03-14-2016, 06:54 AM | #1 |
Registered User
Join Date: Jul 2013
Location: Nova Scotia
Posts: 27
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Weird "bucking" issue
I'm starting to have an intermittent (although more frequent) "bucking" issue with my 1980 C10. (250 straight six, three on the tree). Initially when I start driving it drives very smooth and normal. Sometimes after 5-10 minutes I start getting a relatively major shaking/shimmy through what feels like the drive line. (When I engage the clutch and rev the engine engine is smooth and sounds normal, although shaking continues).
The shaking inceases and decreases with associated speed changes. Usually I pull over for a minute (leaving the truck running), then the problem almost always fixes itself. Sometimes it is fine for the remainder of the drive, sometimes the issue starts again in a few minutes. I just had the clutch replaced in the fall, and had the flywheel machined at that time. The only issue I can see currently with the truck is a small hole in the exhaust pipe (about the size of a dime) just in front of the muffler (have to get that fixed up soon). Although I doubt that would cause such an issue, but I'm not sure. All wheel weights are still on the wheels (although I don't see how a wheel weight flying off would cause an intermittent issue). Any thoughts? |
03-14-2016, 08:17 AM | #2 |
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Join Date: Aug 2011
Location: Rockport, Tx.
Posts: 79
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Re: Weird "bucking" issue
Was the throw-out bearing replaced when the clutch was replaced?
How much free play do you have before the clutch engages? The shaking with the clutch engaged indicates clutch/bearing issues (to me)----good luck! |
03-14-2016, 08:42 AM | #3 |
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Join Date: Jul 2013
Location: Nova Scotia
Posts: 27
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Re: Weird "bucking" issue
The throw out bearing was replaced
I meant to say "disengage the clutch" and rev the engine. Engine runs smooth even with the clutch disengaged, but shaking persists. |
03-14-2016, 09:07 AM | #4 |
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Join Date: Aug 2009
Location: Bowser
Posts: 13,731
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Re: Weird "bucking" issue
Sounds like your heat riser is stuck or not working and you have a cold intake plenum.
How long do you let it warm up before you drive away? |
03-14-2016, 11:55 AM | #5 |
Registered User
Join Date: Jul 2013
Location: Nova Scotia
Posts: 27
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Re: Weird "bucking" issue
I usually let it warm up for 2-5 minutes. Basically once it no longer would stall without giving it a bit of gas.
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03-14-2016, 12:19 PM | #6 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,731
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Re: Weird "bucking" issue
Is your motor all stock?
Is it an integral head motor? After you stop and sit a bit and it fixes itself, does it run much better after that with no bucking sensation? |
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