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Bleeding my Clutch...

Discussion in 'The Garage' started by bigredblzr, Aug 16, 2006.

  1. bigredblzr

    bigredblzr 1/2 ton status

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    So I've tried bleeding my clutch (SM465) numerous times, and it really doesn't seem to retain much pressure (pedal stays soft). I figure it must be the slave cylinder, (it looks a little damp) and I'm hoping to replace it tomorrow. I've bled it with having a friend pump, and then releasing the pressure, and I've also just done a gravity bleed. Both seem to suck equally well. So my main question, is how do you bleed your clutch? Do you just do a gravity bleed, or do you have someone help you. Does one way work better than the other? Also, to pressurize the clutch a little better, I dismounted the slave cylinder so that it could fully expand without activating the clutch fork, sealed everything back up after bleeding, and then remounted the slave cylinder. Is this a good idea, or will it pressurize the system too much, causing seals to go? Thanks!
     
  2. Bushido

    Bushido Registered Member

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    I just changed my clutch slave and master and had to bleed it with a Pheonix bleeder.Basically it pressure bleeds it from the slave and pushes the fluid out through the master.I didn't try my regular pressure bleeder because the Pheonix is easier to hook up.I tried bleeding manually but couldn't get all the air out.
     
  3. bigredblzr

    bigredblzr 1/2 ton status

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    Hmmm. I wonder if that's a common problem. Has anybody else had trouble getting all the air out of their clutch?
     
  4. bigredblzr

    bigredblzr 1/2 ton status

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    Alright, WTF!! I replaced the slave cylinder, let the system gravity bleed, and the pedal still goes all the way to the floor! Does anybody know what's going on?!
     
  5. sled_dog

    sled_dog 1 ton status

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    unbolt the slave cylinder and tilt it so the bleeder is up at the top of the slave cylinder.
     
  6. bigredblzr

    bigredblzr 1/2 ton status

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    The bleeder valve is already mounted at the top...
     
  7. bigredblzr

    bigredblzr 1/2 ton status

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    Okay, so I just tried bleeding it again. No air, only fluid bled out. however this time I was able to see the piston on the slave cylinder moving. I fired up the truck to see if it was engaging the clutch enough, but it seemed to just be pushing the fork part way. It is like there isn't enough pressure in the system to push the piston out all the way. Any ideas?
     
  8. koldsimer

    koldsimer 1/2 ton status GMOTM Winner

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    I messed with my clutch for hours... bench bled both cylinders, turned the slave at every angle possible, let it gravity bleed etc.. I finally went and bought a mityvac pump and they were perfect in 5 minutes.
     
  9. bigredblzr

    bigredblzr 1/2 ton status

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    What does a mityvac do? How much is it?
     
  10. koldsimer

    koldsimer 1/2 ton status GMOTM Winner

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    It's a power bleeder... I got it at AZ for about 30 bucks from what I remember. It's been well worth it. BTW, I bled mine from the master and had the slave bleeder open with a hose running to a bottle of fluid. Worked the first time.
     
  11. bigredblzr

    bigredblzr 1/2 ton status

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    All right, I'm gonna run down to NAPA to see what they got as far as bleeder kits. I'll try the tubing trick (that was suggested to me before, but the concept never really made sense to me) and I may even replace the master... I'll be sure to post up later.
     
  12. u2slow

    u2slow 1/2 ton status

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    My clutch bled easy. Same way I do brakes.

    I get my wife out to do the pedal-work while I crack the bleed screw and keep the reservoir topped up.

    pedal in, crack screw, close screw, release pedal... repeat.
     
  13. bigredblzr

    bigredblzr 1/2 ton status

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    Right, that's exactly the way that I learned, I've done it prolly two dozen times on various vehicles...only this time it isn't working. I really don't get it. The hydrolic system is such a simple concept: Get the air out. To you guys out there that are running SM465s with a hydroclutch, do you have boosters for them? I don't and I think that may be the problem. I've seen manuals with boosters and without boosters, so I would assume that it would work either way...
     
  14. readymix

    readymix 3/4 ton status

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    Same thing I had to do
     
  15. bigredblzr

    bigredblzr 1/2 ton status

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    How do you bleed it from the master? There isn't a bleeder valve. I got the bleeder kit and it had a pump that created a vacuum to draw fluid into a little jar like this:[​IMG]
    The only problem is that instead of sucking the brake fluid, and the air in the lines, it is sucking up air around the bleeder. I would guess that that would indicate that there is significant resistance in the hydrolic system (maybe ther is debris jamming up the lines/cylinders). So I'm gonna try to get the tube on the bleeder valve a little better and I'll give it another shot.
     
  16. bigredblzr

    bigredblzr 1/2 ton status

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    Okay, I tried it again, and I am ceratin that there are no bubbles in the line. I bled through more than a whole quart of fluid, I'm soaked in brake fluid and ready to pull the whole damn thing out and through in the towel. Any last suggestions?
     
  17. POWERMAD

    POWERMAD 1/2 ton status

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    DING DING DING we have a winner.
    Ya have to back bleed the clutch system with a Pheonix bleeder or other such set up.

    A pump on a jug of brake fluid works well too.
    Drain the system, hook the pump to the slave cylinder and pump the fluid untill the master starts to fill up.
    I use this system at work and it works every single time in just a few minutes.
     
  18. Bushido

    Bushido Registered Member

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    I'm not sure if all the models/years are the same but my master is mounted with a downward angle and the line is mounted near the bottom.The air towards the top of the master is the portion that has a hard time being removed.There is no one perfect way to bleed all hydro systems.The pheonix worked on my truck but I rarely use it at work as my vacumn bleeder is the fastest.
     
  19. diesel4me

    diesel4me 1 ton status Premium Member

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    another trick...

    I made a vacuum bleeder from a glass mayonaise jar,to bleed brakes easier when I'm alone...works great on hydro clutches too!..all you need is a long enough peice of hose to go to your engine,and a shorter one to reach the bleeder screw..solder or braze 2 peices of 3/16" brake line tube into the lid of the jar--one goes all the way to the bottom,the other only goes in about 1"..use a jar with a good seal on the lid,so no air can leak in..most food jars fit this bill..

    Fill the jar with enough brake fluid to submerge the tube that goes all the way to the bottom--hook the short tube to a manifold vacuum nipple on your engine or carb,hook the other one to the bleeder screw,and start the engine up...you can use vise grips to pinch off the vacuum supply hose as an "on - off" switch...you'll see the bubbles go into the jar (clear vinyl tubing is best,so you can see the air being removed)...

    It usually takes only a few seconds to suck all the air out of even the stubbornest brake caliper or wheel cylinder,or clutch...and you can do it all alone quite easily--best thing is its cheap to make,the vinyl tubing olny costs 5 bucks tops at Home Depot,and the glass jar can be salvaged from the rubbish!...:D
     
  20. bigredblzr

    bigredblzr 1/2 ton status

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    :eek1: Wow, that's definiteyly the most ingenious technique I've ever heard for bleeding a hydro system, but it sounds very similar to the manual pump that I was using last night. Bushido: that sounds the same as my master. Granted I mounted mine, but it is at a slight downward angle which was bothering me all this time (I thought that may be part of the problem). As I was bleeding the clutch again last night I was thinking that bleeding the system backwards by forcing fluid up through the slave would definitely be the best technique so maybe I'll try that next. Thanks for all your input guys, if you have any other ideas please let me know!
     

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