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11/12" clutch question

JoeliusZ28

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Can anyone tell me if a 12" clutch is a direct fit to a 84 K10 with a 305? Ive got an 11" clutch in it right now and need to replace the throwout bearing so im thinking about doing the clutch while im in there. Also any recommendations on a good clutch / good quality throwout bearing?

Also does anyone know if a 12" clutch have a stiffer pedal than an 11"? That would be reason enough for me to just stick with an 11".

Thanks!
 
You'll have no problem with the clutch as long as it's diaphragm style (multiple fingers for the bearing to depress). The three fingers (borg and beck I think they are called) are terrible when it comes to clutch feel and effort.I don't even try to figure out the 10/11/12" ridiculousness on clutches. Trucks need big clutches, 12" or nothing. That simple. (The trucks with the wimpy manual trans that were very uncommon might have gotten smaller flywheels, but I'm sure those would be 153 teeth)

I *personally* would hold off on replacing a clutch if you are just replacing the throwout bearing, unless you get in there and find out it's jacked up.

If the clutch is bad, you are going to need/want a new pressure plate and flywheel as well, it would be pointless IMO to put a good clutch plate up against a scored flywheel and old pressure plate.

My experience with the clutch I just bought, clutch manufacturers are going to require evidence of a new flywheel in any case to cover warranty.
 
Ok, so you believe I have the 168 tooth flywheel then? The main reason I want to replace it is it chatters ever since I spilled oil on the clutch disc the last time i had it apart despite my best efforts to clean it. I plan on resurfacing the flywheel and doing an entire clutch kit and even a new bearing retainer. I don't want it coming apart again anytime soon, especially if the total cost of everything isnt much more than $200
 
check rockauto prices . I just got a luk for a gmc 7000 dump truck for around 160ish . that clutch is to big for you tho so don't try it .

and chatter = burnt spots = turn flywheel yes . plan on 50-90 bucks for the average rate .
 
wow rock auto is cheap. So for LUK clutches i see an 11", a 12", and a 12" heavy duty. What would the difference be between the 12 and 12 HD? I don't mind upgrading, but i don't want to make my clutch pedal any stiffer than it already is.
 
Probably best to look up the manufacturers info on that part to determine. Pics could be incorrect.

If it's just stock use with light towing, I'd say any 12" would be correct, HD not needed.

FWIW, new flywheels are almost or as cheap as having originals turned. You could order all the parts before you even tore yours down if you go that route.
 
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Rock auto is super cheap but watch the shipping. They aren't too bad but if parts come from multiple warehouses you get multiple shipping charges. The charges will be reasonable. I just ordered a 12" luk with EVERYTHING else, fork, slave, lines, flywheel, pivot ball and bolts from Amazon for $250 delivered. You need to have part numbers to search Amazon with any success, get them off rock auto.
 
Well I ordered the 12" LUK off amazon (which i found according to summit is actually 11 3/4", the HD is a true 12"). Only $90! A shop down the street from me can turn the flywheel for $45 so I'm going to go that route for the savings and not having to scrap the old one. I was tempted to order a brand new one for the exact reasons you said though!
 
The Luk flywheel was $59 shipped if yours won't clean up. Looks like we both get to pull a tranny. It's going to be so much fun!
 
I'd like someone to comment on how much "cleaning up" can be done on the flywheels. I think I have my old one around somewhere still, there are plenty of cracks on the surface, to me that seemed too much to just turn...but I have no idea how much needs removed to get rid of small cracks.

Both it and the clutch worked fine, but it makes a lot of sense to replace them when you swap engines I figured. I think this was a Sachs clutch, ran it for 16 years or so. Smoked it a couple of times on accident, kept chugging along. Figured I might replace it with the same since it did so well, but I couldn't find them on Rockauto, and decided to support a local parts place instead.

Getting sick of Rockautos multiple warehouse shenanigans. Last I tried to order from them (couple weeks back) noticed that two specific things in my cart were in the same warehouse, and multiple other items were in various other warehouses. But when I dropped other items from the cart, the two that were in the same warehouse magically stopped being in the same warehouse. Sad, their prices are great, but apparently that is true only because they make it up on the shipping.

Summit may ship from different warehouses, but my order a week ago had one shipping charge, that did not double even though both items were in different warehouses.
 
I don't know the measurements / scientifics of it, but I've always heard that "most" flywheels can be resurfaced once or twice and thats about it.
 
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