Jim Yergin Posted August 18, 2011 Report Posted August 18, 2011 Occasionally, after it gets hot, my clutch will slip slightly when starting from rest or pulling up a steep hill. Once on level ground or just cruising along it is fine. The next day, when I first start out there is no problem. Only occurs after it has been used for a while. It does not have many miles on the disc, pressure plate, or throw-out bearing though the disc was NOS so who knows how old it is. When I installed my rebuilt o/d transmission a couple of weeks ago, I removed the clutch assembly. It appeared OK and I did not find any oil or other contamination. Is this just a case of a clutch that is wearing out and needs to be replaced? Could it be an adjustment issue? Any thoughts would be appreciated. Jim Yergin Quote
Niel Hoback Posted August 18, 2011 Report Posted August 18, 2011 My guess would be that it is adjusted at the very top of its limit. You might try lengthening the rod just a turn or two to see if that helps. Also, it doesn't cost anything and you can put it back where it was if you don't like it. Quote
Don Coatney Posted August 18, 2011 Report Posted August 18, 2011 How or why do you suspect it is slipping? What are the signs? Quote
Dodgeb4ya Posted August 19, 2011 Report Posted August 19, 2011 Shorten the clutch lever push rod to obtain 3/4"-1" of clutch pedal free play, if there is no free play at the pedal. If it still slips you have a bad clutch disc-too thin/ oil contaminated or a weak clutch pressure plate assembly. Bob Quote
Niel Hoback Posted August 19, 2011 Report Posted August 19, 2011 Indeed, I did type before thinking. You should shorten the pushrod, not lengthen it! Thanks for catching me. I spent a lot of time today putting valve spring keepers on and I am now somewhat insane. Quote
Jim Yergin Posted August 19, 2011 Author Report Posted August 19, 2011 Thanks for the suggestions. I will try the adjustment and see what happens. I take it the idea is that the clutch pedal travel tolerance is so close on my car right now that the heat expansion pushes it out of tolerance and prevents the clutch from fully engaging. Don, when it slips, stepping on the gas does not result in increased speed or increased pull up a hill. Jim Yergin Quote
Don Coatney Posted August 19, 2011 Report Posted August 19, 2011 Don, when it slips, stepping on the gas does not result in increased speed or increased pull up a hill.Jim Yergin Any smell? Any smoke? Quote
Jim Yergin Posted August 19, 2011 Author Report Posted August 19, 2011 Any smell? Any smoke? No and no. Jim Yergin Quote
Niel Hoback Posted August 19, 2011 Report Posted August 19, 2011 No smell, no smoke and engine speed not running away when its pulling says to me that the clutch is not slipping. Quote
Don Coatney Posted August 19, 2011 Report Posted August 19, 2011 No smell, no smoke and engine speed not running away when its pulling says to me that the clutch is not slipping. My thought too. When I have had a slipping clutch the smell hits first and the smoke second. Even when you feather the foot feed there is no hiding the smell and smoke. Quote
Joe Flanagan Posted August 19, 2011 Report Posted August 19, 2011 In addition to the smell, my experience with slipping clutches is that the engine will rev like crazy. Quote
Don Coatney Posted August 19, 2011 Report Posted August 19, 2011 In addition to the smell, my experience with slipping clutches is that the engine will rev like crazy. Good point that I should have mentioned. Jim has a tachometer and would notice the rapid change in RPM's quickly. I think this might be a horse power issue. On a really steep hill when I am in overdrive I can floor it but my speed will not increase unless I downshift. Quote
bamfordsgarage Posted August 20, 2011 Report Posted August 20, 2011 Jim, I had a similar situation to yours two weeks ago with my D25... A relatively warm day, drove to Mom's in the AM and when I left after lunch, I could feel the clutch slipping with the gas floored in third — uphill of course, and even on the level. The feel and sound of climbing engine revs (+500-1,000) was confirmed by my tach but my road speed was basically unchanged. There was no smell nor smoke. And although the weather was pretty warm, I've never noticed any slipping on other, even warmer days. There was no noticeable slipping the next day or since, so I haven't pursued it any further. Just another item on the list when I rebuild the engine this winter. Quote
P-12 Tommy Posted August 20, 2011 Report Posted August 20, 2011 A couple of months ago I had mentioned the clutch was engaging funny. It started slipping a little bit and I shortened the clutch rod and got my 1 inch of freeplay back. It hasn't slipped since. There was also no smell or smoke. Tom Quote
Jim Yergin Posted August 20, 2011 Author Report Posted August 20, 2011 Chris and Tom, Thank you for confirming what I described. I knew I was not imagining it. Jim Yergin Quote
James_Douglas Posted August 20, 2011 Report Posted August 20, 2011 Chris and Tom, Thank you for confirming what I described. I knew I was not imagining it. Jim Yergin I had a clutch slip after a fluid drive seal failure. I could not see or feel any oil on the clutch. I changed it and nothing else and it stopped...my guess is that some fluid vapor misted back onto the clutch. The other thing to keep in mind is that buried in the literature on the pressure plates is information that they used several different sets of spring pressure depending on the engine HP and or weight of the car. On my 5000 pound suburban, I increased the spring pressure when we rebuilt the pressure plate because of the weight of the car. The leg pressure on the clutch was just a hint more, but it is worth it as extra security to help keep the clutch from slipping. Good luck, James Quote
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