air in clutch system?

**Homer J** · 05-06-2011, 09:14 PM

ok, i thought maybe my master or slave were going out, but could i just be some air trapped?

i change the fluid pretty often using the Ranger method, about twice a month. just suck the old fluid out, add fresh, then pump the pedal real fast.

im propbably not the best manual driver, i think i slip the clutch to much on take off.

that is were my problem lies, if im in stop and go traffic and i let the clutch out to begin to start rolling, but not full release the pedal, and push it back down again because of traffic not moving fast or far enough. when i got the release the pedal again, its engagment point is now lower. it olnly takes 3 cycles of creeping movement till the clutch is releasing right off the floor.

or if im pulling into my garage, as a creep in to be sure and not hit the passenger side mirror on the wall, or my wifes car, as a slowly release the pedal, then push it in again, and slowly let it out to creep a little more, its almost at the floor for a release point.

oh, and normal catch point for the clutch is at about halfway up on the pedal travel and fully endgaged by the top of the pedal. all stock as far as i know with about 48,000 miles.

**Homer J** · 05-07-2011, 07:58 PM

nobody?

what does the clutch do or feel like when there is air trapped in it?

the car drives fine after you take off. every other gear shifts great

**Mean Green Z28** · 05-07-2011, 08:09 PM

probably have a bad clutch master cylinder. It's probably not air, just fluid getting past the seal. The reason you don't feel it after you get going is that the fluid just doesn't have enough time to get past the seal, and in slow/repetitious driving more and more fluid gets past the seal when you get on and off it when partially engaged and eventually causing the dead pedal. Haven't driven your car, so this is all hypothetical and is my best guess given the information presented.

Do you keep the car in gear when stopped in traffic or do you shift into neutral and release the pedal? If it is infact seeping past the seal, you'll feel the pedal pressure get weaker and the clutch starting to slip as you keep the pedal pressed; or if the bore is bad, at a certain point in the travel of the plunger.

Hope this info helps

edit: if there's are trapped in there, you're not gonna be able to put it in gear that easy and you're gonna have to pump hard a few times to even get it to go in.

***SMWS6TA*** · 05-07-2011, 09:29 PM

Homer J,

How many miles on the car/tranny? Meaning whens the last clutch change? over 70k and you are needing it, however mine lasted till 110k because the 1st owner baby it, I got it at 108k and well you can see

Other questions: have you done any work to the clutch at all?

Without answers to above I can only guess wildly and it would be a very long post to go over possible everything.

Most likely culprits for slippage over 70k, are:

master/slave failure, clutch pad/pressure plate is worn and need to be replaced, flywheel has been glazed from clutch pad material, usually from burn outs or dropping/riding the clutch to long or any combination of.

In regards to the losing clutch pedal feel this is one of those things that GM didn't do us any justice on. There is a free mod called the clutch mod on ls1howto.com. You basically drill open the orifice on the hydraulic line at the bell housing side. It expands the opening and lets the fluid return faster.

post back answers to my questions and I'll try to go from there.

**Mean Green Z28** · 05-08-2011, 04:45 AM

I don't think the drill mod is the issue here cos it's not like he's speed shifting. If he's gonna have the clutch master out, replace the darn thing with a mcloed or other aftermarket unit while doing the drill mod.

***SMWS6TA*** · 05-08-2011, 01:04 PM

Originally Posted by That Guy 2-1

I don't think the drill mod is the issue here cos it's not like he's speed shifting. If he's gonna have the clutch master out, replace the darn thing with a mcloed or other aftermarket unit while doing the drill mod.

That is what I was pointing out.

**victor111262** · 05-08-2011, 07:51 PM

sorry for thread jacking

but mine does some similar thing it started today but on mine i would completely loose the peddle and have no clutch, im checking it 2morrow morning also it makes a popping noise from the rear passenger side like the axle is broken or something.

**Homer J** · 05-13-2011, 05:11 AM

Originally Posted by SMWS6TA

Homer J,

How many miles on the car/tranny? Meaning whens the last clutch change? over 70k and you are needing it, however mine lasted till 110k because the 1st owner baby it, I got it at 108k and well you can see

Other questions: have you done any work to the clutch at all?

Without answers to above I can only guess wildly and it would be a very long post to go over possible everything.

Most likely culprits for slippage over 70k, are:

master/slave failure, clutch pad/pressure plate is worn and need to be replaced, flywheel has been glazed from clutch pad material, usually from burn outs or dropping/riding the clutch to long or any combination of.

In regards to the losing clutch pedal feel this is one of those things that GM didn't do us any justice on. There is a free mod called the clutch mod on ls1howto.com. You basically drill open the orifice on the hydraulic line at the bell housing side. It expands the opening and lets the fluid return faster.

post back answers to my questions and I'll try to go from there.

ok, the car has about 46,xxx miles. im pretty sure its been babied before i got it. it does have SFC and a strut tower brace. has an SLP lid and aftermarket SLP dual-dual exhaust. the car is very clean.

under normal pedal operation, it starts to release (grab) at about the halfway point and is fully engaged by the top of the pedal travel.

like i said, i may not be the best manual trans driver as i think i may slip the clutch too much on take off. rev a little then slowly let of the clutch, but once it starts to move and not bog i just release the pedal and go.

i talked to a guy at a local shop who actually own a 2002 firebird. i described to him what it was doing and he seems to think its the master as well. said he's had 2 go out on his car.

so, is it best to get a GM master or a parts store replacemant with a lifetime warrenty?

also, do i need to bleed the master after i install it, or there a better way to bleed it before it goes in the car?

is the drill mod really that much different?

**Mean Green Z28** · 05-13-2011, 07:09 AM

Drill mod you would only appreciate during back to back high rpm shifts at the track, you're not gonna gain anything from daily driving; actually you may feel more clutch chatter through the pedal during normal operation/traffic. The restriction was put in there to make it easier/comfortable to drive by restricting how fast fluid goes through.
As far as the master, you could replace it with either and be fine with a stock clutch but I'd upgrade if I was you.
You can bench bleed the master and line before you put it on. I've done it many many times and not once have I had to re-bleed the system after (except when the slave was bad).

**Homer J** · 05-13-2011, 07:39 AM

Originally Posted by That Guy 2-1

Drill mod you would only appreciate during back to back high rpm shifts at the track, you're not gonna gain anything from daily driving; actually you may feel more clutch chatter through the pedal during normal operation/traffic. The restriction was put in there to make it easier/comfortable to drive by restricting how fast fluid goes through.
As far as the master, you could replace it with either and be fine with a stock clutch but I'd upgrade if I was you.
You can bench bleed the master and line before you put it on. I've done it many many times and not once have I had to re-bleed the system after (except when the slave was bad).

ok, so if i get a new master, and transfer my resivor over along with the line that goes to the slave, i can just bleed the system before i reinstall it on the car and i should be good to go?

to bleed the system, can i just mock everything up? put the resivor on a peice of wood above the master, and the line to the slave hanging down and just push the end of line in to let out fluid? or should i rent or buy a mity vac?

***SMWS6TA*** · 05-13-2011, 08:38 AM

If you get a OEM Master from GMpartsDirect (Sponsor) it will be ready to install. No pre-bleeding necessary and it comes with a complete assembly (Master, Reservoir, and Hydraulic Clutch Line). All I had to do was be careful not to spill it while I did the install.

One more thing. Just prior to installing the Master drill out the holes a little bit larger. It will hake it much easier to instal it.

Tick Performance has some nice Masters too, but will cost more ($300) then OEM. They also sell a remote bleeder line ($45) that helps make it a little easier.

THAT GUY 2-1 is correct about the "drill mod" only being a benefit while speed shifting.

***SMWS6TA*** · 05-13-2011, 08:43 AM

A bit of clarification of my above post. I mean to say that if you get a OEM Master form GMPartsDirect the Master will not need to be pre-bleed. However you will need to bleed the system to make sure no air has gotten into the system.

**Mean Green Z28** · 05-13-2011, 09:00 AM

I would mount the master with the line end facing upwards and hold the line going upwards from there. Then I'd hold the reservoir up and slightly higher than the end of the line. Take a small pin or screwdriver and push on the opening of the line and make sure the reservoir is full. You can apply a bit of pressure to the reservoir to push the liquid through and also tap the master and line lightly to make sure all the air rises to the top of the line (not recommended but i used to put my mouth up against the reservoir and blow,lol) and by doing this you'll effectively purge all the air out the system, just make sure you get pure liquid out the line end. Now seal everything (line and reservoir) up and you're good to go!