SoCal General Chat

[Sh3rpak!ng]

posted in the driveline section, figure it can't hurt to post here:

So recently my master cylinder seemed to be going out. I was having inconsistent clutch disengagement and would have to pump it a few times to get good functionality. The slave cylinder is brand new (febi brand iirc) as of a few months ago.

So I installed a new febi master cylinder and now have some very bizarre pedal pressure issues. Not really sure how to describe this. When cycling the pedal with my hand, lifting it up and then pressing down, 4/5 times it feels normal, normal pressure and disengagement effort, but sometimes I get ZERO pressure and the pedal will literally fall to the floor. I mean no pressure whatsoever, it feels like it's just hanging loose as if it's not bolted to the master at all. I lift the pedal, press again and pressure is normal. Sometimes when it "misses" it'll fall straight to the floor, sometimes it catches halfway and feels like normal pressure from there.

This feels very different from, for example, after installing a new slave that needs to be bled and the pedal is soft and travel is longer than normal.

Is the new master cylinder bad?

[Blue55]

Sup people of So-Cal. Back at work after being off for 2 weeks for lower groin hernia surgery. :eeek::eeek::eeek:

Welcome back!

[Blue55]

posted in the driveline section, figure it can't hurt to post here:

So recently my master cylinder seemed to be going out. I was having inconsistent clutch disengagement and would have to pump it a few times to get good functionality. The slave cylinder is brand new (febi brand iirc) as of a few months ago.

So I installed a new febi master cylinder and now have some very bizarre pedal pressure issues. Not really sure how to describe this. When cycling the pedal with my hand, lifting it up and then pressing down, 4/5 times it feels normal, normal pressure and disengagement effort, but sometimes I get ZERO pressure and the pedal will literally fall to the floor. I mean no pressure whatsoever, it feels like it's just hanging loose as if it's not bolted to the master at all. I lift the pedal, press again and pressure is normal. Sometimes when it "misses" it'll fall straight to the floor, sometimes it catches halfway and feels like normal pressure from there.

This feels very different from, for example, after installing a new slave that needs to be bled and the pedal is soft and travel is longer than normal.

Is the new master cylinder bad?

Have you tried power bleeding it? I find these are very finnicky with normal pedal pumpnig method. Power bleeding solved my weird clutch feel issues.

[Sh3rpak!ng]

Have you tried power bleeding it? I find these are very finnicky with normal pedal pumpnig method. Power bleeding solved my weird clutch feel issues.

nope, haven't tried that, but I will. I pedal pumped it when I first installed it and then spent a while pedal pumping/bleeding both MC and slave last night to end up with the same results. I will pickup a new FTE MC (the oem) this afternoon just in case since I have a track day on Saturday.

[2mAn]

E30 got jealous of my spending on my daily so I had to buy a repro Alpina dead pedal from Guten... now i just need to stop spending so I can save for some damn Koni's!

[QUKBMER]

Welcome back!

Thanks man.It's been hell.

[LowR3V'in]

I saw a dark gray e30 in santa ana by the 22 the trunk was totally smashed in.
The guy was there talking to a suv cop. anyone?

[Chilezen]

posted in the driveline section, figure it can't hurt to post here:

...

Hey, I have this problem too, although you didn't specify when this happens. Mine does this about once or twice a month after the car has been sitting for a couple days. I have to pump the clutch pedal to regain firmness. Other days, it's fine; normal. It can sit for days and not exhibit the problem. It never happens during driving, thankfully, only when the car sits for a while.

I changed the brake master a long time ago but never touched any of the clutch components.

I'm no help to your problem though. Try topping off the fluid, over the fill line. I did that once and somehow it felt better? Could have been unrelated.

[Sh3rpak!ng]

Hey, I have this problem too, although you didn't specify when this happens. Mine does this about once or twice a month after the car has been sitting for a couple days. I have to pump the clutch pedal to regain firmness. Other days, it's fine; normal. It can sit for days and not exhibit the problem. It never happens during driving, thankfully, only when the car sits for a while.

I changed the brake master a long time ago but never touched any of the clutch components.

I'm no help to your problem though. Try topping off the fluid, over the fill line. I did that once and somehow it felt better? Could have been unrelated.

It happens to me all the time, like I was literally just sitting and pulsing the pedal with my hand and randomly it would drop to the floor with zero resistance, then after I pull it back up and push down again, perfectly normal operation. Sometimes when it misses, it catches halfway through full travel, sometimes it doesnt catch at all and goes to the floor.

The symptoms you're describing just sound like a an old MC going bad, that was nearly identical to what I was experiencing before I replaced mine (which is why I decided to replace it)

[Chilezen]

A more effective bleeding may be in order

[2mAn]

I have a pressure bleeder that is at my buddies garage in Granada Hills. Not sure when I will be able to grab it for you though

[reelizmpro]

Sounds like a potentially dangerous problem. Must be air in the system or something that's unpressurizing the system. How are the hoses? good condition? nice and tight? was the reservoir kept full during bleeding? are you losing brake fluid?

[Sh3rpak!ng]

I have a pressure bleeder. MC, slave, clutch line are all brand new. Im thinking I need to bleed more. Worst case ill throw another new MC in there that I have on hand. Little worried since I am going to willow springs tomorrow.

[IRON-E]

May be a little off on this but maybe the master is leaking into the booster?

[Sh3rpak!ng]

May be a little off on this but maybe the master is leaking into the booster?

Clutch and brake hydraulics are separate, just share the same reservoir.