GSXR250 brake issues

[JMemonic]

I like JM so I've really little desire to ruffle anyones feathers. But I will add it is worth inspecting each joint after you're done, as often you won't see any fluid spurting out.... theses joints are far more likely to have a very subtle weep, than spurting.

No need to fear brakes, just be thorough and relatively meticulous.

I apologise if my words were harsh, I do appreciate where you are coming from, but I wanted to point out often its not always the most costly or technical thing that causes minor irritating to find faults, and I have see a couple of situations where with no visible leaking of fluid out yet positive air in, one was the gasket/washers the other was a damaged resleeve job on an alloy master cylinder, PBR cylinder off an old 70's valiant I may still have here somewhere, not sure if it was moved or thrown.

[imdying]

Ohhh yeah, seen odd shit with resleeve jobs... very rare now if done by one of the major sleevers... weird stuff like fluid squirting out of the sleeve to body interface etc.

[erik]

sounds like similar problems to what I've got with my bandit. I think they're the same callipers. I think assembling the callipers with rubber grease helped a bit, I think the pistons were retracting too far. But they're still mushy, so I either need to bleed them again or something else is wrong. I don't have much luck with brakes, I rebuilt the sv's front callipers and the lever is noticeably more mushy now than it was before... Maybe I shouldn't admit to that...

[imdying]

The purpose of the square section oring is for it to distort (like a parallelogram) when the piston comes out, and drag it back in as the oring rights itself to a square shape. Some times you need to bleed it up a little to get some pressure inside the system, then use short strokes to move the pistons only a little at a time to let the pistons move out, rather than just out and in like the full stroke gives you (when the pistons are all the way back, say after a pad chage), then completing the bleeding as per normal. Normally this isn't a problem as with new pads a caliper is generally a tight fit to the disc, but worn discs or refitting a caliper with the pistons all the way back but with old pads, you can experience this.

Erik, if the lever is noticeably more mushy than when you started, give the pads a few hundred kms to bed in to the disc (to take any 'fresh pad to worn disc mating tolerance' out of the equation) and rebleed it.

[Pumba]

Rebuilt the master cylinder today, was a little supprised how easy it was (hope that means I haven cocked somthing up). Has made a difference to the lever feel, defently an improvement on what it was, but it still fells like it could be better (or maybe I have just goten used to the feel of the Speed Triples brakes). Will really know more once I get it to the track in a few weeks.

Any way the piston and seals I pulled out had no noticable missing parts (should have taken a photo) but there was deffently a difference between the fit of the seal on the old one vs the new one. The old one also had a significant amount black crud built up within the spirals of the piston. Not sure if this means any thing but surely it would have been effecting preformace, one way or another.

[motorbyclist]

i think to make those brakes any better you'll have to replace the 20 year old rubber lines

can't remember exactly what my old gsxr250 was like but i know it wasn't great

[Pumba]

Grabing hold of the brake today I am starting to think it is not to bad. The line have been replaced with some second hand barided lines I picked up