Drivetrain: how to flush clutch/brake hydraulic system
04-04-2009, 04:03 PM
#1
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how to flush clutch/brake hydraulic system
If anyone has had any weird funky clutch symptoms like. The clutch going limp,stiff or soft or slow to return during high rpm shifts you may want to read this first
What it boils down to is, if you have any of these symptoms you may need to change you brake/clutch fluid , here is a quote from the page above as to why.
There is info on that that tells you how to change the fluid , but this how to is help you do it on the cobalt ss .
You will need :
9mm box end wrench:
10mm box end wrench:
some rags for spills :
jar with a lid: (i used a farly large jar so i could flush in one go with out having to empty it.)
hose: (i forgot the size , but it needs to be large enough to fit snugly around bleeder screw. )
dot 3 or 4 break fluid(dot 4 has a higher boiling point)
a syringe: (or some means of removing fluid from the reservoir ,i used a turkey baster with some hose on the end of it.)
First step , get the car up on ramps or jack stands , how you do so is up to you,cause i wont be held responsible for a car falling on you.
Pop the hood , and find the brake reservoir
And remove the cap then suck out all the old fluid with your tool of choice..mine.. the
Baster...
Remove as much as you can and place it in your jar
Then refill with new fluid.
Now if your fluid looks like this ,its way past time for a change. Gm says to change every 100k , but my car only has 50k on it, i would change it at least every 20-30k depending on how you drive, or change it when ever you notice it changing color.
Now take your jar and lid, and poke a hole in the jar big enough to fit the hose into snugly.
Now you could dump this fluid and fill the jar half way with fresh fluid, but its not necessary if. The old fluid just acts as a seal to keep air for entering the system.
Make sure the end of hose rests on the bottom of the jar when the lid is on.
Now to bleed/flush the clutch, find the bleed screw. Its on the driver side on top of the tranny, but its easer seen from the bottom of the car.
If you lay on your back under the car and look straight up near the front of the car you can see it ,you may need to move some hoses lines out of the way.
Take your 9mm and place it around the screw, push up to loosen it ,down to tighten.
Then place your hose around the nipple. Not gonna lie, its a pain in the as, but it can be done. Once its on , loosen the screw
Place your jar somewhere you can see while you are pumping the clutch. Go inside the car, pump the clutch about 15- to a bajillion times ,until your clear line is filled with fluid, check the reservoir and top it off if needed. And pump the clutch more till all air is out of the line and, you start to see clear clean fluid enter the line. Once that is done , tighten the screw and your done with the clutch. You may have to fill the reservoir several times before its clean and done.
Now to purge the rest of the hydraulic system (the brakes ) move to the furthest point away from the reservoir , and thats the right rear wheels, next is the left rear , then right front and left front.
Pretty much the same as doing the clutch , just a littler easier.
You can take the wheels off the car , but if you have factory 18s and small hands you don't have to.
Find the bleeder screw on the rear wheel . Place your 10mm on it , then your hose, loosen then screw , pump the brakes till your clear line is free of air and dirty fluid, tighten and move on to the next wheel and repeat till you end up at the left front and your done .
Back wheel
Front wheels. From under the car.
What it boils down to is, if you have any of these symptoms you may need to change you brake/clutch fluid , here is a quote from the page above as to why.
first lets start off with those that have not yet experienced this problem or have recently changed all there hydraulics and clutch. The number one most important thing is to keep your clutch fluid clean and fresh. Its cheap and easy insurance to keeping your pedal working properly. Gm recommends changing it every 100,000 miles. This is total crap i don’t think there is any fluid that should be left in your car for 100,000 miles. No one has come up with a specific time frame to change your fluid so i would leave it up to your judgment. If your fluid is black its time to change it but it should be done way before it turns black. You should try to keep your fluid clean and fresh. The harder you are on the car the more frequent it should be changed. I personally recommend a full bleeding of the system if your fluid its dirty but once kept up with you can get away with just swap out the fluid in the reservoir but every once awhile you should still do a full bleed of the system.
You clutch fluid is plain old dot 3 brake fluid. Most run just regular dot 3 but dot 4 will work as well and has a higher boiling point. We all know that brake fluid boils and when it does it essentially breaks down and does not work as it should. The same goes for your clutch fluid as it is brake fluid. one must remember that the slave is located inside the bell housing. That location puts clutch fluid in a very high heat, stress situation. Also the line from the master to the slave is in very close proximity to the exhaust often even closer when you have headers. When launching or high rpm shifting the fluid temperate rises dramatically over regular driving. these situations of increased friction are sufficient to boil clutch fluid. Once the brake fluid has been boiled it will emit a gas or steam which when compressed in a hydraulic system meant for fluid it will cause a malfunction in the system aka you clutch pedal sticking or acting different than normal. Again this is why your fluid needs to stay clear and clean to keep your pedal from sticking.
You clutch fluid is plain old dot 3 brake fluid. Most run just regular dot 3 but dot 4 will work as well and has a higher boiling point. We all know that brake fluid boils and when it does it essentially breaks down and does not work as it should. The same goes for your clutch fluid as it is brake fluid. one must remember that the slave is located inside the bell housing. That location puts clutch fluid in a very high heat, stress situation. Also the line from the master to the slave is in very close proximity to the exhaust often even closer when you have headers. When launching or high rpm shifting the fluid temperate rises dramatically over regular driving. these situations of increased friction are sufficient to boil clutch fluid. Once the brake fluid has been boiled it will emit a gas or steam which when compressed in a hydraulic system meant for fluid it will cause a malfunction in the system aka you clutch pedal sticking or acting different than normal. Again this is why your fluid needs to stay clear and clean to keep your pedal from sticking.
There is info on that that tells you how to change the fluid , but this how to is help you do it on the cobalt ss .
You will need :
9mm box end wrench:
10mm box end wrench:
some rags for spills :
jar with a lid: (i used a farly large jar so i could flush in one go with out having to empty it.)
hose: (i forgot the size , but it needs to be large enough to fit snugly around bleeder screw. )
dot 3 or 4 break fluid(dot 4 has a higher boiling point)
a syringe: (or some means of removing fluid from the reservoir ,i used a turkey baster with some hose on the end of it.)
First step , get the car up on ramps or jack stands , how you do so is up to you,cause i wont be held responsible for a car falling on you.
Pop the hood , and find the brake reservoir
And remove the cap then suck out all the old fluid with your tool of choice..mine.. the
Baster...
Remove as much as you can and place it in your jar
Then refill with new fluid.
Now if your fluid looks like this ,its way past time for a change. Gm says to change every 100k , but my car only has 50k on it, i would change it at least every 20-30k depending on how you drive, or change it when ever you notice it changing color.
Now take your jar and lid, and poke a hole in the jar big enough to fit the hose into snugly.
Now you could dump this fluid and fill the jar half way with fresh fluid, but its not necessary if. The old fluid just acts as a seal to keep air for entering the system.
Make sure the end of hose rests on the bottom of the jar when the lid is on.
Now to bleed/flush the clutch, find the bleed screw. Its on the driver side on top of the tranny, but its easer seen from the bottom of the car.
If you lay on your back under the car and look straight up near the front of the car you can see it ,you may need to move some hoses lines out of the way.
Take your 9mm and place it around the screw, push up to loosen it ,down to tighten.
Then place your hose around the nipple. Not gonna lie, its a pain in the as, but it can be done. Once its on , loosen the screw
Place your jar somewhere you can see while you are pumping the clutch. Go inside the car, pump the clutch about 15- to a bajillion times ,until your clear line is filled with fluid, check the reservoir and top it off if needed. And pump the clutch more till all air is out of the line and, you start to see clear clean fluid enter the line. Once that is done , tighten the screw and your done with the clutch. You may have to fill the reservoir several times before its clean and done.
Now to purge the rest of the hydraulic system (the brakes ) move to the furthest point away from the reservoir , and thats the right rear wheels, next is the left rear , then right front and left front.
Pretty much the same as doing the clutch , just a littler easier.
You can take the wheels off the car , but if you have factory 18s and small hands you don't have to.
Find the bleeder screw on the rear wheel . Place your 10mm on it , then your hose, loosen then screw , pump the brakes till your clear line is free of air and dirty fluid, tighten and move on to the next wheel and repeat till you end up at the left front and your done .
Back wheel
Front wheels. From under the car.
Last edited by phatnackySS; 11-22-2009 at 12:09 PM.
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04-05-2009, 11:07 PM
#6
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i beat the snot out of my brakes and clutch, gonna do this on the next nice day. interesting to know that's how air is formed, due to breakdown of the fluid from boiling, didn't know that... thanks.
04-06-2009, 11:27 AM
#7
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Thread Starter
nether did I ,lol but it explains why so many people complain about bleeding the clutch then days later having to bleed it again despite the lack of leaks in the system, me being one of them.
so far i haven't had any more problems , but i wish i would have used dot 4 or 5 due to its higher boiling point.
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Newfoundlight (10-20-2023)
05-23-2009, 11:38 AM
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yeah same here, the car drive great for about 3 -4 weeks , but i think i may have cought it tolate , and my slave cylender is dead. guess i'll start saving for a new clutch. cause im not gonna drop the tranny just for that.
11-04-2009, 03:48 PM
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The bleed procedure isnt 100% correct. You dont "keep pumping the pedal."
This is correct and straight from the link u posted
u gave the impression the u open the bleeder one time and keep pupming the pedal.
update. just did the clutch and the left front as I had the wheel off already. couldnt get the rubber cap back on and took 20 mins to find the bleeder as I couldnt even see it cause the wires wouldnt move out of the way. will do the other 3 another day. definately a pita but worth a shot if I dont have to drop the trans to fix the stiff clutch when going full throttle
This is correct and straight from the link u posted
The reservoir needs to be full of fluid the whole time, otherwise you will just continue to introduce more air into the system. With the bleeder closed, push the pedal to the floor. Open the bleeder (fluid and air will come out). Close the bleeder, release the pedal, bring it all the way back up. This process gets repeated until you have a firm clutch pedal. Don’t panic – it can take up to 30 minutes to get it bled correctly.
update. just did the clutch and the left front as I had the wheel off already. couldnt get the rubber cap back on and took 20 mins to find the bleeder as I couldnt even see it cause the wires wouldnt move out of the way. will do the other 3 another day. definately a pita but worth a shot if I dont have to drop the trans to fix the stiff clutch when going full throttle
Last edited by stonny9; 11-06-2009 at 01:13 PM.
11-22-2009, 12:03 PM
#14
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Thread Starter
The bleed procedure isnt 100% correct. You dont "keep pumping the pedal."
This is correct and straight from the link u posted
u gave the impression the u open the bleeder one time and keep pupming the pedal.
update. just did the clutch and the left front as I had the wheel off already. couldnt get the rubber cap back on and took 20 mins to find the bleeder as I couldnt even see it cause the wires wouldnt move out of the way. will do the other 3 another day. definately a pita but worth a shot if I dont have to drop the trans to fix the stiff clutch when going full throttle
This is correct and straight from the link u posted
u gave the impression the u open the bleeder one time and keep pupming the pedal.
update. just did the clutch and the left front as I had the wheel off already. couldnt get the rubber cap back on and took 20 mins to find the bleeder as I couldnt even see it cause the wires wouldnt move out of the way. will do the other 3 another day. definately a pita but worth a shot if I dont have to drop the trans to fix the stiff clutch when going full throttle
both methods work , the one man method is easer, and it dose dubble duty of flushing and bleeading at the same time.
What happens if you try and pull it back up. Have you tried cracking open the bleeder then manually pulling it back up? What problems were you having with the clutch before hand.
11-22-2009, 12:35 PM
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i Always leave the bleeder open, they way you described is the 2 man method ,and doesn't need to have bottle and hose. the point of the bottle and hose is to create a closed system that keeps air form getting into the system. on the first few pumps a Little air will be sucked back into the system, but after that there should be fluid from the bottle all the way up to the nipple. then you pump until you don't see bubbles.
both methods work , the one man method is easer, and it dose dubble duty of flushing and bleeading at the same time.
What happens if you try and pull it back up. Have you tried cracking open the bleeder then manually pulling it back up? What problems were you having with the clutch before hand.
both methods work , the one man method is easer, and it dose dubble duty of flushing and bleeading at the same time.
What happens if you try and pull it back up. Have you tried cracking open the bleeder then manually pulling it back up? What problems were you having with the clutch before hand.
Oh, and I have an LNF, I am not sure if it matters or not.
Last edited by tlake84; 11-22-2009 at 12:35 PM. Reason: Automerged Doublepost
11-22-2009, 01:13 PM
#16
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Yeah, i've tried pulling it back up by hand and nothing happends, just springs up or down. I think i really messed up because I had someone hold the pedal down while I opened the bleeder and lost ALL pressure. What can be done at this point?
Oh, and I have an LNF, I am not sure if it matters or not.
Oh, and I have an LNF, I am not sure if it matters or not.
it sounds like you should beable to just open the bleeder and pull the peddle back up.
12-06-2009, 04:51 AM
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Do the brakes share the same reservoir with the clutch?
If so how many pints does the 2.0 s/c take?
If not, how many does each reservoir take?
Thanks for the write up
If so how many pints does the 2.0 s/c take?
If not, how many does each reservoir take?
Thanks for the write up
12-10-2009, 04:15 PM
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01-26-2010, 06:47 AM
#25
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I cant say for sure, i just bought 2-3 of the biggest bottles i could find since i was flushing the system , i never paid attention to how much it actually holds lol.
