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88 f250 351w - vibration after new clutch and flywheel resurface
I have an 88 f250 and my slave cylinder went out but the clutch was still good .
I have a gravel driveway and it's cold and wet so I paid a shop but when i got it back it had a slight vibration sitting still with clutch in or out and while driving also so obviously their is a balance issue right ? the shop said it's a single mass flywheel and they had it resurfaced by napa. the clutch engagement feels great and slips or anything but this vibration can't be right . can anyone point me in a direction I might be able to point the shop? Napa messed up on the resurface? or is the it the pressure plate/clutch? any input would be appreciated. |
Welcome to the site.. A surface cut is uniform and would be less likely for harmonic issues. The pressure plate at times will have welded weights for minor correction. If an incorrect pilot bushing/bearing was installed, the clutch disc wouldn’t center correctly and would have the potential for balance issues. So would the wrong flywheel.. Pressure plate bolts are shouldered to center it to the flywheel. I’ve seen lots of standard bolts used when lost or broken which allow for some ‘shift’ off center. If you can rev the engine and feel the harmonic vibs ranging, meaning intensity changes, somethings wrong with the work done and would be up to the shop to correct. I’ve had a large amount of resurface work done over the years by our local NAPA with no issues. Parts,, there’s another story,, more so since quite a few are manufactured overseas. |
Thanks for the reply .
the shop says they are stumped and don't know what it could be . they said they did everything correctly and double checked after I let them know about the vibration . is their anyway they could have used the wrong pressure plate and clutch or could the parts be defective? |
If the vibrations weren’t there prior to the work, and now are present, they should break it back down to find the cause. I wouldn’t think the PP would be wrong. Never ran across one severely out of balance (that would have normal ops) but have had plenty with release issues/ chatter , or had peddle pressure concerns. Was it a NAPA clutch set, or ? NAPA Auto Care Center do the work? Some years ago I had a friend bring me a 60’s F series that had some vid issues. The truck was originally a 6 cyld. convertered over to a 302. The engine had a pretty horrible harmonic vib. Turned out they used the 6 flywheel on the 302 which through the engine balance off.. |
They said it was a LUK clutch kit.
the shop said they are sure they installed it correctly and the correct parts were used and he said he's sure the vibration wasn't cuased by the work they did but they are going to replace the parts and he didn't sound happy about it because he said he is sure it's not going to fix the vibration. all I know is my motor didnt vibrate like that before they replaced the clutch . it would rev up buttery smooth and low it's not, I can even bring it too high in rpm without cringing |
Are all the bolts tight/engine/tranny mounts tight? I'm guessing some of them were loosened/removed to install the clutch.
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Before I brought it back to the shop I checked everything and they were right. The engine mounts rubber were not in the best of condition but I don't think that's the cause . It deffaintly feels like a balance issue.
kind of like a bad u joint but I can feel it sitting still in neutral at idle or revving it up . the clutch works with no slipping , noise , chatter |
Did they replace pilot bearing??
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Did they replace the pilot bearing ? Some are bronze some a real bearing. If not seated correctly will bind on trans input shaft.
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They never mentioned the pilot bearing .
does it have to be replaced during this work or is it likely they didnt change it ? |
Correction .
I just looked at my receipt and they did replace the pilot bearing |
Some vehicles had an "X" mark on the flywheel that is supposed to line up with an "X" on the pressure plate assy for balance purposes. Don't know if this was on your vehicle..
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No the pilot does not have to be replaced but it keeps the input shaft on the trans lined up and the clutch lined up. It is possible the fly wheel did not seat correctly on the crankshaft. Maybe dirt or rust.
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LUK kits generally come with pressure plate, disc, T bearing and pilot.. |
Yes sir it did .
I was able to find out from the napa what the shop bought and they bought the right parts and I got my same flywheel back resurfaced . I'm wondering if the flywheel was resurface too much or too many times , would that cause it to be off balance from missing too much material and the weight was too less ? could that possibly cause a vibration? |
Generally a flywheel re surface is just a ‘skim’ cut for flatness corrections/true. Unless they removed a huge amount of material, it shouldn’t toss the balance off. Especially if the vibs are pretty substantial as you noted. And I’d guess that the NAPA person doing the machine work,, it wasn’t his first time at the party,,, and if seeing your flywheel was severely in need of deep cuts for correction ( metal on metal contact, or rivet groves etc),, would let you/them know. Sometimes flywheels will have ‘hot spots’ of ‘heat checking’, even shallow surface heat cracks. Most imperfections can be removed without any deep surface materials removed. Given your trucks vintage, the flywheel may have had a cut or two prior in its life. But normally not much material is removed. Most machinists would look at any ‘questionable’ wheel and certainly make it known to who ever dropped it off about what’s needed, or a replacement if a better bet... |
Understood.
I don't think my flywheel was bad because the clutch was still good . The slave cylinder just went bad and I figure might as well have the clutch replaced . Now I wish I didnt |
When are they going to recheck their work? The vib at idle is odd. Normally a balance issue is more harmonic. As RPM increases/decreases, the vib sensations will too. Truck idles smooth?, no running concerns? For me, I keeping going back to it was smooth when dropped off,, now, out of balance it would seem.... |
They said it will be done Friday but he said he is sure they won't find anything .
They said they checked for vacuum leaks , ignition problems and all and did not find anything and they are lost . I told him don't waste your time on that kind of stuff its directly related to the work . they said they took it apart and inspected once but this time they are going warranty the parts . it runs normal , no mis firing . I know the truck well . When I first got the truck it ran poorly with a check engine light and had some problems but now runs good . it still runs good but I'm sure their is a balance issue after the work I'm just trying to figure out what sense they can't |
Got it,, The flywheel is a storehouse of rotational energy/inertia, and does take out vibs out of the crank as does the forward harmonic balancer. Basically a store house to capture force during the power stroke, and evenly redistribute it back in the other 3 cycles. So, as a balanced unit to the specific engine, removing smaller amounts of material, ‘evenly’ around the wheel doesn’t, or shouldn’t greatly affect it’s overall function.. And if it were severely over ground, under sized, I’d doubt it would present itself at idle.. I’ve seen dual mass units that shook so bad they broke the bellhousing. Single mass,, a severe balance offset, or overly off balance, ulikely. But like I mentioned prior, a 6 wheel on a 302,, idle it wasnt noticeable, rev it up and it was like an electric football game in the cab.... |
Before they take the clutch out have them start the truck up wjth just the trans removed. If the vibration is not there it is in the trans. Could be front input shaft bearing. Can you remove slave cyl. and see if it is riding on the throw out bearing ? Some slave cyl used to have and adjustable rod. Maybe wrong slave cyl. Does clutch pedal vibrate when you put slight pressure on it? Check around where bell housing meets block see there are no gaps. I once had a truck have a glob of grease road dirt fall between and bell housing did not meet up flush and played heck with the clutch. Also dowl pins on block could have pulled part way out and not letting bell housing to seat to block. Also check input shaft splines could be hanging up on spline.
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Well it's fixed.
the shop replaced the clutch and pressure plate and the vibration is gone . either someone did something wrong and didn't notice or admit or the parts were actually bad . all I know is it's back to how it was before thanks all |
Thanks for the update.. Glad they stood behind their work. |
Me too I'm so happy to have my truck back .
the guy apologized and offered me a discount on other work but I think I'd rather work on it myself . |
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