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Discussion Starter #1
Hi there fellow cyclists,
I would very much appreciate your help.
I bleed my brakes successfully according to the Formula manual.
When it was time to change brake pads, the pistons were impossible to push all the way into the caliper. I tried with a little bit of force but it didn't work until I unscrewed the bleed-port screw. I am totally sure the system wasn't overfilled!
Later when I tried to bleed the system again, I was impossible to get the brakefluid through the system! Only if I removed the tool (4 credit cards) in-between the brake pads the calipers would move, so it was possible to move the pistons with the pressure from the syringe (bleed kit) but not to get the brake fluid through the system:mad: So it is stop somewhere in the system.
Does anyone have a clue what the cause is and if so what can I do to make the brake work again.
Thank you very much in advance for your help:)
 

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I bleed my brakes successfully according to the Formula manual.
What is the timescale involved here. When did you successfully bleed? When did you change pads?

When it was time to change brake pads, the pistons were impossible to push all the way into the caliper. I tried with a little bit of force but it didn't work until I unscrewed the bleed-port screw. I am totally sure the system wasn't overfilled!
Er. It was. Opening the bleed port resulted in the pistons going back. i.e. overfilled.

This can happen over time if the fluid has expanded because of attracting water. If this was shortly after you bled the brakes then your bleed was probably bad in one way or another.

Later when I tried to bleed the system again, I was impossible to get the brakefluid through the system!
So this is a different problem. Earlier when you said you could get fluid to come out of the bleed port, it was obvious that the fluid was going through the system. So what is different when you attach the syringes?

If you are following the Formula instructions to the letter and still having problems it could be that an internal seal failure has occurred. If you are struggling, take the brakes to a competent professional mechanic at your LBS.
 

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Discussion Starter #3
Hi Petercarm,
thank you very much for your reply:)
The difference from when I first bleed the brakes is that now the brake fluid will only go through the caliper. If I push the pistons back into the caliper and put credit cards in between the brake pads and try to bleed the system with both syringes attached is that it is impossible to get any fluid from one syringe to the next. This has never happened when I've bleed brakes in the past so I guess something must be "jammed" somewhere.

Unfortunately there is no LBS that can help me. Maybe I'll buy a compressor and try to blow through the brake and see if it helps.
 

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If I push the pistons back into the caliper
If the pistons push back, where is the fluid being displaced to? Is this with the syringes attached? Does it just push into the lower syringe?

and try to bleed the system with both syringes attached
My preferred method for bleeding the Ones is to not have the plunger in the top syringe. This way excess fluid just comes out without any resistance and without putting excess load on the diaphragm.

This has never happened when I've bleed brakes in the past so I guess something must be "jammed" somewhere.
If you have flow from the syringe into the caliper, shown by the syringe pushing out the pistons and the pistons pushing back the syringe, then the problem is up at the master cylinder end.

The correct operation of the master cylinder is for:

1. Lever in relaxed position

Fluid has free flow from the hose into the master cylinder reservoir and then into the top syringe.

2. Lever pulled in

The bleed path back to the reservoir is now closed off. Fluid from the hose is not able to reach the syringe.

What can also happen is that seals can swell sufficiently to close off the fluid path even with the lever relaxed. At this point the brake is BROKEN and needs repair.

Unfortunately there is no LBS that can help me. Maybe I'll buy a compressor and try to blow through the brake and see if it helps.
This is a dreadful idea. Do not do this.

If the brake is broken get it sent off to an authorised service centre.
 

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Discussion Starter #5
What can also happen is that seals can swell sufficiently to close off the fluid path even with the lever relaxed. At this point the brake is BROKEN and needs repair.
Thank you very much for your kind reply:)
I guess I located the the problem to the body pump seal as It is very swollen and I suspect the fluid can't get through in the body pump due to this:confused: Well it's not possible to buy the seal on its own and the body pump costs almost as much as half a brake and it is not available anymore (I have the 2008 model). I truly loved the brake while it worked.

Cheers
 
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