hey all, in the process of performing neglected maintenance on my newly purchased 88 fxr-sp. I'm flushing master cylinders and the fluid color is amber clear. I purchased dot 5 according to my manual and its purple.so I assume the wrong fluid is in there.is it ok to remove whats in the master , refill it with the purple dot 5 and pull it all through the lines with my vaccum bleeder until its all purple? could the wrong fluid have ruined my caliper? I read where it says not to mix the two.
blumule
The best method is to take the calipers and masters apart clean them out and use dot 5 to reassemble...next is do as you are but flush with denatured alcohol then refill with dot 5, and lastly do as you have planned.... the less dot 3 that is in there the better... most techs are good with the flush method, but I prefer to do the complete job myself.... many times its OK to reuse the seals in the calipers and master cyls... just check them while they are apart...
As tall terry said ".... the less dot 3 that is in there the better...".
With the cleaning you have been told to do you would not have any DOT 3 left in the system at all. The DOT 3 and 4 are not compatible with the silicon DOT 5 and cannot be used together. Sounds like you are on the right track.
With the cleaning you have been told to do you would not have any DOT 3 left in the system at all. The DOT 3 and 4 are not compatible with the silicon DOT 5 and cannot be used together. Sounds like you are on the right track.
a simple test of taking whats in the brake system now and mixing a small amout of water.
if it mixes then its dot 3 or4 if it seperates its dot 5 . i could have this backwards but one of the dots is a silicon base and wont mix with water. I did this many moons ago when i was unsure. when i started molesting my fxr
if it mixes then its dot 3 or4 if it seperates its dot 5 . i could have this backwards but one of the dots is a silicon base and wont mix with water. I did this many moons ago when i was unsure. when i started molesting my fxr
I'm With TT again. DOT 5 will be purplish or maybe bluish. Another indicator is the bubbles that stay suspended in the DOT 5. This is EXACTLY the reason DOT 5 CAN'T be used in bikes with ABS.
Water will mix with DOT 3 and 4 while it also stays semi-suspended in DOT 5.
Water will mix with DOT 3 and 4 while it also stays semi-suspended in DOT 5.
thanks guys, excellent information.ill do a complete flush on the rear. I'm sure I'm in for a complete rebuild on the fronts as both calipers seem to be leaking.also, I'm in need of several parts. whats a good online source for quality parts without dealership prices. this new member of the family is high maintenance.
Old DOT 5 loses its color and goes amber or straw colored. Rub some between your thumb and forefinger while applying considerable pressure. DOT 5 will keep feeling slippery under pressure, while DOT 3 or 4 will resist sliding. It's hard to explain, but easy to feel the difference if you try this with known samples.
DOT 3 and 4 are hygroscopic, which means they absorb water. This is why you should always use a fresh, unopened container and not one that has been sitting around for a while. When too much water is absorbed it lowers the boiling point of the fluid, and boiling your brake fluid causes air bubbles in the system and lack of braking.
DOT 5 won't absorb, or mix with water, but it's very susceptible to aeration, which is why it can't be used in an ABS system (ABS pumps acting somewhat like a paint shaker). Avoid the urge to shake your bottle of DOT 5 before you uncap it and break the seal, or you'll be bleeding for a very long time because of aeration.
Mixing DOT 3 or 4 with DOT 5 is a bad idea, but probably not the fatal mess that most forum posts would lead you to believe. I ran across an article a while back where a guy tried to replicate the assertion that mixing the two would cause the fluid to gel, and try as he might, he just couldn't make it happen. Hot, cold, different ratios, didn't matter. They would separate, but wouldn't gel. Some will also claim that one or the other will damage seals made for the other. There's no chemical reason that glycol based and silicone based fluids will act much differently on rubber or plastic seals. In fact, HD uses the same MC rebuild kits across some of the years that use different fluids (The MC part numbers change because of the writing on the lids for different fluids).
So clean and flush as well as you can.... Denatured alcohol does a good job, but get it all out because it actually can damage seals. Fill with the recommended fluid and don't worry much about what may or may not have been mixed.
DOT 3 and 4 are hygroscopic, which means they absorb water. This is why you should always use a fresh, unopened container and not one that has been sitting around for a while. When too much water is absorbed it lowers the boiling point of the fluid, and boiling your brake fluid causes air bubbles in the system and lack of braking.
DOT 5 won't absorb, or mix with water, but it's very susceptible to aeration, which is why it can't be used in an ABS system (ABS pumps acting somewhat like a paint shaker). Avoid the urge to shake your bottle of DOT 5 before you uncap it and break the seal, or you'll be bleeding for a very long time because of aeration.
Mixing DOT 3 or 4 with DOT 5 is a bad idea, but probably not the fatal mess that most forum posts would lead you to believe. I ran across an article a while back where a guy tried to replicate the assertion that mixing the two would cause the fluid to gel, and try as he might, he just couldn't make it happen. Hot, cold, different ratios, didn't matter. They would separate, but wouldn't gel. Some will also claim that one or the other will damage seals made for the other. There's no chemical reason that glycol based and silicone based fluids will act much differently on rubber or plastic seals. In fact, HD uses the same MC rebuild kits across some of the years that use different fluids (The MC part numbers change because of the writing on the lids for different fluids).
So clean and flush as well as you can.... Denatured alcohol does a good job, but get it all out because it actually can damage seals. Fill with the recommended fluid and don't worry much about what may or may not have been mixed.
So clean and flush as well as you can.... Denatured alcohol does a good job, but get it all out because it actually can damage seals. Fill with the recommended fluid and don't worry much about what may or may not have been mixed. Good advice here ... However I have seen fluid gel/coagulate ( in automotive systems ) using different fluids and it can be a mess.
So my 2014 SG came with Dot 4. Do they use that at the factory since some of the bikes have ABS? Mine doesn't. I would prefer to use Dot 5 as in the other bikes I have..
I have seen amber dot 5 before. As stated dot 3&4 are hygroscopic while dot 5 is not. You could take a sample of the fluid with a turkey baster and then put it in a aerosol cap and put a few drops of water in. If the water disperses into the fluid then it is dot 3 or 4, if it stays seperate then it is dot 5.
I do know that when building brake systems for classic cars and trucks we always lubed the seals with the fluid we are going to run. It seems like the rubber swells a little funny if it is exposed to two different fluids, but that is just my observation.
A good flush should help, personally the only thing that I put in brake systems is brake fluid and I to use a check valve with clear tubing on the bleeder to pressure bleed the system since it moves the fluid a little quicker and (at least in my mind) get more debris out.
If I were going to pull apart calipers that might be 29 years old I would just have a new seal kit ready to go back together with. At that point I would likely over think it and put all new rubber components in the system.
I do know that when building brake systems for classic cars and trucks we always lubed the seals with the fluid we are going to run. It seems like the rubber swells a little funny if it is exposed to two different fluids, but that is just my observation.
A good flush should help, personally the only thing that I put in brake systems is brake fluid and I to use a check valve with clear tubing on the bleeder to pressure bleed the system since it moves the fluid a little quicker and (at least in my mind) get more debris out.
If I were going to pull apart calipers that might be 29 years old I would just have a new seal kit ready to go back together with. At that point I would likely over think it and put all new rubber components in the system.
I've seen jelled fluid. But have no idea why it jelled....
I said I had never seem amber dot 5 that doesn't mean it doesn't exist, every bottle I've ever opened has been purple or a strange blue....
Now on the aerated dot 5 fluid, yes, I've seen dot 5 hold tiny bubbles all day if someone pumped the lever or pedal, after opening the system,,,as there is air in the lines and it all mixes up... just walk away and come back later... much later, like tomorrow...
Now someone explain how, an abs pump can aerate brake fluid if no air is present in the system? Dot 3, 4 or 5.
I said I had never seem amber dot 5 that doesn't mean it doesn't exist, every bottle I've ever opened has been purple or a strange blue....
Now on the aerated dot 5 fluid, yes, I've seen dot 5 hold tiny bubbles all day if someone pumped the lever or pedal, after opening the system,,,as there is air in the lines and it all mixes up... just walk away and come back later... much later, like tomorrow...
Now someone explain how, an abs pump can aerate brake fluid if no air is present in the system? Dot 3, 4 or 5.
Excellent question. I think MCs are vented to atmosphere to allow the fluid to move, but I can't imagine air making it downhill to the pump.
All master cylinders vent to atmosphere, through a tiny hole in the cap, above the bellows that seals the fluid of the system...
Air would have to be present in the system to aerate the fluid, by pump action...no air, no aeration..if air is present, the brakes will be spongy or non functioning....
So, I believe the use of dot 4 by the moco is purely a cost cutting move, and nada to do with better, safer brake action..
Air would have to be present in the system to aerate the fluid, by pump action...no air, no aeration..if air is present, the brakes will be spongy or non functioning....
So, I believe the use of dot 4 by the moco is purely a cost cutting move, and nada to do with better, safer brake action..
You might want to research this ... DOT 5 fluid will aerate and this is the main reason it is not used in ABS systems.
Damn, got me thinking too. The air has to be in there to aerate. Most fluid mfg's just say to not use it with ABS, which was always good enough for me.
The issue is that there is "dissolved air" in the silicone fluid, which is why it is more compressible than glycol fluids. http://www.sector111.com/images/products/performance/brake_bits/torque/The ABCs of Brake Fluid.pdf
This air can be extracted using a vacuum pump:
The rapid valve action can whip this up so that it is not dissolved. Which means brakes go from OK, to not OK quickly.
The issue is that there is "dissolved air" in the silicone fluid, which is why it is more compressible than glycol fluids. http://www.sector111.com/images/products/performance/brake_bits/torque/The ABCs of Brake Fluid.pdf
This air can be extracted using a vacuum pump:
The rapid valve action can whip this up so that it is not dissolved. Which means brakes go from OK, to not OK quickly.
They claim it is vacuum. I am tempted to give it a try next time I have an open bottle kicking around. My A/C vacuum pump draws down to about 29 in hg, so if it happens that should do it.
I usually try to understand rather than just accept, but most of my chemistry knowledge is that if it ends in ane, ene, or ine it will burn. Maybe a little more, but not much.
I usually try to understand rather than just accept, but most of my chemistry knowledge is that if it ends in ane, ene, or ine it will burn. Maybe a little more, but not much.
I inadvertently filled my recently purged and rebuilt DOT5 spec'd front brake system with DOT4 fluid. The system had been completely disassembled and cleaned and rebuild kits installed.
When I recognized the error (before I rode the bike) I disassembled the system once again and found that the pistons were impossible to remove with air pressure, (as they had been at initial disassembly) being very tightly stuck in their bores. I had to rejoin the halves and use the M/C to pump them out.
The 2 o-rings between the caliper halves were swollen enough that they no longer fit into their installation recesses.
The M/C was stiff and slow to return to the rest position.
All of this would definitely affect the operation of the brake system, and likely render it unsafe.
I was lucky that the system was clean and I didn't have to deal with the gelling of the brake fluids that occurs with a mixing of them.
One reads that it is possible to convert the brake systems from one DOT fliud class to another with a scrupulous cleaning. I will say that it is untrue that a DOT 5 system can safely be backward converted to DOT 3 or DOT 4.
When I recognized the error (before I rode the bike) I disassembled the system once again and found that the pistons were impossible to remove with air pressure, (as they had been at initial disassembly) being very tightly stuck in their bores. I had to rejoin the halves and use the M/C to pump them out.
The 2 o-rings between the caliper halves were swollen enough that they no longer fit into their installation recesses.
The M/C was stiff and slow to return to the rest position.
All of this would definitely affect the operation of the brake system, and likely render it unsafe.
I was lucky that the system was clean and I didn't have to deal with the gelling of the brake fluids that occurs with a mixing of them.
One reads that it is possible to convert the brake systems from one DOT fliud class to another with a scrupulous cleaning. I will say that it is untrue that a DOT 5 system can safely be backward converted to DOT 3 or DOT 4.
Dot 4 vs Dot 5
I recently had a conversation with a buddy of mine that works for HD in the service/repair dept on if he knew of any issues on the 2017 HD bikes, as I was considering buying one. He mentioned Harley had gone back to Dot 4 on the new bikes, which is corrosive over time on the seals, because they were having leakage issues with the Dot 5. I was looking to see if there were any threads about it yet and didn't see any, but thought it was worth mentioning on this one in case anyone was thinking about changing their 2017's from Dot 4 to Dot 5.
Cheers!
I recently had a conversation with a buddy of mine that works for HD in the service/repair dept on if he knew of any issues on the 2017 HD bikes, as I was considering buying one. He mentioned Harley had gone back to Dot 4 on the new bikes, which is corrosive over time on the seals, because they were having leakage issues with the Dot 5. I was looking to see if there were any threads about it yet and didn't see any, but thought it was worth mentioning on this one in case anyone was thinking about changing their 2017's from Dot 4 to Dot 5.
Cheers!
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
