While working to get rid of the looseness in the steering of the 11' Touring, we found out that the holes for the kingpin/spindle bolt have become worn wide with a slight oval to them. They are worn to the point that the threads on the bottom of the bolt cannot engage.
I searched on the MTFCA site and found a thread (no pun intended) suggesting using Time-Serts or heli-coils or something to that effect.
However, I'm not sure how those fixes would work if the holes have worked themselves into a slight oval shape. For now, and since we're rapidly approaching the Boone tour, we just put some shim stock in there and removed the egregious play. With the castle nut on the bottom tightened down. But I'm wondering what the better, long term fix is. Not many 11' front axles lying around. And I don't like the idea of boring a lot of material out of what is already there to get it back to circular.
Could the holes be filled, redrilled, and tapped? I don't see why not.
Sounds like a job for "Stevens Front Axle Tool". Dan
Bob, I would borrow a later axle from a friend to go on tour. I would not put my faith in shim stock. Steve Jelf has the answer.
This is what was done to my axle 15 years ago and it is still working. I took it to a friend who has a home machine shop so that he could center and drill a hole perpendicular to the flat surface on the axle. He drilled tapped and placed a helicoil. It is important to get the helicoil straight. Take new spindle bolt along so the helicoil can be fitted to the right thread.
I have also seen a kit with which a cone shape is cut from the bottom of the axle and a new cone shaped threaded piece is inserted from the bottom. I don't know what the name of the kit is or whether it is available from vendors today.
Depending on how much they're ovaled, I would think that in most cases the helicoils will work fine. I just did one last week for a buddy. The drill is 33/64 for the helicoil tap. Run that in and if you have fresh drilled metal inside the radius of the hole, you'll be OK.
HeliCoils are the answer. Drilling the hole for a HeliCoil probably wont thin the wall any more than it already is. You have 2 weeks before Boone. That's plenty of time to install HeliCoils. Just be aware that the threads do not begin until somewhat below the upper surface. The coil will have to run in below the surface then the excess trimmed off the bottom.
Dan, in regards to the Stevens tool, what keeps the tool "in line". In my case of ovalled holes, how do you know that the proper centerline path, so to speak, is maintained? In other words, if centers of the two worn out holes are no longer in line, wouldn't the newly reamed holes be off line?
This is the thread that I had picked up in my search:
Of those who are advocating helicoils, what is your opinion of Time-certs?
It seems that time-certs are more expensive and would be tougher to get, but have a better reputation or are stronger?
In the case of ovalled holes, do you think that if the helicoil tap takes off *any* metal at all that you'll be OK. Or do you think that you need to see fresh metal all around the hole?
You will never have an issue with the strength of helicoils. Your link is the first I've seen of Time Certs. They look very good but not having ever tried them I can't comment further on them compared to helicoils.
You mentioned alignment above. When I helicoiled my axle, I made a drill holder with a 1/2" shank that held a stub length 33/64" drill. The 1/2" shank of the holder slid up into the upper end of the axle, the drill was inserted into the holder and the hole was drilled using a hand held drill motor. The upper end of the axle guided the drill into the lower hole. It was tapped in a similar fashion. The egg shaped hole probably still caused some misalignment but it would have been minimal.
It doesn't have to clean up 100%. The helicoil tap will remove even more material. (I know you asked Kenny, sorry for butting in.)
The Stevens tool is made to fix the axle on the car. The tool fixture lines up the cutting tools so the holes are in alignment. This fix is better than the a new axle. Search this forum for Stevens Front Axle tool. There are pictures on here of the tool in action. PM me for more info. Dan
Try this link
I have used both helicoils and timeserts for this job. I am now reluctant to use helicoils. when threading a helicoil in from the bottom and stopping it short so there is the usual plain section to start the kingpin, you have to break the tang off the helicoil. This can result in a slight dislodgement of the coil threads at the break, making starting the bolt problematical. Also, I have had one coil wind out the bottom as I wound the bolt in. Probably the instalers fault, but timeserts are much easier to instal and are more forgiving of slight mis-alignment. They are a solid steel tube and have no issues starting the thread from either end. Their external thread is also not as deep, so installation is easier. On king pin threads, the external thread is a standard size so no extra tap is needed if your workshop is well equipped.
Just my experience.
Allan from down under.
Dan Hatch has the Stevens Tool, the inserts that the Stevens Tool installs, and he has the experience & knowledge to use it.
I know these facts first hand, because he installed a set in my '26 Pickup front axle back in May of this year. I watched- he worked. It was fun.
He also has a set of alignment rods that make it easy to tell if the axle is bent- and mine was.
So it sounds like the thread repair can be done by helicoil, Stevens tool, keensert, or time-sert. What about repair of the top hole?
It looks like the Stevens tool will work for that, but I'd assume you wouldn't put a helicoil or other threaded fix in there. The other options beyond the Stevens would be just bore it out and put in a bushing, or, as Steve Jelf suggests, fill it completely and bore a new hole altogether.
And a question for the tapered Stevens insert. I assume the inner diameter is not tapered? Just the OD?
Bob, sorry for the delay. Jerry answered the question well. I've done 6 axles with helicoils and have not had any problems. The tap will take out additional metal for the helicoil to screw in to since the ID of it is 1/2".
The Stevens tool will ream a tapered hole in the top of the axle, into which a tapered (OD) bushing is installed. It has the correct ID. Additionally, the Stevens tool will drill/tap the lower hole and a specially made threaded bush is fitted. All of these pieces can be purchased from Dan Hatch or Langs and perhaps others.
I'm going to check with the guys in the local club. But if no one has one, Dan, do you sell the tool or just the inserts and reamers/tap?
Or perhaps someone who has one is going to be at the MTFCI International Tour in Boone in a couple of weeks? It seems like the Stevens tool fix should be do-able in the parking lot......
Dan, I sent a PM
@Allan Bennett or other helicoil users,
Why do you have to thread the helicoil from the bottom? I would have thought you bring it in from the top.
Also, on the McMaster Carr website, they have helicoils without the tang. I suppose you have to cross your fingers that you can get it screwed into place without the tang. But if you do, you wouldn't have to break it off with a punch and possibly knock the coil off a thread or two.
Another thought - if you use a punch to break off the tang that is very close to the ID of the helicoil, wouldn't you make it impossible for the coil to "jump" a thread?
I put helicoils in my front axle. The helicoil insert is taller than the axle threads, so some of it will stick out. You will want to trim the excess helicoil so that both ends are down far enough below the surface of the axle so that the sharp end of the helicoil can "bite" into the hole, preventing the helicoil from rotating when you screw the spindle bolt in and out. If some time in the future, you have to remove the spindle bolt and the helicoil does rotate and try to come out, it's no big deal, you just have to wind it the rest of the way out and install a new helicoil insert (the kit comes with lots of inserts).
Bob: Check your email. Dan
Here is the relevant portion of the T-202 B drawing showing the threads in the front axle.
I've regularly done the repair installing the helicoil from the top with Red lok-tite, run it down in a bit less than half way through and trim off the excess out the bottom with a small Dremel cut-off wheel - no need to smack the "tang" or anything. Let it set up over night, check the thread fit of the new spindle bolt and if too snug, run a tap through it - go easy - usually won't disturb the lok-tite.
If the top yoke hole is elongated, well then, it needs to be repaired one way or another and the Stevens tool kit does a great repair.
I just noticed that Snyders has a front axle repair kit with cones for the top and threaded inserts for the bottom. I think the price was around $18.00, so may be very reasonable option and worth a try.
The trick, though, Kenny, seems to be keeping the centerlines of the holes the same, especially when you can't trust the worn holes. It seems like it is either the Stevens tool or a more intricate milling setup.