Replacing Brake & Clutch Fluid

Hello All:

Having purchased my 2000 VFR used, I read in the owner's & service manual that the clutch and brake fluid should be replaced every 12K. Coming from an Automotive repair background ( and now an electrical engineer ) I question why this is neccessary. In the automotive world, brake systems often go the life of the vehichle (or well over 100K) without ever replacing the brake fluid.

Now I can see this if the fluid was contaminated with water, dirt, etc. Or if you lived in the mountains, and you somehow managed to Boil the fluid from excessive heat. And yes there is a small amount of o-ring material that ends up in the fluid due to o-ring wear. But really, the system is a closed system with no exposure to the outside elements.

What is it about motorcycle brake systems that causes the manufacturer to reccommend this so often? Don't get me wrong I want my brakes to be safe, I'm just thinking this is way to drain your wallet, by playing on the fear factor.

Is the brake fluid really bad at 12K? what about at 12,500? Does it matter if your 12K is mostly highway, or stop-and-go city? Any comments? I'm missing something?

Thanks:smile:
Live to Ride and Ride to live

 

I went four years before I changed it on my 2000 VFR and it looked like a really dark tee or coca-cola in the glass jar. The new stuff is almost perfectly clear. I don't know what is actually happening to it, but you can see its not good. I try to keep it changed every 2 years now.

Btw, that bike is not fun to change the fluid on. There are 11 lines and 7 bleed points (one under the seat!). You need the manual to understand how to bleed them - it is a bit confusing at first, but read the diagrams - you'll have a few "that's interesting" commnets for sure.

 

Thanks for the insight Jrock. I'm sure others will comment

 

I try to do mine about every two years. I think one or more of my cars actually recommend the same thing. It may be one of those things that few people actually do, but is recommended.
Personally, goin gover the same stretch of road I also use my brakes on the bike more often. Just ride much more agressive than I drive.
I think also the idea is that you maintain a bike to a much higher level than a car. Sort of like a plane, but not to nearly the same extent. Any problems on a bike have the capacity to much more problematic than a similar issue on a car. So you do more preventative mait. to avoid the possibility of an issue. Just a theory of mine though.

 

I just had my brake fluid changed this past weekend. The fluid that was removed was six years old and had 40k miles of use. While the brakes seemed to work fine, my mechanic said the fluid was discolored and had sediment in it. The job was overdue. I may have the job done sooner next time around.

 

I like your point about maintaining to a higher level of safety and I'm just trying to understand "why" so often. 12K miles is not alot of miles between fluid changes. Maybe there's a Honda tech out there that could give his/her reasoning

 

As brake fluid ages, the corrosion-inhibiting additives in it break down. The earliest signs of chemical decomposition can often be detected within a year or so, or after 10,000 to 12,000 miles of normal driving. Hard use that elevates brake temperatures and pressures can accelerate the rate at which the fluid additives break down even more.

As time goes on, heat and chemical activity continue to erode the fluid's ability to prevent corrosion. Oxidation starts to eat away at metal surfaces creating dissolved acids and sludge that are carried with the fluid as it surges back and forth with every application of the brakes. Some of these contaminants are abrasive and increase seal, piston and bore wear in the calipers, wheel cylinders and master cylinder. As the fluid gets dirtier and dirtier, it accelerates mechanical wear in the brake system. If not corrected, it may cause some components to fail prematurely. ABS solenoid valves, in particular, are sensitive to this type of attack - and can be very expensive to replace.

Moisture also creeps into the system to further add to the contamination problem. Humidity in the air can be drawn into the fluid anytime the fluid reservoir is opened for inspection or anytime a brake hose, line or bleeder valve is opened when servicing the brakes. Even if the fluid reservoir is never opened, moisture will still infiltrate the system through microscopic pores in rubber brake hose. The rate at which this happens depends on the age of the vehicle and the type of brake hose used. Newer hose made with linings that are less permeable to moisture help extend the life of the fluid. Even so, moisture can still slip past piston seals in wheel cylinders and calipers.

As the fluid becomes contaminated with moisture, its boiling temperature drops. Only one percent moisture can lower the boiling point of some DOT 3 fluids down to 369° F. Two percent water can push the boiling point down to 320° F, and three percent can drag it all the way down to 293° F - which is getting dangerously close to the minimum DOT requirements.

If only I had a Nickel for every time I had to explain this to a customer at the auto shop I would have a new VFR ................. :smile:


More here : http://www.babcox.com/editorial/bf/bf40142.htm

 

Very good explanation. While I agree that the fluid will brake down, my sticking point is the 12K miles interval. That assumes that all 12000 miles are driven equally. Clearly someone living in a mountainous area and towing a trailer in stop and go traffic, is not the same as a salesman driving 12000 highway miles.

My 2005 Honda Civic owners manual reccommends the brake fluid be changed every 3 years regardless of mileage. Well in 3 years I could easily put on 60K miles. Am I to change my brake fluid 5 times in 3 years. I think not.

The other problem with the website explanation is that its geared towards selling a brake flush service to reluctant customers. This would lend some bias to the article.

Thanks for the reply.

 

Well then I would recommend that you get a moister content reader as I have in the shop and maybe even some copper paper strip testers. Its not hard to do so why not? If you want to understand the effects of water molecules into your braking components and the effects of wear and corrosion from contaminates then get a biochemistry degree and maybe major in Metallurgical field. Otherwise you can sit it and wait and see if there is an answer your waiting for like some guy that says its not needed ..... Im not trying to get on you but the internet is loaded with information about every topic. If you want to know the facts do research, and do test yourself. Its not a mileage think for brake fluid to have high moister only time and conditions. If you think you dont need to change your brake fluid that often - dont. Might as well skip the oil change and coolant too........

 

I agree with your assesment that its not neccessarily a mileage thing. If you read my opening post, I'm just trying to determine why or how Honda comes up with changing it every 12K with no reference to time or riding conditions. I think I'll use 3 years as good benchmark, and not be too concerned with the mileage.

 

I am a little hesitant to do it myself because it seems like such a pain in the ass. How much are you guys paying to have this done at a shop?

Mel

 

There are certain things you can stretch, and certain things you shouldn't. Good, reliable brakes can mean the difference between life and becoming one with a bus that blew a red light...

I've got a 99 I'm in the process of replacing the entire brake system. Got it with 4800 miles, and the brakes looks show-room fresh, but they're 8 years old...

I know this from dealing with airplanes, component replacement intervals are both time based (hours used) and AGE based... Some things are done at certain intervals whether the plane flew or not.

 

I just got my system flushed and the front pads replaced and was charged 2.5 hours of labor.

Hey SLOVFR,

Do you also change your coolant and fork oil on regular intervals? If so, about how often?

brian

 

I just got my bike last year and just got done changing my oil, clutch, brake, forks, and coolant (changed to Koolaide for track). I plan on doing the oil every 3,000 miles or 3-4 months (I don't ride a lot). Change my clutch, brake, and coolant every year (Maybe people have not seen what bad coolant can do to eat aluminum), and change my fork oil every 10k miles. Its not had to do on my 97 and fluid is cheaper than parts. Oh and dont forget to clean and oil chain every 500 miles.
I work in the Automotive service field for the past 25 years. I cannot count the number of engines I had apart and seen failed due to lack of fluid changes. Old coolant is corrosive and will eat a hole thru aluminum. Bad brake fluid will cause calipers and cylinder bores to rust and freeze as will the clutch system. I think we all know what old oil will do to your engine ..........

 

I called my local shop about bleeding my lines and they quoted me $150. (!!) I think I'll just wait to the 12k service and have them do it then.

 

I don't have linked brakes so its a lot easier for me, but if you can figure out how to do it, a new bottle of brake fluid is only like $10, compared to the $150 they quoted you, it might be worth the hassle to do it yourself.

 

Honda must account for all customers, in all situations, so maintenance schedules are to the lowest common denominator. They have to recommend something, so they chose 12k. Remember the typical customer will not be able to determine what catagory they will fall into.
If the colour is dark, change it. Usually means it is contaminated. If it is still clear/hard to see, leave it alone.

 

I can't speak for your 2000 with multi point bleeders, but doing the bleed on clutch and brakes on my '95 is pretty easy.
If anyone is interested, I'm building 2 piece reverse bleed syringe kits. One syringe good for your clutch and one for your brakes. Reverse bleeding IMHO is quicker, not prone to introducing bubbles, and more efficient on fluid use.

See a previous reply about it here:
http://vfrworld.com/forums/mechanics-garage/6668-brake-fluid.html

Shoot me a PM if interested.

 

After all this discussion. I checked the Honda Service manual. In there they do reference 12K miles or 2 years whichever comes first. They just don't give you a time reference in the owner's manual. That makes more sense. I'm inclined to follow the 2 years or 12K reccomendation.