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How to properly bleed your hydraulic clutch

This method of clutch bleeding will work on pretty much any car.
Forget about what the manuals tell you!

First off you'll need the following:

1) Goggles or other form of eye protection to prevent brake fluid from splashing into your eyes.
2) Get a clutch pedal buddy, a person that can push the clutch pedal in and hold it to the floor, and then lift the pedal off of the floor on command.
3) Jack stands and a jack so you can properly support the front of your vehicle while you bleed the system.
4) Brake fluid, and a pan of some sort to catch brake fluid as you bleed the system.
---I like to use a length of hose that fits snuggly onto the bleeder screw hose barb of the slave cylinder and then position the other end of the hose in a mason jar filled about 2 inches deep with brake fluid.
---This will prevent air from entering the slave cylinder when you are bleeding the Master Cylinder.
5) You'll need some rags handy just in case you spill some brake fluid. Remember, brake fluid is very corrosive, it will damage skin, eyes, paint etc...
6) Last but not least, a 10mm Flare Nut Wrench, this is a must, without it, you will round off your bleeder screw hex if the bleeder screw is on tight.

Procedure:
1) Properly support the front of the vehicle on jack stands.
2) Install Clutch Pedal Buddy in driver's seat. (DO NOT PUMP THE PEDAL AT ALL THROUGHOUT THIS ENTIRE PROCESS).
3) Remove Master Cylinder Reservoir Lid.
4) Top off reservoir with brake fluid.
5) Next, you'll be opening and closing the Slave Cylinder Bleeder Screw.

CAUTION: Protect your eyes from squirting brake fluid.

6) (Helper) Press clutch pedal in fully to the floor and hold.
7) (You) Open the bleed screw to allow fluid to flow.
8) (You) Close bleed screw.
9) (Helper) Release clutch pedal. You may have to pick the pedal up off of the floor, do this slowly and smoothly all the way up.
10) Repeat steps 6-9 two times, and then top off the reservoir.
11) Repeat steps 6-9 three more times, and then top off the reservoir.
12) You're not done yet, but you just bled the master cylinder and the hydraulic line, next you have to bleed the slave cylinder. (This is what the manuals don't tell you).
13) There will be no further action needed with the clutch pedal, so remover your Clutch Pedal Buddy from the driver's seat.
14) Make sure the reservoir is topped off.
15) Now, you're about to properly bleed the slave cylinder.
16) Place a pan or equal under the slave cylinder bleed screw, and completely remove the bleed screw from the slave cylinder body.
13) Your helper should have the bleed screw and a wrench ready to tighten the bleed screw into the slave cylinder.
Please remember to protect your eyes and those of your buddy's.
14) With the bleed screw removed, firmly press and hold the slave cylinder push rod into the body of the slave cylinder. Yes you read it right, push the rod into the slave cylinder and hold it.
15) Be careful, as soon as you push that rod back into the slave cylinder, it will and without remorse squirt brake fluid onto anything within reach.
16) Have your buddy reinstall the bleed screw and tighten it with the flare nut wrench all the while you're still holding the push rod in.
17) Once the bleed screw is tight, release the rod and as it comes out, guide it into the proper position on the clutch arm.
18) Work your clutch pedal a couple of times, and notice that your reservoir is filled right up to the Max Fill Line.
19) Install reservoir lid, lower the car, and give a test drive....
 

Mech Addict

Supporting Member
1,154
545
Jun 9, 2019
Jackson, Wyoming
Based on this write-up I tried the procedure.

Simply having a wrench that can open the slave bleeder screw on a 1g AWD is difficult. It’s deeply surrounded by obstructions, and even when you get a tool to fit on the “bolt” part of the screw, there is little room to swing even a regular 10 mm combo wrench. It’s easier with a deep 1/4 drive ratchet, but that precludes being able to attach a hose to the nipple to collect the bleed fluid.

I tried replacing the standard bleed screw with a speed bleeder type. It makes it so you can loosen it a bit (socket), put a hose on, and then simply press the clutch in and pull it out. I tried to push in somewhat briskly, and pull back (yes, you actually pull because of the odd over-center return spring) rather slowly. I did all this after adjusting the clutch pedal rod for maximum stroke (checking that the slave piston could still be pushed by hand).

I did try the complete “removal of the bleed screw so the slave piston can be pushed all the way in” method described in the post.

What a mess. Trying to hold the slave piston against a spring all the way compressed with one hand and trying to even start the bleeder back in (even though the tip is pointy!!) with your other hand, and all just after both hands and everything around them is freshly coated in slippery brake fluid, would take more skill than I could muster. Thinking of having another person try to thread their hands somehow into this party to assist in any beneficial way was hard for me to imagine (without laughter).
I also have used a hand vac for this kind of thing on brakes and such. The speed bleeder I have didn’t seem to want to allow any fluid out, under just the vacuum I could raise by hand pump.

Notes:
The m.c and slave are brand new Mitsubishi. The slave does have a swapped 2g rod to compensate for a slightly self-clearenced clutch pedal shaft end. I replaced the original rubber hose in hydraulic line with a new NAPA equal. No visible fluid leaks (other than while fiddling with the bleeder). The trans is newly rebuilt by reputable shop. Clutch kit w/ t.o. is all new Exedy (and NSK) stock-type. Flywheel refinished by reputable shop. Essentially everything is as close as I could get to fresh factory-original. Pivot ball shimmed with a decent thickness (grade8) washer.

After all this, and despite a big fail on the bleeder-out slave piston push method, the clutch seems to work nicely now. I put a little caliper grease back on the bleeder screw threads (keeps air from sucking back in), and did the speed-bleed process three or four strokes, tightened it up, topped off the res., and voila.

I’d love to hear that someone actually can do this on a 1g AWD (bleeder location differs from FWD).
 

pauleyman

DSM Wiseman
8,434
2,953
Nov 19, 2011
oklahoma city, Oklahoma
Simply having a wrench that can open the slave bleeder screw on a 1g awd is difficult. It’s deeply surrounded by obstructions, and even when you get a tool to fit on the “bolt” part of the screw, there is little room to swing even a regular 10 mm combo wrench.

I'd like to see a pic on this. I've done it dozens if times on both 1g and 2g AWD with nothing more than a 10mm wrench. I am aware as you stated the AWD slave is physically different. I put a 10mm box end on the screw then attach a hose although I do have flare wrenches I don't find them necessary.
 

Mech Addict

Supporting Member
1,154
545
Jun 9, 2019
Jackson, Wyoming
I found a set of h.f. Extra deep offset box wrenches that can get right on it, but it is too long to swing. Cutting it in half may be ideal, but it’s one of a set of 8, so kind of makes the set odd. I can get an open end on it by angling it, but you can’t apply much torque that way without fear of rounding the corners.
Which part do you want a photo of, pauleyman? The slave? I’ve already taken the car off jackstands, so hard to get a photo now. It’s all as stock as it can be. Perhaps everyone who replaces the steel hard lines with s.s. Braided gets better access. Mine still has hardlines. The fwd slave screw is in a much more favorable location, it appears, and I don’t see why they moved it for awd models.
 

pauleyman

DSM Wiseman
8,434
2,953
Nov 19, 2011
oklahoma city, Oklahoma
Perhaps everyone who replaces the steel hard lines with s.s. Braided gets better access. Mine still has hardlines.
This was on a totally stock car with just a simple off the shelf 10mm wrench. The box ends are usually angled and it was no big deal. Plenty if room to place the wrench and swing it.
 

ist dwa

10+ Year Contributor
622
377
Nov 5, 2009
Centerville, Ohio
How to bleed a clutch in a dsm.

1. Fill the reservoir all the way up and leave the cap off.
2. Crack the bleeder screw at the slave cyl. Top off the reservoir if fluid gets to the "L" while gravity bleeding.
3. Let it drain into a pan until it is a solid stream and then close bleeder.

Done.

Note- If no fluid is draining out when the bleeder is cracked your master cyl main rod is screwed in to far, slowly unscrew it until fluid begins to flow, that ensures maximum extension of the clutch pedal travel.
 

DSSA

Supporting Vendor
655
485
Jul 26, 2002
Hatfield, Pennsylvania
Based on this write-up I tried the procedure.

Simply having a wrench that can open the slave bleeder screw on a 1g AWD is difficult. It’s deeply surrounded by obstructions, and even when you get a tool to fit on the “bolt” part of the screw, there is little room to swing even a regular 10 mm combo wrench. It’s easier with a deep 1/4 drive ratchet, but that precludes being able to attach a hose to the nipple to collect the bleed fluid.

I tried replacing the standard bleed screw with a speed bleeder type. It makes it so you can loosen it a bit (socket), put a hose on, and then simply press the clutch in and pull it out. I tried to push in somewhat briskly, and pull back (yes, you actually pull because of the odd over-center return spring) rather slowly. I did all this after adjusting the clutch pedal rod for maximum stroke (checking that the slave piston could still be pushed by hand).

I did try the complete “removal of the bleed screw so the slave piston can be pushed all the way in” method described in the post.

What a mess. Trying to hold the slave piston against a spring all the way compressed with one hand and trying to even start the bleeder back in (even though the tip is pointy!!) with your other hand, and all just after both hands and everything around them is freshly coated in slippery brake fluid, would take more skill than I could muster. Thinking of having another person try to thread their hands somehow into this party to assist in any beneficial way was hard for me to imagine (without laughter).
I also have used a hand vac for this kind of thing on brakes and such. The speed bleeder I have didn’t seem to want to allow any fluid out, under just the vacuum I could raise by hand pump.

Notes:
The m.c and slave are brand new Mitsubishi. The slave does have a swapped 2g rod to compensate for a slightly self-clearenced clutch pedal shaft end. I replaced the original rubber hose in hydraulic line with a new NAPA equal. No visible fluid leaks (other than while fiddling with the bleeder). The trans is newly rebuilt by reputable shop. Clutch kit w/ t.o. is all new Exedy (and NSK) stock-type. Flywheel refinished by reputable shop. Essentially everything is as close as I could get to fresh factory-original. Pivot ball shimmed with a decent thickness (grade8) washer.

After all this, and despite a big fail on the bleeder-out slave piston push method, the clutch seems to work nicely now. I put a little caliper grease back on the bleeder screw threads (keeps air from sucking back in), and did the speed-bleed process three or four strokes, tightened it up, topped off the res., and voila.

I’d love to hear that someone actually can do this on a 1g AWD (bleeder location differs from FWD).
An 10mm offset wrench works best. 1/4 drive with a short 10mm makes a mess but works. I've been doing them that way for 25 years.

I'm glad someone posted this procedure. I did a similar one about 10-15 years ago on here, but I still get calls from people on the regular that they "replaced everything, yet still can't get their clutch to release".

Only difference is that I let the "helper" stay in the vehicle. They do the first part, "pump/open", but then I have them do it a couple of times again: "Pump, open, squeeze slave shut while they're holding it down, close bleeder, release all". Repeat 3x to be sure, and you're done.

Good write up, any specific brand of fluid ? Dot 3/4? Synthetic?
Pretty much doesn't matter on these cars. Cheap, clean, NEW DOT3 will work. It's not like a Corvette C5/C6/C7 where the slave is inside the bell housing and getting constantly heated. Save your money for good brake fluid---used in your brakes.

How to bleed a clutch in a dsm.

1. Fill the reservoir all the way up and leave the cap off.
2. Crack the bleeder screw at the slave cyl. Top off the reservoir if fluid gets to the "L" while gravity bleeding.
3. Let it drain into a pan until it is a solid stream and then close bleeder.

Done.

Note- If no fluid is draining out when the bleeder is cracked your master cyl main rod is screwed in to far, slowly unscrew it until fluid begins to flow, that ensures maximum extension of the clutch pedal travel.
This won't bleed the slave cylinder, which will put you back at square 1 with a heavy clutch.

Look at a disassembled slave cylinder on these cars. Take note of where the fluid goes in--then comes out. The air can sit behind the piston in the slave and never move.

If you had said "zip tie or use a/an "X" to compress the slave cylinder while you do this)--then I would agree that you could probably gravity bleed it over time.
 

Mech Addict

Supporting Member
1,154
545
Jun 9, 2019
Jackson, Wyoming
An 10mm offset wrench works best. 1/4 drive with a short 10mm makes a mess but works. I've been doing them that way for 25 years.

I'm glad someone posted this procedure. I did a similar one about 10-15 years ago on here, but I still get calls from people on the regular that they "replaced everything, yet still can't get their clutch to release".

Only difference is that I let the "helper" stay in the vehicle. They do the first part, "pump/open", but then I have them do it a couple of times again: "Pump, open, squeeze slave shut while they're holding it down, close bleeder, release all". Repeat 3x to be sure, and you're done.
Yes, I finally found a deep-enough offset box wrench that works. I bought the whole set at HF and they’ve proven to be very handy all over the car. Still not much room to swing it around the slave, and I’m not seeing why the AWD slave was done like this when the FWD serves the same exact function in the same location and surroundings but is more accessible.
 

dwb

Proven Member
359
191
Sep 9, 2021
Broomfield, Colorado
TBH, I've never had an issue using a standard open end wrench on my 1g AWD. Really only one angle that it will fit, it's kind of offset and will only turn about 45deg, but it's enough to open the bleeder. Never rounded one off.

I'm often doing this solo. It's no fun. Pump the clutch, prop it with a stick against the seat, crawl under the front and pop the bleeder open/closed, crawl back out and repeat. I'll push the slave in by hand a couple times with the clutch pressed and bleeder open as well.

I've tried gravity bleeding without any positive results.
 

DSSA

Supporting Vendor
655
485
Jul 26, 2002
Hatfield, Pennsylvania
Yes, I finally found a deep-enough offset box wrench that works. I bought the whole set at HF and they’ve proven to be very handy all over the car. Still not much room to swing it around the slave, and I’m not seeing why the AWD slave was done like this when the FWD serves the same exact function in the same location and surroundings but is more accessible.
I have one that (amazingly) I've never lost over the years that is my "go-to". It's an old Craftsman offset box-end wrench (10 & 11mm) that was probably my father's at some point.

No, there's not much room to swing it under there. I usually loosen the bleeder as far as I can with one swing (which isn't enough to open it), reposition the wrench, and turn it again. This usually opens it enough to bleed. If not, I go one more swing.
So long as you close it before releasing the pedal and/or slave, it doesn't matter.

That said, it's always best to have two people doing it. One just needs to be able to follow the directions: "Pump, pump, pump...HOLD.......Release"

I've done it myself with a vacuum bleeder (air version) while squeezing the slave closed and holding it while I tighten the bleed screw, but I always feel more confident manually bleeding it with someone sitting in the car.
 

Mech Addict

Supporting Member
1,154
545
Jun 9, 2019
Jackson, Wyoming
I’ve tried the vacuum bleeding on clutch and brakes, but you can often get some air leaking around the bleeder screw. That can be sealed with a little caliper grease, but I agree there is something more definitive with have the pedal pressed for positive pressure bleeding. My wife rolls her eyes when it involves working on the car. As if sitting in the driver’s seat is going to end up covered in grime. The cat is too small, even if I could train him. I do have a fellow gear head in the neighborhood, but we mostly just talk about wrenching, and both seem like to work alone. That way nobody’s around to witness the mistakes. :rolleyes:
 
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