Has anyone tried using the Valvoline synthetic DOTt 4 brake fluid in their hydo. brake systems? This fluid exceeds the current DOT 3 & 4 federal standards and has a higher boiling point. I am just getting set to bleed my Hayes brakes after installing some Goodridge lines and wanted to see if there was any feedback on this. Thanks in advance.
Motul has a reputation of having superior lever feel. This is from field (or empirical) GP racing experience (ie the riders and mechanics say they get improved lever feel)
5.1 is far lower viscosity than 4 that is why 5.1 is recommended in Antilock systems where low viscosity is critical to operation.
Why are you being obstinate? If you want to run weasel piss in your brakes, by all means be my guest.
Motul has a reputation of having superior lever feel. This is from field (or empirical) GP racing experience (ie the riders and mechanics say they get improved lever feel)
5.1 is far lower viscosity than 4 that is why 5.1 is recommended in Antilock systems where low viscosity is critical to operation.
Why are you being obstinate? If you want to run weasel piss in your brakes, by all means be my guest.
Obstinate? I'm just looking for the facts to back up your claims. Believe it or not, I'm trying to learn something while you prefer name calling (first silly, then obstinate). If I'm missing something about brake fluid, I'm opening minded to learning and hearing opinions of others.
Reason I mention this is because I regularly hear that Motul 600 has great wet/dry boiling points, but is relatively more hygroscopic and a better 'short-term' fluid. From http://www.shotimes.com/SHO3brakefluid.html:
Motul Racing 600 is a very exotic and expensive synthetic fluid with high wet and dry boiling points. I use this exclusively in my race cars. Too expensive for the street and requires frequent changing due to its hygroscopic nature. Sold in plastic bottles. It is not suitable for the street because it absorbs moisture quickly.
That is a quote from Dave Zeckhausen (www.zeckhausen.com) that sells hi-perf brake systems.
You state that DOT5.1 has a 'far lower viscosity' than DOT4. Earlier, it was stated that Motul was 'wickedly more powerful'. You'll recall that this is what prompted my initial response. If someone can show me this is the case, I'm all for it. But, maybe I need a little more empirical evidence than this. Grumpy, if my desire for clarification to what you (or others) are saying, and my request for a source for your info upsets you or hurts your feelings, that was not my intent. No hard feelings.
BTW, you should try Castrol SRF. It is THE brake fluid of choice among my track buds, but I haven't yet tried it. At about ~$80/liter, I think the price is a bit "silly".
Is'nt lever feel and boiling point the two ends of the continuum?
Is there a fluid that performs both of these functions?
I personally use shimano stuff (xt 755, mineral oil) I boil my oil 2% of the time - Do I wish I had 100% no boil? you bet! I do like my lever feel though.
Good luck with the weasel piss, these guys are hard to round up.
When I asked if you were kidding that $10 every 3 years on brake fluid was "spendy" you replied
"Nope, not kidding. Yes, I think it is spendy"
So the answer is; Yes you are an obstinate little troll spoiling for a fight.
That should have clued me then and I shouldn't have spent any (more) time on your trolls. (BTW I happend to be out in the barn and checked, the last 1/2 liter bottle of Motul DOT 5.1 that I bought at my local cycle shop (retail) cost me $6.95)
So you and your "track buds" can run $80 weasel piss if you want, but i'll say now what I should have said to your earlier post
I personally don't mind the difference in cost. I would just like to know for sure what is already in my master cylinders. Sure I would have to mail order 5.1, but what if I do and the master cylinder really has DOT 4 in it? Seems like the only safe thing to do is buy something and flush all the old out when any is added. Am I wrong?
Also how full should the master cylinder be filled on a Hope? Some brands say overfill and then put lid on. Is this the procedure for Hope?
BTW, Watermoc, I completely agree with the Motul being more fade-resistant; it has excellent boiling characteristics. But, I'm curious as to the 'wickedly more powerful' claim. How do you mean?
The lever feel is a bit more firm and positive when the brakes are cool, as mentioned by others, and much more firm and positive when they are hot. I have a season pass at the Whistler bike park, weigh 210 lbs, and like to ride really fast and jump a lot and generally beat the crap out of my bike. On a good weekend I'll do over 2000 jumps (49 per run on my favorite loop), bottoming my 8" bike with extra-stiff springs several times per run. Under these conditions, the Motul RBF is worth the extra few $$ for the reduced arm-pump alone. I didn't keep track, but probably went through around 6 sets of Hayes full metallic brake pads last season on my Mags, and didn't have to bleed the brakes once.
Not sure why it's cheaper here, but the local moto shops sell RBF for $7-8 a bottle. I gotta try that weasel-piss, sounds like good stuff. Also haven't had any problems with getting water in my brakes, including some really wet riding that seized BBs and pivot bearings.
The lever feel is a bit more firm and positive when the brakes are cool, as mentioned by others, and much more firm and positive when they are hot. I have a season pass at the Whistler bike park, weigh 210 lbs, and like to ride really fast and jump a lot and generally beat the crap out of my bike. On a good weekend I'll do over 2000 jumps (49 per run on my favorite loop), bottoming my 8" bike with extra-stiff springs several times per run. Under these conditions, the Motul RBF is worth the extra few $$ for the reduced arm-pump alone. I didn't keep track, but probably went through around 6 sets of Hayes full metallic brake pads last season on my Mags, and didn't have to bleed the brakes once.
Not sure why it's cheaper here, but the local moto shops sell RBF for $7-8 a bottle. I gotta try that weasel-piss, sounds like good stuff. Also haven't had any problems with getting water in my brakes, including some really wet riding that seized BBs and pivot bearings.
Good to know...thanks for your input. No doubt that Motul RBF600 is the shizzle. Just for clarification (not necessarily to you, Watermoc, but to others following the thread), there might have been a bit on confusion between Motul RBF600 and Motul 5.1; RBF is DOT4 and 5.1 is (obviously) 5.1. RBF600 actually has higher boiling points (wet and dry) than 5.1...the difference is viscosity (I just learned this today). So, RBF600 would be a better choice for higher boiling points and 5.1 if you're looking for better viscosity (for things like ABS). Knowing this, it makes perfect sense that you're feeling a more solid lever considering the riding that you do (I'm jealous), due to the RBFs ability to absorb more heat.
paddlefoot64...In general, you can mix DOT 4 and DOT 5.1 fluid (even though the Hope manual says not to) since they are both glycol based. Just understand that you'll compromise the better specs of 5.1 by mixing. It's a good idea to completely flush the system (as is often recommended) just to get all new fluid in there.
Grumpy, settle down. If my honest answers to your questions (kidding? and spendy?) offend you and come across as obstinate, like I've already said, that's not my intent...I didn't realize you were so sensitive, especially in light of your abrasive replies. But as to the third name (troll) that you've called me in the same thread...GFY.
I personally don't mind the difference in cost. I would just like to know for sure what is already in my master cylinders. Sure I would have to mail order 5.1, but what if I do and the master cylinder really has DOT 4 in it? Seems like the only safe thing to do is buy something and flush all the old out when any is added. Am I wrong?
Also how full should the master cylinder be filled on a Hope? Some brands say overfill and then put lid on. Is this the procedure for Hope?
Yes fill to rim and then try to trap as little air under the seal as you can, same as other brakes.
The thing about what fluid is in the brake and wether you need to purge it if you change spec is confused. Here is my take; although 3, 4 and 5.1 are chemically similar the Hope service manual says don't mix. Who knows for sure why that was put in, or what any given system was filled with to begin with (there seems to be some confusion on that as well). BUT my take is why worry? Purge the system with the new fluid it's only a couple dollars worth of fluid and then you will be correct no matter what. (just my theory that ANYTHING I can do to make the bike more trouble-free is worth doing).
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