Clutch wont bleed, need it for Nationals

[Jabeo]

As you all will know by now, in the last month and a half i have removed my engine and box for a full engine reseal and a few bolt on mods, which included a replacement lightweight flywheel and heavy duty Xtreme clutch, both previously used without issue on the same gearbox and engine. When i removed the engine from the car, the slave stayed connected up in the engine bay, the rod on minimal extension like when the clutch fork is not engaged. Recently, i was in the car fitting a wideband and silly me put my foot on the clutch and the pedal went to the floor and drained the reservoir of fluid, the slave rod now fully extended.

On engine reinstallation i could not get the clutch rod depressed to sit it in the clutch fork, so cracked the bleeder to relieve the pressure and depressed the slave enough to get it all mounted up. The car is running and ready to go, except for the fact that the clutch is not engaging. Today Tony and I have spent the day trying all manner of means to get the clutch lines filled with new fluid and bled so that i can finalize the car for the drive to MR2 nationals. No matter what we do we cannot get pressure to build in the clutch system to engage the rod/clutch fork.

We started by filling the reservoir with fluid, and cracking the the bleeder nipple with a hose attached going above the nipple (because air rises), we pumped continuously by hand on the pedal, the reservoir slowly dropping and before we knew it the old fluid was out and there was clean new fluid at the master and the slave. we then tried the classic pump and bleed method, we pumped the pedal full strokes a few times, held it down, cracked the nipple, tightened and repeated, a few bubbles coming out each time. Kept this up for a while but there was no difference in the pedal feel, still straight to the floor. We also tried pressurizing the master cap with a bottle to promote movement in the lines but nothing. We put a syringe on the line to create some vacuum which did manage to pull some fluid and air through, but even after trying that for a while the pedal keep going straight to the floor. We cracked the nut on the master hard line and no air came out, just fluid. closed it, pumped it, opened it and again only fluid. We even went as far as to buy a hand held pressure/vacuum pump and after pressurizing the line on the slave the reservoir slowly filled up and a couple of bubbles came through. We tried to pull vacuum on the line, cracked it and some bubbles came through rinse and repeat but still the pedal went to the floor. We noticed that even with the nipple closed and vacuum was applied, bubbles were still coming into the lines around the bleeder. either from behind the hose end or the nipple threads perhaps, which was annoying me. When the nipple was slightly cracked open the fluid would soon pool on the underside of the threads and drip off. We decided to start messing with the slave rod, pumping while i applied pressure to it, cracked it open , rinse and repeat. When i applied pressure to the actuator, tony could feel the resistance at the pedal and the rod would try push out, and would then reach a point where it would not extend any further (engaging the clutch fork, and i know for a fact that it can extend further than it is) and the pedal still hitting the floor. we also clamped the rubber line going into the slave to see if the pedal felt any resistance but nothing happened.

We spent all day trying all manner of things to sort this out as it is the only thing i need to do to get the car moving for mr2 nationals. Can anyone offer any sound advice based on my description and what to try. the master and slave worked perfectly before i removed the engine, but i am thinking i might need to check their mechanical operation. i feel like the master is pumping somewhat as i can see the slave rod slightly moving the fork but nothing notable, and it moved clean fluid to the slave bleeder. My next thing to check will be to pull the boot on the slave rod and see if there is any leaks or anything, however aside from the bleeder area it is completely dry. I would assume that even if there was a really small leak i might expect some fluid to come out or for there to still at least be some sort of pressure before it is lost but this is not the case. None of the clutch lines are leaking under the car from the master to the slave. could it still just be air causing this even after trying all day? or could my master/slave not be pumping/flowing properly? I have googled and researched all day, but nothing we tried gave us much success.

I really want to take my car to nationals, and its going to be a shame if this is the only reason it doesnt come. i appreciate any and all help you might be able to offer, cheers!

[Mr-Paulio]

Funny, I just had clutch bleeding issues too. Turned out mine was a bunged up bleed nipple. Quick shot of high pressure air sorted that guy! If you've lost fluid it does take quite some time to pump pressure in. But from what you are saying this sounds like more. Those vaccum tools are great aye? The wife loves that i dont need her now to come to the shed and pump the pedal!!

If you clamped the rubber hose before the slave properly and still couldn't build pressure it's the master. Or a leak. It doesn't have to loose much fluid to go soft. How long was it without fluid? Seals in the master could have dried up or gone bad?

[Jabeo]

Funny, I just had clutch bleeding issues too. Turned out mine was a bunged up bleed nipple. Quick shot of high pressure air sorted that guy! If you've lost fluid it does take quite some time to pump pressure in. But from what you are saying this sounds like more. Those vaccum tools are great aye? The wife loves that i dont need her now to come to the shed and pump the pedal!!

If you clamped the rubber hose before the slave properly and still couldn't build pressure it's the master. Or a leak. It doesn't have to loose much fluid to go soft. How long was it without fluid? Seals in the master could have dried up or gone bad?

Yeah so far all signs are pointing to maybe the master being the issue, maybe providing enough movement to slightly move the slave rod and move fluid but as soon as it meets pressure it just gives up and goes to the floor. Tomorrow i want to clamp the line again and just confirm that that was the case. and maybe get a master on order. Someone suggested that maybe it is just severely airlocked somewhere in the frunk but we pushed and pulled fluid all day with no improvements

The master was maybe dry for about just over a week and a half before today i would say. Maybe i over extended the master or slave and a seal just lost it or something. ill work my way from the front to the back

[Benckj]

Been in your situation before with the clutch and it’s a right pain. Short answer is there is still air trapped in slave cylinder. Only way to bleed is to apply a vacuum on hose connected to bleed nipple. Need to keep positive pressure on nipple when pumping petal regardless if your pushing or holding. This is different than brake hydraulics as clutch sort of acts like a double cylinder which is why air enters on backstroke if nipple open.

Helps to have RH side of car jacked higher to promote air movement. Keep trying as it will come back.

[Jabeo]

Been in your situation before with the clutch and it’s a right pain. Short answer is there is still air trapped in slave cylinder. Only way to bleed is to apply a vacuum on hose connected to bleed nipple. Need to keep positive pressure on nipple when pumping petal regardless if your pushing or holding. This is different than brake hydraulics as clutch sort of acts like a double cylinder which is why air enters on backstroke if nipple open.

Helps to have RH side of car jacked higher to promote air movement. Keep trying as it will come back.

Yeah I also have a feeling that an airlock might be the case, but would I not expect some pressure to build, even slightly If I had the rubber line clamped down to restrict flow into the slave ? There was no pressure at all but I am going to try a few things tonight before I start buying parts. I will go from the master to the slave, checking everything is working right

[*84vvt]

On the Clutch pedal in the car back the push rod off a little so its no pressing against the master cylinder ( free play )
then bleed as you have been doing .
if /when you get clutch feel readjust the "free play "
Iv done this a couple of times it may or may not work.

[85AW20v]

Try wrapping some thread tape around the bleed nipple thread on the slave, or even thick grease if you don't have thread tape. The threads will let air back in to the slave when you pull the clutch pedal back and that's what you're trying to stop.

I had the same issue years ago in the AW and if I remember right, I got it sorted by leaving the pedal on the floor and applying pressure to the reservoir end. It wasn't a lot - I may have even just blown into it. You won't feel much if anything change as you are not moving a large volume of fluid or air, like you do when blowing up a balloon. It's the constant low pressure that moves the fluid/airlock. Use a long piece of bleed hose off the nipple as well, tied up to above the master cylinder level.

[mickeyduck]

I had a similar problem with my AW a couple of years ago.

Turned out that the master cylinder was not pulling itself back to fill with fluid, when you lifted off the pedal. I had to sort out the return spring part of things. The reason it worked before was because the system was fully pumped up with fluid and therefore the clutch returning was actually forcing the master cylinder to return, thus making it draw fluid from the reservoir. But once you let fluid out that doesn't work anymore.

There was one other thing that went wrong in my case too. The pedal presses against a small rod that fits into the master cylinder. But there was a black plastic bush on the back of the pedal which that rod pressed against. The plastic bush fell apart and that meant a gap, so not enough oomph against the master cylinder's piston when you pushed on the pedal. I used a small nut and bolt to replace the bush. Search my Rides thread for "clutch" (using "Advanced Search" from the gear icon thing) and you'll find what I'm talking about.

[Jabeo]

So a couple of recent developments since sunday. Yesterday after work i got home and clamped down the hose to the slave pretty damn hard but could not build pressure in the pedal at all. I then tried to vacuum bleed it from a the nipple a but but no improvement showed, same issues as sunday with bubbles and a drip. I took the bleed valve off a spare old slave i have and put it in and it didnt seem to be pulling bubbles into the line when it was closed nor did it drop when slightly cracked open like the old one. Did a few cycles pulling vaccuum on the bleeder and then noticed the pedal was no longer slamming to the floor and starting to build pressure just as it reached the floor.

Kept this up for a bit and the pedal progressively got better to the point where it would build pressure about 2/3rds of the way down and would return to the top after letting go which it didnt do previously. did a few more cycles with the hand pump but the pedal didnt get better, so resorted to manual bleeding, 5-10 pumps at a time slowly, crack the nipple, close it, and pull the pedal up and repeat. We did this till no more bubbles would show themselves. all the while i could see the clutch fork and hose moving with every pump, however it would not improve, still building pressure around 2/3rds of the way down. I adjusted the pedal so that it would pressurize earlier in the stroke which felt good, but then what appears to be a cruise control switch clicks every time i depress the pedal, so i readjusted back to where it was and the pedal feel changed and the click stopped.

Do you think that air could still be present? the fork moves a decent amount when ive adjusted the pedal and feels like its doing its job and the click isnt a major concern to me cause i deleted the CC. I do also have a spare new master cylinder on hand if i need to change it but i dont want to do the job if i dont need to and risk my car not making it

[4CylinderSpecial]

Well that seems like good progress to me! Have you now tried putting it in gear with the car running? I thought that mine wasn't properly bled for a while until I adjusted the pedal - I guess it had self adjusted all the way to the floor (mine had the original 1996 clutch in it) so needed bringing up. Once I did that I could go into every gear easily.

The CC switch clicking makes sense to be higher up the pedal - you wouldn't want the CC working when you're trying to change gears

[Jabeo]

Clutch is grabbing literally as my foot begins to move back, so im doubting whether the clutch is even fully disengaging at all. Its an effort to get into gear a little bit. The master cylinder rod has also been threaded out from the pedal into the master cylinder as well. I have not yet taken the car for a proper drive yet do to a coolant leak issue, so its hard to say for sure, but im not liking my chances of the car making it to manfield after all the time and money i have put into it

[jeffsw20]

Did you find the solution? I have an SW20 clutch line I cannot bleed and I have been working on this for 3 weeks now and have pumped for hours and hours.
I have got to the point where I have continuous fluid no bubbles flowing out of the bleeder using a vacuum tool: sucking from back and drawing fluid from master cylinder but the master cylinder will just not build up any pressure. The pedal just goes to the floor!!!!!
Have undertaken the following steps:

1. disassembled master cylinder and put in new seals and filled with liquid rubber grease,
2. disassembled slave cylinder cleaned bore with 200 grit and put in original seals which appeared in good condition and filled with liquid rubber grease: [would have put in new seals if Supercheap had sent the right sized 7/8 seals instead the 13/16 they list on their website],

3. 3. kept continuous pressure on bleed valve [using Benckj method (with fluid in tube well above bled valve so no air can get sucked back in),

4. sealed bleed valve threads with seal on tape so no air can bleed back in, [grease does not work and still lets air in]

5. filled around entire slave cylinder inside with lithium grease so that no air can get sucked back into the slave cylinder by vacuum pressure. [ prior to me packing slave cylinder with grease when I sucked with vacuum tool I sucked in air through the seals in the slave. I knew this was fixed when the vacuum tool held continuous vacuum for hours and did not drop),

6. bleed each of the frunk bends by individually cracking the 3 nuts at each of master cylinder, gold block top and bottom and pumping master cylinder slowly until fluid comes out of each nut.


7. The only thing I have not tried yet is: 7. slave cylinder holds an air bubble that does not get displaced (even though the end of slave cylinder with in the region of pipes in and out is full of fluid. There is nothing to displace this air bubble inside the cylinder). The suggestion is squeeze the cylinder in fully to displace this bubble when the vacuum bleeder is on and bleeder open and you should see the air go out. (The Morris Minor slave has same problem and recommendation there is turn unbolt and turn the slave so bleed valve goes to highest point in cylinder and air escape by floating to the top).

I am out of ideas as to how to bleed this clutch and would really welcome any advice to make this clutch hydraulics function again.

[ClanFever]

Did you find the solution?

Is this a brand new clutch or are you trying to bleed a worn one? Have you tried doing it with two people with one using their foot and the other pouring in fluid and doing up the lines?