Peach. Posted October 30, 2013 Share OK - boffins? here's a question for you...I know about the DOT fluid that will destroy rubbers (Mineral oil systems) etc etc. but what will happen if I swap my dot system with mineral oil? surely the DOT resilient rubbers will not be affected by mineral oil? Or are the inherent hydraulic action of the two types of oils so different that they are not inter changeable? {hi-jack off} I heard of a dude that bled his M4's with Mineral oil and destroyed all the seals. Link to comment Share on other sites More sharing options...
rouxtjie Posted October 30, 2013 Share I beg to differ, you should see how that stuff reduces friction Avid's own that tech like a baws Mountain Bru 1 Link to comment Share on other sites More sharing options...
Cassie Posted October 30, 2013 Share According to my hairdresser I am going grey But I was actually waiting for some wise person to tell me "brake fluid isn't a lubricant"...... You let me down on your reply... WHO said that??? :eek:In emergency situations..any lube is better than no lube... Link to comment Share on other sites More sharing options...
Guest Travis. Posted October 30, 2013 Share What happened to the sheriff, skip town? I can appreciate that these are good brakes (they sure look'it )but I found new 4-pots for under 3k.. AVID He probably realized that one cannot talk sense to illogical folk. Wyatt Earp 1 Link to comment Share on other sites More sharing options...
Cassie Posted October 30, 2013 Share I heard of a dude that bled his M4's with Mineral oil and destroyed all the seals. weird?? because DOT is spposed to be more aggressive than mineral oil 9I'd guess the DOT rubbers will be more resilient than minral oil rubbers) But I'll google and see what comes up... Link to comment Share on other sites More sharing options...
rouxtjie Posted October 30, 2013 Share weird?? because DOT is spposed to be more aggressive than mineral oil 9I'd guess the DOT rubbers will be more resilient than minral oil rubbers) But I'll google and see what comes up...Various ways you can destroy seals....do a ghetto bleed with shimano XT and force the syringe down hard....pop goes the weasel. A good test is to take two rubber o-rings and put them into dot5.1 and into mineral oil. check daily. Anyone keen on a billguy the science naai experiment? Link to comment Share on other sites More sharing options...
GoLefty!! Posted October 30, 2013 Share OK - boffins? here's a question for you...I know about the DOT fluid that will destroy rubbers (Mineral oil systems) etc etc. but what will happen if I swap my dot system with mineral oil? surely the DOT resilient rubbers will not be affected by mineral oil? Or are the inherent hydraulic action of the two types of oils so different that they are not inter changeable? {hi-jack off} Dot Systems typically use silicon seals. Silicon seals are not compatible with Mineral oil. Mineral oil systems typically use urethane, butyl rubber, nitryl rubber or flouronated rubber (VITON ) seals. These are quite hard wearing and typically are compatible with a broad range of materials but the composition porosity or the seals is important to understand. Generally VITON is compatible with both alkylated, alcohol or ether based materials as well as conventional hydrocarbon materials. But again you need to know whats in the brake system from the factory. Follow the manufacturers recommendation and you'll be fine. Theres good reasons why they recommend what they do. If you have a DOT based brake system, after you have opened the container with Dot Brake fluid, use it and dispose of the remaining fluid. It is highly hygroscopic (that means absorbs water) and will degrade in weeks. DoT3, DoT4 and DoT5.1 are compatible. DoT5 is silicon based and is NOT COMPATIBLE with any of the others nor with mineral oil based systems Edited October 30, 2013 by GoLefty!! Link to comment Share on other sites More sharing options...
G00SE Posted October 30, 2013 Share That's why you should bleed brakes with brake blocks in, not pads... or rotors... that also eliminates issues when you have too much fluid when you put new pads in... and clearance issues... This is something I found out on my first bleeding attempt.My second attempt I was wise enough to remove pads and put a block in.... here's some more advice though.DONT put your pads in a nice clean ice cream tub, and position said ice cream tub directly under your caliper --- I now keep my pads on the other side of the garage when attempting a brake bleed, and everything is cleaned up nicely with isopropyl alchohol before the pads come any where near the bike... Link to comment Share on other sites More sharing options...
rouxtjie Posted October 30, 2013 Share Dot Systems typically use silicon seals. Silicon seals are not compatible with Mineral oil. Mineral oil systems typically use urethane, buytyl rubber, nitril rubber or flouronated rubber s (VITON ) seals. These are quite hard wearing and typically are compatible with a broad range of materials but the composition pourosity or the seals is important to understand. Generally VITON is compatible with both alkylated, alcohol or ether based materials as well as conventional hydrocarbon materials. But again you need to know whats in the brake system form the factory. Follow the manufacturers recommendation and you'll be fine. Theres good reasons why they recommend what they do. If you have a DOT based brake system, after you have opened the container with Dot Brake fluid, use it and dispose of the remaining fluid. It is highly hygroscopic (that means absorbs water) and will degrade in weeks. DoT3, DoT4 and DoT5.1 are compatible. DoT5 is silicon based and is NOT COMPATIBLE with any of the others nor with mineral oil based systemsThere it is, the term I was looking for. thanks lefty.... Link to comment Share on other sites More sharing options...
V12man Posted October 30, 2013 Share There it is, the term I was looking for. thanks lefty.... It is hygroscopic - but the level of water contamination from air is absolutely minimal - and should not affect performance for more than 2 years of being open in a container - BUT - water through a seal is the issue - I have previously posted on the subject, and posted a listing of brake fluid wet boiling points. My opinion is that on an MTB you have to assume your fluid is wet during any kind of long endurance event, and plan accordingly (BTW - that is the same issue for mineral oil - it also gets contaminated by water - just does not absorb it - and that water will boil...) rouxtjie 1 Link to comment Share on other sites More sharing options...
Guest Omega Man Posted October 30, 2013 Share I'm learning a lot here. Please keep it coming guys. Had no idea the dot fluid degrades. Why do motorcycle systems use DOT tho? surely there's some sort of advantage over mineral oil? Edited October 30, 2013 by Omega Man Link to comment Share on other sites More sharing options...
Peach. Posted October 30, 2013 Share It is hygroscopic - but the level of water contamination from air is absolutely minimal - and should not affect performance for more than 2 years of being open in a container - BUT - water through a seal is the issue - I have previously posted on the subject, and posted a listing of brake fluid wet boiling points. My opinion is that on an MTB you have to assume your fluid is wet during any kind of long endurance event, and plan accordingly (BTW - that is the same issue for mineral oil - it also gets contaminated by water - just does not absorb it - and that water will boil...) I have water in my Hydraulic rim brake HS33 and it feels awesome.Much smoother and less resistance than oil.and you can even have a drink while bleeding V12man 1 Link to comment Share on other sites More sharing options...
rouxtjie Posted October 30, 2013 Share It is hygroscopic - but the level of water contamination from air is absolutely minimal - and should not affect performance for more than 2 years of being open in a container - BUT - water through a seal is the issue - I have previously posted on the subject, and posted a listing of brake fluid wet boiling points. My opinion is that on an MTB you have to assume your fluid is wet during any kind of long endurance event, and plan accordingly (BTW - that is the same issue for mineral oil - it also gets contaminated by water - just does not absorb it - and that water will boil...)Thanks V12...net result is still the same, won't touch brakes using dot. End van prent Link to comment Share on other sites More sharing options...
jatho Posted October 30, 2013 Share This thread is all boring now, I miss Wyatt and Someguy. I'm gonna start a Bianchi is better than Pina thread! Link to comment Share on other sites More sharing options...
Peach. Posted October 30, 2013 Share I'm learning a lot here. Please keep it coming guys. Had no idea the dot fluid degrades. Why do motorcycle systems use DOT tho? surely there's some sort of advantage over mineral oil? Yip, good to do a fluid change at least every 2nd year, makes the brakes feel and respond better.you will be surprised what color fluid comes out. Link to comment Share on other sites More sharing options...
rouxtjie Posted October 30, 2013 Share I'm learning a lot here. Please keep it coming guys. Had no idea the dot fluid degrades. Why do motorcycle systems use DOT tho? surely there's some sort of advantage over mineral oil?I can only assume the higher boiling point, but then again a motorcycle weighs ten times more than a bike and generally goes ten time quicker. So boiling point is a real benefit. I also suspect the motorbike calipers have a better seal design...since weight doesnt matter. Link to comment Share on other sites More sharing options...
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