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Recommendation For Thread Locker For Exhaust Flange Nuts?
On my '69 N14 car, the collector flange nuts don't stay tight for much longer than 2 or 3 typical weekend drives. (Has anyone else had this issue?) Currently using extra length brass nuts with helical lock washers.
Is there a medium strength, high heat thread locker that will work in this application (the preferred solution) or would installing standard length nuts and double-nutting them be the right fix?
If you do a search for Loctite threadlocker you'll find several different types - removable and permanent . They all have about the same working temperature window. As I remember , you have to heat up the permanent locker in order to remove the nuts. I usually use blue in order to remove the nuts down the road.
I had this issue with just the drivers side a few years ago. Not being a fan of putting loctite in this location. Generally this is a place for copper anti-seize. I looked into why these nuts kept coming loose. I too was running the extra long brass nuts with lock washers. Found that pipe not properly mounted further down the line. was loose at the mount at the tailshaft of the transmission area. and no mount at all in the rear diff area. Getting the exhaust pipe mounted correctly further down the line cured the issue of the manifold nuts coming loose. Thousands of miles on it since the repair. never came loose again and no loctite.
I would use a "bent tab" locking washer. see example below. You can probably make your own from fender washer at your local hardware store at 1/10th the price.
I would try a "flange" type 3/8" nuts. They have them at our local Ace hardware store or Fastenal. The nuts have a built in flange and on the under side they have a serration that bites into the metal to keep them from loosening up.
The exhaust manifold outlets are assembled with special "prevailing torque" nuts. They are "crimped" so they stay tight.
The other option would be brass exhaust manifold nuts. I bought a bag full of these. They have a lot of other fasteners for our old cars. You might be able to see how these nuts are squeezed so they lock on the studs
Last edited by stingr69; Jul 24, 2022 at 10:25 AM.
Rockset. Medium strength comparable to Locktite Blue. Temp rated to 1500 deg F. Can soak in water to help release. Very popular for mounting muzzle devices on rifles.
Recommendation For Thread Locker For Exhaust Flange Nuts?
