Brakes question

Right-o, last weekend fitted new pads, cleaned up pistons etc., and this weekend changed the brake-fluid as the stuff that was in there was manky and the brake-lever was stupidly spongy.

After bleeding from just about everywhere possible (including raising calipers and tapping bits and bobs to get air-bubbles to rise), and doing the cable-tied-overnight trick, the brake lever's still spongy. The bike will stop just fine, and I can lock the front wheel at 10mph with only using half the lever travel, but the lever comes all the way back to the bar if you pull it back fairly hard. The adjuster's set on number 1, btw, on number 5 it gets to the bar before the brakes are fully on.

I've ordered some braided lines as I'm pretty sure that these are knackered (nearly 27k on 8 year old stock rubber hoses), but my dad's also suggested that the master cylinder may be allowing fluid to flow back through it.

Any other suggestions?

I found the front brakes quite spongy still after fitting braided lines and overhauling the calipers. I think it's an SV thing. My rear brake has always been very spongy.

Master cylinders, perhaps?

[flymo]

Originally Posted by Neeja

Right-o, last weekend fitted new pads, cleaned up pistons etc., and this weekend changed the brake-fluid as the stuff that was in there was manky and the brake-lever was stupidly spongy.

After bleeding from just about everywhere possible (including raising calipers and tapping bits and bobs to get air-bubbles to rise), and doing the cable-tied-overnight trick, the brake lever's still spongy. The bike will stop just fine, and I can lock the front wheel at 10mph with only using half the lever travel, but the lever comes all the way back to the bar if you pull it back fairly hard. The adjuster's set on number 1, btw, on number 5 it gets to the bar before the brakes are fully on.

I've ordered some braided lines as I'm pretty sure that these are knackered (nearly 27k on 8 year old stock rubber hoses), but my dad's also suggested that the master cylinder may be allowing fluid to flow back through it.

Any other suggestions?

Its possible that the m/c seals are in need of replacement. Sounds likely that you still have some air hanging around in there. Make sure there isnt any at the top of the brake lines where the banjo joins the master cylinder. You can open up the banjo slightly to bleed but I prefer to just make sure there is an uphill path right the way to the reservoir by leaning the bike to its left on the sidestand and turning the bars fully to the right.

Feel free to pop over to my place if you want a second pair of eyes on it.

Only thing I have to say about this is that my housemate's brakes are fantastic - on the number 1 setting on the adjuster it only comes back about an inch and won't go any further than that at all, so it can't be 100% SV specific

[johnnyrod]

I'm with Flymo, when my master cylinder seals had gone it felt a lot like you couldn't bleed all the air out.