DOT 5 - Is this new to anyone else?

[John D.]

Re: DOT 5 - Is this new to anyone else?

This SAE paper is still relevant on this topic and appears to indicate a lot of the hoopla about starting with no traces of other fluids while ideal has no real impact on the brake system components even at high mix rates.

[Patrick H.]

Re: DOT 5 - Is this new to anyone else?

Patrick,
Takes weeks to get them to swell.

Dom

The seals were in the test silicone DOT5 from Cartel for a month. Nothing happened.
Same size, same consistency, same everthing.

I’ve installed the new repro master cylinder in the car, rebuilt both front calipers with Raybestos seals, and used Cartel DOT5 in the system.
I will let you know if anything happens.

If the master cylinder alone fails, I will suspect that they do not use quality seals. If so, I’ll then install the Raybestos ones.
If the front calipers fail, then the Raybestos seals were not as advertised.
If the rear calipers fail, then either the old seals were done for, or we can think about the fluid.
If some combination of the above fail, then I’ll also look at the fluid.

Patrick

[Don A.]

Re: DOT 5 - Is this new to anyone else?

I have had one new front caliper piston o-ring from Lone Star Caliper soaking in Cartel silicone from 3 May until 12 May (10 days).
I measured the o-ring with a vernier caliper but they are flexible so I may be off a little with my diameters. The results are 0.212" growth in diameter or 11.4%. It looks like a lot when compared to an original. The durometer of the material is also noticeably changed (softer).
Reportedly, 5% growth is considered normal which would be 0.093". So it is over double what I would have expected.
I followed up with a call to Lonestar Caliper. According to their technician Brad, they have found the results with Cartel is no different than other silicone products. They all cause excessive swelling.
As a result, I have rebuilt all of my calipers and master with new seals and flushed the system with denatured alcohol and installed DOT 3 fluid. I wish I knew what was going on but my personal results convinced me that the -o-rings and silicone are NOT compatible. I would prefer to use silicone but its not to be for me.

[Jim D.]

Re: DOT 5 - Is this new to anyone else?

Unfortunately Don, I've come to the same conclusion. I'll be using DOT 3-4 in my latest build as CSSB won't warrant their products if DOT 5 is used. I wish there was difinitive proof of whether it was a change in fluid or poor quality seals. I'm betting it's the latter.

[Joe L.]

Re: DOT 5 - Is this new to anyone else?

I have had one new front caliper piston o-ring from Lone Star Caliper soaking in Cartel silicone from 3 May until 12 May (10 days).
I measured the o-ring with a vernier caliper but they are flexible so I may be off a little with my diameters. The results are 0.212" growth in diameter or 11.4%. It looks like a lot when compared to an original. The durometer of the material is also noticeably changed (softer).
Reportedly, 5% growth is considered normal which would be 0.093". So it is over double what I would have expected.
I followed up with a call to Lonestar Caliper. According to their technician Brad, they have found the results with Cartel is no different than other silicone products. They all cause excessive swelling.
As a result, I have rebuilt all of my calipers and master with new seals and flushed the system with denatured alcohol and installed DOT 3 fluid. I wish I knew what was going on but my personal results convinced me that the -o-rings and silicone are NOT compatible. I would prefer to use silicone but its not to be for me.

Don-------


With respect to the 0-ring seals, who knows if they are even DOT-compliant? They may just be using standard o-rings.

[Ed D.]

Re: DOT 5 - Is this new to anyone else?

It would be interesting to know what the government specifications are for the seals they are using with DOT 5 in their vehicles.
Ed

[Jim D.]

Re: DOT 5 - Is this new to anyone else?

Don-------


With respect to the 0-ring seals, who knows if they are even DOT-compliant? They may just be using standard o-rings.

The manufacturers I checked with offer both lip seal and o-ring calipers and they all say there is no warranty if you use DOT 5 regardless of what type of seal you choose.

[Patrick H.]

Re: DOT 5 - Is this new to anyone else?

I have had one new front caliper piston o-ring from Lone Star Caliper soaking in Cartel silicone from 3 May until 12 May (10 days).
I measured the o-ring with a vernier caliper but they are flexible so I may be off a little with my diameters. The results are 0.212" growth in diameter or 11.4%. It looks like a lot when compared to an original. The durometer of the material is also noticeably changed (softer).
Reportedly, 5% growth is considered normal which would be 0.093". So it is over double what I would have expected.
I followed up with a call to Lonestar Caliper. According to their technician Brad, they have found the results with Cartel is no different than other silicone products. They all cause excessive swelling.
As a result, I have rebuilt all of my calipers and master with new seals and flushed the system with denatured alcohol and installed DOT 3 fluid. I wish I knew what was going on but my personal results convinced me that the -o-rings and silicone are NOT compatible. I would prefer to use silicone but its not to be for me.

I am suspecting then that it may be the seals, not the fluid, at least based on my testing here.

As noted, I will continue to update.

[Ed D.]

Re: DOT 5 - Is this new to anyone else?

Here is a photo of a box that re manufactured calibers came in, for a Post Office Truck that used Dot 5 since 1988. The garage that services these trucks tells me no issue with seals.


E

[Patrick H.]

Re: DOT 5 - Is this new to anyone else?

Here is a photo of a box that re manufactured calibers came in, for a Post Office Truck that used Dot 5 since 1988. The garage that services these trucks tells me no issue with seals.


Ed

I suspect that the specifications for the seals there haven't changed, but they have for some/most Corvette brake rebuilders.

There are only two things that can change - the fluid or the seals.
The fluid makers state they haven't changed their formula - at least some of them put that in writing.
However, we the consumer have no idea what seals are being used. I'm guessing lowest cost is winning over best quality, and thus the downhill slide begins.

FYI - that company sells rebuilt calipers. Perhaps we should use them in our Corvettes since the Corvette guys can't get them right?

http://bbbind.web2market.com/disc-brake-caliper-17257.html

[Gary B.]

Re: DOT 5 - Is this new to anyone else?

...
However, we the consumer have no idea what seals are being used. I'm guessing lowest cost is winning over best quality, and thus the downhill slide begins...

I for one would gladly pay a higher cost to get seals that work with DOT-5. I doubt we're talking many tens of dollars for just the seals.

Gary

[Patrick H.]

Re: DOT 5 - Is this new to anyone else?

Update:

Fail.

Calipers and MC installed Sunday, and today at noon I went to start working on the car.
Both calipers and the master cylinder are leaking fluid. It’s thankfully not a lot, but I just ordered new seals for all 3 items so I can replace them all this weekend.

What has me surprised is that all 3 failed. I’ll know more upon autopsy in the next few days, but the calipers had brand new Raybestos seals, and the MC had whatever the repro company installed. Now I’m just hoping that the repro MC takes stock-sized seals.

So, I will have to agree at this point that it appears that DOT5 and current seals do not work even though a test set of seals appeared fine after a month sitting in DOT5 fluid. The rear calipers have “old” seals and all I did was bleed them...and they don’t leak at all. Go figure.

Hopefully I’ve got it all done by next week’s Regional...

Patrick

Update: no fluid on the back of the MC indicating leaking seals in that direction. Most of the fluid was on the bottom of the MC toward the back, so I had assumed it was leaking there. It might be the connections to the hoses, in which case swapping seals will have zero effect.
Stay tuned.

[Gerald C.]

Re: DOT 5 - Is this new to anyone else?

If I was to put Dot 4 and Dot 5 in glass containers and compare the two containers, can I see a difference in consistency, etc???

[Donald H.]

Re: DOT 5 - Is this new to anyone else?

If you put Dot 4 in one container and Dot 5 in another container then add water to each and shake them up, you can tell the difference very quickly. The Dot 4 and water will mix and stay mixed. The Dot 5 will separate in a few seconds. Picture on the left is Dot 3 (Dot 3 and Dot 4 are both glycol ether based and are hygroscopic and absorb water). Picture on the right is Dot 5 which is silicone based and does not absorb water.

[Gerald C.]

Re: DOT 5 - Is this new to anyone else?

Thanks Don