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Dot 5 Brake Fluid

Posted: Wed Apr 29, 2015 6:50 pm
by 76124
Anyone running Dot5 Fluid in their Spider? After pulling the motor ands seeing what occasional spills and leakage has done to the paint under the master cylinder and behind the steering box, the thought of fixing all that and having it happen again kills me. Im way more careful than the prior owner of 12 yrs probably was, but still. Dot5 does not eat paint, it being silicone this makes sense. It also does not absorb water like Dot3-4 so long periods of hanging out wont creat problems as they can now.

Thoughts from those who know more?

Re: Dot 5 Brake Fluid

Posted: Wed Apr 29, 2015 8:39 pm
by 81SPIDERMATT
i will tell you what I remember from my research ..... using dot 5 it is recommended that you completely flush out current system ... mixing 5 with 3 was not recommended .... some say dot 5 will have softer pedal feel because it holds more air in suspension .... some say dot 5 will absorb moisture and should be change more often than dot 3 .... lots say they use it and love it ... and it does not eat paint as you stated .... brad chimed in on my questions way back and recommended something blue (sorry cant remember ) .... it was great because you could tell when the new fluid was coming out (its blue) ... wish I had more for you .... brakes should not leak ....and mine don't so I never worried much about paint ...and quick cleanup of any spills should work also

Re: Dot 5 Brake Fluid

Posted: Wed Apr 29, 2015 10:45 pm
by So Cal Mark
you don't want Dot 5, you want Dot5.1

Re: Dot 5 Brake Fluid

Posted: Wed Apr 29, 2015 11:53 pm
by fredguaz
I use DOT 5 brake fluid on my restored Triumph 750 motorcycle. Both Lockheed calipers were rebuilt with new seals and stainless master cylinders and new hoses. Lockheed recommends against using DOT 5 based on seal swelling but this was dated and many, including me, have used it with zero issues. I do, however flush and bleed the brakes annually. Definitely do not mix the 2. It will gel up. Would highly recommend all new lines and rebuilt/new MC and calipers before switching over. Haven't decided if I'll go DOT 5 on my spider. Paint protection little more critical on a bike. I have noticed that the purple DOT 5 (I purchased from Harley Davidson) turns a murky clear when I flush it (??).

Re: Dot 5 Brake Fluid

Posted: Thu Apr 30, 2015 12:30 am
by ScotcH
Don't do it. DOT 5 is a much more compressible fluid ... if your brakes are spongy now, they'll be worse with DOT 5. A good quality 3 or 4 is perfectly fine for several years, though ideally you should run 1/2L or so through the system annually.

The Blue fluid is ATE super blue, which is the same as ATE Type 200, just blue dye in it. It is very good fluid used by many track dudes. The super blue is no longer available in NA due to some bullshit DOT rule that brake fluid must be colourless, but the Type 200 is readily available.

Re: Dot 5 Brake Fluid

Posted: Thu Apr 30, 2015 5:24 am
by DieselSpider
Don't use synthetic unless you are 100% sure that all rubber in your brake system has been upgraded to a formulation that is compatible with synthetic brake fluid. Mine had NOS brake components in it that failed in less than a year turning to putty from the synthetic brake fluid. It can be a roll of the dice which you can loose at easily. One problem is that much on the shelves out there as DOT3 is really some universal low end synthetic formulation which may not really be mentioned on the labeling except for in a language other than English.