stupid question of the day

[boathead]

with your (to borrow basscliff's word) indulgence, i might start a stupid question of the day, as i am so new at this that many if not most of the posts leave me a few PhD's short of understanding..

so today's question:

i want to bleed the brakes/change the brake oil. on the front, each side has a bleeder valve. do i have to some how bleed both simultaneously? or can i do it separately?

bonus stupid question: i cannot find locally DOT 4. can i use DOT 3?

[Steve]

No need to do them simultaneously. Recommended practice is to start at the one farthest from the master cylinder, then work your way back. In this case, they are about the same distance, so it really does not matter.

Bonus answer: What does the book (or the master cylinder cover) call for?
If it suggests DOT3, then DOT3 will be fine. DOT4 is more tolerant of heat and will be suggested for heavier vehicles or when racing, but DOT3 should be fine for our bikes. Regular or synthetic DOT3 will work, but do NOT use DOT5 thinking that "if 4 is better than 3, then 5 must be better than 4". DOT5 is silicone-based and is not compatible with the components installed on your bike.

By the way, there aren't too many 'stupid questions'.
I have seen, however, some rather stupid answers.

Oh, and it's brake fluid, not oil.

.

[Mark M]

1) You do each side separately. To do a fluid change, I use a clean rag or paper towel to soak up all the fluid in the master cylinder, then fill the reservoir with the fresh fluid and start pumping.

2) Yes, DOT3 just has a lower boiling point than 4. For street use, this is of no consequence. I believe 3 also is more stable over time, but I am not sure of that.

Mark

[boathead]

Oh, and it's brake fluid, not oil.

.

hahah. see?

thanks for the responses.

[Steve]

Ahh, but it's not so 'hahah'.

I don't know of any brake oil, but there is brake grease.

Yup. Hi-temp stuff that lets the pads slide on the pins in the calipers. It's hi-temp so it doesn't drip onto the pads.

.

[lurch12_2000]

1) ...To do a fluid change, I use a clean rag or paper towel to soak up all the fluid in the master cylinder, then fill the reservoir with the fresh fluid and start pumping.

Mark

I used to do it this messy way with a rag, but I found one of my kid's old nasal suction bulbs and it works great. In 1 or 2 suctions the master cylinder is empty and ready to put clean fluid in. You can even get the little residue gunk at the bottom with it or douche it with new fluid to get it really clean!
It's short, shaped like a light bulb, has a pointed tip the size of an pencil eraser, and is very flexible. The rubber doesn't break down or harden like plastic ones. NO mess and squeeze the old fluid right into a waste container.
Now if I can find all these snot suckers we had for our 6 kids and then I'd reuse them in the garage for the rest of my life!