Mr.Atlantis Posted October 26, 2014 Share Posted October 26, 2014 Just put a new clutch master cylinder in, and it will not regain pressure. I adjusted the rod under the pedal just so i could make it go into gear. But i shouldn't have to do that. Things ive done: - New clutch (bearings and all) - New clutch slave cylinder - New clutch master Cylinder - Bled system about 50 times. - Slightly adjusted the rod in order for it to disengage it self. It seems so simple, but this nothing like brakes, i don't care what the manual says. There has got to be some super secret method of bleeding this thing. P.S. its NOT leaking. Any advice? Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 26, 2014 Author Share Posted October 26, 2014 *2008 Outback 2.5, non-turbo Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 26, 2014 Author Share Posted October 26, 2014 Sorry, i was just reviewing my post and realized i sound like a jerk. I apologize, i am just tying to be thorough while maintaining sanity this Sunday afternoon. I'll try and use more , haha's and "lol's" next time to lighten the air. Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 26, 2014 Author Share Posted October 26, 2014 Posted twice. My mistake... I'll be checking the Clutch fork. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 26, 2014 Share Posted October 26, 2014 If the MC is adjusted too far forward the vent port in the bore may be blocked. Adjust the MC pushrod so it is pulling the pedal forward just slightly, this will ensure the MC piston is pulled all the way to the back of the bore. Crack loose the bleed screw on the slave cylinder. Unbolt the slave cylinder from the bellhousing and hold it in your hand so you can push the pushrod by hand back into the cylinder. Open the bleed screw, push the pushrod all the way in and hold it there while you close the bleed screw. Now slowly let the pushrod back out. Do this two or three times. Check/Add fluid to the MC reservoir each time to avoid pulling air back into the MC. Bolt the slave cylinder back to the bellhousing and make sure to tighten the bleed screw down snug. This is the best and quickest way I've found to bleed hydraulic clutches on most cars. It may help to stick a small piece of hose on the end of the bleeder and run the hose into a bottle to avoid making a mess. Quote Link to comment Share on other sites More sharing options...
Stevo F Posted October 27, 2014 Share Posted October 27, 2014 If the MC is adjusted too far forward the vent port in the bore may be blocked. Adjust the MC pushrod so it is pulling the pedal forward just slightly, this will ensure the MC piston is pulled all the way to the back of the bore. Crack loose the bleed screw on the slave cylinder. Unbolt the slave cylinder from the bellhousing and hold it in your hand so you can push the pushrod by hand back into the cylinder. Open the bleed screw, push the pushrod all the way in and hold it there while you close the bleed screw. Now slowly let the pushrod back out. Do this two or three times. Check/Add fluid to the MC reservoir each time to avoid pulling air back into the MC. Bolt the slave cylinder back to the bellhousing and make sure to tighten the bleed screw down snug. This is the best and quickest way I've found to bleed hydraulic clutches on most cars. It may help to stick a small piece of hose on the end of the bleeder and run the hose into a bottle to avoid making a mess. This is exactly the same problem I had on my impreza. I just loosened the master cylinder from the firewall until it was about 1/2" away from the firewall, then I was able to bleed it. Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 27, 2014 Author Share Posted October 27, 2014 If the MC is adjusted too far forward the vent port in the bore may be blocked. Adjust the MC pushrod so it is pulling the pedal forward just slightly, this will ensure the MC piston is pulled all the way to the back of the bore. Crack loose the bleed screw on the slave cylinder. Unbolt the slave cylinder from the bellhousing and hold it in your hand so you can push the pushrod by hand back into the cylinder. Open the bleed screw, push the pushrod all the way in and hold it there while you close the bleed screw. Now slowly let the pushrod back out. Do this two or three times. Check/Add fluid to the MC reservoir each time to avoid pulling air back into the MC. Bolt the slave cylinder back to the bellhousing and make sure to tighten the bleed screw down snug. This is the best and quickest way I've found to bleed hydraulic clutches on most cars. It may help to stick a small piece of hose on the end of the bleeder and run the hose into a bottle to avoid making a mess. So this method eliminates the whole 'buddy in the car, pushing pedal technique' huh? That's convenient. I'll give this a shot tonight when I get home. Thanks again! Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 27, 2014 Author Share Posted October 27, 2014 If the MC is adjusted too far forward the vent port in the bore may be blocked. Adjust the MC pushrod so it is pulling the pedal forward just slightly, this will ensure the MC piston is pulled all the way to the back of the bore. Crack loose the bleed screw on the slave cylinder. Unbolt the slave cylinder from the bellhousing and hold it in your hand so you can push the pushrod by hand back into the cylinder. Open the bleed screw, push the pushrod all the way in and hold it there while you close the bleed screw. Now slowly let the pushrod back out. Do this two or three times. Check/Add fluid to the MC reservoir each time to avoid pulling air back into the MC. Bolt the slave cylinder back to the bellhousing and make sure to tighten the bleed screw down snug. This is the best and quickest way I've found to bleed hydraulic clutches on most cars. It may help to stick a small piece of hose on the end of the bleeder and run the hose into a bottle to avoid making a mess. Just thought, did you mean crack loose the Master Cylinder while pushing on slave in hand? Just going through the scenario in my head and it seemed logical since air is going to want to travel upwards. Or did you really mean Slave Cylinder? I'll try the way you told me the first time, I just want to be sure there wasn't a typo. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted October 28, 2014 Share Posted October 28, 2014 probably still have air in them. they are a debacle to bleed, not simple. usually people replace the hose when they replace the slave cylinder too. not sure a hose would cause problems, but thought i'd mention it. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 28, 2014 Share Posted October 28, 2014 Just thought, did you mean crack loose the Master Cylinder while pushing on slave in hand? Just going through the scenario in my head and it seemed logical since air is going to want to travel upwards. Or did you really mean Slave Cylinder? I'll try the way you told me the first time, I just want to be sure there wasn't a typo.Slave cylinder. This method pushes most or all of the air and fluid in the slave cylinder out through the open bleeder on the slave while you compress the piston. The the piston sucks fresh fluid through the line and pulls any air out of the line with it. That air is then expelled when you repeat the process. 1. Open bleeder 2. Press slave cylinder pushrod IN and hold 3. Close bleeder 4. Release slave cylinder pushrod If the slave cylinder does NOT have a bleeder, its becomes a bit trickier to bleed properly. Generally you have to completely remove all of the hydraulic lines and the slave cylinder, fill the slave cylinder with fluid, point the opening upwards, attach the line loosely and pour fluid in until it trickles out around the line. Snug the line then cap the other end to keep the fluid in. Fish it all back into the car connected together and attach it to the MC. Then you can pump the slave cylinder a few times to push bubbles at the top end of the line up into the MC and hope they work their way up into the reservoir. 1 Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 28, 2014 Author Share Posted October 28, 2014 Slave cylinder. This method pushes most or all of the air and fluid in the slave cylinder out through the open bleeder on the slave while you compress the piston. The the piston sucks fresh fluid through the line and pulls any air out of the line with it. That air is then expelled when you repeat the process. 1. Open bleeder 2. Press slave cylinder pushrod IN and hold 3. Close bleeder 4. Release slave cylinder pushrod If the slave cylinder does NOT have a bleeder, its becomes a bit trickier to bleed properly. Generally you have to completely remove all of the hydraulic lines and the slave cylinder, fill the slave cylinder with fluid, point the opening upwards, attach the line loosely and pour fluid in until it trickles out around the line. Snug the line then cap the other end to keep the fluid in. Fish it all back into the car connected together and attach it to the MC. Then you can pump the slave cylinder a few times to push bubbles at the top end of the line up into the MC and hope they work their way up into the reservoir. Well, I'm home now. I'll go give this a shot. The slave does have it's own bleeder. so this shouldn't be too hard. I'll repost my results. Thanks again! Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 28, 2014 Author Share Posted October 28, 2014 I tried the bleeding trick you mentioned. No luck. No air came out either, it was just pure fluid. I repeated the process about 10 or 15 times just to be sure. Couldn't I just fabricate a pin identical to the one between the slave cylinder piston and the clutch fork, but about a 1/4" longer? It would solve my problem, though if it ever decides to pressurize anymore I suppose that would present a problem huh? There doesn't seem to be any more air in the system and I can't spot any leaks. I feel as though my only options are to adjust the pin behind the pedal to it's max or make a longer pin to push fork. Sound crazy? Has this ever been done? Quote Link to comment Share on other sites More sharing options...
Gloyale Posted October 28, 2014 Share Posted October 28, 2014 Check your clutch fork/ it may be bending. Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 28, 2014 Author Share Posted October 28, 2014 (edited) Check your clutch fork/ it may be bending. Was actually in my garage when you sent this, so I just scoped out the fork again, and no, it's not bending. The clutch fork assembly is operating as it should. However, I did notice something. I am able to depress the slave cylinder all the way with my hand (and I'm not very strong) when all bleeders are closed. I mean, I can actually get my finger between the nipple and fork and push back. Shouldn't there be more pressure in the lines preventing me from doing this? I should also mention that no matter how I adjust my clutch, even when it was working, the nipple that pushes on the fork would jiggle when not in use. I could actually hear it if I was at a stop if it was quiet enough. I would sometimes slightly press the clutch to make it stop, especially at drive-thru windows where it was most noticeable. This was the reason why I just replaced the master cylinder. I just did the slave cylinder about 3 months ago. I'm running out of options. ...I'm sure at this point, you guys must think I'm crazy. Edited October 28, 2014 by Mr.Atlantis Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 28, 2014 Share Posted October 28, 2014 However, I did notice something. I am able to depress the slave cylinder all the way with my hand (and I'm not very strong) when all bleeders are closed. I mean, I can actually get my finger between the nipple and fork and push back. Shouldn't there be more pressure in the lines preventing me from doing this? That's normal. There should be NO pressure in the hydraulic lines until you start pushing the pedal. If you are unable to press the slave cylinder pushrod back into the cylinder, that's because the vent port in the master cylinder is blocked. This would become a major problem as the fluid heats up. Brake fluid does expand a bit when it gets hot, and the expansion of the fluid would cause the slave cylinder to start pushing against the release fork, thus making the clutch start to slip. The vent port in the MC allows fluid to be released back into the MC reservoir, to avoid pressure buildup in the system. When you press the pedal, the MC piston moves over and covers the vent port, then the pressure builds and fluid is moved through the hydraulic line to the slave cylinder. By pushing the slave cylinder pushrod in, you're just forcing fluid backwards through the MC and up into the reservoir. The Slave cylinder should not apply pressure to the fork when you are not pushing on the pedal. Pressure against the fork causes the TOB to engage the pressure plate and will cause the TOB to spin constantly, which will overheat and wear out the bearing. Normally there should be some heavy grease on the end of the SC pushrod where it meets the socket on the release fork to keep it from jiggling or rattling. I still think the release fork may be to blame here. The release forks on these have roughly a 2:1 ratio. I.E: An inch of travel at the Top equates to a half inch at the Bottom. IIRC the Hydraulic clutches have a closer ratio than that since the fork is shorter in length than the old cable systems. Probably closer to 1.5:1 ratio. But you'll only see about 3/8" of travel at most at the pressure plate end of the fork, since that's all that's required to fully release the clutch. Seeing the fork flex would be difficult since less than 1/8" of flex is enough to make the difference between full release and partial release of the clutch. You can certainly can try a longer pushrod. Just don't make it so long that it bottoms the slave cylinder piston against the back of the cylinder. Did you happen to keep the old slave cylinder? You might try comparing the pushrod on that cylinder to the new one. 1 Quote Link to comment Share on other sites More sharing options...
naru Posted October 28, 2014 Share Posted October 28, 2014 Check the crankshaft endplay. What happens if you reinstall the original MC? Quote Link to comment Share on other sites More sharing options...
Gloyale Posted October 28, 2014 Share Posted October 28, 2014 Pull teh boot around the fork and shine a light down the shaft to examine the pivot. Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 29, 2014 Author Share Posted October 29, 2014 Ok, no laughing at my diagram. There are some questions embedded in the image which should be self explanatory. FairTax, When you mentioned to adjust the pin until it just slightly pulls the pedal forward, which way did you mean? (See cut-away view of 'U-bracket'). - What should the travel distance of the slave cylinder be? How far should the fork be pushed basically. I want to know so i don't over adjust it. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted October 29, 2014 Share Posted October 29, 2014 More thread inside bracket slave should travel about 3/4 inch. 1 Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 29, 2014 Share Posted October 29, 2014 (edited) The only reason I brought up adjusting the MC pushrod is to make sure the MC piston is able to return all the way to the back of the bore. If the pushrod is adjusted so there is very little thread inside the U-bracket, that could start pushing the MC piston forward, which could cause it block the vent port in the MC. There's almost no way you'll get it to bleed properly if the vent port is blocked. As for pedal free-play, there is no adjustment. The pushrod adjusts pedal height, which will change the pedal height at the release point of the clutch. If you adjust the pushrod to its longest point (least amount of thread in the u-bracket. This will raise the standing height of the pedal) this will allow more pedal TRAVEL, which will in turn increase slave cylinder travel by a small amount, but adjusting this too far can cause the vent port in the MC to be blocked. There is no adjustment on the slave cylinder that I'm aware of. Like Gloyale said, the slave cylinder pushrod should extend roughly 3/4" when the pedal is pushed down. If you have at least that much travel at the slave cylinder, the problem is not a hydraulic issue. Edited October 29, 2014 by Fairtax4me Quote Link to comment Share on other sites More sharing options...
Mr.Atlantis Posted October 29, 2014 Author Share Posted October 29, 2014 (edited) More thread inside bracket slave should travel about 3/4 inch. The only reason I brought up adjusting the MC pushrod is to make sure the MC piston is able to return all the way to the back of the bore. If the pushrod is adjusted so there is very little thread inside the U-bracket, that could start pushing the MC piston forward, which could cause it block the vent port in the MC. There's almost no way you'll get it to bleed properly if the vent port is blocked. As for pedal free-play, there is no adjustment. The pushrod adjusts pedal height, which will change the pedal height at the release point of the clutch. If you adjust the pushrod to its longest point (least amount of thread in the u-bracket. This will raise the standing height of the pedal) this will allow more pedal TRAVEL, which will in turn increase slave cylinder travel by a small amount, but adjusting this too far can cause the vent port in the MC to be blocked. There is no adjustment on the slave cylinder that I'm aware of. Like Gloyale said, the slave cylinder pushrod should extend roughly 3/4" when the pedal is pushed down. If you have at least that much travel at the slave cylinder, the problem is not a hydraulic issue. I re-adjusted the pin so to be sure that when the pedal is relaxed, the MC is operating as it should. I'll be re-bleeding tonight when I get home to rule out any previous adjustment errors. I appreciate all the help you've given me thus far guys. Hopefully I can return the favor one day. Edited October 29, 2014 by Mr.Atlantis Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.