So how are you supposed to put the lid on the front brake reservoir?

I've just changed the oil, filter, plugs and brake fluid. It was an 'interesting' exercise and took rather longer than it should have I'm sure.

The main question I have havind done it is what's this flappy bit of black rubber under the lid of the front brake fluid reservoir. After I've finished changing fluid and bleeding how should I go about properly putting this back on. As it was I spilt brake fluid all over the place as it got displaced. For the time being I've just shoved the lid on but I'm sure that's wrong as it's now over the full line. But how to know how much to have in there before adding the lid?

Also having changed the fluid the brakes are as soggy or possibly worse than they were before (Baph - you remember how bad they were!). There is a lot of movement in the lever before it feels like they are biting and then it's soggily comes back to the bar if you pull hard enough. Is this normal for pointy breaks. Do I perhaps need braided lines or did I just fluff the fluid change?

Thanks in advance peeps.

/2mths

Sounds like a bad change, though you might still have a little air in the lines. So it might be adviseable to tie the leaver back over night and see what its like in the morning. If its still spongy in the morning you need to look at it again, if not then see what its like after a few hours released, if it sponges back up you probably have leak. In my case the master cylinder needed servicing too.

The lid should go on with the rubber cap pushed back so that it can expand over time and the fluid should be full to the max line on reservoir.

[the_lone_wolf]

Originally Posted by 2mths

As it was I spilt brake fluid all over the place as it got displaced.

can't help with the lid but you might want to get all the brake fluid off your paintwork before it removes it

Braided hoses would no doubt improve the brakes, but as they were reasonable before the change I'd think you've got a little bit of air still lurking Andy.

Still as you get more experience with v twin engine braking you'll find you don't need the brakes anyway.

They stopped the bike ok but the lever feel before the change wasn't great. I think I need to get some more fluid (used all mine up doing my mate's bike up afterwards) and top up to try bleeding and then top up the reservoir correctly.

I understand about the engine braking but I would like to be nice to my rear tyre and chain as they aren't cheap either

Not sure whether I'm answering the question you want but its possible that the black rubber 'thing' has extended slightly. It happend to me when I changed my fluid and I ended up with the fluid overflowing when I put the rubber back in. It should be fairly compressed with a flat bottom. Have a play and you'll see what I mean.

Andy, you probably had air in the system somewhere (probably in the master cylinder) before, and it sounds like you've got more of it now!

Personally, at that stage, I'd drop the fluid out & start again. I start from the bottom using a MityVac & push fluid up. Watch the reservoir whilst you're doing this, as you want to stop when the fluid appears and top it up a little from the top end.

Are you sure your bleed nipples are torqued up properly, and did you put some PTFE tape around them before you put them back in? Could be an air leak here.

If you've done all that, cable tie the lever & leave it overnight, it does magical things when the brake pixies come out to play.

As for the little rubber cap inside the reservoir, that's to help the seal stay tight. Pop that in (right way up) & screw the lid on, then put the retaining metal on & screw that in place. Worth noting what Andyb said, if the bit of rubber has got out of shape, it won't do it's job properly, so have a fiddle with this too.

Should be job done

[northwind]

It's not a question of getting out of shape, that's what it's supposed to do, it's a diaphragm- keeps fresh air out, when fluid volumes drop it pulls the diaphragm downwards, avoiding a buildup of pressure or letting new moist air in. Some people like to pre-expand it to reduce the volume of air to a minimum, but I don't think that's really needed. All you have to do is pop it back to the starting position though, like the others have said, just in a nit-picky mood It'll draw back down as fluid displaces into the calipers (as the pads wear)

Originally Posted by Baph

Are you sure your bleed nipples are torqued up properly, and did you put some PTFE tape around them before you put them back in? Could be an air leak here.

Never heard of anyone using PTFE tape. Gonna put my head on the block and say it's not needed

[northwind]

PTFE tape can be handy, stops fluid from leaking down through the thread while you're bleeding, which is good with pressure bleeders. Can also compensate for damaged threads, and I suspect may help prevent seized nipples. And you don't want seized nipples But not neccesary at all.