Rear Brakes !!! Why does this happen !?!

[Hairyblackdude]

Hey all,

My brother is having some issues w/ his 02 Blaster & I have the same issue every now and then.

The problem is with the rear brakes, they don't seem to work wortha damn!! You step on the rear brake & the quad just keeps rolling..

I know the inside of the brake fairly well and I understand how it is supposed to work- but its just acting wierd.

I removed the pad & cleaned up the inside of the caliper so the pad shouldn't have any trouble sliding. I basically remove the white plastic cap & turn the plunger on the bottom so it recedes back into the mechanism.

I install everything back togther & I turn the white cap clockwise (it clicks), so the plunger that pushes on the pad screws out. I usually screw it in until I can start the see the whole assembly pushing out of the caliper. This ensures that theres no slack between the pads & the plunger.

I install the cap back on the caliper & it is trying to pop off a little bit due to the spring thats inside the cap. I have to make sure to not spin the plastic cap too much, because then the brakes are waaaay too tight & they drag.

So, I put everything back together & the brakes appear to be working fine.

I take the quad out into the street, pull a wheelie or something & the brakes don't work again.

We gotta pull it all apart again & repeat the process for the brakes to work.

Am I missing something here? Why do the brakes work when we test them out rolling the quad back & forth, but they fail when you try to stop??

I thought they were self adjusting, but you can pump the lever all day & they don't tighten up !!!

Anybody got any tips, tricks or pointers for making the rear brake work well & stay working well??

ANy info is appreciated. THANKS !!!

 

[nitronate]

Usually cleaning the caliper makes a big difference, but you've already done that....

The only other thing I did to get my rear brake working was change the cable.
The stock cable runs all the way to the handlebars and seems to cause alot of slack in the cable. I recommend buying the cable off eBay that eliminates the portion of the cable that goes to the bars. It is only a couple feet long and goes only to the rear brake pedal. Adjustments are simple and you have a much more direct feel. It works great for me, I can lock the rear wheels.

 

[nitronate]

eBay Motors: YAMAHA REAR BRAKE CABLE KIT YFS200 BLASTER YFS 200 (item 380010609273 end time Apr-01-08 11:11:32 PDT)

Theres a link to the cable I bought.
It installs easily.

 

[Hairyblackdude]

I have that brake cable on my Blaster, but my brother is using the stock cable.

I also noticed that when using the rear brake, you can't hear that little white wheel clicking like when you spin it with your fingers..

I would assume this wheel would click & would be audible through the caliper when using the brake lever..

The brake cable seems to work okay, it definately pulls in when you step on it- but maybe its stretched??

The service manual doesn't really explain anything in detail..

I just needed to know if there were any extra steps or tricks to setting it correctly that I am overlooking...

 

[lhslax007]

hey i got the same problem. i stepped on the brake pedal without the cover on and could see the cable pull all the way so i dont think thats the problem. i pulled apart the whole brake assembly and i noticed that after the plunger pushes the brake towards the disk, how is the brak suppossed to return to starting position? wouldnt it stay right on or close to the disk? Also in the blaster manual someone posted in the DIY section it goes real in depth about the brakes and says that the plunger is suppossed to self adjust like hairyblackdude said and i sat there for fifteen minutes stepping on the pedal and it didn't do sh*t.

 

[Hairyblackdude]

My brother ended up opening the rear caliper back up & placing 2 washers behind the brake pad..

His was worn down pretty good, so we thought maybe it just didn't have enough pad to push completely. Plus, the back of the pad had a small dent from where the plunger was wearing into it. He stacked up 2 washers & it seems to work okay now...

I would suggest just turning the white plastic disc until the assembly starts to push out of the caliper housing. Make sure the pads are pretty damn close to the brake rotor first. When you install the cap on the caliper, make sure that it has some light pressure on it trying to push the cover away. This ensures that the plunger is pushed all the way out & the pads are as close as they could be. Just don't screw the cap in too much because it will cause the brakes to drag.

I'm sure that plunger has a limit on it, so make sure your pad is still thick, enough so it reaches w/ ease. Also, remove the one pad & clean up the inside of the caliper real good & grease it up so it slides easily.

You have to make sure when youre putting it back together, that you insert the peg from the brake assembly INTO the hole on the brake pad. If you fail to do this, the whole thing doesn't work right. Most times, you'll have the run the threaded adjuster on the cable itself all the way into the caliper so you have enough slack in the cable to install the assembly correctly. After everything is back together, make sure you adjust the cable back out to tighten up the slack in the foot pedal.

GOOD LUCK !!!