Problems when reassembling front brake set up

[-Ali-]

I bled the system fine and left the bike outside without the brake caliper attached to the hose. Now i'm trying to get it all working.

I've filled up the master cylinder with brake fluid, attached all hoses etc and now pumping the lever hardly sends any fluid through the hose(infact its a mere trickle). Its so bad that pumping the brake lever and releasing the bleed nipple still causes no fluid to exit the system, and if you carry on pumping the lever with the nipple closed you can't feel the pressure build up on the lever.

I'm stumped as what to do.

[Itchy]

Erm

If any part of the system gets exposed to the open air, air gets into it, thus needs rebleeding this includes the bleed nipple! Maybe bleed it from the top (takes longer and lots of pumping). Since you removed the caliper off the end of the hose, air I think has gotten into the system via the bit open to air. The caliper off the hose is also exposed to air so there will be air in that too.

Does the fluid level drop after pumping? If so keep at it you need to get a shed load of air out of it. A trick Sickie recommended a while ago was to fill your caliper with fluid up before attaching it. You spill a bit it just minimises the amount of air that you have to expunge out of the system. But then all you need to get rid of is the air inside the hose and the small amount in the calipers.
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Spain 2008France 2007Big one 2009 We all die. The goal isn't to live forever, the goal is to create something that will. In the end, your life will flash before your eyes. Make sure it is worth watching.

[-Ali-]

The fluid level isn't dropping after pumping, must have pumped it 100 times straight.

[Itchy]

Hold on how come a trickle comes through when you pump then? If a trickle comes through the hose with the caliper off then a small amount of fluid is getting through.

Albeit in very small amounts the amount which gets pushed through each pump is miniscule. Which implies you need to pretty much refill the caliper and the hoses, which will take more than 100 or so pumps. I fixed my bound brakes on my NTV where only the caliper was empty and 100 pumps was nothing. The only other thing I can suggest is maybe get a syringe and fill it via the bleed nipple. But as said when fitting new hoses seals or whatnot it has always filled up pretty quick then needing the long labourious task of bleeding.
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[dodgydog]

You need to get as much fluid as possible into the system first, fill the caliper if you can.
You can try holding the caliper up, higher than the master cylinder, (put a bit of wood between the pads so the pistons don't come out too far)
Another thing is to get a big syringe, attached to the bleed nipple, and try to suck the brake fluid through, (keep an eye on the level in the master cylinder)
The system will certainly be full of air and will take ages to bleed through just using the brake lever.

Dog
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[Blue_SV650S]

[HD]

If your going to fill up your calliper by pouring it in, make sure you wipe it off and maybe even clean it. Just saying that as people forget it is so corrosive
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Rusty '02 Vito Camper + CBR600F3

[-Ali-]

Thanks to itchy and you guys i managed to bleed the system and eventually remove the pistons from the caliper, it just took alot of perseverance. I firstly gave the caliper to some local car mechanics to try an get the pistons out and they have broken the metal edge around where the dust seal sits. Will i be able to use this caliper or should i start looking for a new one?it's a ball ache to find parts for this bike so would much rather utilise the one i have.

https://img222.imageshack.us/img222/3434/img1041jb.th.jpg

[Itchy]

Did it look like that before? If not the mechanic messed up big time.


You might be able to reuse it. Since from the blurry picture it looks as if the internal seals are far enough away from the edge (my NTV was like that) to be usable. Your dust seal on the outside is going to be burgered though.

I'd put my finger around the internal edge of the cylinder hole and feel for burrs if it cuts your finger and makes you bleed then very carefully file it off. But DON'T file the inside of the cylinder just any burrs which may score the pistons which will ruin your seals.
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Spain 2008France 2007Big one 2009 We all die. The goal isn't to live forever, the goal is to create something that will. In the end, your life will flash before your eyes. Make sure it is worth watching.

[Noxious89123]

I'd say that was fucked and ready for the bin. Without a dust seal I'd expect it to get full of crap and corrosion and seize up in no time.

Also, how the hell were they going about things to cause that damage?! I thought the general way of getting the pistons out was to either pump them out or use compressed air?
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[Teflon-Mike]

I reckon its not worth taking risks with brakes, its THE number one thing you want to ALWAYS work.

Looking at it..... tough call, but thinking outside the box, its a 'visible defect' what do you think an MOT inspector would think about it?
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[-Ali-]

I'm not quite sure how they managed it.Any way it doesn't cause any ill effect to the internal seals and the other shoulder for the dust seal recess isn't damaged. I may just build it all back up, get it working and look for a replacement once thats done

[HD]

Charge the garage for new ones! They would have worked before, you just wanted to strip and clean them and they fcuked them up!

Sorted
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Rusty '02 Vito Camper + CBR600F3

[-Ali-]

[dragstaar]

You can't really tell from the photo, but if it is far away enough from the seals, and there arent any leaks when the pistons are in, you might be able to get away with it long enough to find a replacement on ebay/steal from the annoying guy down the road lol.

[Vincent]

That caliper needs scrapping.

Kind of the people who fu**ed it up not to charge you