Front brake probs, advice needed.

[Dirty Baz]

Hey-oop, a little advise regarding front brake woes needed. My K3 brakes used to require a decent 2 fingered squeaze to bring on full braking power and the lever would only ever travel a small distance. In October I took my calipers off and gave them a clean and I noticed a drop in braking feel but not lever travel, this was fixed with a good clean of the pads which had got a touch of copper slip on them.

The brakes were back to normal until earlier this week. Since the roads roads were dry I was practising some emergency stops etc and now the lever has suddenly started coming back to about 2cm away from the grip before full braking force is applied :shock: . I'm obviously a bit worried that the lever might come back even more and trap my fingers before I can get the braking done.

So, what do you guys think could be the cause?? Brake fluid is full to the brim, I've never had to even fill the resevoir!! Also, pads were in good nick in October as I've never used alot of the brakes (relying on engine braking) and I'm sure the pads will still be good now because my winter was very relazed.

I'm thinking there is an airbubble in the lines which is suddenly showing itself??? How could I check for this?? Is it just a case of opening up the bleed nipples and letting some fluid drip out and then top it back up???

Help appreciated as always chaps!! 8)

[Red ones]

Try cable tying the lever back against the bar over night (keeping the brakes on hard). This usually forces small bubbles back out.

Alternatively you may find you need to replace the caliper seals.

[northwind]

Tying the lever back is a great trick... I hate bleeding brakes, so I love that shortcut :)

[Warren]

if you do the "pin back the lever trick over night", does that mean that you dont need to bleed your system ?


im hoping thats not the case cos i spent ages doing my 125cc's brakes last weekend out in the rain :(

[jakeblues68]

sounds like your fluid has past its sell by date and requires renewing.

A top tip for bleeding brakes:
Go to your local car parts geezer and purchase 2 lengths of 2 feet or so of CLEAR windscreen washer pipe.
Instead of trying to pump the brakes, keeping the reservoir topped up, place the CLEAR tube over the first bleed nipple, open it and suck on the pipe until the fluid is near yer gob, close the nipple. Do the same with the other side with the second piece of tube. This will give the fluid a head start (especially if you have fitted goodridge hoses etc and have an empty system). You can now pump the lever and fluid should flow.
TIP: Dont drink the fluid, it tastes rank.

Hope this helps.

[northwind]

Really don't drink the fluid :shock:

[Philbo]

If it's happened over night then it's probably something on the disks and pads again... Have you tried cleaning them again?

[Dirty Baz]

thanks chaps. tonight I'll clean up the pads, disc and pistons and then cable tie the lever over night. question, do I need to open the bleed nips to get this trick to work??

if that doesn't work then I'll try bleeding the whole system, thanks for the tip about using the tubing, and erm, I'll not be tempted to taste the fluid! :lol: how much fluid does the system use?? I've got a small 300ml bottle of fluid, will that be enough?

I'm worried I've gone and wrecked the caliper seals when I cleaned the pistons with Dot4 (a tip on this website!!! :? ). how much for a new set of seals then???

I've got insurance and 1st years service next month and we've just put an offer in for a house! :shock: gonna be a bloody expensive month!

Cheers

[BillyC]

Yup... brake cleaner on your discs... and clean out the ventillation holes on the discs before hand. Might be worth getting a wire brush to your pads too (a clean one)... Mr Squid did this to mine, and took off a lot of crap.

[Dirty Baz]

would dirty pads and discs cause the lever to travel further?? :?

sorry, still fairly new to all this. :wink:

[northwind]

Shouldn't do really... A warped disc could though. Still, on an SV you want to clean the brakes often anyway so no loss trying it. I think Jake's maybe right, your fluid might just want changing... It's also not impossible you've got a damaged line which is swelling up somewhere.

[TSM]

would dirty pads and discs cause the lever to travel further?? :?

sorry, still fairly new to all this. :wink:

If you had dirty pads and they did not grip enough, you would have to pull further back to get more pressure on the disks to stop.

I drained my out front and back, cleaned out all the crap on the pads and greased them all up and put some new fluid in. The diffrence was huge, i had more confidence to brake harder. It was giving a much better feedback. It was over 2 years since they were last done.

Next thing will be get some HEL lines fitted.

[northwind]

Aye, but not usually that much further...Sound like Baz is talking about a huge difference.

[Dirty Baz]

Aye, Northy's right, it's a major difference.

this is a rough guess of the lever distance from the grip for full braking power before:

LEVER
.
.
.
.
.
.
GRIP

and now:

LEVER
.
.
GRIP

[northwind]

I'd offer to help but I'm rubbish at brakes so you're probably better off yourself :)