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Lump In Clutch Reservoir?


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As title says....

Clear lump of snot consistency stuff with a grey tinge about 5mm dia..



Clutch feels and works fine not losing fluid or leaking......

And no I didn't sneeze near it!!

So WTF is it??

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top tip. i am working on a clutch actuation system rig at work at the moment. all very interesting stuff. anyway, bleeding.

Basically, there is only one way to successfully bleed a modern hydraulic clutch system, and that is to pressure fill from the bleeder on the slave cylinder, and force fluid back up through the master cylinder and into the reservoir. it is a bit of a pain, because you have to keep removing fluid from the res.

Reason - in modern cars there can be inline devices to damp out vibrations from the crank / diaphragm spring fingers. a bit like a two way valve against a seat, with a little spring. these only open at a certain line pressure in both directions, so if any air is stuck there, it most definitely aint getting out if you try and bleed the old fashioned way. i have used clear pipes either side of such devices on the rig to evaluate bleeding methods.

Some people use a vacuum device to suck the fluid out from the bleeder on the slave cylinder, but this is defo not as effective as forcing it in from the bottom, ahem.

Pumping it in from the res is not so good either. The air is always trying to go up, so you can't really guarantee you have all all out. Also, if you do have a bit of air in there, if you pump the pedal a load of times, the air goes into an emulsion, and the 'pedal comes back' and it feels like everything is ok. Eventually the air will come out of emulsion if left long enough, and you can be in trouble again.

I have used a couple of syringes, one to remove excess from res, and the other to feed it into the bleeder on the slave.

I will most certainly be using this method to bleed brakes when i have put new lines on in the future. 10 mins job, instead of hours!!

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I will try that the next time I have to bleed the typical Prilla back brake which I also did today and ended up with what seems a good brake...

But because they decided to lay the M/C down and have the bleed nipple on the bottom of the calliper it forms a shite system that needs bleeding every 3 months.......

Today I took the caliper off and cable tied it to the foot rest so the nipple was at the top of system and managed to get some air out!!

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