SSBC rotor rubs on bolts for steering knuckle

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Stihl011

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I bought a W153 front disc brake conversion kit from SSBC. I was putting it together and found the bolts that hold the steering knuckle to the adapter plate and spindle rub on the rotor. I talked to their tech support and they told me that the bolts have to go in from the outside. I don't think this is possible because their threaded plate mounts on the outside and the bolts aren't threaded to the top. As soon at the bolt stops being threaded, the bolt will not longer go in. Even if this wasn't the case, the bolt head is the same size as the nut (3/4) so it would still rub. I told them this and they have not gotten back to me (been about 3 weeks).



It seems to me like the rotors are just a tad too small on that internal diameter where the rubbing occurs. Tried multiple combinations 1/2-20 bolts/nuts (the original parts had two different bolt lengths and nut widths to hold on the drums) and both rotors on both sides of the car with the same result.

Anyone else had this problem? My best idea so far is either to grind the edges of the head of the bolts down once tightened, or to have a friend get the rotor on a lathe and take off some material there. Neither seem like great options to me.

Yes this is a repeat from the end of my last thread which started out as a different subject. Hoping the fresh post will get some eyes on it.

As always, thank you.
 
Looks like the bolts are installed from the wrong direction. Not familiar with SSBC but normally the bolt goes in from the outside and nut on the backside.
 
Looks like the bolts are installed from the wrong direction. Not familiar with SSBC but normally the bolt goes in from the outside and nut on the backside.

Thanks for the reply.

When I took apart the drums, the bolts were definitely put in from the rear. Backed up by service manual.

As I said, the bolts aren’t threaded to the top of the bolt head, and the adapter plate is threaded, so putting them on from outside-in won’t work because the bolt would start threading into the plate, then stop once the treads ran out about 1.5” from the head of the bolt. And if it did, the bolt head would probably rub, since the bolt head and the but heads are the same size, 3/4”.
 
See linked video of the bolt going through the adapter plate from the outside-in, its hard to explain in words what I mean, but you can see it won't go all the way in because the plate is threaded and the threads of the bolt don't go to the top.




What am I missing, something obvious no doubt?
 
I see.

Are you to use something other than stock type bolts?
 
where in wa are you located?
The bolt shank going thru knuckle must fit snugly, and must go in from inside out, like your oem app. Make sure bolt shank and knuckle holes are very close to same size. I would think just a couple of 0.001" or so. You don't want a lot of slop there, certainly not the threaded end, because that would be too much slop. Maybe you can find a smaller hex nut with 1/2 x20 thread. Maybe a 12pt nut. I don't know for a fact, but I should think they should be gr8 fasteners.
 
maybe they don't intend for you to nut the outside end of the bolt. maybe you're just supposed to loctite it and torque it. How thick is the adapter? I should think it would have to be 1/2in thick if you have 1/2in thread.
 
I see.

Are you to use something other than stock type bolts?

No, not yet anyway. Everything I've shown here is with the stock nuts and bolts.

The stock bolts are a bit too short, and I think I will eventually need to get longer ones (after going through plate, only about 4 threads show through) That being said, the stock bolts heads/nuts are the same diameter as your typical grade 8 1/2-20 bolt, so they will all rub (and do).

The stock nuts that were are it are two different widths to clear some of the drum brake components, but it doesn't matter which I put on, the both rub. The nuts are too wide, not too long. See pic below. The first two are stock, the last one is from the auto parts store.

maybe they don't intend for you to nut the outside end of the bolt. maybe you're just supposed to loctite it and torque it. How thick is the adapter? I should think it would have to be 1/2in thick if you have 1/2in thread.


Could be, The plate is 7/16 thick. Not sure what they intend, the instructions show a bolt head on the outside, and tech support said the same thing, but as I say, it can't possibly work that way. All the instructions say is to use the stock hardware. Thanks for the idea though. Maybe I'll e-mail them again and ask that.

IMG_1378.JPG
 
where in wa are you located?
The bolt shank going thru knuckle must fit snugly, and must go in from inside out, like your oem app. Make sure bolt shank and knuckle holes are very close to same size. I would think just a couple of 0.001" or so. You don't want a lot of slop there, certainly not the threaded end, because that would be too much slop. Maybe you can find a smaller hex nut with 1/2 x20 thread. Maybe a 12pt nut. I don't know for a fact, but I should think they should be gr8 fasteners.

Sultan, WA.
Bolt shank and knuckle holes are the same size 1/2" fits pretty snugly. Just the width of the nuts seems to be the problem.
 
maybe they don't intend for you to nut the outside end of the bolt. maybe you're just supposed to loctite it and torque it. How thick is the adapter? I should think it would have to be 1/2in thick if you have 1/2in thread.

This is genius. Went back and looked at instructions...pic posted below. They don't actually say to put the nuts back on. Thanks rusty.
instructions.PNG
 
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