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#1 |
Registered User
Join Date: Nov 2011
Location: Lancaster PA
Posts: 23
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The case of the mysterious clutch. (71 C10)
Hi All,
This is my first post here. I recently bought a 71 C10 and just love it. I'm new to working with trucks, but I'm pretty well mechanically inclined and I want to do as much of my own work as possible. That said, I'd like to tell you all about my problem and get some feedback. In a nutshell, I think my clutch is going bad. Here is why. Basically, the clutch pedal has back pressure and feels like it's operating normally, but when I push the pedal down, the clutch itself is not engaging. If I turn the engine off, I can put it into whatever gear I want. When the engine is running, I can only put it into reverse or neutral (from whatever gear I had it in). So I guess that firstly, I'd like some confirmation that my clutch is going bad (or other suggestions) and secondly, a little help on what I'd need to do to get to the clutch to work on it/replace it if it is going bad. Thanks! Other things to note: - The guy who had it before me put in a 3 speed transmission with a hearst shifter and linkage. - I have a 1 ton hoist to pull the engine if I need to. |
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#2 |
Registered User
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,151
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Re: The case of the mysterious clutch. (71 C10)
I would adjust the clutch before I assume it is bad. Sounds to me it could be a clutch linkage issue.
__________________
'83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project |
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#3 |
The Older Generation
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Location: Montezuma, Iowa
Posts: 25,518
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Re: The case of the mysterious clutch. (71 C10)
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I guess the first thing I would do is to check the adjustment. There is an adjustable rod that goes from the clutch linkage cross shaft to the clutch fork. The end that connects to the pivot is threaded and is the adjustment for the clutch. Lengthen the rod and see if that helps. Don't get carried away with it, just go 2 or 3 turns at a time and try it. Also check the linkage under the dash. The splined shaft that rotates as the pedal is pushed could be stripped and letting the arm slip. It would move the linkage but not far enough to really do anything. LockDoc
__________________
Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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#4 |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: The case of the mysterious clutch. (71 C10)
First check the above carefully and then remove the bottom dust shield so you can observe the action from under the truck. Be sure and use parking brake and chock the truck tires.
Depressing the pedal forces the throwout bearing into the pressure plate fingers and releases or dis-engages the clutch disc. If this is not happening then more than like the pressure plate is bad or clutch disc is badly worn. If you do find you have to replace parts be sure and get both the disc and pressure plate asm and have the flywheel turned. Also be aware that new parts from local auto parts are not what they used to be and may be new defective. If you can afford it, buy from a reputable parts place that hopefully has parts made in the U.S. One more thing, make sure all of the shift linkage bushings are in place and not worn. |
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#5 | |
Registered User
Join Date: Nov 2011
Location: Lancaster PA
Posts: 23
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Re: The case of the mysterious clutch. (71 C10)
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#6 |
Florida Edition
![]() ![]() Join Date: Oct 2010
Location: Fruitland Park, FL
Posts: 4,025
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Re: The case of the mysterious clutch. (71 C10)
Welcome from Central Florida! I see you have already figured out that this forum rocks. I am an automatic kinda guy so I'll leave the manual advice to the experts, I just wanna see a picture of your truck.
__________________
70 GMC Short Stepside "Rose"-An American Beauty: Factory 402/TH400, AM/FM, AC, Tilt, Tach, Buckets, Posi, PS, PB, 3-5 Drop, Complete Resto-Rod 67 C-20 Slant Back Wrecker "Mad Max" 67 C-10 Ratrod "Step-N-Wolf" 71 Serro Scotty Sportsman camper "Scotty" 97 LT1 Z28 "The Hornet" Link to more pics of "Rose" http://67-72chevytrucks.com/vboard/a...p?albumid=1684 Check out my "Cheap Tricks" thread and add to it if you can, lots of good info there. http://67-72chevytrucks.com/vboard/s...d.php?t=489394 |
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#7 | |
Registered User
Join Date: Oct 2009
Location: Denton, Texas
Posts: 1,724
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Re: The case of the mysterious clutch. (71 C10)
Quote:
Welcome from North Texas. Keith |
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#8 |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: The case of the mysterious clutch. (71 C10)
re. LMC: I've bought stuff from them before and overall I wasn't dissatisfied. However, it was not major components. Some parts providers try to get the cheapest they can so they have them imported from Taiwan or China. I haven't done a clutch in a long time so I don't know for sure the best place to get one. These days, it seems sort of a crap shoot.
Re. buying from local auto parts: Many years ago I bought a new pressure plate from a local auto parts and it wouldn't release the clutch properly. It was a pain because you don't know how it works until you install it. I didn't want to take the chance on redoing it so I got my money back and got one from NAPA. Not sure if NAPA's quality is still the same though. Forgot to say welcome... Welcome from semi central Texas. |
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#9 |
Registered User
Join Date: Nov 2011
Location: Lancaster PA
Posts: 23
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Re: The case of the mysterious clutch. (71 C10)
So the end that I should adjust is the end connected to the "Cross shaft", or down at the other end?
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#10 | |
The Older Generation
![]() ![]() ![]() Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,518
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Re: The case of the mysterious clutch. (71 C10)
Quote:
LockDoc
__________________
Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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#11 |
Registered User
Join Date: Nov 2011
Location: Lancaster PA
Posts: 23
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Re: The case of the mysterious clutch. (71 C10)
Considering my latest update, do you think that I should keep going farther or do I have a bigger problem on my hands? I don't want to go to far like you warned.
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#12 | |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: The case of the mysterious clutch. (71 C10)
Quote:
Were you able to do any of the things I mentioned in my first post. If adjustments won't help, you need a pressure plate, clutch, throwout bearing pilot bearing and have the flywheel turned all at the same time or you won't be happy with it. Trust me. |
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#13 | |
The Older Generation
![]() ![]() ![]() Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,518
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Re: The case of the mysterious clutch. (71 C10)
Quote:
First off from what you said in your first post you need to lengthen the rod between your cross shaft and clutch fork, not shorten it. Also 1/2 inch adjustment at a time is WAY too much. Put it back where it was when you started and lengthen it 1/8 inch at a time, AND NO MORE. Then try it. LockDoc
__________________
Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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#14 |
Junior Member
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
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Re: The case of the mysterious clutch. (71 C10)
I too think it is a linkage adjustment problem. Changing the clutch on a truck with a 3 speed is not real complicated and does not require removing then engine.
It is not a two person job, but a second set of hands helps. A transmission jack is helpful but not necessary. I normally buy a clutch kit when I replace a clutch, they are not real expensive and includes every thing you need, matched. I also check the pilot bearing in the end of the crank shaft, most times I just go ahead and change it since it is part of the kit.
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'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
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#15 |
Registered User
![]() Join Date: Nov 2007
Location: Hermiston, OR
Posts: 947
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Re: The case of the mysterious clutch. (71 C10)
You can see a nut on the end of the "clutch rod", in the pic, the part sticking out beyond that is threaded and this is the adjustment.
__________________
Running in place gets you nowhere fast. -me 1968 GTO 4-spd covnvertible 1970 K-20 4-speed, factory AC. |
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#16 | |
Registered User
Join Date: Nov 2011
Location: Lancaster PA
Posts: 23
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Re: The case of the mysterious clutch. (71 C10)
Quote:
On a side note, thanks for all of the help. I'll be hanging out here quite a bit I think. Cheers! |
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#17 |
Registered User
Join Date: Nov 2011
Location: Lancaster PA
Posts: 23
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Re: The case of the mysterious clutch. (71 C10)
Update:
I tried to adjust the linkage to no avail. I threaded it down about a half an inch and nothing changed at all. That said, it's still got more space to get shortened up. But considering that this issue just abruptly started happening and nothing has changed in the half in of shortening that I've already done, would you guys think that I would be wasting my time to go under and tighten some more? Also, unrelated to this, after I had fired it up to test the clutch and then turned it off again, I noticed that antifreeze was literally streaming out of the engine. It seemed to be coming from an area directly behind the fan. It pissed antifreeze for a good 30 seconds after I shut it down until it slowed to a trickle and eventurally stopped. Any thoughts? |
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#18 | |
Registered User
Join Date: Feb 2000
Location: Center City, MN, USA
Posts: 3,254
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Re: The case of the mysterious clutch. (71 C10)
Quote:
If you end up determining that it came out of the pee tube, note the level in the radiator when everything is cold. That is the proper level for your system.
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'70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN |
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#19 | ||
"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,940
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Re: The case of the mysterious clutch. (71 C10)
Get a service manual... it will show you exactly how to do the job.
![]() Gary
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'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
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#20 |
Junior Member
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
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Re: The case of the mysterious clutch. (71 C10)
The anti-freeze coming out sounds like the water pump shaft seal.
If you are not sure of the clutch and are going to keep and drive the truck quite a bit it is not that hard or expensive to change out the clutch. I think the last kit I bought from a local parts store was right at $150. Like I said in a previous post it is best to get a kit, that way every thing is matched.
__________________
'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
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#21 |
Registered User
Join Date: Nov 2011
Location: Lancaster PA
Posts: 23
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Re: The case of the mysterious clutch. (71 C10)
So, an update for everyone. I finally got around to pulling out the clutch. I tried shortening the linkage, to no avail.
The good news is that I found the problem. Two fold really, one, the throwout bearing just fell out of the thing when I got it out and two, the springs in this picture were just bouncing around in front of the pressure plate. ![]() I have a new clutch already and will be putting it in once I get the flywheel machined down. Any tips for the process of putting it back in? |
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#22 |
Registered User
Join Date: Jul 2010
Location: Leesburg, VA
Posts: 420
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Re: The case of the mysterious clutch. (71 C10)
If you get some good tips or figure it out on your own, I'd be interested in hearing what you end up doing to get everything back together. I'm not as mechanically inclined as you are and think I'll be needing to replace my clutch soon as well.
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Curt 1970 C/10, 250 L6 with Rochester BV carb, SM465 4 speed, 3.73 open rear |
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#23 | |
Senior Member
Join Date: Jul 2010
Location: South Dakota
Posts: 4,093
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Re: The case of the mysterious clutch. (71 C10)
Quote:
Posted via Mobile Device
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1969 Chevy c20(Miss Hackjob) |
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#24 | |
Registered User
Join Date: Oct 2009
Location: Denton, Texas
Posts: 1,724
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Re: The case of the mysterious clutch. (71 C10)
Quote:
Good luck! Keith Last edited by lil hoodlum; 01-09-2012 at 08:19 PM. Reason: speling |
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#25 |
Registered User
Join Date: Nov 2011
Location: Lancaster PA
Posts: 23
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Re: The case of the mysterious clutch. (71 C10)
Oh and here is my truck, not the best shot of it, but it's all I got.
![]() And here is me! http://a6.sphotos.ak.fbcdn.net/hphot...97694780_n.jpg |
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