Front Brake Problem

[kar_the_terrible]

I fitted in a new cylinder, capiler seals and pads in my front caliper. BTW a nice way to bleed/fillup empty lines in the calipers fast, is to use some clear tubing (autozone sells a cheap fuel siphon) that fits exactly over the bleeder bolt. Sucking air through this pipe will get out all the air from your lines faster that just letting it sit.

OK now my problem:
With the system bled, the brakes do not exert much force at all... I can push the bike with the brake lever fully depressed!!! I measured 4.7mm on the brake rotor (I think the absolute minimum in the manual is 4.5mm) I even see the pads pushing against each other, but Im not sure the displacement is sufficient. What could the problem be? How can I be sure that all the air is bled out from the system, or is there a problem in the master cylinder assembly that I am overlooking. BTW I rebuilt the master cylinder assembly too...new seals and everything.

Thanks in advance.

[TechTMW]

You probably still have air in the system ... Back to bleeding !!!

[kar_the_terrible]

So how does one know that the system is bled of all air??? just keep doing it till the brakes work???

dayum

[9000white]

start bleeding from the top down--banjo bolts down to bleeder--then let it sit for a few minutes and take a plastic hammer or a piece of wood and tap on banjo bolts to move air bubbles to top and bleed again.

[Quick 350]

I found the easiest way to bleed the brakes on a bike is to buy one of those brake bleeding kits that forces the fluid up from the caliper to the reservoir. Has not failed me yet. I bout mine at Auto Zone for around $20.00.

In your case if your front caliper was no good then most likely you might need to rebuild the master cylinder and reservoir. The kit runs for like $7.00 and is not hard to do at all.

Good Luck!!!

and post back!

Mike

[kar_the_terrible]

All done,
It was a bleeding problem. I finally just let it sit overnight, and completed the bleeding in the morning... works just fine now... even went out on joyrides


Oh BTW for all xs400, xs360 owners. Most aftermarket rear master cylinder rebuild kits are the wrong diameter . And yamaha showrooms charge $50 for two rubber seals and a spring... so here's an easy fix.

Most Harleys have rear master cylinder pistons of the correct diameter. Any harley repair shop (which is just about any motorcycle shop) stocks these with seals for about $5-10 (dont forget to haggle). Get the 'wrong' aftermarket parts online, and join the two using JB-Weld. JB-Weld should be solvent resistant anyway, plus the two parts are being pushed against one other, so they work just fine in my assembly. I'll post pics when I have them.