Currie Front UCA Install ?s

[mrblaine]

Play is bad and it will only get worse. Get the size bolt you need.

Why would there be play?

[Schmo]

Other than it being a hardened bolt sleeve that typically has a couple of dimpled in areas to center the 10mm bolt, why is it bad to drill?

The difference in diameters between the two holes is exactly .045 or about the thickness of 2 nice business cards. So, he'd be removing the thickness of 1 nice business card per side.

Not even an issue structurally, and the only other problem is the hardened part.

I've been able to drill some, and others rip the flutes off of cobalt bits like they were made of tin foil.

The difference was very minimal when I held the bolt up to the hole in the bushing. That's why I thought it would be fine structurally to drill it out a tiny bit . . . I'm just worried about not being able to drill it out due to it being hardened . . . I have to buy the right size bit anyway, what type of bit would I have the best luck with?

Why would there be play?

When I placed the stock bolt thru the hole in the new contol arm, there was noticeable room between the bolt and arm . . . I was worried that would cause play and with added force, over time could distort the holes on the arm. The new arms are not nearly as thick on the non-JJ end vs the older version and I thought they might be more vunerable.


I was going to give Currie a call and see what they advise.

[mrblaine]

The difference was very minimal when I held the bolt up to the hole in the bushing. That's why I thought it would be fine structurally to drill it out a tiny bit . . . I'm just worried about not being able to drill it out due to it being hardened . . . I have to buy the right size bit anyway, what type of bit would I have the best luck with?

Buy a relatively inexpensive bit. If it's hardened, it will ruin any bit you use because you aren't drilling the bore, you're knocking the tops off of several dimples that protrude into the bore. If it's not hardened and I've seen a very rare few that weren't, just about any bit will do the job.

When I placed the stock bolt thru the hole in the new contol arm, there was noticeable room between the bolt and arm . . . I was worried that would cause play and with added force, over time could distort the holes on the arm. The new arms are not nearly as thick on the non-JJ end vs the older version and I thought they might be more vunerable.

Everyone that wrenches should benefit themselves by spending some time learning about the science behind bolted connections. No you don't want grossly oversized holes, but not because that will generate play later, but because it interrupts the function of the fastener's faying surfaces.

If your bolt in that application ever becomes loose enough to wallow out the hole in the arm, then the connection failed long before that and you should have paid more attention to your bolt torque specs and been better on your maintenance. It is that simple.

I was going to give Currie a call and see what they advise.

Alright

[Schmo]

Buy a relatively inexpensive bit. If it's hardened, it will ruin any bit you use because you aren't drilling the bore, you're knocking the tops off of several dimples that protrude into the bore. If it's not hardened and I've seen a very rare few that weren't, just about any bit will do the job.

Everyone that wrenches should benefit themselves by spending some time learning about the science behind bolted connections. No you don't want grossly oversized holes, but not because that will generate play later, but because it interrupts the function of the fastener's faying surfaces.

If your bolt in that application ever becomes loose enough to wallow out the hole in the arm, then the connection failed long before that and you should have paid more attention to your bolt torque specs and been better on your maintenance. It is that simple.

With that being said . . . would it make more sense to either buy the proper length 10mm bolts (10.8), washers, and nuts and leave the bushing alone . . . or to attempt the drilling to fit the supplied 7/16 greaseable bolts? Would one be better than the other as far as strength and durability? If I do attempt to drill and it's hardened, will it mess up the bushing or just the bit?

[mrblaine]

With that being said . . . would it make more sense to either buy the proper length 10mm bolts (10.8), washers, and nuts and leave the bushing alone . . . or to attempt the drilling to fit the supplied 7/16 greaseable bolts? Would one be better than the other as far as strength and durability? If I do attempt to drill and it's hardened, will it mess up the bushing or just the bit?

You don't need the greaseable bolt. Buy a duplicate in grade 8 and save that one for when you do the JJ conversion up front.

If you try and drill and the bit grabs because it catches on the dimples, if you try and horsepower through it like our nameless friend has done in the past, you run the risk of spinning the bushing and tearing it free of it's bond to the rubber.

Once that happens, the bushing is trash and will need to be replaced. If you do that to the one in the cast mount, you'll be on here crying like a little baby trying to figure out how to remove it. That will be after you try all the internet crap about using drills, torches, jackhammers and large amounts of explosives.

Pick your poison.

[Schmo]

You don't need the greaseable bolt. Buy a duplicate in grade 8 and save that one for when you do the JJ conversion up front.

If you try and drill and the bit grabs because it catches on the dimples, if you try and horsepower through it like our nameless friend has done in the past, you run the risk of spinning the bushing and tearing it free of it's bond to the rubber.

Once that happens, the bushing is trash and will need to be replaced. If you do that to the one in the cast mount, you'll be on here crying like a little baby trying to figure out how to remove it. That will be after you try all the internet crap about using drills, torches, jackhammers and large amounts of explosives.

Pick your poison.

Sounds like it might make more sense then to go with the 10mm bolts, torque them down to 60 foot pounds like the insructions say, check them regularly, and just leave the bushings alone until I upgrade to the JJ's on the axle. From what you mentioned earlier, it doesn't seem like there is much of an upside to drilling out the bushings, if as long I keep the bolts torqued properly, it won't affect the holes in the arm. Did I understand that correctly?

[mrblaine]

Sounds like it might make more sense then to go with the 10mm bolts, torque them down to 60 foot pounds like the insructions say, check them regularly, and just leave the bushings alone until I upgrade to the JJ's on the axle. From what you mentioned earlier, it doesn't seem like there is much of an upside to drilling out the bushings, if as long I keep the bolts torqued properly, it won't affect the holes in the arm. Did I understand that correctly?

You did.

[Max7]

Why would there be play?

Grossly oversized holes Click,click,click...at best. Educate me, what is the fastener faying surface?
Best, Max7

[mrblaine]

Grossly oversized holes Click,click,click...at best. Educate me, what is the fastener faying surface?
Best, Max7

Examine the underside of the head of a quality hex head cap screw sometime. (we rarely use bolts for what we do, the vast majority of our fasteners are cap screws of some kind)

You will notice that the hex part doesn't come into contact with the surface being clamped together. There is a very slightly raised ring on the underside of the head. That surface is what comes into contact with whatever is being fastened together and is/are the faying surfaces.

The end of the bolt sleeve in the bushing is another faying surface as is the area on the side of the control arm U that comes into contact with the end of the bolt sleeve.

All cap screws that we use, with rare exception, are engineered to operate purely in tension. In other words, once you apply the correct torque value, the fastener is stretched and clamps the connection together. The friction developed amongst all the faying surfaces is what keep the body of the fastener from seeing any shear force. Once that tension is lost and the shank of the fastener and it's corresponding connection components see any shear force, the connection has failed or it's design parameters have been exceeded.

[mrblaine]

Here, study this a bit-

http://www.fandisc.com/tti.htm

Example- A typical lower control arm bolt is 9/16-18 in grade 8 and with a lubed torque value of 130 ft lbs, it will generate 18,250 lbs of clamping force to stop your arms from wiggling around in the mounts.

Can you fathom how much force that is? You could hang 4 1/2 Jeeps from that bolt before the connection failed and then you would only have overcome the clamping force generated, the bolt would still be below it's proof load capacity.

btw- zinc plating acts as a lubricant, so unless the bolts are raw steel, dry with no oil, don't use the dry torque value.

The average rim held on with 5 lugnuts has 72,000 lbs of clamping force holding it in place.

[Schmo]

You did.

Thanks mrblaine!

[Max7]

1st semester nuts

Examine the underside of the head of a quality hex head cap screw sometime. (we rarely use bolts for what we do, the vast majority of our fasteners are cap screws of some kind)

You will notice that the hex part doesn't come into contact with the surface being clamped together. There is a very slightly raised ring on the underside of the head. That surface is what comes into contact with whatever is being fastened together and is/are the faying surfaces.

The end of the bolt sleeve in the bushing is another faying surface as is the area on the side of the control arm U that comes into contact with the end of the bolt sleeve.

All cap screws that we use, with rare exception, are engineered to operate purely in tension. In other words, once you apply the correct torque value, the fastener is stretched and clamps the connection together. The friction developed amongst all the faying surfaces is what keep the body of the fastener from seeing any shear force. Once that tension is lost and the shank of the fastener and it's corresponding connection components see any shear force, the connection has failed or it's design parameters have been exceeded.

Blaine,
Thanks for the lessons I see fasteners much differently now thanks to you. What you wrote made a lot of sense. I think I might find myself in the fastener isle today studying up.
Sincerely, Max7

[RAT]

[quote=mrblaine;117653]Other than it being a hardened bolt sleeve that typically has a couple of dimpled in areas to center the 10mm bolt, why is it bad to drill?

quote]

This is why (your very own words) I'm just not as elloquent as you are...

Quote:
Originally Posted by Schmo
With that being said . . . would it make more sense to either buy the proper length 10mm bolts (10.8), washers, and nuts and leave the bushing alone . . . or to attempt the drilling to fit the supplied 7/16 greaseable bolts? Would one be better than the other as far as strength and durability? If I do attempt to drill and it's hardened, will it mess up the bushing or just the bit?


If you try and drill and the bit grabs because it catches on the dimples, if you try and horsepower through it like our nameless friend has done in the past, you run the risk of spinning the bushing and tearing it free of it's bond to the rubber.

Once that happens, the bushing is trash and will need to be replaced. If you do that to the one in the cast mount, you'll be on here crying like a little baby trying to figure out how to remove it. That will be after you try all the internet crap about using drills, torches, jackhammers and large amounts of explosives.

Pick your poison.

[mrblaine]

[QUOTE=rat patrol;117755]

Other than it being a hardened bolt sleeve that typically has a couple of dimpled in areas to center the 10mm bolt, why is it bad to drill?

quote]

This is why (your very own words) I'm just not as elloquent as you are...

Quote:
Originally Posted by Schmo
With that being said . . . would it make more sense to either buy the proper length 10mm bolts (10.8), washers, and nuts and leave the bushing alone . . . or to attempt the drilling to fit the supplied 7/16 greaseable bolts? Would one be better than the other as far as strength and durability? If I do attempt to drill and it's hardened, will it mess up the bushing or just the bit?


If you try and drill and the bit grabs because it catches on the dimples, if you try and horsepower through it like our nameless friend has done in the past, you run the risk of spinning the bushing and tearing it free of it's bond to the rubber.

Once that happens, the bushing is trash and will need to be replaced. If you do that to the one in the cast mount, you'll be on here crying like a little baby trying to figure out how to remove it. That will be after you try all the internet crap about using drills, torches, jackhammers and large amounts of explosives.

Pick your poison.

You said this-

I wouldn't drill the sleeve. Not a good idea. Find the right grade 8 bolt to fit. Like Chris said, you compromise the strength of the bushing when you modify it, and isn't that what you have been having the most problems with?

In your reply, you make it sound like the bolt sleeve will be compromised in it's performance, function or designed service life which is simply not the case. If you can find a safe non destructive way to clearance those dimples to get a bolt through, you've affected nothing.

When I do it, I take a stone in my Foredom and carefully grind the points off the dimples and slide the bolt through.

[RAT]

[quote=mrblaine;117758]

You said this-



In your reply, you make it sound like the bolt sleeve will be compromised in it's performance, function or designed service life which is simply not the case. If you can find a safe non destructive way to clearance those dimples to get a bolt through, you've affected nothing.

When I do it, I take a stone in my Foredom and carefully grind the points off the dimples and slide the bolt through.

Didn't feel the need to go into detail at that point. If he would have asked further I would have elaborated.I hardly ever answer these, and this is why. Too many cooks...