1150 GSA Front brakes

[GhostCav]

Sorry, just a suggestion, my 02 gs has rubber pipes, but its not an adv.

Trust me fella, any suggestion is very welcome. Pulling my hair out here!

 

[(RIP) DitchWater]

Bah... Bobbins & washers replaced & slide pins as mine had some corrosion. Felt good for a while but went bad again on way to MOT centre. Fella ran the bike on the rollers (But not as a retest) & it still is going from 100% to 50% braking with the lever in the same place. Doesnt seem to happen in sequence to the rotation of the disc though. Would of replaced the pads as well but MW sent the wrong ones. Will try tomorrow & failing that I guess new discs even though I can't detect any warp using my primitive screwdriver taped to foek leg method. Whats left to try after that?? Master cylinder?? I am bleeding the brakes at the calipers only, am I missing another bleed point (Non ABS bike)?

Did you remove the discs and place them on a flat surface, e.g. your kitchen work top, and detect any deviation from flatness? If not they should be okay. I've had loads of bikes, doing different things, and ridden all year, and never suffered from warped discs: This includes trackday bikes whose discs have been blue'd.

Therefore since you have serviced and replaced parts on your brake calipers then they should be okay. Are you happy with the job you have done?

Now, your bleeding brakes method. Are you doing the traditional hose on the end of the bleed nipple? If so, this can be a problem and I would suggest both of the following:

1) Wrap a couple of turns of PTFE tape around the bleed nipple's thread, in an anticlockwise direction so it does not undo itself when opening and closing the bleed nipple, to stop any air leaking past.

2) Get yourself a Mityvac vacuum pump to assist your hydraulic system bleeding. It really helps, especially with a newly built dry system.

Regarding the charging of a dry system:

i) Get the master cylinder air free. Do this by pumping the lever and ensuring the pistons outlet is at the highest point by turning the handle bars fully to the right.

ii) There may be a banjo bolt to the left had side of the front shock, when viewed from the front wheel, which is part of the splitter for the the left and right calipers. You could try checking this is fully fastened.

Further to this, check the complete hose run and banjo bolts for any signs of fluid leakage whilst pumping the brake lever. Incidentally, does it feel any different? If not then tell your MOT tester to ride it and verify for himself that the brakes don't work or go somewhere more sympathetic. I take my GSA to old duffers that don't expect SuperBike performance.

PM me if you need any help and I'll send you my number: It 's much quicker than this.

 

[GhostCav]

Cheers for the reply Ditchwater, new pads just arrived so will see what happens then. May well get in touch if this fails. I did take the discs off & checked them on a sheet of glass, could not see obviously any sign of warpage.
As for MOT guy, he is really sound to be fair. The brakes did suck on the ride back to be fair.

 

[GhostCav]

New pads, another bleed of the whole system & a trip for a retest.

Better on rollers, MOT guy brought his helmet in & took it for a road test. No noticeable failable issue when moving only on rollers. Bike given MOT...YAY.

Now expect monsoon season to begin!

 

[Aidjay]

So changing the pads solved the problem?

 

[littleredrooster]

I've very recently done a check on my front disc and can concur with everything DitchWater says except for the part about the pistons. Mine are made from a plastic compound, ....

That's the heat insulator. The pistons are hiding underneath.