JAA 4.2

Hi all,

I was wondering if anyone has front knuckles for sale? The pinch bolt in my passenger one is extremely stuck. I'd rather just replace the whole upright when I do the control arm swap that it needs.

I searched around and couldn't find anything for sale. To be clear my car has the 345mm rotors with 4 piston calipers.

Thanks,
John

BrianC72gt

...but penetrating fluid, heat and an impact wrench are your friend. MAPP gas, penetrating fluid and time will prevail. Heat the bolt, cool the bolt, heat it, cool it...the expansion/contraction should break the bond. If you get a new to you upright, you'll be wondering about the bearings..

90SQ

+1

Both of mine were stuck and got them with heat and cold water, impact wrench and zip gun...you're better off working on them in a vice.

S8ilver

I dreaded removing mine, but they came right out with no heat, no oil...just a ratchet. I'm guessing this is an issue on east coast cars. The hardest part for me was getting the ball joint to separate with the bolt removed. Every part of me wanted to wedge a large screwdriver in the slot and pry it open, but didn't want to screw up the aluminum. I ended up tapping a wood shim in the slot until the joint popped free. Then I had to hacksaw out the shim. That method's probably not in the Bentley, but I did what I had to do. Reassembly was much smoother than disassembly.

All that work to replace the damn inner CV boots, but learned a lot in the process. I ended up rebuilding both axles and all 4 boots. Fun times, and about 8 hours and $50 in parts. Sure beat the $6xx or whatever Audi wants for one axle. I have yet to do control arms, but alignment still sets at 0.000 and not a groan from any bushings, yet.

JAA 4.2

I tried using a torch, PB Blaster, and an air hammer. In the end after heating it up and then hitting it with the air hammer the bolt broke off 1/4" inside the housing instead of pushing out. It's ridiculously stuck. Not sure why. I didn't have any real issues when I did the upper control arms on my A6 4.2 a few years ago.

So, short of pulling the knuckle and finding some way to use a press on it, the bolt is not coming out.

BrianC72gt

Maybe one regular nut, and one skinny jamb nut? Tighten them together. Then turn the inner nut to run it out from that end. Hell, you could even try to tighten a nut all the way in to pull the bolt through. Once you break the bond, you are home free. I suppose you could try a vise grips but then you are burning your ship - cozy up to the native girls, fellas, cause we ain't goin home.

Your upright is steel, yes? Corrosion makes the uppers a bitch on these. The upper through bolts on alloy facelift uprights are usually no problem, but tricky getting the lower arms separated. I'm guessing you were using an Impact gun, not an air hammer, yes? So now heat and cool the bolt, soak with good penetrating fluid and maybe air hammer with a single point to push from the broken end while you turn with the nuts? Vibration and steady turning pressure may yet win the day.

What kind of torch? Propane? Meh...MAPP is hotter, Oxy/Acetylene (aka the fire pliers, the blue wrench...) hotter still. Again, try to turn from the nut side while applying heat. Mind the plastic wheel well liners. Fire bad.

Some combination of heat, vibration and pressure simultaneously applied nearly always wins the day. break for swear words, throwing tools and penetrating fluid. We feel your pain.

JAA 4.2

My car has the aluminum uprights. I used MAPP gas on them with an air hammer (not impact).

S8ilver

Can you not just drill the bolt out at this point?

JAA 4.2

Also possible, but I don't want to try it on the car. I was hoping to just have a pile of parts to swap onto the car. Looks like no one has a used set.

BrianC72gt

Nuts. I'd be afraid to try anything hotter than MAPP on the alloy upright. So you've got some kind of galvanic bonding going on there. That's above my pay grade. I'll keep an eye out for another. Right side, S8