Another thread repair question. Male threads….

[JHZR2]

Specialty bolt, still available from Mercedes for around $60.

Won’t thread into the second still good captive but very far.

Not that I forced the matter. Are the threads repairable with a good nut or an actual quality chaser?

 

[Trav]

Try running a die over it.

 

[eljefino]

You can start with a thread comb then run the die over it. Thread combs are basically files that happen to share your thread pitch. They also make split dies that start off a little loose but have an allen screw you tighten to bring things together.

 

[racer12306]

What’s it holding?

 

[D60]

Yeah I'd run a die over it and move on.

Yes, the die will remove material that's in the way. No, the world will likely not end

 

[JHZR2]

What’s it holding?

Brake force rod/aka guide rod mount. Holds the mount bushings to the body.

 

[mrbreezeet1]

You can get a chaser, It won't hog out good metal used for the thread to hold! It should just shape the damaged threads.

 

[D60]

You can get a chaser, It won't hog out good metal used for the thread to hold! It should just shape the damaged threads.

I'm not sure I see a chaser doing much there. Since they don't cut they often won't make it past severely damaged threads. But hey, hope springs eternal!

 

[Astro14]

It’s holding the control arm onto the car. Those threads are buggered right where it engages with the nut.

I’d be fine with chasing the threads and smoothing them out, if the engagement took place at a different spot on the bolt.

But with the damage you show, even after chasing them, you’re going to have significantly reduced thread engagement right where it matters on a structurally significant part.

I would replace that bolt.

 

[Fla]

You can start with a thread comb then run the die over it. Thread combs are basically files that happen to share your thread pitch. They also make split dies that start off a little loose but have an allen screw you tighten to bring things together.

X 2 but they're called Thread Chasers.

I'm sure that the OP can reform the threads on the bolt but it's missing a lot of material and I don't know how much load it's under or if the missing material will weaken it too much.

 

[ElectroMechanoMan]

I have to agree with Astro14. That bolt appears to be a structural component and I’d err on the side of caution with that. It more than likely would work after cleaning it up, but I don’t like to cheap out on anything that looks like it could effect safety in any way.

 

[Marcozi]

Get the specs for the bolt and then head over to www.mcmaster.com to find a replacement.

 

[D60]

How many threads remain exposed once installed? It may be possible to source a longer nut like heavy hex or coupling.

But realistically, OP said they're available for $60. Just cough up the $60 and write it off as the cost of owning what equates to cult vehicles in the States

 

[D60]

Get the specs for the bolt and then head over to www.mcmaster.com to find a replacement.

For a flange head bolt with a custom radiused fender washer incorporated? I'd be shocked.

I was gonna suggest facing off the existing hex head and thru-drill the fender washer for reuse, then get the appropriate metric fastener to slip thru the washer (as the exact radius would be difficult to replicate). But IIRC OP has limited fab ability or access to machine tools, so just buy a new one for $60

 

[Fla]

You can get a chaser, It won't hog out good metal used for the thread to hold! It should just shape the damaged threads.

I like these but I don't know if you can still buy them new. These won't remove any metal they just push it back where it should be. One nice thing about these is that each "stick" has 8 different threads on it so three sticks will cover about 98% of all commonly found threads.

 

[Astro14]

If you’re looking to save a few $$ on this, @JHZR2 - Measure the bolt carefully (looks like a 12mm?) and then head over to www.belmetric.com to get a flanged bolt of exactly the same diameter and length.

Cut this one in half at the shank and pull it out. Re-use the washer with a new bolt.

Might have to expand the hole, just a touch, to fit the threaded portion through. Which is why you want the flanged bolt - to spread the load over the slightly enlarged hole in the washer.

I’ve replaced several “captured washer” bolts on European cars - they come with a new bolt, and new washer. They don’t come like that one, with the washer fitted inside the threads. So, a new bolt with the old washer will be fine.

 

[IndyIan]

If I didn't have the $60 or needed it to go to work in the morning, I'd double nut it after cleaning up the threads and probably forget about it.

 

[dfarr67]

I think this might be a case that you wished you spent the $$ down the road.

 

[thastinger]

Buy the new bolt, don't halfazz steering & suspension components.

 

[Astro14]

If I didn't have the $60 or needed it to go to work in the morning, I'd double nut it after cleaning up the threads and probably forget about it.

You can’t double nut this. This is the access…he can barely get the square nut back in there…

Holding a broken captive nut

On my 1991 mb 350sd I can tell the guide rod mount is loose. So I’m going to replace it, the bushings, and the lower control arm bushing. Everything went well until the captive nut on one of the main bushings broke. There is very little corrosion but apparently enough on this bolt to cause an...

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