need to bleed??

[TYRiAN]

I went out and bought some new brake pads earlier - Once I have swapped them with the old crunchy sounding ones will i need to bleed the brakes? or is it a case of just a straight swap?

cheers in advance for any help for this mechanical n00b.

Tyz

[Mattis]

You shouldnt need to bleed em, just push the piston/s back to get enough clearance to get the pads in. Then just pump the brake lever or pedal once it is all back together to get the pistons back in the correct position.

If the brakes are still shite after the pad change then possibly look at replacing the brake fluid by bleeding the brakes through until you see the new fluid appear.

If they are still crap after that then braided lines, a master cylinder rebuild or disk replacement might be in order.

[Ev]

cheers in advance for any help for this mechanical n00b.
Tyz
[/b]

Noob do you know to watch your reservoir as you push the pistons in just in case it is about to flood over as your pushing the pistons in

[Rob]

No real need to do it at a pad change I spose. but yea I'd go new oil if that was my bike.

[Foofie Foofie]

The brake pistons should never be pushed in with the buildup of dust on them. Everyone allways pushes them in and the dust and shit off the pads goes into the dust seal and sometimes past it, making the brakes later down the line drag.

Allways wipe the pistons clean and spray them down with contack cleaner as you push them in.

Brake fluids are better kept fresh than old, so if you need to , maybe not, should you ... yea sure. Just do it, good brakes are life savers.

[Ev]

contack cleaner .
[/b]

never cleaned em much before myself but good point, I will be more thorough next time

What is that? alcohol or something else,

[Rocket]

You can buy a pressure pack of brake cleaner. this is great stuff for cleaning them for pushing the pistons back in.
It also has a hundred and one other cleaning uses too.

I've used carb cleaner too which seems to be just fine.

+1 on the new brake fluid too.

[Captain Starfish]

My 2 cents

I did the [new pad + push 'em in] combo 18 months ago or so, then left the bike alone for a while. They gummed up to the point where they were jamming on - not fully, just dragging a bit when I release the lever.

No worries, he thinks - push the pistons out a bit, clean 'em up and push them back in. Nope - I was cleaning up little chunks of rubber. Time for a complete strip, clean, seal replacement and new fluid too.

If there's just a little gunk on 'em, clean them up. If it's looking crusty I would seriously consider rebuilding them. Not too hard - and the earlier you do it the easier it is.

The difference new pads and fluid makes to your braking performance is unbelievable.

Just remember to bed your new pads in properly (search the forums for 200 posts on how to do this).

Cheers

[Foofie Foofie]

never cleaned em much before myself but good point, I will be more thorough next time

What is that? alcohol or something else,
[/b]

Its isopropyl alcohol for most parts, and the gentlest cleaner. Wont strip paints or damage rubber and plastics (most).

[wazcat]

I took my pads out last weekend to inspect how much meat is on them in ready- ness for the trackday at he end of the month. Cleaned the pistons then did the pads yesterday. Unbelieveable how much more powereful the brakes are. Hard to notice as your brakes slowly get worse until you really need to use them.
Also did the brake fluid. not hard to do, just a bit awkward trying to keep the fluid from spilling on any surfaces of the bike.

[Ryder]

It can never hurt to bleed them. I tend to find myself bleeding the brakes more often than I change the pads - not because there's air in there, but because it seems the fluid sitting in the calipers goes to crap pretty quickly. Still pulls you up very well but loses some crispness. Particularly doing track days.

Just remember to fit some plastic tubing on the end of the bleed nipple, it greatly reduces the chance of sucking any air back in by accident. plus you can see the smallest of bubbles

[Madkat]

If they are still crap after that then braided lines, a master cylinder rebuild or disk replacement might be in order.
[/b]

People alwasy mistake Spungy Brakes as a line problem, Braided lines wont fix a Spungy Brake Leaver it is a Caliper Problem.. if you find this then you need to rebuild your Calipers with new seals and stuff..

easy way to tell.. remove your lineds from the top and block it off if you have a hard leaver it's not master cylinder..

[Desmo]

People alwasy mistake Spungy Brakes as a line problem, Braided lines wont fix a Spungy Brake Leaver it is a Caliper Problem..
[/b]

Not true.
Spongey brakes can be air in you fluid, old flimsy lines or worn components.
It's not just 1 issue that causes spongey brakes, but many.

[Madkat]

Not true.
Spongey brakes can be air in you fluid, old flimsy lines or worn components.
It's not just 1 issue that causes spongey brakes, but many.
[/b]

I beg to differ but air in your brakes wont give you a spungy leaver it will give you no leaver at all.. your leaver will have more movement in it than just a spungy leaver..

As for old Flimsy line's. yes you maybe right, But most of the brake lines have a longer shelf life than the bike it's self, Worn componets would be..

There is a big diffrence in the Spungy brake's and air.. thats all i'm trying to say

[Ryder]

Depends how much air youre talking about. A half dozen bubbles the size of a pin head will easily make your brakes spongey. You can have quite a bit in there before they'll stop working altogether

[Desmo]

I beg to differ but air in your brakes wont give you a spungy leaver it will give you no leaver at all
[/b]

Well, me and everyone I know must have been wrong all these years.

[Madkat]

Well, me and everyone I know must have been wrong all these years.
[/b]

I never said you were wrong..

all i said was people miss interperate there lack of brake leaver as a brake line problem...

if you eliminate the caliper from almost any brake system by clamping the hose just before the caliper you will get a much better feel from the leaver.. even better than braided lines..

Fell free to come around and i'll show you on one of the many bikes i have build.. Braided lines are good.. i have them on all 3 of my race bikes.. but for a road bike there is no great advantage..

but like i said it is my opinion.. not everyone will have the same..

[TYRiAN]

cheers for all the replies - I ended up dl the haynes manual read that and it didnt mention having to bleed them for a pad change. I have now changed the pads and they are working well (like fark...over the bars) kinda well. as someone mentioned above after cleaning the pistons etc there sure is a world of difference.

cheers peeps

[Foofie Foofie]

As for old Flimsy line's. yes you maybe right, But most of the brake lines have a longer shelf life than the bike it's self, Worn componets would be..
[/b]

Your right that the brake lines will survive the bike, but they do go soft, and do cause pressure drop. What Ryder is talking about is quite true aswell, the beer froth type bubbles make a 4 finger line.

One other thing, brake bads have a life. Not only a comsumption life, but a time line life, meaning they take so many heat cycles and they arent the same pad you had when you bought it. Meaning you can have half pad left, drop on new brake pads and get a whole new feel. I do a couple meets on my 1000RR and then drop in new pads. My mates get the hand me downs, and they still love em, but i allready notice the feel of the new ones.