Clutch pressure lost and then back?

[Scoped_GST]

So basically i asked a shop to replace slave and master because my master was leaking. Long story short it felt way too light when i first drove it around, but engaged fine. 30 minutes into the drive back home and after traffic (engaging it a lot) it looses pressure entirely between a 4-5 shift and wont go into any gears.
Stopped by the side, no leaking anywhere, so i started pushing the pedal down and pulling it up with my hand and pumped it like that a bunch of times and then it magically came back to life.

Now, could it have just been an air bubble or something caught in the system?
Or would it most likely be a defective OEM part?

I just went outside after leaving it for 40 minutes and it has almost the right amount of pressure, but only after a few pumps will it have its normal amount of pressure, which i believe is normal for most hydraulic systems....?

 

[talon210]

This same thing kinda happened to me one morning when I went to go start my car, and I pushed the clutch in to start it and it just stuck to the floor, so I did what you did, I pulled the clutch back out with my hand and the pressure came back. I found out later that it was my master cylinder that was bad but i went ahead and replaced the master and slave and that fixed it. Stupid question but have you tried bleeding the system?

 

[FORMONTOYA]

The hydraulic system (brake or clutch) is a closed system and shouldn't require any "pumping up".

The first thing to do is to check the fluid level in the clutch reservoir and see if it's gone down. If not, then more than likely all that needs to be done is to bleed the system properly...............take it back to the shop and have them re-do it.

If the fluid level is down.............then it's either a defective part or they didn't put everything back together properly.........take it back and have the shop re-do it.



The clutch is a little more trouble to bleed properly as it has more of a tendency to dribble when the bleeder screw is opened. That's one of the reasons I use Speed Bleeders on my brakes and clutch.

http://www.speedbleeder.com/

 

[1990talon]

The hydraulic system (brake or clutch) is a closed system and shouldn't require any "pumping up".

The first thing to do is to check the fluid level in the clutch reservoir and see if it's gone down. If not, then more than likely all that needs to be done is to bleed the system properly...............take it back to the shop and have them re-do it.

If the fluid level is down.............then it's either a defective part or they didn't put everything back together properly.........take it back and have the shop re-do it.



The clutch is a little more trouble to bleed properly as it has more of a tendency to dribble when the bleeder screw is opened. That's one of the reasons I use Speed Bleeders on my brakes and clutch.

http://www.speedbleeder.com/

I think I am going to get some what size should we use for brakes? for slave?

 

[FORMONTOYA]

I think I am going to get some what size should we use for brakes? for slave?

There's an application chart on the above linked site for the brakes.
http://www.speedbleeder.com/automobile_applications.htm#Mitsubishi
However, I had to call them up for the size on the slave. It's been a couple of years and I've forgotten the exact size. Just give them a call and they'll help you out on that one.

 

[Scoped_GST]

well this is great news.
so i had the guys replace both master and slave with new OEM parts.
30 minutes after driving back home
SAME PROBLEM.

im pretty much lost here. theres no fluid loss. everything is tightened and fastened on correctly. but after 30 minutes of driving on the freeway not pushing the clutch in at all it will proceed to loose just about all of its pressure.

any ideas anyone?
please?

 

[FORMONTOYA]

Is the clutch hydraulic system loosing pressure?
Or is the clutch slipping after driving it a while?

If it's loosing pressure there has to be a leak somewhere, it just hasn't been found yet, or if it's not loosing any fluid.....it needs another bleed job.

If the clutch is just slipping after having been driven a while..............the pedal "free-play" needs to be adjusted.
"Clutch Adjustment", toward the bottom:
http://www.roadraceengineering.com/clutchandflywheeltech.htm

 

[Scoped_GST]

well problem is solved. they said they bled the clutch "perfectly" when i talked to them, but turns out that when i bled it myself, this milky white substance came out. thats how much air was mixed in with the fluid. . a good bleed and its better than ever.

conclusion: dont take car to shop.
i wouldnt reccomend precision motorsports either...