front knuckle lower control arm tapered insert

[Docter]

So i recently had the joy of breaking a front knuckle and figuring out that there's a half year where the lower control arm ball joint is 12mm or 14mm. the older, pre november 2009 production year knuckles arent available anywhere but a salvage yard. The newer production year knuckle can still be purchased new. The salvage yard wont know what you are talking about or what you need if you explain it to them and even wolfautoparts doesnt distinguish between the split year. I even found a knuckle with the same part number as my broken one but it was a 14mm ball joint so it had a different insert size! So it's either your car doesnt get back on the road or you come across just the right knuckle. Now I thought the inserts could be pressed out and swapped to the newer knuckle but in Audi's infinite wisdom the inserts have different outside diameters so they cant be swapped. If anyone has this issue im having an insert machined that will fit the 12mm control arm ball joint but also fit into the newer split year knuckle. Is anyone interested in purchasing an insert that has a november 2009 and earlier B8?

[Smac770]

They are different part numbers. There's also the KSM vs Cobapress issue. 8K0 407 253R / 254R is the M12 Cobapress, 8K0 407 253T / 254T is the M12 KSM. You need to match the type you have on the other side. What's the part number off the one you broke? The M14 ones are rev AA (KSM) and rev AB (Cobapress). They are still current.

https://www.genuineaudiparts.com/oem...kle-8k0407253r (Cobapress)
https://www.genuineaudiparts.com/oem...kle-8k0407253t (KSM)

https://wolfautoparts.com/spindle-wh...7g-ps6553.html
Rev G is the predecessor to rev R.
Apparently the only visual indicator of KSM vs Cobapress (assuming it's not actually stamped on the thing) is that opening below the wheel bearing, it's different shaped between the two.

[Docter]

Like I said both have the same square ish hole, the same part number. They are both stamped cobra 8k0407258g. I'm having an insert made that will replace the 14mm steel insert, press into the knuckle with a ball joint press after the insert is frozen and allow me to use my, 12mm ball joint on the control arm, in the updated 14mm knuckle.

[Smac770]

Oh, that wolf listing is 257G, not 253G. 257/258 are not the Audi stock part numbers; they are stamped on the main component piece. But as you see, that doesn't mean the rest of the parts that make up the 253 composite part revision are the same. As you said, you're not going to be able to get any help from some stock boy in this regard. But on the statement of you can't buy them new anymore, that's not accurate.

Interesting that both the M12 and M14 variations use the same stamped part number revision (257G/258G). One would think they'd put something on there somewhere to know which is which out of box.

[Docter]

Yes from my original research I was wrong about buying them new but who wants to spend roughly $600 when someone has to be economical and buy used. Although they are hard to find and the 14mm knuckle is much easier, my best bet and possibly someone else's, is to manufacture this insert to use in the 14mm knuckle and that's what I'm trying to gauge. When the supply of used 12mm knuckles are so short you can't readily find them this would be a viable alternative.

The stock boys at salvage yards are very much a dead end and so was ebay. Most parts were already packaged and the part numbers not correctly annotated. A simple "can you measure this one dimension" along with my supplied picture of what to measure was too much to ask.

I do think I have the right knuckle on the way but this insert is being machined locally and will probably be done before that gets in. I thought I'd just make a problem solver so if others are in a pinch or in my situation it would help.

[Smac770]

No, A for effort there. Outside my comfort zone there. Electronics, any day; machining, that's for others to do. Post up how the retrofit goes and how the end result plays out.

[Docter]

I'll update and take pictures. I forgot to before I dropped off the 14mm and 12mm Inserts for the machine shop to use as a model. I'd hopefully be able to help someone out in the future by selling them an insert, if they needed to buy a 14mm knuckle, cause they can't find a 12mm one.

[NitroViper]

I'll update and take pictures. I forgot to before I dropped off the 14mm and 12mm Inserts for the machine shop to use as a model. I'd hopefully be able to help someone out in the future by selling them an insert, if they needed to buy a 14mm knuckle, cause they can't find a 12mm one.

Are you talking about this? Im having the same issue finding the right arm, ive ordered 3 now from 3 different sleves and it is always wrong. The sleeve is to big. I am going to try to press the sleeve out tomorrow. I know the post is kinda old but wondered if this is what youre talking about.

[Docter]

I'm talking about the sleeve in the knuckle its self for the rearward control arm ball joint in the front end, but the sleeve you need looks the same. It's the smaller 12mm ball joint that you have and you have been getting the 14mm ball joint version. Have you tried ordering the forward control arm from FCP euro? What's the production date on the driver's side door from say? It'll be in this format mm/yy
[IMG][/IMG]

[eljay]

I am going through this right now... :(
The used knuckle I got came without sleeves. I still have sleeves pressed into my old broken knuckle, so I hope I can press them out that they would be the correct size for the replacement knuckle (they both have the same part number etc.)
The question is: do these sleeves just press out? And anything special required to press them back in? Any Loctite etc? Or do they press in and stay in place? I don't want them to start spinning when I torque down the ball join nuts.

[Docter]

With a digital caliper masure the ID underneath the knuckle that doesn't have sleeves then measure the same spot on your broken knuckle. Make sure on your broken knuckle you aren't measuring the ID of the sleeve but the hole the sleeve is pressed into. If they are the same the sleeve will fit. I used a 12 ton press but a ball joint press will work. After removing the sleeve freeze it in the freezer for an hour then it'll press back in like butter. Which year model A4 do you have?

[Docter]

Are you talking about this? Im having the same issue finding the right arm, ive ordered 3 now from 3 different sleves and it is always wrong. The sleeve is to big. I am going to try to press the sleeve out tomorrow. I know the post is kinda old but wondered if this is what youre talking about.

Sorry I didn't see this earlier. Did you sort out your issue?

[Docter]

No, A for effort there. Outside my comfort zone there. Electronics, any day; machining, that's for others to do. Post up how the retrofit goes and how the end result plays out.

So I was able to get a sleeve machined that would work but the correct knuckle came in at the same time. I kept the retrofitted sleeve as a model so I could make more and installed the used knuckled.

[eljay]

With a digital caliper masure the ID underneath the knuckle that doesn't have sleeves then measure the same spot on your broken knuckle. Make sure on your broken knuckle you aren't measuring the ID of the sleeve but the hole the sleeve is pressed into. If they are the same the sleeve will fit. I used a 12 ton press but a ball joint press will work. After removing the sleeve freeze it in the freezer for an hour then it'll press back in like butter. Which year model A4 do you have?

Perfect!
Just measured them and they are identical (=/- 0.01mm due to moving the calipers finding the max inner dimension). For reference, the larger hole is 28mm ID, the smaller is 24mm ID.
This is for a knuckle from 2016 A4 Allroad. I'll check my build date later if that would help others.
The part number on the sticker with QR code on it is 4G0407241C.
Part number pressed on the knuckle is R8k0407257ABSJ2Fr with Coba logo on it. It has the trapezoid opening on the knuckle.
The replacement knuckle is identical except for the missing inserts.

I'll be swapping my wheel bearing/hub into the replacement knuckle as I don't like how that one grinds when moving. It came from a lower mileage car, but must've been sitting a while as there's corrosion on the hub splines. So, I also need to get new wheel bearing bolts... Sigh. And then I hope I can separate the bearings without issues. I have a 10-ton press, so that should help.

[Docter]

Perfect!
Just measured them and they are identical (=/- 0.01mm due to moving the calipers finding the max inner dimension). For reference, the larger hole is 28mm ID, the smaller is 24mm ID.
This is for a knuckle from 2016 A4 Allroad. I'll check my build date later if that would help others.
The part number on the sticker with QR code on it is 4G0407241C.
Part number pressed on the knuckle is R8k0407257ABSJ2Fr with Coba logo on it. It has the trapezoid opening on the knuckle.
The replacement knuckle is identical except for the missing inserts.

I'll be swapping my wheel bearing/hub into the replacement knuckle as I don't like how that one grinds when moving. It came from a lower mileage car, but must've been sitting a while as there's corrosion on the hub splines. So, I also need to get new wheel bearing bolts... Sigh. And then I hope I can separate the bearings without issues. I have a 10-ton press, so that should help.

Sweet! Good luck. My issue was the part numbers were the same within a small window when the B8 to B8.5 Switch happened but the sleeves were different. You'll have better luck finding the correct suspension parts for your B8.5 cause they are more plentiful.

[eljay]

Sweet! Good luck. My issue was the part numbers were the same within a small window when the B8 to B8.5 Switch happened but the sleeves were different. You'll have better luck finding the correct suspension parts for your B8.5 cause they are more plentiful.

Well, yes, but I've experienced the same as you above. Junkyards don't want to spend any time at all on verifying compatibility or sending me a picture of the part and they all want payment before they go pull it from the car if they don't already have it on the shelf. Frustrating.
I even called the local Audi dealer with a VIN of the donor car and asking them to confirm that knuckle will fit my VIN. The guy was very honest and said that he knows my dilemma and because of all the variations they will not order a knuckle without physically seeing it to match it to the inventory. i.e. they will not order by part number or VIN. How crazy is that?!

[eljay]

Another quick question while I have the captive and helpful audience... as I mentioned, I want to swap my bearing/hub to the replacement knuckle. I will buy new stretch bolts, but I hope it's OK to thread them into the existing bearing, right? That is, I assume it's only the bolt stretching and not the female thread on the bearing housing. My car/bearing has only 75k kms, so I don't want to buy a new bearing if I can avoid it.

[Docter]

Another quick question while I have the captive and helpful audience... as I mentioned, I want to swap my bearing/hub to the replacement knuckle. I will buy new stretch bolts, but I hope it's OK to thread them into the existing bearing, right? That is, I assume it's only the bolt stretching and not the female thread on the bearing housing. My car/bearing has only 75k kms, so I don't want to buy a new bearing if I can avoid it.

I've experienced the same lazy junkyard man delema. What stretches is the part of the bolt that isn't in contact with the female threads Or the neck of the bolt. So just got new bolts. Personally I just reused the bolts and I've been fine.

[eljay]

I've experienced the same lazy junkyard man delema. What stretches is the part of the bolt that isn't in contact with the female threads Or the neck of the bolt. So just got new bolts. Personally I just reused the bolts and I've been fine.

Thank you! Hmm, thinking of re-using, but I'll have to see how my removal process goes. If I have to hammer on the bolts too much, I'll get new ones.

[Docter]

Thank you! Hmm, thinking of re-using, but I'll have to see how my removal process goes. If I have to hammer on the bolts too much, I'll get new ones.

If the head of the bolt is damaged at all replace it. The head is so shallow I wouldn't risk stripping it out.

[eljay]

If the head of the bolt is damaged at all replace it. The head is so shallow I wouldn't risk stripping it out.

Got the bolts out without damage. Only one whack of hammer on each popped the bearing out, so they should be good to re-use. It's $40 for new ones around here.
I cannot get the spindle into my shop press at a correct angle to press out the sleeves, so I got a ball joint press kit. Let's hooe that works.
Can/should I apply some antiseize to the outside of the bearing or does it have to be a friction fit into the spindle? I think the bolts are what is holding the bearing in, correct?

[eljay]

Still fighting with the sleeve for the rearward control arm. I can't position the knuckle in my press no matter what tetris moves I tried and the ball joint press thingy always puts the cup on an angle, so it slips. :(
Also, the sleeve for the tie rod end went into the new knuckle almost too easily. I hope it won't spin when I insert the tie rod end.

[Docter]

Still fighting with the sleeve for the rearward control arm. I can't position the knuckle in my press no matter what tetris moves I tried and the ball joint press thingy always puts the cup on an angle, so it slips. :(
Also, the sleeve for the tie rod end went into the new knuckle almost too easily. I hope it won't spin when I insert the tie rod end.

I had to use some jury rigging and sockets to space the knuckle just right so it was flat in my press. You could use antiseize but I didn't. But the right cup for the bearing press won't sit perfectly flat but it'll work.

[RPMtech147]

Map gas and brass punch and it should tap out. I've actually had it pull the sleeve when trying to remove the ball joint.

[eljay]

I didn't want to use any heat on it as that is how the shop damaged the upper pinch bolt area. It got weak from heating and then they just tightened the pinch bolt with their air gun without proper torque.

I tried a 7-ton puller on the sleeve and it wouldn't move. I ended up taking it to a shop and had it pressed out and transferred to the new spindle.
My 10-ton press has a crossbar and every which way I tried, I couldn't get it in there even close to a center position.
Also, that other sleeve on the tie rod end kept popping out, but once the tie rod is tightened down, it's not moving. Hope this helps someone else.

The spindle is back, now I just need to tighten everything in loaded position.

[Nico audi help]

Hello, i nede help with the same problem