Author Topic: 'Upgraded' the front calipers on my C10, no front brakes now...  (Read 3305 times)

Offline Charliedog

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So I wasn't satisfied with the front brakes on my C10 after re-building the calipers and trying several different brands of pads, I researched the threads on the Nissin/Tokico caliper upgrade.  I got the parts-decided on a set of Nissin calipers off a CBR600RR, installed everything, pulled the fluid thru the Galfer two-line system with a Mity-Vac and finished it off with the old-fashioned pump-open-close-release method to bleed the brakes until no bubbles came out BUT there is no resistance at the lever.  It feels like there's air in the system rather than fluid.

When I got the calipers, had I pushed the pistons back in their bores before cleaning everything with Brak-Kleen and an old toothbrush.  I'm reasonably sure the new pads are now resting against the rotors.  I did take the bike off the center stand and rock it-just could feel the slightest bit of stopping power when I gripped the lever, just a hint really. 

Right now the lever is bungee corded against the grip, and hopefully it will make a difference tomorrow morning.
I'm open to suggestions.  If I don't get this resolved by the weekend, I'll re-install the original calipers-I'm heading to Indy next week.  I did stock up on crush washers and decided to never re-use 'em, just for my own peace of mind.  TIA     
CharlieDog
Bristol, TN

Offline works4me

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Re: 'Upgraded' the front calipers on my C10, no front brakes now...
« Reply #1 on: July 29, 2014, 05:44:51 pm »
You have to prime the master cylinder :
Remove the hose at the master cylinder,
put your thumb over the hole,
pump the lever until enough pressure builds
to squirt fluid past your finger,
replace hose, top off reservoir, then bleed normally.
Should work now. Wait a day, bleed again. HTH

Offline throb

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Re: 'Upgraded' the front calipers on my C10, no front brakes now...
« Reply #2 on: July 29, 2014, 05:54:19 pm »
How freely did the pistons travel when you pushed them back in?  I did the same mod and the Nissin calipers I got were off a 2003 CBR600RR.  They were filthy and at least 3 of the 8 pistons were hung up and it took a good deal of work with compressed air and different wood blocks and sweet talk (well, okay; actually lots of inventive swear words) to get them out.  After that I cleaned everything up and replaced ALL the seals.  The pins which the pads slide on were also corroded.  They were replaced as well.  They work like a charm now.  Whomever replaced the pads in them before also put the wrong ones in as they were too long from the pins to the bottom of the pads (only about 3/4 of the back of the pad was in contact with the pistons) and it must have also cut their braking efficiency down by about 25% since not all the pad would have been clamping down on the rotor!   :o

http://www.ronayers.com/FRONT-BRAKE-CALIPER-03-04-C186988.aspx

Also the Nissin calipers also have a rubber seal (part #6 in the fiche diagram) which is solely responsible for allowing brake fluid to travel from one half of the caliper to the other.  If yours were tended to (or not tended to at all) by the same sort of incompetent person as mine, you may want to give serious consideration to a complete rebuild!
'05 Concours, SISF's 2 min jet mod and exhaust cam sprocket, snarf's block off plates, risers, SS lines, fork brace, T-Cro's stick coils & shift linkage, ZZR1200 rear shock, MS rear wheel.

Offline MAN OF BLUES

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Re: 'Upgraded' the front calipers on my C10, no front brakes now...
« Reply #3 on: July 29, 2014, 06:43:44 pm »
I've never liked using a mightyvac, they induce more issues than the supposed simplicity they are supposed to have. It will also tend to pull any tiny port blocking stuff in the m/c into the valve, making things difficult. There is clearly air caught between the left and right caliper, somewhere near the junction at the M/C because you are using a 2 line system.
Also trying to pull fluid down thru one side, with the vac, allows air in the opposite line to be pulled back and forth.
The vac will also pull air in thru the threads of the bleeder fitting when the system is "closed".
try this.
go to one side and begin pulling fluid at one caliper. Have a clean bottle there with a substantial amount of fresh fluid. when the hose is full, raise it above the bleeder with the bleeder locked down, now quickly place that full hose into the jar of fluid without making an airbubble in the line, or as minimal of one as possible. with that hose now submersed crack that bleeder open again, go to the other side, and vac that side, drawing fluid from the bottle as the supply, don't mess with the m/c, just keep pulling fluid up and over. this should purge the lines between both calipers. Don't run the bottle dry...close that bleeder before getting distracted.
If you have no resistance at the lever, and it goes totally flat, doing the bungie thing won't help at all, that only works when there is at least half a lever resistance, and it is spongy.

after you get those lines purged side to side, go back and do the normal pump/lock/repeat bleed method.

in essence what you are needing to do, is to pull fluid from one set of calipers, along with the air entrapped there, up to the junction (bubbles flow up to top) then back down and out of the opposite caliper. Trying to push air out of 2 lines into 2 calipers is like chasing bubbles.... ;)

30 YEARS OF KAW.....

Offline Charliedog

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Re: 'Upgraded' the front calipers on my C10, no front brakes now...
« Reply #4 on: July 30, 2014, 06:25:22 pm »
Thanks for all the helpful suggestions, especially works4me.  Believing in the least expensive, least intrusive approach, I did what he said.  Almost.  Before I had a chance to bleed the system, I noticed a steady stream of tiny bubbles coming up into the reservoir.  Almost like foam in beer-we all know what that looks like.

Thinking it would be easier to let the air out that way rather than pushing it down the lines, thru the calipers, and out the bleeder screws, I let it go.  I noticed if I grabbed the lever, the bubbles would stop.  When I released it, they would return-sometimes a bigger one would pop up.  I started to feel the lever firm up.  It also helped to squeeze the lever, then let it 'snap' back to get more bubbles up and into the reservoir.  I did that so many times I almost raided a blister on my index finger.  Eventually the bubbles got smaller and smaller, and when they finally stopped the lever was as firm as any of my other bikes-a couple of FZ1's and an SV650. 

I took the bike around my neighborhood, making a few gentle stops from 20 mph, and I think once the pads get bedded in, the brakes will be just about perfect.

Again, thanks to all.   
CharlieDog
Bristol, TN

Offline Leo

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Re: 'Upgraded' the front calipers on my C10, no front brakes now...
« Reply #5 on: July 31, 2014, 09:30:55 pm »
I would like to add a caution about using you skin as a check valve with brake bleeding.  It works and I have done it many times.  That is the problem, you get used to doing things a certain way, leaving yourself open to injury.

I am not sure of all the circumstances but a mechanical repairman at work was doing that and at a point the pressure was enough to pierce through his skin and cause enough damage that he ended up getting a finger amputated.  Right after that the safety people warned against it.  I started using a piece of  rubber between my finger and the master cylinders or bleeders.  That works also, and I feel a 1/4 inch of rubber will give adequate isolation for prevention.
Yep, still riding the old one

In Indiana, missing Texas