front brake master

beanbagsj · October 12, 2011, 10:57:39 PM

My front brake master is leaking. I am down to 10 percent front braking power. The previse owner told me he had already replaced the gasket before. Is there an upgrade too this problem or just replace the gasket and move on? I also notice the screws are rusted and are instantly stipping and refuseing to back out.

terryk · October 13, 2011, 01:40:17 AM

This may help as I recently had a similiar issue. 1) Make sure the splash guard is in place, helps during operation and bleeding. 2) Any crud or residue on top of the resevior or on the bottom of the cover can cause issues. I had some mild build up on the top lip of my reservior that apparently was just enough to let in air. This need to be carefully cleaned up to ensure the surfaces mate and the gasket seals. 3) Fill level counts, when the bike leans over the fluid seeks level and can uncover vital areas of the brake reservior and let air into the system.

So, I cleaned it up, BTW if the screw are crudo I would replace those as well for cosmetics. I filled it up and made sure the splash guard was properly in place. I was patient with bleeding, although my tools are barbaric, a plastic water bottle and a clear plastic hose. Done, fixed.

FJmonkey · October 13, 2011, 08:01:36 PM

Quote from: terryk on October 13, 2011, 01:40:17 AM
. 3) Fill level counts, when the bike leans over the fluid seeks level and can uncover vital areas of the brake reservior and let air into the system.

Fluid level is important but not for that reason. When bikes turn and lean over in a corner a Centrifugal force is created that keeps fluid pulled towards the bottom of the bike as if it was stopped and on the center stand. That is why you feel planted on the seat and not feel like you are going to slide off the low side. The same effect also helps when the fuel is low.

Good advice on keeping the bits clean, breaking is way more important than acceleration. That is unless you are suicidal or a fatalist.

RichBaker · October 13, 2011, 11:15:57 PM

There is a rebuild kit for the master cyl., new piston and seals. It does NOT include the cover gasket, though.

terryk · October 14, 2011, 09:45:58 AM

No really, I think this did happen to me. The reservior got low, lean over, the fill hole is exposed to air, instant shot of air intoi the system and bleed tome.

BTW - what day are you riding and where/when are you meeting for the ride on the Ortega this weekend?

craigo · October 14, 2011, 11:45:47 AM

I am wondering why you just do not upgrade the master to a 14mm instead of rebuilding the stock one? The benefits are very rewarding and you do not have to worry about if you got the old one rebuilt properly. Then it's a simple matter of getting the blue spot calipers for it.

Then you will have amazing brakes instead of marginal.

Just a thought,

CraigO

1tinindian · October 14, 2011, 04:37:07 PM

Quote from: craigo on October 14, 2011, 11:45:47 AM
I am wondering why you just do not upgrade the master to a 14mm instead of rebuilding the stock one? The benefits are very rewarding and you do not have to worry about if you got the old one rebuilt properly. Then it's a simple matter of getting the blue spot calipers for it.

Then you will have amazing brakes instead of marginal.

Just a thought,

CraigO

+1

fj11.5 · October 14, 2011, 07:10:48 PM

Quote from: 1tinindian on October 14, 2011, 04:37:07 PM
Quote from: craigo on October 14, 2011, 11:45:47 AM
I am wondering why you just do not upgrade the master to a 14mm instead of rebuilding the stock one? The benefits are very rewarding and you do not have to worry about if you got the old one rebuilt properly. Then it's a simple matter of getting the blue spot calipers for it.

Then you will have amazing brakes instead of marginal.

Just a thought, makes for amazing brakes, I thought the braided lines were an improvement , added blue spots and an xjr master cylinder , fantastic brakes ,

CraigO

+1

Pat Conlon · October 14, 2011, 07:33:29 PM

Not mentioned by the OP but he has a '86.
It's a bit of work to assemble the parts to needed convert over to the R-1s
Remember the R-1's do not bolt up to the early forks. On the Early FJ's you need to convert over to a 17" rim and '89+ FJ lower fork sliders needed to fit the bolt pattern of the R-1 calipers.

Still in the long run for the R-1 brakes, it's totally worth it........ In the short run; just re-build your oem m/c.

If anything, get rid of those rotten oem soft rubber brake lines...Do that right NOW.

[edit] Has anyone used a 14mm m/c and kept the FJ oem early 2 piston calipers? I'm not aware of anyone who has done this.

fj11.5 · October 14, 2011, 08:58:50 PM

Woops, forgetting I've upgraded my 84 some days , I had the 14mm master with. Standard calipers for month or 2, worked better than standard , but lack of feel at the lever like having wooden pads

Pat Conlon · October 15, 2011, 02:52:57 AM

Rod, could you clarify what you just said? Perhaps say it in a different way? Did the 14mm m/c give a wooden feeling front brake? ...or was ...??

fj11.5 · October 15, 2011, 08:32:36 AM

I tried the 14mm master with the standard gold fj calipers, may have been the type of pads fitted, but they gave more a sence of slowing down than actually stopping, never tried the original 1100 calipers as I converted the front end four years ago ,those single pot callipers scare me , I had a gsx 750 as my first (big bike) other than handling, it also didn't like stopping

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front brake master