Topic: DOT 5 Silicone Brake Fluid

[POPS 911]

Are you saying all those 4 wheels auto I saw the past weekend at my track had WATER ONLY in their engines ........ and me on my AIR COOLED CM400A was the only track safe 2 wheeler going down the track ? Thanks HONDA FOR THE AIR COOLED bikes of the past....... those many BUSA'S had radiators full of what ? the old KZ was air cooled that I had to race first round. I was .07 of the mark and I lost [ so cold temp in Ohio] they hurried up the rounds.

POPS BK911

[Captain]

 Here's a question that has some bearing on what everyone has to say. 
 Who has actual experience using it......Correctly  

 Totally stripped and cleaned system (seal, cups etc.) and then Dot5 filled.

 Captain

[slikwilli420]

Here's a question that has some bearing on what everyone has to say. 
 Who has actual experience using it......Correctly  

 Totally stripped and cleaned system (seal, cups etc.) and then Dot5 filled.

 Captain

Can't say that I have, but compatibility is an issue. I was told that the seals in my Brembo parts were not compatible with DOT5. No reason to try with RBF660 being such high performance.

[Jerry Rxman Griffin aka MuthaF'er]

I did on the restore.

[NitroHunter]

Here's a question that has some bearing on what everyone has to say. 
 Who has actual experience using it......Correctly  

 Totally stripped and cleaned system (seal, cups etc.) and then Dot5 filled.

 Captain

I experienced no issues with using DOT 5 when I installed my PM brakes, lines, and master cylinder.
Also, when I replaced the brake system on my Corvette, the kit shipped with DOT 5 included.
To be clear, there was nothing of the original systems reused in either case.
However, I also used that same DOT 5 fluid in my stock F-2 system after a quickie clean and rebuild with new seals, didn't have any problems in the 3 years I kept that one and the fluid didn't discolor, staying nicely purple.
No question it is not the best choice for every application, but it seemed to be fine for mine.
FYI we use DOT 4 in our drag racers and maintain a regular brake bleeding schedule. Something I've noticed, the vehicle which still uses steel rotors and Brembo calipers has noticeably quicker darkening of the fluid than our toys required to have carbon rotors and Strange calipers.

[MRieck]

Here's a question that has some bearing on what everyone has to say. 
 Who has actual experience using it......Correctly  

 Totally stripped and cleaned system (seal, cups etc.) and then Dot5 filled.

 Captain

I experienced no issues with using DOT 5 when I installed my PM brakes, lines, and master cylinder.
Also, when I replaced the brake system on my Corvette, the kit shipped with DOT 5 included.
To be clear, there was nothing of the original systems reused in either case.
However, I also used that same DOT 5 fluid in my stock F-2 system after a quickie clean and rebuild with new seals, didn't have any problems in the 3 years I kept that one and the fluid didn't discolor, staying nicely purple.
No question it is not the best choice for every application, but it seemed to be fine for mine.
FYI we use DOT 4 in our drag racers and maintain a regular brake bleeding schedule. Something I've noticed, the vehicle which still uses steel rotors and Brembo calipers has noticeably quicker darkening of the fluid than our toys required to have carbon rotors and Strange calipers.

I'd guess the steel rotors generate much more heat and retain it for a longer period of time. The carbon cools off very quickly. Hydraulic clutches on bikes have the same problem with the fluid getting dark and becoming "soft". That problem is directly related to the fact the slave cylinder is attached to (or very close to) the engine. High heat kills the fluid.
 I tried DOT 5 with my original CB 750 brake system. Rebuilt the master and caliper and new Russell AN-3 brake lines. It made a marginal brake system worse as it was spongy no matter how many times bleeding was performed. Caliper piston retraction wasn't good. Also lever pull was smooth....it was a bit creaky (swollen master piston cup?). The caliper bleeder also had some teflon tape to try and prevent air from reentering the caliper when the bleeder was cracked open.
 That was back in the early 80's not that long after DOT5 came out and Bel Ray was selling it.
 Another problem I heard of ( I haven't experienced it because I never used 5 after that) was water will still get into the system. While the water will mix with DOT 3 and 4 it will not in DOT5. The water will puddle and corrosion can concentrate in particular areas (I assume the lowest points in the brake system.)
 
 

[NitroHunter]

And here I was so happy, I just thought it was just how those stock rubber lines were. 
The complete PM system felt entirely different.
Before the carbon brakes days, I worked for a FC driver who had arms large enough that he could hold the brake handle tight enough through out the run that: #1 didn't smoke the tires. #2 so much heat it distorted the drilled holes in the rotors oblonged.