How to fix stripped threads

[Marster]

I have a garden tractor that two bolt holes stripped out on one of the mounts on the rear end. Evidently they pulled out over the years of use. The only way to get to them to drill and re-tap the threads, is to remove the rear end from the unit. This requires a good deal of labor.

I was wondering if I could use J B Weld or Permatex makes a thread repair kit that doesnt require drilling and tapping. I plan on retiring the tractor at the end of this season so if I can just get it to hold until then, I'd be happy.

Another thought I had was self tapping bolts. I think that was what was in there before. It has taken 8 years for them to pull out so.....by chance maybe this would work???? Or maybe a shim?

The rear end is die cast alluminin (sp?)

Anyone have any ideas or solutions you have tried on stripped threads?

 

[hh3f]

http://www.amazon.com/Helicoil-5546-10-Metric-Coarse-Thread/dp/B0002SRF80

You can try a helicoil. The old Volkwagen head bold used to strip out and were replaced with helicoils.

This is probably not what your looking for because you would still have to tap the hole for the heicoil. I think with a few pics you might get some better ideas
for your temporary repair.

 

[EatenByLimestone]

Are you anchoring into the aluminum?

Larger bolt or helicoil is all I can think of. I hope there is enough metal around the original bolt to hold a larger one.

Matt

 

[pastera]

What size bolts? Sometimes you get lucky and a metric bolt will be just sligtly larger - just run the metric tap down the hole, you won't get full strength threads but it'll hold

If you want removable, you're going to have to run a tap down the hole (even if you need to shorten the shank).

Otherwise, clean out the holes real well and JB Weld a stud in place and put a nut on the end.

Aaron

 

[Marster]

Thanks for the replies. I thought about using a helicoil but I think that still requires drilling the hole out. In order to do that, I'd have to take the rear out of the tractor........which is something I'm trying to avoid.

It's a 1/4 inch bolt. Since I lost the bolts, I did put in a metric bolt that appears to be holding in place but not tighting up completely.I'm sure it's only a matter of time till they pull out.

I am achoring in the aluminin (sp?) There is enough room to enlarge the holes to the next size bolt but again I would have to drill which I can not get to unless the rear is removed.

I picked up some J B Weld yesterday. I was just going to put it on the metric bolts I have in there and hope and pray it welds to the case. I dont think I will ever have the need to remove these bolts so that is not an issue.

Anyone ever use J B Weld? The claims they make about it sounds like it should do the job.......I never used it.

Any ideas or advice?

 

[Dune]

Get some laquer thinner and clean the area well. If you have compressed air, blow it out reaaly well too.

 

[pastera]

You would be better served by using a longer bolt with the head cut off to act as a stud.

Clean both surfaces with acetone, break cleaner, or whatever solvent is handy. When dry mix up a small amount of JB Weld coat the threads on the bolt. Also put a small amount on the end of the bolt to fill in and push back into threads.

Screw it down hand tight and let it set for 24 hrs. JB Weld will harden in a few minutes but takes overnight to actually cure to full hardness. The repair will be able to be machined later if you want a permanent repair.

Aaron

 

[fbelec]

definite on the j b weld. i had a 71 sportster, the case was aluminum. i had a crack that was getting bigger and leaking oil. cleaned the case with brake clean sanded the area to ruffin it up brake clean again and put on a bead that looked like a weld. solved the problem and that was 22 years ago and it is still working.

 

[Marster]

Again, thanks for the replies. Very encouraging to hear J B Weld lasted for 22 years. This week I am going to tackle this job. It sounds like the prep is very important to this stuff working. I have carb cleaner and finger nail polish removal. Will either or both of these do the trick in cleaning the area?

Marster

 

[fbelec]

i'm not sure about the polish but carb cleaner will leave a white residue. make sur you clean that off with clean rag or go get some brake clean

 

[gpcollen1]

If you are getting a good hold out of the metric bolts, just take them out and put some Loctite on them and put them back in.

 

[Marster]

If you are getting a good hold out of the metric bolts, just take them out and put some Loctite on them and put them back in.

I was going to give this a try since one of the bolts seem to be holding better than the other. (There are 2) The other one is loose and just spins but doesnt seem to be backing out. I was hoping J B Weld would do a better job. Maybe I can try using both. Seeing which type of fix last the longest.

Thanks!

 

[drizler]

If it is really important to you yet you don't want to take it to a machine shop there is something better than JB Weld. It is called DEVCON, made by permatex and it is more expensive but easier to use since JB tends to run all over the place before it sets. I only use mine where the JB is going to drip away before it hardens or if I need something stronger and more durable. I fixed a leaking head on my Chevy v6 with it years back and it's still holding. It has ceramic in it and tends to stick right where you put it . Great stuff, the best I have ever seen by far when it comes to glues and epoxies. If it really valuable and needs to be strong you likely best find the local machine shop and see what he says.
They do make a sort of aluminum brazing rod called Magic Missle Rod. Similar types are sold by other names and you may even find it at a local welding supply though they seem to treat the rod as snake oil for whatever reason. I have used the cheep version made in China on some small projects and it works very well. All you have to do is get it hot enough to start leaving a trace behind as in soldering and just build it up until it is solid and ready to be redrilled. You can do all this with a propane torch unless the casting is so big that it sinks out the heat faster than you can heat it and you can get at the part without a major disassembly needed. Then you need to drill and tap it with a blind tap. Again that is something best left to the neighborhood el cheapo machine shop though it will be much stronger than any epoxy repair.

 

[d.n.f.]

I get a hit/miss with JB Weld. I have used it to fix my snowboard, motorcycle parts, and on a thread (once).

I love the product but know it does have it's limitations.

It worked better on the snowboard crack than the thread by the way but the thread had a lot of shear forces on it.

 

[Marster]

Finally got to use the J B Weld on these stripped threads. So far so good! I've mowed 8 yards with it and it appears to be holding. Will keep an eye on it........but now I found another problem that I will post on a separate thread.

Thanks to everyone for your advice! Much appreciated