XS11 Special for sale from New England Motorcycle Museum

[Radioguylogs]

I believe that is why it is not used in high performance applications. Did you have fun bleeding it? It easily suspends air in tiny bubbles. Lastly, does DOT 5 require routine fluid changes as with DOT 3?

I had no touble bleeding it in all three systems - using the basic fill-the-resevoir and pump technique.

Regarding service, my stategy is to rebuld the system and never open it after that unless necessary. No new air = no new moisture. So, I've never even opened the resevoirs after I rebuilt them 5 years ago.

[DEEBS11]

Master cylinders are not perfectly sealed. They have tiny orifices to let in make up air. Moisture does enter the system over time. It is one of the most missed items on a bike service. This is why calipers lock up over time even when stored in a dry garage over a long period of hibernation. Brake fluid is hydroscopic. I have rebuilt many, many brake systems over the last 40 years. All of them the victim of neglect.

[jetmechmarty]

Master cylinders are not perfectly sealed. They have tiny orifices to let in make up air. Moisture does enter the system over time. It is one of the most missed items on a bike service. This is why calipers lock up over time even when stored in a dry garage over a long period of hibernation. Brake fluid is hydroscopic. I have rebuilt many, many brake systems over the last 40 years. All of them the victim of neglect.

So, you’re saying DOT 3 or DOT 5 makes no difference in service interval?

[DEEBS11]

Marty, I change any type brake fluid in my bikes or customer bikes every two years. Cheap insurance. I can do it quick with a Mytivac. I open the master cylinder cap and use the vac hose to pull the old fluid from the reservoir. Then I clean the inside of the reservoir. Then pour in fresh fluid. Add teflon to each bleeder screw. Attach the vac to the bleeder screw at the caliper and pull the clean fluid through until it comes out clean. Lock it all back up and it's ready for a few more years. I also write the date on any brake fluid bottle I open in the shop because I toss it after about a year once it's open. This does not happen too often because I go through a lot of it in a year.

The top three important & neglected fluids in a motorcycle that require service the most and can potentially cause the most damage:

Engine Oil
Brake Fluid
Untreated gas in the carburetor

The other neglected fluids but can go for a longer period within reason:

Transmission Gear Oil
Fork Oil
Coolant

And I guess I should also mention the other part of a bike that is usually neglected that needs to be done every service is cable lube. This would include speedometer, clutch, choke, and throttle(s).

[cajun31]

So, you’re saying DOT 3 or DOT 5 makes no difference in service interval?

One of the main reasons the DOT 5 interests me is the fact that it does not harm paint. I have done a lot of reading over the past few days and much of what everyone is saying in one form or another applies. Main thing is that should I go the DOT 5 conversion I would be looking at taking everything off and apart to thoroughly clean everything to get all the DOT 3 remnants out. Might even go ahead and order all new rubber parts for the masters and calipers. Silicon based should not harm rubber seals, but some think that the glycol based fluids do something concerning sealing the seals against the steel. They then state that putting the DOT 5 in the same system without rubber refresh allows the silicon based DOT 5 to seep past the seals. Of course that caused a lot of discussion and debate with some saying (BS) and others saying why take the chance. My stance on that debate would be, if I am taking the time to disassemble and clean then why not refresh/replace? One of the other things that I read was that some seem to think that DOT 5 does not give you the stiffness in your braking system that the glycol based fluids do. On my 2002 HD Night Train it came from the factory with DOT 5. All new Harleys now come with DOT 4. That decision was not made because of any performance issues with DOT 5. When most modern bikes including Harleys started implementing ABS then DOT 4 was implemented. The reason being that DOT 5 can foam up because of the oscillating nature of ABS. I have also read a lot concerning being careful to not introduce air when using DOT 5. Like Deebs I own a mity vac and would never do my brakes on anything I own without it. it truly makes doing the brakes a one man job. Just like Deebs I simply take the cover off the master and just suck all the fluid through the system while topping off the master. Once i see clean fluid coming out of the caliper I simply bleed the brakes a couple of times (really just habit then a necessary step with the mity vac) and the brakes are hard as a rock.

Some of the other things I read were tricks that some use when pouring the DOT 5 to help eliminate air. Most just suggest to use a screwdriver and just pour the fluid down the screwdriver into the master. The last time I did my brakes on my Night Train a couple of months ago I replace all of the fluid front and back as well as the brake pads. I was just careful while pouring it into the masters to avoid creating bubbles. Of course you wouldn't want to shake a bottle of DOT 5 up before using either. Come to think of it I wouldn't do that to glycol based DOT 3, 4 or 5.1 either.

I am probably going to go ahead and move my MNS's over to DOT 5. I will also be upgrading two of those to stainless brake lines too. Many swear that DOT 5 gives you a softer brake feel, especially with older rubber brake lines. They swear by if converting to DOT 5 then stainless lines are a must. We all already know that stainless lines make a world of difference no matter what kind of brake fluid you are using.

As for how often DOT 5 should be changed some stated they had never changed theirs in 20 years with no problems. My experience is that because the DOT 5 is silicon based it really does last a lot longer then the glycol based fluids simply because it does not absorb moisture. As Deebs pointed out, that does not mean moisture can not enter. As others stated because water and silicon do not mix the water will settle to the lowest point in the system (calipers) and would need to be addressed. My thinking on that is you should still check on that every couple of years or sooner depending on how you ride and when you ride. Outside elements being the factor, riding in the rain or getting crazy with the water hose when washing your bike etc. Living in high humidity areas, like we do here in the Southeast might also be a factor. To me that is where the mity vac or something similar would pay dividends. Just hooking up to the calipers and pulling a small amount of fluid out then check it for moisture. Only takes a few minutes to do that and would give you peace of mind. When I changed the Night Train fluids, being honest I had not done it in the 21 years I have owned the bike. The fluid was a bit off color. A light tinted yellowish brown color. If you have never dealt with DOT 5 when it is new it is a clear purple color. So over all those years I never experienced any brake failure or no brakes at all etc... I own too many bikes the point being i ride some more then others and none of them enough, if you get what I mean. I fear my age is having more to do with that then any other factor. Moral of this story is that I think DOT 5 will cause me less brake headaches as far as maintenance goes and it will save me from constantly having to touch up my brake master cylinders and calipers.

[jetmechmarty]

Marty, I change any type brake fluid in my bikes or customer bikes every two years. Cheap insurance. I can do it quick with a Mytivac. I open the master cylinder cap and use the vac hose to pull the old fluid from the reservoir. Then I clean the inside of the reservoir. Then pour in fresh fluid. Add teflon to each bleeder screw. Attach the vac to the bleeder screw at the caliper and pull the clean fluid through until it comes out clean. Lock it all back up and it's ready for a few more years. I also write the date on any brake fluid bottle I open in the shop because I toss it after about a year once it's open. This does not happen too often because I go through a lot of it in a year.

The top three important & neglected fluids in a motorcycle that require service the most and can potentially cause the most damage:

Engine Oil
Brake Fluid
Untreated gas in the carburetor

The other neglected fluids but can go for a longer period within reason:

Transmission Gear Oil
Fork Oil
Coolant

And I guess I should also mention the other part of a bike that is usually neglected that needs to be done every service is cable lube. This would include speedometer, clutch, choke, and throttle(s).

Before you get the wrong idea, I've never been one to neglect fluids. Brake fluid service about every two years. I simply pour it in the top and pump it out the bottom until I see clean fluid in the line. It's just the bleed procedure.

[jetmechmarty]

I am probably going to go ahead and move my MNS's over to DOT 5. I will also be upgrading two of those to stainless brake lines too. Many swear that DOT 5 gives you a softer brake feel, especially with older rubber brake lines. They swear by if converting to DOT 5 then stainless lines are a must. We all already know that stainless lines make a world of difference no matter what kind of brake fluid you are using.

I don't know everything about DOT 5 and why I asked Mike about replacing it. It's a liquid and as such, it can't be compressed. It does have a reputation for suspending air in tiny bubbles. That air can be compressed. That softer feel is the result of air in the system. Done completely, you won't know one brake fluid from the other.

As an aside, I just acquired a motorcycle from the original owner. It's a one owner 1980 model. He told me the brake fluid is original. I gotta tell ya, the brake still works! That's one piece of original equipment going in the trash.

[Radioguylogs]

Master cylinders are not perfectly sealed. They have tiny orifices to let in make up air. Moisture does enter the system over time. It is one of the most missed items on a bike service. This is why calipers lock up over time even when stored in a dry garage over a long period of hibernation. Brake fluid is hydroscopic. I have rebuilt many, many brake systems over the last 40 years. All of them the victim of neglect.

I am listening so I can learn something.......but those vent holes in the master cylinder are above the diaphram? The point of having the diaphram is so the brake system is sealed, and the diaphram can move up and down as the brakes are applied without introducing new air or leaking fluid. The vent holes allow the air above the diaphram to come and go.

You would never want to expose your brake fluid to rain or the garden hose.

Honestly, the fuild would be leaking out the master cylinder if it were vented. I had a master cylinder that leaked fluid below the diaphram and I had to get it to seal so it would stop leaking fluid.

Therefore, if you never open the system, it seems like it should last a long time before moisture becomes a problem.

PS: A bit of trivia.....the term is hygroscopic. Took me a few years to notice.

I am listening if there something for me to learn.

[DEEBS11]

"Hygroscopic substances include cellulose fibers (such as cotton and paper), sugar, caramel, honey, glycerol, ethanol, wood, methanol, sulfuric acid, many fertilizer chemicals, many salts (like calcium chloride, bases like sodium hydroxide etc.), and a wide variety of other substances."

Thanks Mike, much respect, I have been saying that incorrectly for many years. However, the good news is, later on for dinner, I will be having basgehtti and then a quick stop to the labratory for a pee,

My brake comments come from repairing hundreds of motorcycles from every marque over the past 40 years. When I come across trouble with a hydraulic brake system locking up it is always a moisture issue and it usually enters from the master cylinder which is visually indicated by a crusty master cylinder cap and dark brown brake fluid. Lots of aluminum oxide. It's the weakest seal in the system other than the piston seals. Perhaps in my line of work I see the worst ones. I guess it's possible for brake fluid to last for years under some circumstances. I just would not let it go for too long. Just some friendly general advice to folks at home that are new to restoration.

[Radioguylogs]

I agree- letting the fluid go too long is what causes problems.

Basgehtti - that's funny. Our family used to call it that to joke about my younger brother's pronunciation. BTW, Those noodles are hygroscopic!

We also used a gru-dryber to turn screws.

My sister once asked my mom, "Mom, what is gletispray?" Mom says, "Where did you hear that?" .......Lynn said, "The priest keeps saying it."

It was fun growing up in a big family.