991, I chose DOT-5 for reasons mentioned above. However, in my circle, they all thought I went that route to prevent damage to my paint in case of a spill. Would I be that stupid?

 

Anyway, the 300 or so miles I logged since that brake job, all was well. You’d never know the difference and I felt it was perfect for a project in hibernation. Why flush every 2 or 3 years with zero miles sitting in one spot in the garage for 30+ years?

DOT-5 grief occured in 2023 when my hyd. brake light switch failed. A new switch had a slip inside “NOT DOT-5 COMPATIBLE!”

 

I sent my leaky power booster and functional master cylinder to the same shop where they found a corroded bore. I forgot to tell them DOT-5. They primed it with DOT-3. I Took a chance and continued with DOT-5. All cups swoll-up, failure.

 

Ron Francis provided a low pressure silicone compatible hyd. switch but recommended against DOT-5 (nice gentleman).

 

By this time, I embarked on completely re-doing the single circuit brake system to purge anything exposed to DOT-5. Replaced Made-in-USA flex hoses with Made-in-China hoses that has visibly inferior crimps.

I then found rusted bores in all wheel cylinders!

 

With new Chinese parts, I re-filled with a superior Bosch brake fluid.

 

Lesson Learned on my 3X-the-charmer Riviera or, 4X when I replace my still leaky but rebuilt power booster or, 5X if I do a dual circuit conversion!

[Hazdaz]

I didn't think this was going to be such a hot topic! 

 

Do we have a similar set of opinions on coolant?  What about on oil?  If this was a more modern car, I'd always follow the manual, but on a 60 year old car, I wonder if there is stuff out there better suited to a car of this vintage? 

[XframeFX]

I'd just drain the radiator and refill with green or yellow coolant.

I still have some quarts of Prestone rejuvinator, now discontinued.

Also, if your ride is to sit idle, I'd use synthethic oil. Speed shops usually have a selection of high-end oils. "Driven" has a 10W-30 synthetic with ZDDP.

 

 

In Canada, Prestone is dominant, most all in yellow jugs.

I always buy concentrate. Last year after heater core #2 and timing chain swap, Home Depot had the best price.

 

Last January, I had to move the Riviera with -37 deg. C outside and -26 inside the garage with the furnace off for vaca'ing in AZ. The block heater was plugged-in 3 hours in advance but, the nailhead was still stone cold! Under the radiator cap, ice crusts!

 

I went back to the shed through the snow to check on those empty jugs. "Ready-to-Use"! What happened to the "Pre-Mix" Label?

I grabbed the wrong jugs last year.

White Cap on yellow jugs for pre-mix and Black Cap on yellow jugs for concentrate. A detail not observed by many.

 

Not happy having to run to the store and change coolant in sub-zero weather the night before a flight.

 

BTW: With my Riviera back in hibernation, I will be a spectator at car meets, no Riviera!

Edited July 8 by XframeFX (see edit history)

[Chasander]

My 63 hyd brake switch failed  using Dot 5 fluid. My master cylinder rebuilder warned “using Dot 5 would void warranty “. 

[EmTee]

35 minutes ago, Chasander said:

My 63 hyd brake switch failed  using Dot 5 fluid. My master cylinder rebuilder warned “using Dot 5 would void warranty “. 

Too 'slippery' I guess.  The DOT5 must be able to bypass the seal in the switch and 'cups' in cylinders.  In the latter case i wonder whether it's really surface finish of the cylinders that is to blame.  A rougher finish may leave voids that the silicone can squeeze through.  I wonder whether there would be a problem using DOT5 with sleeved cylinders?  What do the classic Corvette guys use...?

[Bloo]

The sleeve issue comes up because one old well known and respected resleever offers no warranty if DOT5 is used.

 

It shouldn't make any difference to the sleeve. If I were a betting man, I know where I would put my money. People can't seem to get DOT5 bled and I imagine they blame the cylinders when they can't get a pedal. The phone support time and handholding needed is probably way beyond reasonable. I have never actually asked him this so I could be all wet, but I doubt it. I just use a different shop because I might want to use DOT5.

 

The hydraulic switches are reputed to be incompatible with DOT5 in most cases. Some people have used a Harley Davidson switch, as Harley Davidson uses DOT5 fluid and their switch would need to be compatible.

 

Edited July 8 by Bloo (see edit history)

[Bloo]

9 hours ago, Hazdaz said:

Do we have a similar set of opinions on coolant? 

If by similar you mean "all over the map", then yes. You'll get all sorts of dire warnings. In my opinion just ignore any "long life" claims on the bottle and change it fairly often. Ethylene glycol turns acidic when the additives get used up.

[XframeFX]

9 hours ago, EmTee said:

The DOT5 must be able to bypass the seal in the switch and 'cups' in cylinders. 

Tim. I try to limit my research and not put too much thought to off-the-shelf products.

 

Again, silicone brake fluid functioned the same until switch failure which initiated the can-of-worms there after.

 

DOT-5 might be good for the Military and "Hardly Drividsons" but, the product snowballed in my application. Plus, all 4 wheel cylinders AND Master Cylinder Bores scored with rust just the same.

[NTX5467]

Back when DOT 5 silicone fluid first came out, it was touted to be the best stuff around.   Even compatible with normal DOT 3, they claimed, although some did some testing in a beaker and discovered the two would separate to different layers in the beaker together.  They claimed that was not an issue.  So all appeared well.

 

A good friend had a used '79 Corvette he had bought.  He decided to do a fluid change.  The best price he found was at the local Harley shop, so he bought it there.  Did the normal bleeding procedures of the time.  He noted that for the first week or so, the pedal did feel mushy, but then one day, it got firm as a rock.  He was pleased.  This happened back in about 1982.  He later sold the car after several years, so no knowledge of durability of the brake system.

 

The mushy pedal could well have been from residual air in the system, which finally worked its way to the master cylinder and "out".  No issues with brake switches as they were all electric on that newer car.

 

I evolved into using the old Castrol GT LMA DOT 3 fluid in my '77 Camaro I bought new.  When it got archived, it had over 700K miles on it WITH the stock, maybe rebuilt once, calipers and the new GM rear wheel cylinders we installed with my 11x2 rear brake upgrade at about 200K miles.   

 

NTX5467 

[bob71GS]

On 7/6/2024 at 10:55 PM, Seafoam65 said:

People who claim there is something wrong with DOT 5 don't know what they are talking

about.......I have 47 years of proof that it works, and the brakes on my cars that use it will stop on a dime and give you nine cents change. I used it in my customer's classic cars for 45 years with never one complaint or one hydraulic failure. It is worth every penny that it costs and then some.....as I said it is an absolute no-brainer.

I agree 500%. I've been using DOT 5 in my 71 for at least 30+ years with absolute no problems. 

[XframeFX]

On 7/7/2024 at 9:36 PM, XframeFX said:

With new Chinese parts, I re-filled with a superior Bosch brake fluid.

No research. I used this product because of the Bosch name.

 

ESI6 does not stipulate which DOT it is, has all three on the tin.

 

It appears to be their own formula, a superior formula:

 

Direct Replacement for DOT 3, DOT 4, and DOT 5.1;

Quart

ESI6 is the next generation brake fluid designed for today's modern braking systems. Designed by the industry's leader in braking technology for vehicles using DOT 3, DOT 4, and DOT 5.1 brake fluid.

Features & Benefits:

High compatibility. Use with or direct replacement for DOT 3, DOT 4, and DOT 5.1 brake fluid

Extended Service Interval (ESI): Lasts 100% longer than DOT 3, 50% longer than DOT 4, and 10% longer than DOT 5.1

Exceeds all DOT 3, DOT 4, and DOT 5.1 standards

Wet boiling point ~ 365°F / Viscosity at -40 °C ~ 670mm2/s

 

 

 

Edited July 10 by XframeFX (see edit history)

[EmTee]

Note that DOT 5.1 fluid isn't the same as DOT 5.  DOT 5.1 is not silicone based.

 

https://safebraking.com/what-is-dot-5-1-brake-fluid/

[XframeFX]

On 7/10/2024 at 6:07 AM, EmTee said:

Note that DOT 5.1 fluid isn't the same as DOT 5.  DOT 5.1 is not silicone based.

While waiting for my turn at the parts counter, noticed this DOT-3 Lucas Product on the shelf. Says "Silicone". So not Ether Glycol but silicone based? Compatible with all fluids except DOT-5.

Wet Boiling point is only 140 deg. C

 

 

[EmTee]

Hmmmm, the label says 'synthetic', not 'silicone', so it isn't silicone based .  From the SDS (https://www.lucasoil.com/pdf/SDS_Lucas-DOT3-Brake-Fluid.pdf):

 

 

The main ingredient looks like a polyethylene glycol compound (https://www.fishersci.com/us/en/browse/cas/9004-74-4).  Since it is a DOT-3 fluid, it should be safe to mix with other DOT-3 or 4 (glycol-based) brake fluids.

 

 

Edited August 24 by EmTee (see edit history)

[Bloo]

That confused me the first time I saw it. It took way too much time and effort to get an answer. As it turns out, all glycol brake fluid is synthetic. That's how it's made. Nothing new here. Apparently somebody in marketing thought "synthetic" sounded modern or premium or something. It's just ordinary brake fluid.  

 

A bit like advertising gluten-free cola I think, or maybe sugar free black pepper.