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Clutch bleeding: Motive bleeder or "petal pushing"


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Which method is better?

I ask because I recently bought a Motive bleeder to do my brakes & clutch. As luck would have it, it arrived with a cracked gauge glass (no consequence) and was missing a sealing gasket at the filler mouth. Until I figured out why it wouldn't build pressure and made a temporary fix with teflon tape, I had great difficulty getting the job done. By the time it was done, I had used the full amount of new fluid through the brakes and had a full-to-the-rim resevoir.

Rather than continue with the defective Motive unit, I followed the info here and bled the clutch by "petal-pushing", until my resevior level had dropped midway between min & max level. I had to quit here even though it did NOT bleed enough to see the color change to the ATE super blue I had added. However during the bleeding process I never saw evidence of released air from the older fluid in the line, so I didn't sweat it much.

The car performed flawlessly with a noticeable difference in petal feel from both the clutch & brakes. However, today (a week or so after the job) my clutch petal has "hung up" and failed to fully return twice. Pumping it or gently pulling it up corrects the problem with no major incident. Still, this can't be good.......

I felt confident about the job I did, but hey, I'm human and could have introduced air in there at some point of struggling with the defective Motive or my pedal-pushing. Would you suspect a simple "air in the line" issue, or am I unaware of another common weakness in the system that could be the culprit (like a failing master or slave cylinder).

Lastly, I would like to commend Motive for immediately answering my concern about the defective unit and sending me the missing sealing ring. I only wish I had tested the unit prior to opening the super blue!

Thanks in advance-

Andrew

PS: Problem is on a 2000 C2 cabriolet.

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Did you follow my procedure in the DIY section? You MUST bleed the clutch with the pedal all the way to the floor (and held there during the bleeding process). Then manually (and slowly) pull the pedal back up.

It sounds like you have air in the system and will need to re-bleed the clutch.

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Did you follow my procedure in the DIY section? You MUST bleed the clutch with the pedal all the way to the floor (and held there during the bleeding process). Then manually (and slowly) pull the pedal back up.

It sounds like you have air in the system and will need to re-bleed the clutch.

Yes, I was pumping the petal by hand several times then I wegded a cut length of 2x4 between the bottomed out pedal and drivers seat to hold it down while opening the valve to bleed. Then close the valve, pull up gently on the petal, repeat......

Tomorrow I'll give it another shot with what fluid I can spare before hitting the "min" mark on the resevior. I dont have another can of Super Blue around, nor do I know a non-mailorder source to get some immediately. I hate to introduce something substandard from the local automart to only have to flush it back out later.

But, I'll inquire again: which method might be preferable.......Motive or petal pump?

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The Boxster shop manual also says to pressure bleed the clutch with the pedal to the floor. But I have never done it this way. Perhaps you need the pedal to the floor if the master cylinder has been replaced, but if you are just flushing new fluid it is not necessary.

When you did the pedal pumping method did you have a helper to open and close the bleed nipple? If not you may have sucked in air like Loren says.

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The Boxster shop manual also says to pressure bleed the clutch with the pedal to the floor.  But I have never done it this way.  Perhaps you need the pedal to the floor if the master cylinder has been replaced, but if you are just flushing new fluid it is not necessary.

When you did the pedal pumping method did you have a helper to open and close the bleed nipple?  If not you may have sucked in air like Loren says.

No I did it all myself; helpers generally prove to be more of a distraction than a help. But as I mentioned before the petal was firmly held down by a 2x4 while I opened & closed the valve.

Furthermore, I rigged up a nifty collection device for collecting my old fluid. I took an empty 2 liter soda bottle, drilled a hole in the cap, fit a tight rubber grommet and then ran my vinyl tubing into that. When conecting my collection bottle to each nipple, I'd squeeze the bottle to get air out before connecting and create a minor vacuum to reduce the likelihood of air from being drawn back into the nipple when the fluid stopped coming out and I was closing the valve. When I used it on the brakes, it was easy to see the vacuum effect still at work when my leaky Motive had losts its positive pressure, but the collection bottle with its minor vaccuum was still drawing a slight flow of fluid as I closed each nipple.

I really thought I had crafted the perfect DIY proceedure, but as I admitted before, I'm human..........I do make mistakes. I'll attempt a second bleed tomorrow with what fluid can be spared before it gets down to the "min" mark. I'll also enlist a helper to do the pedal work, to eliminate the possibility my 2x4 rig allowed some pedal play.

It sounds like the pedal pushing method is more commonly used / suggested, so I'll stick with that, but the Motive would be SOOOOOO much easier, unless there is some reason the clutch master /slave cylinder system isn't as tolerant to its use like the brake system is. It is the same principle and the fluid is drawn off the same resevior; in theory the Motive should be just as good for clutch bleeding as it is for brakes.

Correct me if I'm wrong.

Thanks for the help thus far-

Andrew

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All I can add is that I have used the Motive several times to flush the fluid on Boxsters and never had an issue. Before I had the Motive and worked on other cars by myself I would do the same as you. I had a short broomstick handle and would wedge it between the seat and clutch pedal so that the pedal was down. Open and then close bleed nipple. Let pedal up. Repeat. Sounds like what you did.

I have asked Peter before if there is anything special about bleeding the Boxster brakes and clutch and he said no - you can do it the old fashioned way.

You have a mystery. More so since you said it was fine for a week. If you sucked air into the system then you would know it the minute you first depressed the clutch pedal.

Ray_brake_004.jpg

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I forgot to mention my $2 power bleeder before I bought the Motive. :o

I bought a cap and drilled a hole in it and put in a wheel valve stem. Attached my air chuck with the regulator set to 20 psi and bled away on the brakes and clutch. Hard to haul a 100 pound air compressor around in the Boxster to our work on cars days so I finally bought the Motive bug sprayer.

brake_bleeder1.jpg

cap6.jpg

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I forgot to mention my $2 power bleeder before I bought the Motive. :o

I bought a cap and drilled a hole in it and put in a wheel valve stem.  Attached my air chuck with the regulator set to 20 psi and bled away on the brakes and clutch.  Hard to haul a 100 pound air compressor around in the Boxster to our work on cars days so I finally bought the Motive bug sprayer.

brake_bleeder1.jpg

cap6.jpg

I know a BMW owner (not to pick on BMWs) who built the same thing.

First, he mocked me for ordering a Motive bleeder, but I suspect it was mostly because he is too cheap to spend 40 bucks on a simple tool.

Later he confessed how he ran the resevior dry during one of his bleeds and had to do the job all over again.

At least with the Motive, you don't have to continually monitor the cars reservior. Also, the more times you have to open & close that cap or pour fluid, the greater the likelihood of an accidential splash on the paint. I can't see how anybody would use another method, and $40 bucks for the tool is far cheaper than having any mechanic perform the service.

My project for today will be to redo the clutch. It concerns me too that the problem appeared after several hundred miles of backroads driving. If it persists, it can become the dealers problem............although they will automaticly fault me since I did a recent bleed service. I can hear it now........."Gee Mr. Lawton, your warranty doesn't cover failures due to you performing your own maintenance". My reply wouldn't be fit for posting on this board..........

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I re-bled the clutch using the pedal method and my wife as a helper to ensure the pedal stayed firmly to the floor. I could see some air released with the first bleed; the next two bleeds were all fluid.

We went out to lunch later and I thought I felt it hang up ever so slightly one time. I was suspicious whether I was that worried about it (and imagined the problem) or it really happened.

Upon returning home, I discovered fluid running down the gearbox and the nipple had spit off the rubber bleeder cap. Bad news.......

To troubleshoot it further, I cleaned up all traces of leaked fluid, then hooked up the Motive bleeder and put 15psi on the reservior. I first waited about 15 minutes to verify it held pressure, which it did. I crawled back under the car and found more leakage. I wiped it off again and laid there a good 5 minutes until a I saw a drop flow through the nipple. The nipple is leaking somehow. I'm confident I have it closed plenty tight.......manhandling further might strip the threads.

At least I know the source of the problem. Now the challenge is going to be explaining to the dealer that I expect them to warranty the leaking nipple regardless of the fact I had recently performed my own brake & clutch fluid service. They seem to have the mentality that owners are clueless and shouldnt perform any of their own maintenance.

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Sounds to me you have not closed the bleed nipple tight enough?  It is a pain to get a wrench in there on a Boxster and I doubt if it is much more fun on a 996.  Sometimes I will use a socket rather than an open or closed end wrench.

I wish it were that simple........

Actually theres a fair amount of room to work with and i really feel I've gone as tight as I dare. The last thing I want is to strip somrthing. That something would more likely be the aluminum housing, not the steel nipple.

I think theres a bad o ring or peice of trash in there.

I still have warranty coverage and a laundry list of other items to be looked into, so I'm going to let the dealership take it from here (provided they don't give me a bunch of hassle about it). At least I can save them the time to troubleshoot the clutch failure.

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I got my hands on another can of super blue and decided to give it one more try.

I removed the bleeder, cleaned & checked its condition, q-tipped the recess it sits in & pushed a 1/4 can of fluid through the open hole, all in an effort to dislodge and flush anything that might be interfering with the bleeder seal. Once reassembled, I bled it even more with another 1/4 can.

It still leaked...........I did it all over again............it still leaked. All told, another liter of Super blue through the car and straight to the collection jug.

Although I've been totally confident in my ability to properly tighten the bleeder (without stripping it), i took it one step further and linked a second combination wrench to my 11mm, and went just a touch tighter with the increased leverage.

Still leaks..........

I give up. I had my wife follow me to the dealership to drop it off last night. Hopefully it isn't due to damage i've caused by bleeding my clutch; I consider myself above-average in mechanical competance, but who knows?

In a perfect world, there would be a TSB out that suggests replacement with a different valve..........maybe something with a Viton tip. I was somewhat surprised to see these things seal metal-to-metal, no o-rings or Viton tips.

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