After calliper rebuild, squishy brakes

[rehmh05]

Finished rebuilding front calliper of my bandit 600 SK1 (mk2) (new pads inserted aswell). After rebuild, accidentally let the master cylinder get drained under gravity as I was putting the brake line onto the callipers.

I filled the master cylinder up with new fluid and tried to get the fluid into callipers. Now i pumped it a few hundred times literally but the brakes are squishy. What surprised me more is that the front wheel drags but brakes do not work. I roll the bike forward and there is a very small force in the braking.

My questions are; how do i rid the squishyness and the wheel drag?

P.S I am most certain I put pressure seals in the right way.
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- CBT 31/10/12 - CBR 125 bought 01/11/12
- Theory: 07/11/12 - Mod 1: 19/11/12 - Mod 2: 28/11/12
- 24/08/13 - Bandit 600

[Nobby the Bastard]

Have you actually attempted to bleed the brakes?
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[zapmole]

Sounds like there is air in the system. Bleed the brakes first and it should solve the problem . If they are only slightly catching that will soon wear down. Long as they release after pulling them.
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Honda CG 125 red 1991

[evilbond]

As said above bleed the brakes.

Aslong as you have the oil seal in first and the dust seal in second you should be fine.

The oil seal is square so doesnt matter which way round you put it in, i thought they went in one way with a lipped edge making the seal, but these ones apparently are not lipped.
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Bike: K2 Bandit 600S
Car: Astra GTC

[BillyJ]

https://www.therevcounter.co.uk/motorbike-articles/34369-motorbike-brakes-beginners-information-bleeding-guide.html
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Had: '06 CBR125R + '01 GSF600 + '07 SPRINT ST 1050 + '80 CB250 RSA + '93 Ducati 900SS
Have: '13 GSXR-1000 + '01 CB500S
"The aryan confuser"

[Major Doss]

front wheel drags= bound piston(s). are you sure that the pistons are pukka/clean? ineffective brakes when you have not bled=air in system. either is no good, strip and redo as per. sometimes can be a drag (sic) depending on system, some are easier than others. as far as lips go, this will be the fluid seal, this is innermost of the two seals, and the narrowest bit goes towards the back of relevant piston. flat square seal is pad side, just a dust seal. start by trying to bleed for now, this will determine if the M cylinder seal is carp, before you strip all else.

soz about grammar, poxy thing won't auto whatever, im playing darts with beer!
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Antisocial phucker.

[Nobby the Bastard]

[Major Doss]

bugger. BillyJ beat me up! karma, dude!
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Antisocial phucker.

[Major Doss]

could be, Nobby, could be. Doubt it. but could be.
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Antisocial phucker.

[Rogerborg]

What they said, you can pump away all day long, but unless you twist the nipple, you'll never get really hard.

If you tell us exactly what you have and haven't done, you can get detailed, helpful advice.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[exuptoy]

Either reverse bleed them with a big syringe or when you've bled the calliper, put a rubber tube from the bleed nipple into an old pot of brake fluid and pump until no more bubbles appear through the tube.

Brakes could be dragging if the seal is in backwards.
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Chaos, panic, destruction....my work here is done

[Major Doss]

A simple clean up and bleed, turned into a £200 rebuild. My customer quite rightly would not pay for the entire amount. His insistance on knackered bearings should not of swayed me when I suggested a £20 SH set of discs we had lying about and £20 labour. More fool me. I were right, yet cost my pocket. Go for the easy stuff. ONCE you have all the info. Use your noodle, eh? We all learn.
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Antisocial phucker.

[Major Doss]

[bladerunner]

If your bleeding the brakes...do the M/C first or you'll never win! Pump the lever a few times and undo the banjo bolt ...you'll hear if any air escapes or see bubbles. Once that's bled then your good to do the calipers.
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[Nobby the Bastard]

Jesus, the echo in here is fucking deafening....
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Major Doss]

[Major Doss]

[Major Doss]

[rehmh05]

sorry for the late reply guys, cant use the bike, so was on foot all over the place. got back recently.

Well, as i said i rebuild it correctly to the best of my knowledge and ability. I do believe i put the seals in the right way. most certain meaning there is a slight chance of human error.... apart from that i had let the M/C drain accidental as i tried to bolt the calliper to the brake line.

I was planning on bleeding the brakes after they got stiff which never happened..... I suppose that is the mistake i am making?

The bleeding is to be done first? I am advised to bleed the master cylinder? How is that done, can you elaborate? And i thought the master cylinder pushed everything down,incl. the air bubbles?

And then I should bleed the callipers 2nd should I? I have the tube thing but only a small 10 ml syringe atm ....
____________________
- CBT 31/10/12 - CBR 125 bought 01/11/12
- Theory: 07/11/12 - Mod 1: 19/11/12 - Mod 2: 28/11/12
- 24/08/13 - Bandit 600

[Major Doss]

See BillyJ's link.
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Antisocial phucker.

[rehmh05]

ok
____________________
- CBT 31/10/12 - CBR 125 bought 01/11/12
- Theory: 07/11/12 - Mod 1: 19/11/12 - Mod 2: 28/11/12
- 24/08/13 - Bandit 600

[rehmh05]

can someone confirm if the RH calliper is bled first or the LH (as i sit on it?) I have seen otherwise ....?

Also, will master cylinder need bleeding aswell if the whole brake line system is bled?
____________________
- CBT 31/10/12 - CBR 125 bought 01/11/12
- Theory: 07/11/12 - Mod 1: 19/11/12 - Mod 2: 28/11/12
- 24/08/13 - Bandit 600

[Major Doss]

[bladerunner]

Do the MC first like I said before.....not included in the link! Your brake line is a tube of liquid and thus air bubbles will rise to the top. If air is in the top as you let the fluid drain out of the MC then it will compress making the MC ineffective at pressurising the system and the air bubbles will keep rising faster than you can pump them the length of the brake line.good luck with bleeding that! Your just wasting brake fluid and not removing the air......it's more of an issue on bikes that have the top banjo bolt higher than the lower part of the MC piston travel.

I've explained how to do it already. Once you know that's done your ready to bleed the calipers.........once you get the air out of them...job done. Then you can look at what's causing your other issues. I've known new seals and pistons take a bit of bedding in to get the best out of them.
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[mogstar]

and don't over-tighten the bleed nipple unless you want more grief

plenty of brake bleeding vids on youtube too