Beaten to death topic

[Tinster]

But I am an old man with a poor memory and no auto
mechanic experience to speak of.

What is the Proper TR6 brake fluid and what to do
if you used the wrong type.

Not a clue what that thick, dirty brown stuff DPO Pedro used.

David and I installed a new brake master cylinder, 2 new
rear wheel cylinders, I installed new clutch master cylinder
and slave cylinder, stainless steel hydraulic hoses.

Pedro's brown goop was drained and DOT 3 brake fluid was
installed.

Is this correct fluid?
If not, what will be the consequences
(in my lifetime? 4 years or less.)

If not correct, how do I fix it?

thanks,

d

 

[Cyberpyr8]

DOT 3 is what I used in my Spitfire. I was told that was the correct fluid.

 

[Mickey Richaud]

Flush it out and use Castrol/Girling GT-LMA fluid.

 

[Brosky]

That should be fine. David would never let you install the wrong fluid when you put the brakes together.

Get in car, start it and drive.

 

[AltaKnight]

DOT3's fine.
Keep it off your paintwork though!

 

[70herald]

DOT3 is just fine. In the old days the rubber bits supposedly were affected by anything other than Girling brand fluid, but whatever rubber bits you have have long since been rebuilt with modern rubber bits and any DOT3 fluid will be just fine.
Every two years you must flush out the brake system (actually with the humidity on the island you might want to do this yearly)
You take the old fluid out of the master cyl, a turkey baster works perfectly for this. then you put in new fluid. Then at each wheel the brake needs to be opened up and the brake master cyl pumped until nice clean fluid comes through. The easiest way to do this is by getting speedy bleeders, which are a sort of one way valve. then it is a one person job and only takes a few minutes.

 

[Mickey Richaud]

That should be fine. David would never let you install the wrong fluid when you put the brakes together.

Get in car, start it and drive.

OOPS - didn't see that!

Yep, stick with what you got.

 

[Tinster]

Yisrael-

Why don't you consider a more southern route to Phoenix
with a 3 day layover in San Juan? It will be real cold
in NY or Chicago connecting flights. Beside we have better
food and bikini babes as opposed to snow bunnies covered with
Nanook parkas and other eskimo clothes.



d

 

[Tinster]

Thanks all-

Good to know I didn't make a major screw up!!

It's getting ready for a major gully washers, so
looks like no Amos drive today.

d

 

[kc_doyle]

DOT3 in my Spit...

 

[jdubois]

Pedro's brown goop was drained and DOT 3 brake fluid was installed.

That 'brown goop' wasn't anything special. That's just what brake fluid looks like if it doesn't get flushed frequently enough.

I use DOT5 in my cars because I don't want the typical rust from the brake fluid spilling and attacking the paint. But other than it's paint attacking properties, DOT3 is a fine fluid and costs about a quarter of what DOT5 costs. The differences in braking properties between DOT3, 4, 5 & 5.1 doesn't really matter that much for street use.

One note, however, you must not mix DOT5 with DOT3, 4, & 5.1 fluids! But since you replaced the master and the wheel cylinders that's not going to be a problem. If you don't know if there is DOT5 or DOT3/4 in your system, there are ways to tell. If it's fresh, you can tell DOT5 because it has purple dye in it. If it's not fresh, and the dye has faded, take a sample and put it in a clear glass with some water. If the water forms a separate layer from the brake fluid, it's DOT5. If the water blends with the fluid, it's DOT3/4.

 

[TR3driver]

One note, however, you must not mix DOT5 with DOT3, 4, & 5.1 fluids!

I disagree. DOT 5 is (by law) fully compatible with the others, and I have mixed them in my own cars for many years without bad results. The only downside is that you don't get the full benefit of the DOT 5 if it's mixed with lesser fluids. But if the only DOT 3/4 remaining is what doesn't come out when bleeding, then it's not likely to eat your paint after a spill.

Considering how many show cars I've seen with paint ruined by DOT 3/4, that feature alone with worth the price of admission, IMO. But since none of my cars are show cars, I use DOT 5 because it doesn't rot & have to be replaced every few years, nor does it corrode brake system components from the inside out (as DOT 3/4 does).

 

[jdubois]

I disagree. DOT 5 is (by law) fully compatible with the others

Wow, really? That's against everything I've ever read! DOT5 is a totally different beast, being based on silicone rather than polyethylene glycol like DOT3/4. I assume when you say "by law" you're refering to the DOT regulations? (FMVSS #116 to be exact). I don't have access to the text of that regulation so I can't actually check what it says.

The reason I've heard given not to mix is because when you put DOT5 in a DOT3/4 system, the deterioration and contamination that is caused by DOT3/4 binds to the silicone and creates a gelatin that gums everything up.

 

[Geo Hahn]

... we have better food and bikini babes as opposed to snow bunnies covered with Nanook parkas and other eskimo clothes.

Thought I was in the same old brake fluid thread... then this. Were you just seeing if we're paying attention?

BTW -- I like DOT% for the paint preservation but what you have should stop the car which I think is most important.

 

[Bugeye58]

From the MG X Power website:


Silicone Brake Fluids

<span style="color: #FF0000">Silicone, or DOT 5 Brake Fluids are based on polydimethyl siloxane and are specialist fluids intended for racing applications. Silicone Brake Fluids may be used in conventional braking systems, as they are compatible with the standard brake components. However, they do not mix with conventional Brake Fluids and should only be considered for use after a complete brake system drain and overhaul. Mixtures of Silicone and conventional Brake Fluid may result in additives transferring between the phases thus resulting in reduced performance. </span> However, because they do not absorb moisture as readily, they tend to last much longer in service. In addition, to the enthusiast that values his/her paintwork, they are much kinder than the normal brake fluid formulations. To this end, classic car enthusiasts often use this. However, be aware that the Bulk Modulus of silicone fluids is lees than that of normal brake fluids, and because of this slight compressibility, it can lead to a slightly spongy pedal feel. This is because ideally, one would work with differing master and slave cylinder dimensions to overcome this property, but since so few OEMs are willing to invest in this, silicon has failed to achieve any OEM or motor manufacturer approval.

Emphasis mine.
Jeff

 

[jdubois]

Hmm, ok, I'm turning up some interesting stuff. I think I see where TR3driver is coming from. I found the text of FMVSS #116. Section S6.10.3 tests the given brake fluid (including DOT5 fluids, although using slightly different procedure) for compatibility with a reference fluid (as described in SAE RM-66-04) by combining the two and letting it sit for 24 hours, then seeing if there is any "slugging, sedimentation, or crystallization". It then repeats the test at high temperature and checks immediately (no 24 hour wait) for the previously stated issues.

So, yes, it would seem that by law DOT5 fluids have to be "compatible" with DOT3/4 fluids. (I'm making the assumption that the SAE reference fluid is a glycol based fluid). However, mixing the two together in a clean test tube for 24 hours is a far cry from mixing the two in an active, dirty brake system. So, I think I'm still on the "don't do it" side of the fence.

 

[TR3driver]

https://www.fmcsa.dot.gov/rules-regulations/administration/fmcsr/fmcsrruletext.asp?section=571.116

I've seen the "gelatin" you refer to ... but since by definition it is not in any place that fluid actually moves, and it's not actually sticky (when coated with DOT 5) nor solid, it doesn't seem to be a problem. And it's no worse IMO than what happens when running pure DOT 3/4 (eg the brown goop that Dale reported).

I converted a 1980 Chevy to silicone back in 1988 or so, by replacing the one caliper that was leaking and just bleeding DOT 5 through the rest of the system. When I finally junked the car in 2003, I had never touched the hydraulics again ! That means 3 corners plus the MC had an estimated 250,000 miles total on them, mostly with DOT 5, and never a single leak. And that's after reaching the end of a 'normal' life on DOT 3 !

I've done several other conversions the same way, with similar results. On the motorhome (where I could not find a rebuilt caliper or seals to rebuild mine), the silicone actually stopped the leak ! I eventually found the seals ... which are still on the shelf in my garage.

I live near mountains and love to drive my Triumphs very hard ... brake fade is no stranger to me. If there was any way that mixing DOT 5 and DOT 3 was inferior to DOT 3 alone, I probably wouldn't be here to tell you about it.

The papers presented to the SAE talking about things like DOT 3/4 sucking water and salt directly through brake lines; and having to develop new testing methods to test DOT 5 to failure; are too big to post here. PM me if you'd like a copy (about 1.2Mb total).

The point about OEMs not using DOT 5 is well taken. Even after the US armed forces and post office insisted on it, car makers still don't want to spend the extra money on each car for something that has no direct benefit to them. If you follow their directions on changing brake fluid every few years (rarely mentioned in ads, but usually found in the fine print of the service manual), then the brakes will last beyond the warranty period. And that's really all they care about.

It's also true that DOT 5 is very slightly more compressible than DOT 3/4. Nelson Riedel did a whole lot of math on this topic, and found that it amounted to considerably less than 1/2" at the pedal under anything approaching normal conditions. He then took some actual measurements, showing he could achieve 1/4" more travel by applying the maximum effort possible (with the engine running). Not enough to worry about, IMO. If it does worry you, you can more than compensate by converting to Teflon/SS flexible brake lines.

I have no problem with those who choose to use DOT 4 in their LBCs. But I've used DOT 5 for many years now, and have not found anything not to like about it (except price and availability). IMO, it's just not as bad as all the "nay sayers" would have you believe.

Almost as evil as dihydrogen monoxide ... did you know that 100% of the convicted killers in the US were exposed as children to dihydrogen monoxide ?
:^)

Randall

 

[Brosky]

I've used the silicone in my clutch hydraulics all summer long and I have no complaints with it. The pedal feels the same as before, so I'm switching over my brakes to silicone as soon as the chassis work is completed.

I'm installing everything new, from the steel lines to the cylinders, calipers and cables. I'll keep my old parts for spares for the future. After 34 years, they owe me nothing.

 

[Guest]

After 30+ years of everyone seeing British cars with the paint all peeled off near the brake/clutch masters, I'm at a loss as to why anyone would use anything but silicone fluid. Silicone fluid is still cheaper than paint work, at any price.

 

[prb51]

Cool,
I'd heard one must bleed the system then purge it with alcohol (or whatever) prior to converting and then do an exorcism with chicken bones.