Idler Arm bolt

[D Cluley]

I'm replacing the idler arm on my '65 Chrysler and yes, I'm probably overthinking this.

The old one had the bolt installed from the bottom and a castle nut/cotter pin on top.

The new one has a regular bolt/nut with no provision for a cotter pin.

First, it seems like it would be better to put the bolt in from the top, so it can't fall out, if the nut were to come loose

Second, the castle nut/cotter pin setup seems more secure in general.

So, my thought is to reuse the old bolt/nut but install it from the top rather than the bottom.

Thoughts?

 

[vdk2010]

You can use the original bolt if it's in good shape still, sure.

But If you use the new bolt and nut and use blue Loctite with it, you're fine as well!

 

[CBODY67]

Does the new nut have any plastic in the threads (as in "prevailing torque" addition) or does the new bolt have any color to it (as in threadlocker already applied, usually blue)?

Also look for two other possible things. The nut is "squashed"/deformed to make it a tighter fit ("prevailing torque", either squahed a bit for a little bit more elonged thread hole or in a triangle) or are some of the threads on the bolt shallower in the middle than in the end. Either way, "prevailing torque" might replace the cotter pin/castle nut. Newer things which were not in use when the car was designed/spec'd out.

Sometimes, the bolt positioning might have more to do with how the mechanism was assembled on the assy line, which would be different than "in the field" at replacement time.

Re-using the old bolt/nut can be done, as long as there is no wear on the main part of the bolt, ususally.

Just some thoughts,
CBODY67

 

[PurpleBeeper]

See above. The castle nut only works if the new idler arm bolt has a hole for the cotter pin

 

[1971 300 Alvah]

Doing the same thing right now. You could put the bolt in from the top... I couldn't get the bolt into the top hole unless I removed the motor mount (I think it was the motor mount, I can't remember exactly what was in the way). I used generous amounts of Loctite blue on the nut.

 

[D Cluley]

Thanks for the info.

The new nut did seem to be slightly out of round. I hadn't ever seen one like that before, cool!

Did end up reusing the old ones, but flipped over. If nothing else, it should be much easier to remove the cotter pin next time, since you can actually see it on the bottom.

Only took a quick drive, and didn't notice any difference in steering, but the pull to the left when braking is gone.