ff6cav Posted August 7, 2015 Share Posted August 7, 2015 I'm looking for somebody to point me in the right direction/give some advice for trying to adjust the clutch on my C85. It's just started occasionally slipping while under load in 4th and 5th gear, and I'm hoping an adjustment will help, as opposed to replacing/rebuilding. I looked over the manual for the truck, but had some trouble wrapping my head around what it was saying; maybe because that was before my daily cups of coffee? Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/ Share on other sites More sharing options...
gearhead204 Posted August 8, 2015 Share Posted August 8, 2015 is it a single ot 2 disc clutch? also is it a push or pull style? if you post the manual info i'm sure we can help! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-299365 Share on other sites More sharing options...
ff6cav Posted August 16, 2015 Author Share Posted August 16, 2015 It's a single plate, push type. Here's a pic from my manual, I'll also try to get a pic of the actual truck in the next day or 2 to compare Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-300355 Share on other sites More sharing options...
ff6cav Posted August 19, 2015 Author Share Posted August 19, 2015 Here's the shots I could get of the transmission:Also, any thoughts on what the yellow thing is? It appears to me to be a switch of some kind going from the transmission to the pump panel Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-300673 Share on other sites More sharing options...
1958 F.W.D. Posted August 20, 2015 Share Posted August 20, 2015 Switch is probably the (waterous) pump-in-drive indicator. Is there a green light next to the vernier throttle on your pump panel that says "When light is on ok to advance throttle" or "Light indicates pump in drive" or something along those lines....? 1 Quote TWO STROKES ARE FOR GARDEN TOOLS Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-300741 Share on other sites More sharing options...
j hancock Posted August 20, 2015 Share Posted August 20, 2015 Have you had a chance to look inside to see what sort of gap you have right now? Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-300819 Share on other sites More sharing options...
Freightrain Posted August 20, 2015 Share Posted August 20, 2015 How much freeplay in the pedal? Does the clutch engage at the top of the travel? Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-300825 Share on other sites More sharing options...
ff6cav Posted August 20, 2015 Author Share Posted August 20, 2015 Have you had a chance to look inside to see what sort of gap you have right now?I haven't gotten that far into it quite yet, will hopefully be able to look into it in the next few daysHow much freeplay in the pedal? Does the clutch engage at the top of the travel?I haven't paid all too close attention to that, but now that you mention it, it does seem to be more towards the top when it engages. The thing I've noticed is, when I first bought it back in February, there was no slippage at all, and the more I've driven it, it seems to have developed- could it be that the linkage has worked itself loose from lack of use, and now being used more since I bought it? Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-300830 Share on other sites More sharing options...
ff6cav Posted August 28, 2015 Author Share Posted August 28, 2015 Here's a pic I took of the back side of the clutch. Any thoughts on where I should start with attempting an adjustment? I'm still somewhat lost in trying to understand the manual Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-301822 Share on other sites More sharing options...
41chevy Posted August 28, 2015 Share Posted August 28, 2015 Looks like a lot of oil. None on the disk is there? Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-301823 Share on other sites More sharing options...
ff6cav Posted August 28, 2015 Author Share Posted August 28, 2015 Looks like a lot of oil. None on the disk is there? I haven't gotten to delve into it that far quite yet, but that's going to be the first thing I check once I can Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-301826 Share on other sites More sharing options...
1958 F.W.D. Posted August 29, 2015 Share Posted August 29, 2015 Yeah.....Lotta oil in there. Keep the thought of a blown rear main seal in the back of your mind. Check the pad thickness- if it's pretty worn, between that and the oil, you can adjust that thing all you want but it'll keep slipping, You may have to drop the clutch and send it out for a rebuild. Aaaaaand since you have the tranny and clutch down, you may as well drop the pan and roll a new rear main seal in there. If you do wind up dropping the clutch and tranny, don't forget to check the flywheel surface and get that machined if necessary. Quote TWO STROKES ARE FOR GARDEN TOOLS Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-301849 Share on other sites More sharing options...
ff6cav Posted August 29, 2015 Author Share Posted August 29, 2015 After investigating things a little more today, I think I've narrowed down the problem. There appears to be oil leaking from behind the fuel pump, where it connects to the side of the engine, which extends back along the side and underside of the engine and transmission. The closer to the fuel pump you get, the more fresh and thick the oil is. The rig had sat without being run for about a year before I bought it, so my best guess (and based on you guys' suggestions) is that the gasket between the fuel pump and engine went bad, and the more I drove it, the more oil pushed out and began getting into the clutch, eventually causing the slippage. My question now is, how should I go about trying to clean the oil off the parts in the clutch? Thoughts/suggestions? Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-301945 Share on other sites More sharing options...
41chevy Posted August 29, 2015 Share Posted August 29, 2015 Generally once the clutch has oil contamination it's toast. Slipping generates heat and can cause problems with flywheel and pressure plate surfaces. You can remove it and "try" to cook it out with a torch (rarely really works more than 50% of the time), clean and scuff the flywheel and pressure plate. I'd fix the leak(s) rebuild the clutch assembly, check the rear seal on G.P. and start fresh. Less trouble in the long run and less labor in the end. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-301948 Share on other sites More sharing options...
fxfymn Posted August 30, 2015 Share Posted August 30, 2015 I agree; once it is oil coated it is pretty hard to get the clutch disc to work correctly again. But, you could try the obvious since the adage of "nothing to lose by trying" applies here. Use brake cleaner very liberally and let it run off, spin the engine a 1/4 turn and do it again, when it is as clean as you can get it do it again while the clutch pedal is depressed. Spin the engine a 1/4 turn, spray again, etc. I doubt it will work, but it is a lot easier and cheaper than pulling the engine or tranny to re-build the clutch. If it comes down to a re-build I would seriously consider pulling the engine in lieu of removing the tranny so you can replace all of the oil sealing gaskets and properly clean and paint it. It will take a serious lift, so you may want to get a shop to do it if you don't have a big hoist or fork truck.Good luck. Quote Money, sex, and fire; everybody thinks everyone else is getting more than they are! Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-301999 Share on other sites More sharing options...
dek1581 Posted August 30, 2015 Share Posted August 30, 2015 hey fx, I'm with you on the brake cleaner try. I have gotten grease on the rotors (and pads as a result) from lubing the ball joints and if it worked for brake pads maybe if the clutch is made from a similar material what have you got to lose? Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-302019 Share on other sites More sharing options...
ff6cav Posted August 31, 2015 Author Share Posted August 31, 2015 ...But, you could try the obvious since the adage of "nothing to lose by trying" applies here... If it comes down to a re-build I would seriously consider pulling the engine in lieu of removing the tranny so you can replace all of the oil sealing gaskets and properly clean and paint it. It will take a serious lift, so you may want to get a shop to do it if you don't have a big hoist or fork truck.Good luck.hey fx, I'm with you on the brake cleaner try. I have gotten grease on the rotors (and pads as a result) from lubing the ball joints and if it worked for brake pads maybe if the clutch is made from a similar material what have you got to lose?That's pretty much my theory right now- might as well try brake cleaner, the worst that can happen is that it doesn't do anything or does something bad to the clutch, which would need rebuilt either way. If it doesn't work, I'm going to just keep everything together to get me to 1 or 2 more musters this year, and do the heavy work over the winter. Thanks for the advice and input so far! Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-302107 Share on other sites More sharing options...
41chevy Posted August 31, 2015 Share Posted August 31, 2015 Do it with the clutch disengaged so you can get the surfaces. Good Luck with it post how it comes out. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-302119 Share on other sites More sharing options...
fxfymn Posted September 1, 2015 Share Posted September 1, 2015 Do it with the clutch disengaged so you can get the surfaces. Good Luck with it post how it comes outI agree, but get as much off as possible with the clutch engaged before you disengage it. I would prop a piece of wood between the seat and the pedal to hold it down while you spray it. Quote Money, sex, and fire; everybody thinks everyone else is getting more than they are! Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-302264 Share on other sites More sharing options...
ff6cav Posted September 4, 2015 Author Share Posted September 4, 2015 I just want to confirm before I try the brake cleaner- would the circled area here be the best place to spray it in? Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-302558 Share on other sites More sharing options...
j hancock Posted September 4, 2015 Share Posted September 4, 2015 Yup, spray away. Spray from the bottom also.Try to find a rubber hose that will fit the plastic stray that comes with the brake clean which will make it easier to direct the spray around while keeping the can upright. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-302563 Share on other sites More sharing options...
ff6cav Posted September 4, 2015 Author Share Posted September 4, 2015 Yup, spray away. Spray from the bottom also.Try to find a rubber hose that will fit the plastic stray that comes with the brake clean which will make it easier to direct the spray around while keeping the can upright.Great, thanks! I'm working all weekend, but will give it a shot on tuesday Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-302564 Share on other sites More sharing options...
fergusonsystem Posted September 5, 2015 Share Posted September 5, 2015 Another trick to take out the oil is baby powder, used that on plenty of old CAT dozer clutches,get a big jug of baby powder and have at it Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-302691 Share on other sites More sharing options...
ff6cav Posted November 22, 2015 Author Share Posted November 22, 2015 Quick update: I've tried the baby powder idea, dumping it in the top opening with the clutch disengaged, and it doesn't seem to have done anything to help. I feel that the baby powder isn't getting to the actual clutch face; I may try more brake cleaner when I get a chance. I've pretty well adapted my driving to compensate for the slippage, but it gets pretty slow on long upward grades. Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-312521 Share on other sites More sharing options...
Swishy Posted November 22, 2015 Share Posted November 22, 2015 http://www.bigmacktrucks.com/index.php?/tutorials/article/43-spicer-clutch-adjustment-for-mack-trucks/ Quote Link to comment https://www.bigmacktrucks.com/topic/41274-clutch-adjustment/#findComment-312524 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.