Slave cylinder/throwout bearing advice needed. | Ford Explorer - Ford Ranger Forums - Serious Explorations
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Slave cylinder/throwout bearing advice needed.


September 29, 2010
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City, State
Year, Model & Trim Level
91 xlt
Back in April got the '91 XLT back on the road. With rebuilt M5R1 transmission, new Luk clutch, Fisher auto store master cylinder, NAPA clutch line, slave cylinder and throwout bearing and resurfaced flywheel, I was expecting too have a nice long break from clutch/transmission work. No such luck. By the end of June, I woke to find that my truck wouldn't go into gear while running. Reservoir was missing about 1/4 of it's fluid. At this point I wasn't overly concerned. I figured I hadn't completely bled the clutch line, so I proceeded to do just that. After bleeding line everything was A-Okay. That is for a couple weeks, when I woke up, fired up the explorer and repeat --- about 1/4 light on clutch fluid and clutch not disengaging while running. Added fluid, re-bled, worked like a charm ---- for a few weeks, then repeat of problem. Since then on irregular/unpredictable intervals (though increasing in frequency) I find my clutch hydraulics leaking, varying in amounts, but getting progressively worse. I did check around master and quick disconnect by wrapping with clean white clothes and waiting for leak to occur. It did, but it was at neither end of the clutch line or at master. Therefore, I deduced that my new Napa slave cylinder is the culprit. Well, like a fool and procrastinator that I am (and not wanting to drop the tranny-PITA!), I just kept adding fluid and occasionally bled when I couldn't get enough pressure for clear clutch disengagement. Well, looks like I've put off real fix for too long! I have developed a noise that can probably best be described as a whine. It's frequency coincides with RPMs which IMO points towards transmission input shaft bearing or throwout bearing. My guess and what I am going with for now is bad slave cylinder that ruined the throwout bearing. I think that the leak from the slave cylinder is probably showering my throwout bearing with hydraulic fluid, which unfortunately is not a lubricant.
A few more details to provide info for those who may supply me with a better/more likely cause for noise and/or leak. What I really mean is info so that I may get some help thru advice. I plan on dropping the transmission next Sunday and replacing the slave cylinder and throwout bearing (even if this isn't causing noise, I need to stop the hydraulic leak).
When I start the vehicle in neutral there is a very quiet chattering/vibrating type noise. When I press in the clutch (when it's working right ) the noise goes away. ( I'm thinking this is spinning throwout bearing that should have spun down, but still spinning though not coinciding to engine speed.) Then while going down the road I get a noise sort of between a hum and whine ( I've heard this noise in Rangers that are running just fine; my brothers has made this noise for years, since he bought it with no adverse affects and it has same M5R1 transmission --- My noise, though, is much louder) This noise is a little bit louder in low gears (although it may just be engine is quieter and I can't hear it as well) but it's frequency matches RPMs in all gears, it quiets noticeably or can't be heard on deceleration. ( I'm thinking sticking throwout bearing ) Yes, I did check transmission and transfer case fluid level and both are okay. Only other info I can think of that may mean something, though I don't know what, is that 1700-1800 RPMs seems to be loudest and decelerating seems to have less bearing on alleviating the noise at this engine speed. This may not be of any significance, for I haven't got it over 45 MPH since noise started and I seldom break 1800RPMs. I'm driving as gently as I can, because if it is a bearing problem as I suspect, I would like to get it fixed before it breaks down completely. Loose metal pieces, moving about in any part of engine or transmission is sure fire way to dramatically increase damage and extent/cost of repair. While in there, I will be sure to check play in input shaft, but guy that did my transmission rebuild is top notch and I doubt that a missized shim is likely or it wore out this quickly. And I will also take a peak at needle bearing - doubful, but just in case. I plan on putting in a Brute Power slave and throwout from Fisher auto parts this time. (The Napa stuff is under warranty, but I don't feel it's a good idea to put in a slave cylinder of the same make that started leaking after a couple of months.) Before replying---I can't afford Ford original. One last thing -- If anyone knows the distance from the back of the slave cylinder to the face of the throw-out bearing when disengaged/out of the box, please, please let me know. I am afraid that in spite of what Napa said and Fisher says that this distance may not be correct. Both say it is for the Explorer, but I have a fear that it may be off (maybe for ranger specs). My reason for this fear has to do with the fact that last time I redid clutch, etc. The throwout bearing that came with the clutch kit inserted in old slave cylinder didn't match original length of slave and throwout. I tried throwout bearings from Advance and Autozone that were supposed to go in my '91 and neither one was right length either; That is why I ended up with the Napa slave/throwout pair that I am about to replace.
Thanks for any help in advance,

ASIDE - You folks have been great coming through for me in the past, and I truly appreciate it. I am not a mechanic and I can't begin to tell you how much this site and everyones participation has helped me and inspired me to get in there and get my hands dirty and bruise a few knuckles. Not to mention save a few dollars. Thank you all.