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Cone diff?

janbanan

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My cone diff has bottomed on one side only. Question is, should I be lathing just one side and shim it, or should I do the same on both?
Or...should I throw it away and buy a clutch type diff.
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I know there are those who repair them (I don't call what's done rebuilding because it's not) but I have never seen one that was machined and shimmed last more than a summer of mixed use. I would either sell it to someone that thinks they're good, or toss it and replace it with a Tru Trac...
 
I know there are those who repair them (I don't call what's done rebuilding because it's not) but I have never seen one that was machined and shimmed last more than a summer of mixed use. I would either sell it to someone that thinks they're good, or toss it and replace it with a Tru Trac...
Well......if I had your prices I would not hesitate buying Eaton True Track, but I live in Sweden and with shippingcost and taxes it will cost me around 1000 dollar. But....your advice force me to reconsider what to do.
I have shaved 0,7 mm(around 0.03 inch). If I decide to use it, should I go thicker than that on the shim or should I have the same as shaved?
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I've been doing these for years and they last more than a summer or two. I even have one customer running a 440 6 pack Challenger running 11's at the track and the first time I did his, I didn't see him again for nearly 5 years. The first time I don't shim them but will the second time. Clay check the side that's good and see what the clearance is. I'm betting it's getting close. And don't machine off more than around .030" off the faces. You just don't need to do that and when you do take off more, you're just making them thinner and have less grip.
 
What you are mainly doing when you shim them is you are pulling the spider gears back into the original tooth contact. Just because you take off .030 from the face, it doesn't mean the cone is going to sit .030 deeper into the cup. The angle dictates how far down the cone sits. And many think you're shimming them for more grip. That's somewhat true but it's much more for tooth contact between the spiders and the side gears. I'll tell ya, when the thing tries to spin one and not the other wheel, you're getting lots of force exerted on it for grip. One of the biggest killers of limited slip rears is having one wheel on good hard surface and the other off the shoulder and on dirt. I also try not to be on the gas hard when making a turn at a traffic light. One more thing....7mm is nearly .300" isnt' it? 1mm is .039" If you've already taken that much off, oh well. It'll work still. Wait...you said .7 never mind lol
 
I know there are those who repair them (I don't call what's done rebuilding because it's not) but I have never seen one that was machined and shimmed last more than a summer of mixed use. I would either sell it to someone that thinks they're good, or toss it and replace it with a Tru Trac...
Hey, any that you get that needs machining that you don't want, send it to me. I'll gladly machine it and use it! What usually happens to these things once they start single tracking is people have a tendency to lean on them more trying to make it lock up. That's not going to happen but what usually happens is it trashes the spiders and cross shaft and that usually ruins it for good. I've heard of some repairing the case halves when the cross shaft spins but man, that ain't worth it. I've run 'repaired' unit for many years afterward and I don't drive all that easy....
 
I've been doing these for years and they last more than a summer or two. I even have one customer running a 440 6 pack Challenger running 11's at the track and the first time I did his, I didn't see him again for nearly 5 years. The first time I don't shim them but will the second time. Clay check the side that's good and see what the clearance is. I'm betting it's getting close. And don't machine off more than around .030" off the faces. You just don't need to do that and when you do take off more, you're just making them thinner and have less grip.
Thanks, I think I will give it a try,they are really easy to take apart anyhow. When you shave them the first time without shimming, how much do you take? Would you shave them both, even if one of them look like new?
 
Thanks, I think I will give it a try,they are really easy to take apart anyhow. When you shave them the first time without shimming, how much do you take? Would you shave them both, even if one of them look like new?
The side that looks like new could be 10 miles away from bottoming out. That's why I mentioned to use some clay to check how much clearance it has. Roll up a couple of 5 or 6mm balls and stick em into the case and then lay the cone into place. You don't even have to put anything else together. Just tap the cone down into place with a hammer handle and then pull the cone out. The clay will tell you how much it has left. The clay could be paper thin telling you it doesn't have much left to go. They usually wear fairly evenly and the one that's already bottomed just did it recently. I usually get them well after bottoming and they are usually showing signs of slipping all across the face. .025 to .030 is what I take off of them..... 0,7 mm is fine.
 
What you are mainly doing when you shim them is you are pulling the spider gears back into the original tooth contact. Just because you take off .030 from the face, it doesn't mean the cone is going to sit .030 deeper into the cup. The angle dictates how far down the cone sits. And many think you're shimming them for more grip. That's somewhat true but it's much more for tooth contact between the spiders and the side gears. I'll tell ya, when the thing tries to spin one and not the other wheel, you're getting lots of force exerted on it for grip. One of the biggest killers of limited slip rears is having one wheel on good hard surface and the other off the shoulder and on dirt. I also try not to be on the gas hard when making a turn at a traffic light. One more thing....7mm is nearly .300" isnt' it? 1mm is .039" If you've already taken that much off, oh well. It'll work still. Wait...you said .7 never mind lol
Thanks for helping me. I am a bit confused over the shim. I have seen pictures on internet were the shim is placed over the gear but when you tell me the purpose is to put gears back together again...the shim must be placed between gear and cup?
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Yup....I have a list of Ford part numbers for shims. Not sure if they are available there or not but if you're interested, I can give the numbers to you. Hopefully Ford still carries them since it's been several years since I bought some. The spiders and side gears (axle gears) are pretty tough and I've never had a problem not shimming them the first time.
 
Yup....I have a list of Ford part numbers for shims. Not sure if they are available there or not but if you're interested, I can give the numbers to you. Hopefully Ford still carries them since it's been several years since I bought some. The spiders and side gears (axle gears) are pretty tough and I've never had a problem not shimming them the first time.
Yes I´m interested. I have been at my local partsdealer today, trying to find shims but I didn´t find any.
Yup? Does that mean putting shim between gear and conecup?
 
The smallest shim they have is .025" and the number is EOAZ-4A324-G-.025 Next is .030 and uses the same number but 'H'-.030 'C' is .035 'D' is .040 and 'F' is .040
I've never used anything over .025"....one on each side. And yes, between the cone and gear. You might have to trim the O.D. of the shim depending on how the cone was cast. I've found they vary just a bit right at the seat where the gear seats against the cone.
 
The smallest shim they have is .025" and the number is EOAZ-4A324-G-.025 Next is .030 and uses the same number but 'H'-.030 'C' is .035 'D' is .040 and 'F' is .040
I've never used anything over .025"....one on each side. And yes, between the cone and gear. You might have to trim the O.D. of the shim depending on how the cone was cast. I've found they vary just a bit right at the seat where the gear seats against the cone.
I live in a small town and it takes time to get parts so I did my own in stainless steel. I hope they are hard enough?
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Cool! What grade of stainless did you use? Nothing is spinning against the shims but there is movement because of the clearance in the splines. I guess you noticed there is some fretting between the gear and the cone, right? Whenever I'm inside one, I always hone the gear face smooth....
 
Yup....I have a list of Ford part numbers for shims. Not sure if they are available there or not but if you're interested, I can give the numbers to you. Hopefully Ford still carries them since it's been several years since I bought some. The spiders and side gears (axle gears) are pretty tough and I've never had a problem not shimming them the first time.
 
What should I expect to pay for reconditioning this type of suregrip?
 
Cool! What grade of stainless did you use? Nothing is spinning against the shims but there is movement because of the clearance in the splines. I guess you noticed there is some fretting between the gear and the cone, right? Whenever I'm inside one, I always hone the gear face smooth....
I do not know what grade of stainless it is.It was just a piece I found with the right thickness. It was austenitkind because there was no magnetism on it.
My theory is that some debris got in there and maybe because of that pushed the cone to hard.
I have polished surfice on the gear but marks on cone are to deep.
 
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