Brakes: help/advice needed

[Anonymous]

I'm having a bit of a saga with both my front and rear brakes, and this is where YOU lot come in.

Backstory:

Maybe 4 months ago I (with the assistance of my brother, former owner of my bike) completely dismanted both my front and rear brakes. Took the calipers to bits and thoroughly cleaned them, removed the old hoses (originals) and replaced it all with new twin front braided hoses and rear hose. Brake pads were generic but ok, so they stayed on. Calipers had been binding a bit, so changing the hoses were only half of the reason it was done.

Since then my brakes have had a huge ammount of travel in the lever, and basically have been worse than they ever were. To cut a long story short the brakes have been bled once to no effect, and a few weekends ago I dismantled the calipers again (leaving the lines attached and just pumping the cyls out to clean them) and gave it all another good scrub.

There's been no leaking around the bleed nipples, and the fluid levels are good (DOT4) on both brakes.

Currently:

My brakes are still appauling. I've taken to not even using the back because it has no effect. I can pull the front lever right back to the bar, and whilst this stops me pretty sharp, the first 50%-70% of movement has no effect bar letting other people know I'm trying to slow down. With the change in the weather I'm fairly anxious to get this sorted out; freezing hands don't pull levers very well.

Solutions:

Well this is where you lot come in. I'm guessing that there's some sort of pressure problem, but beyond that I have no idea where to start. I don't really want to take it to a dealers and have them charge me 8 hours labour to fix something bloody stupid that I've done which realistically will take 5 minutes.

So...
(a) is there anything stupid I've overlooked from what I've described here?
(b) would Soho be interested in taking a look? :D



And to make it all worth while even if you can't help, here's why they got dismantled first time round:
http://homepages.nildram.co.uk/~lolvenom/pics/badpistons-8x6.jpg

[Mike1234]

Hopefully when you put new seals in you coated them with a lot of rubber grease after cleaning all the corrosion out of the channels the seals fit in to.

If you just used brake fluid and/or didn't replace those seals then you will have had a lot of air get in. Chances are you probably still have air in the system.

Try bleeding it a couple more times and put some new pads in. The extra bulk of the pads will reduce your lever travel dramatically.

[simon-temple]

I'm not sure if this is going to be a problem on the SV but it was on my TZR250 with RGV front end.

The air gets trapped in pockets within the castings. Try taking the whole system off and hang them upside down, calipers at the top, for as long as you can. Keep tapping the length of the hose with a spanner to try loosen any bubbles stuck to the side walls.

Then when you come to bleed them again try it with the calipers above the the reservoir, then the bubbles won't try to rise up in the hose again.

If this is all Blks I'm sure we'll find out soon. :D

[davyf]

If there are no leaks & the braking system was fine before hand then you aren't bleeding it properly. If the lever was soft before hand you probably need a master cylinder seal kit.

For bleeding do one side at a time
Position the bike so that the bleed nipples are at the highest part of the caliper. If necessary move all joining unions & hoses to the steepest vertical angle so the air goes up to master cylinder moving & tapping dislodges trapped air pockets.

Use one way valves for the fluid or better still a vaccuum bleeder.

If you dont have these only release the bleed nipple when pulling lever in & tighten nipple before releasing lever.

Forcing the pads back with the nipples loose & some clear hose on them generally forces out some air.

If this does not work take the calipers off pack out between the pads rock the calipers to dislodge any air bubbles.

The last desparate mesure is take the whole lot of hng it up in a garage to bleed it nostalgia to early gixxers & kawasaki owners (the SV is not that bad though).

Sorry if some of this is a bit basic but though it not rocket science you'll be suprised what some people try.

[weegaz22]

not sure if a gunsons eezi bleed wll fit onto the svs(sv naked wont fit as its square) resivoir, but if you know someone with one its worth a try, should bleed all the air out of the system in a matter of seconds with the pressure involved(33psi, works off the front tyre)

[simon-temple]

I like the sound of that. What is it and how does it work?

[weegaz22]

all it is is a bottle that you fill with brake fluid, the bottle cap has 2 hoses on it, 1 attaches to the tyre valve, the other comes from the bottom of the bottle up to a special cap which screws on to your resivoir making an airtight seal, you then attach the tyre valve and it pressurises the bottle, when you open the bleed nipples, the eezi bleed tops up the resivior and forces the fluid through the lines and calipers

http://www.motormania.co.uk/products/medium/185.gif

they are about 15 quid from any auto shop or halfrauds

[Anonymous]

Thanks for the advice chaps, I was sort of planning to bleed them out again to see if that solved it, but didn't think it would. After all, the last time I did the fluid came out with literally NO air in. Guess it's time to just give it another try.

[Barty_b0y]

when all else fails give up :D

no seroiusly try this method everyone is telling you to bleed your brakes but as your no good at it obviously this wont help so try this method of doing it
you say you have stainless hoses but not how many there are ie 2 or 3 hoses on the front

get a pair of mole grips ( brake pipe clamps would be better but i doubt you have one )and very slightly clamp the line to your first caliper at the caliper ( check the feel of the brake )

better ??? if yes air in the lower section calipers if no dodgy master cylinder to check this clamp half way down the pipe not too close to the master cylinder

reclamp the pipe to the second caliper just after first caliper junction it is bound to be worse as for the floating disc but how much worse is it

first remove your pads and pump your cylinders out untill your pretty certain they are going to pop out but dont let them pop


if its a 2 hose system after 20 minutes (this will let the fluid settle and air will collect in a pocket it needs time to do this )of waiting after pumping the cylinders to popping
put a clamp on the line from the master cylinder at the first caliper (this stop fluid going up into the mastercylinder and overflowing . ;) release the bleed nipple slightly on the nearest to master cylinder and press the brake cylinders back into the caliper ( so basically your BACK BLEEDING IT )

this has 2 effects
1 you are shiffting alot of fluid quickly
2 because your shifting it quickly air is less likely to get trapped

before you hit the stop on the piston hitting into the caliper body tighten the nipple back up if your not used to it it can be fiddly doing two things at once so get a woman to help :D

remove the clamp and fit your pads and try but put a clamp just after this caliper and befroe the next caliper

better?????

use the clamp for each caliper at the caliper junctions and push the pistons back to jettison the fluid fron the nipples

you may have air in the bit that goes over the mudgaurd in a two line system so in this case to eliminate this pump the pistons out clamp the right hand side caliper inlet >>> to master cylinder line make sure your pads are fitted to this caliper ( so not to push out pistons when your backbleeding ;))
and open this bleed nipple and push the pistons in on the other side

this will force all the fluid from the nearside caliper out and up the pipe to the offside caliper and out of the bleed nipple

this will do it trust me :D

things to note here are
1 do not crush your brake lines by too much pressure from molegrips (but you need enough to stop flow its a feel thing treat it like a new woman -- gently gently ;) )

2 read re- read and read again what i am trying to describe here untill you are exactly sure what i`m saying

3 get some help but dont listen to them listen to me (an unsure person when your unsure is dangerous)

just tell them to shut up and fill the master cylinder or loosen a nipple
4 Work on one side at a time (any side your not working on just pop the pads back in ;) this way you wont press the pistons out by accident


Hope this helps illeviate any BLEEDING problems you lot have on here to all of the none knowing fraternity

you now know :D