Brake failure by plastic sight glass melting!!

[iamverb]

Hey Dawgs, it's been a long time since I've posted anything - but I didn't quite make it to the end of my street today when my brake reservoir sight glass cracked and brake fluid shot out everywhere.

I turned around and went right back home to see how it happened - and evidently, my sight glass was plastic, and had dissolved into goo on the inside, where it was in contact with the brake fluid. It looks like it just got thin enough and cracked under pressure.



Anyways, if you have a plastic sight glass, and it doesn't seem as clear as it used to, or if you can bend it by pushing your finger on it - it should be replaced, and preferably with a glass one, or at least one that won't dissolve in brake fluid. A new brake reservoir would be a really cheap investment in peace of mind if you find yours is a flimsy piece of plastic like mine was. The safest riding in the world won't save you if hit the brakes and brake fluid shoots into your eyes instead of stopping.

I was lucky enough to be going slow, and right by home, and have a Kymco replacement reservoir (with a glass sight glass) handy in the garage. A couple turns of the wrench, a brake fluid flush, and a little cursing at my ruined pants and gummed-up paint, and I was back on my way. But yeah, check your sight glass before you ride - it'd be easy to not be so lucky.

In other news - anybody have a spare Kymco brake switch handy?

[Steven Spielburgman]

Feb 26, 2010 18:04:39 GMT -5 iamverb said:

Hey Dawgs, it's been a long time since I've posted anything - but I didn't quite make it to the end of my street today when my brake reservoir sight glass cracked and brake fluid shot out everywhere.

Wow. I think you just saved a few lives.

[♣Luke♣]

iamverb, how's it goin'??been a long time huh!
same thing happened to my 50cc scoot back then. you need two things to remedy that:
1)penny ( reddish U.S.coin)
2) jb weld (buy it from wallmart $5)

drain the brake fluid,clean the area surrounding the transparent plastic thoroughly,sand paper it (better). the penny fits perfectly on the circumference of the round plastic, put the penny there and apply jb weld around it's periphery to seal it .be careful not to put any jb weld inside the oil reservoir. allow it to dry for about 8 hrs. then refill with fresh brake fluid. good luck veby!!

[Steven Spielburgman]

I think that is a federal offense haha

[scooterdad1]

Great answer Luke. I used a Dime on a friends Qlink 250. He has been riding with it for 2 years now, and seems to be holding up well. I thought I was the only one trying that.. Lol.

[leo]

Aug 15, 2010 11:41:17 GMT -5 ♣Luke♣ said:

iamverb, how's it goin'??been a long time huh!
same thing happened to my 50cc scoot back then. you need two things to remedy that:
1)penny ( reddish U.S.coin)
2) jb weld (buy it from wallmart $5)

drain the brake fluid,clean the area surrounding the transparent plastic thoroughly,sand paper it (better). the penny fits perfectly on the circumference of the round plastic, put the penny there and apply jb weld around it's periphery to seal it .be careful not to put any jb weld inside the oil reservoir. allow it to dry for about 8 hrs. then refill with fresh brake fluid. good luck veby!!

a penny was too big, so was a dime.
broke out the grinder and ground off the edge around the penny until it fit into he hole.
mixed up the JB weld and slapped it on.
by golly it works!

to the first poster:
fluid doesn't "shoot out" because it's under pressure.
in fact it doesn't "shoot out" at all because there IS no pressure in the master cylinder.
the fluid is pressurized by the piston in the cylinder, and it is located right before the brake line.

[jimh]

Is there a difference between dot3 and dot4 brake fluid that one is more caustic than the other? My scoot specifies dot4, a Hyosung Korean and warns against anything but in the owners manual.

[silverfox96]

dot3 and dot4 brake fluid difference. dot 4 is less moisture absorbant, although it still will absorb moisture. Just not as much and not as fast. I think there is a difference in the boiling point of the two also with the dot 4 having a higher boiling point.