Head bolt leaking

[Lt.Mike]

I split my Cub yesterday to replace the TO bearing and that leaking head bolt was right there staring at me. Ok so I got a 6point socket and my little 3/8” breaker bar which I felt I couldn’t get enough pressure with to break the bolt. I got lucky and it came out without issue.
In fact the damned cotter pin behind the TO bearing gave me far more trouble.
A new grade 8 bolt will replace the head bolt but I have one quick question , this is the stuff to use?
https://www.autozone.com/sealants-glues ... lsrc=aw.ds

[Bill V in Md]

Yes, that particular Permatex is good for sealing FCub head bolt threads.

[tst]

Teflon sealer

[Lt.Mike]

Thank you !

[tst]

if it leaks it is probably not sealed, which would make me wonder if the others are

[tnestell]

Teflon sealer

That is the best in my opinion!

[Glen]

Hi,
I suggest you wash down through the bolt hole with clean water from a garden hose with a nozzle before putting in the bolt.
Antifreeze leaves a sticky film on metal, and the sealer has to stick some to bare metal.
My opinion is it should be washed off.
Leave the drain plug out under the radiator when washing in the hole, and the water will run out.
I suppose you have drained the coolant, since you took the bolt out.

Dry the threads with compressed air before putting the bolt in.
Blow air down the hole for a while.
Use your safety goggles when using the water and air.

Permatex Aviation Form A Gasket can be used on head bolt threads. It is a non hardening liquid.
It comes in a small can, they sell it at NAPA here in the west.
If you buy one, stir it before using, it can settle some in the bottom of the can sitting.
Below is a pic.

[Lt.Mike]

if it leaks it is probably not sealed, which would make me wonder if the others are

It’s just the one that’s leaking so it’s just the one that will get fixed.
I got lucky in how it came out without breaking so I’m not going to press my luck.
Falling back on the old adage , “if it ain’t broke, don’t fix it”.
As for cleaning the hole I’ll use CRC electrical contact cleaner. Good stuff as it’ll remove the grease and glycol and then evaporate.
Figure to hit it with a 9mm bore brush too.

[tst]

I have had several customers call because their tractor did not start through the years, many had sat during the winter, when I check them out the engine was seized, pull the head and find it full of antifreeze and cylinders/pistons badly cored from the antifreeze, many times the head gasket was replaced recently and the bolts were not sealed so sitting for a few months it creeps into the cylinders, for someone who uses it a lot may get away with it

[Lt.Mike]

I have had several customers call because their tractor did not start through the years, many had sat during the winter, when I check them out the engine was seized, pull the head and find it full of antifreeze and cylinders/pistons badly cored from the antifreeze, many times the head gasket was replaced recently and the bolts were not sealed so sitting for a few months it creeps into the cylinders, for someone who uses it a lot may get away with it

This guy does get used a lot and in the 12 years with me the heads never been off.
There is no off season for my tractors.

[Gary Dotson]

The PTFE sealant in the Auto Zone link is the one I generally use. Pretty much any PTFE pipe joint sealant will work.