So i just did my yearly brake bleed and thought I would do my clutch. I had a full reservoir and got on to the slave cylinder with my 10 mil ring spanner. Had my son pump the peddle a few times, then down while i released the bleeder valve. Did it a couple of times to get clear liquid. On the last push the peddle went to the floor and stayed there. I pumped the peddle 20 times and got some pressure back, then bled a huge amount of air out of it and it came good. So just on the last couple of pumps the peddle went to the floor again, wtf, how was air getting in, I had the bleed tube looped so i could see if there was any air going back up and none. So i had to go around and pump 100 times and slowly got pressure back enough to get it off the ramps and back into my garage. So how could i suddenly do a master cylinder? I have no leaks of fluid or air getting in that I can see. Has this happened to anyone before? I'm probably just going to order a new master and slave anyway cause i don't want to be stranded.

 

I cant say being I wasnt there but is there a chance that you werent closing the bleeder fast enough before your son let off the pedal?

 

you have to fill the reservoir to the brim, bleed a little, then fill, bleed a little, repeat. squish the hose to the clutch master a few times to release some air.
I just use a vacuum/transfer pump, and dont really mind the 'bubbles' with that method

 

You are correct, I've been reading some threads, seems to be a known issue with air getting back into the lines some how. It can't be via the master cylinder or slave cylinder as there would be fluid leaking from the seals which there isnt. The clutch master cylinder line comes from the bottom back of the reservoir and you would think that if you had it almost full of fluid there would be no issue, but it seems that you need to have it almost to the top of the rim.

 

i thought about that but i had the drain tube looped on the nipple, so there is always fluid in it and air cant get back in otherwise i'd see it.

 

i always thought that air comes thru the threads of the bleeder (using the vacuum method)

 

I'm presently in the garage doing it myself, i'm pumping the peddle then holding it down with a block of wood,, then opening the bleeder and bleeding it and some air has been coming out, then i leave the bleeder open for 10 mins then close and repeat, I've actually got a bubble of air to come up from just squeezing the tube going to the master. I've got it almost right. I might order a vacuum pump

 

Get someone to help you. Easier with a 2nd person.

 

I use this now. cheap and available everywhere but not the one with a clear hose though
https://www.evolutionm.net/forums/ev...l#post11945919

 

I use an electric vacuum pump (the style you use to evacuate an AC system) that goes on the reservoir. Literally takes 10 seconds to bleed it. No cracking valves, no 2 people needed, no worry about getting all the air out. It just works. Same thing works for bleeding brakes and coolant.

 

if you're in your garage you mean

 

That's a great idea, never thought of doing that. Thanks for sharing.

 

Nah, thats what extension cords are for! Haha

 

i've messed this up as well. i think it has to do with pulling the clutch pedal back up off the floor too quickly, cuz it just pops back up. have him try fighting that and just slowly letting it back up.

but agree, i think it works better with a pressure bleeder when it comes to the clutch.

 

No problem. On my Cobalts, they dont have a bleeder for the clutch so I had to do it with the vac pump. I will never again use the standard pedal pump method after I saw how well it worked. And like I said, it works great on bleeding coolant too. No need to wait for the thermostat to open. It sucks all the air out and replaces it with coolant instantly.