Every two weeks I have to tighten the big brass nut that hold the exhaust pipe to manifold I tighten it real tight but just like clock work in two weeks it is loose does anyone know why and how to keep it tight?
The vendors sell a small device that tightens around the pipe and then a fold up tab goes against the flat on the nut and keeps the nt from turning or you can use a hose clamp tight up against the nut both work good.
Mine would work loose once an hour. I got the part from the vendor that Rick mentioned. It never came loose again.
An exhaust pipe to muffler clamp will cause this too.
Another option. Go to the hardware store and buy a metal strap about 2" long and roughly 3/32 thick. They are usually used to strap together 2 pieces of wood and have a hole at each end.
Bend it in a vice to a "Z" shape so that when the bottom of the Z is clamped to your exhaust pipe, the top of the Z fits snugly over a flat on the exhaust nut.
Same thing the vendors sell, just cheaper and instantly available. Works great.
The threads on my manifold didn't hold the new brass nut. I took a hack saw and cut one side of the nut and formed a quality s/s hose clamp around it. When I was sure the threads were started I tightened the clamp then tightened up the nut and a final on the clamp when the pipe was snug. This clamped the nut tight on the manifold threads and hasn't loosened now in years.
Re-tighten it when hot. Brass expands more with temperature than iron, so heat will loosen it up a bit. Of course, if you need to break it loose later, you will have to get it hot.
You have to tighten it with a big wrench. A pair of channel lock pliers won't get it tight enough. Tighten the nut one time with a proper wrench. You won't ever have it come loose.
Here's the wrench my grandfather Adolph Peterson made for this task.
See this old thread from 2009 in which a member was having problems keeping his exhaust manifold packing nut tight.
Pay particular attention to Ed's post at 12:05 pm April 14, 2009. It shows a very innovative item for locking the packing nut once it is tight. Sort of like a very large version of the bendix nut lock washer. When you click onto the link Ed provided, the part will not appear because it is no longer a new item, but you can access it, by clicking onto exhaust system to the left of the page. This thread also suggested tightening the nut when the manifold is hot, which seems to have worked for the member having the problem. Jim Patrick
Oops. Might help if I post the thread .
I've purchased the nut lock, but haven't had to use it yet. Using the proper wrench I snugged as tight as poss cold. Warm the engine up and tighten some more. Go for a drive and tighten some more. I also use dry graphite to lube treads and ease the tightening. So far, I haven't had to use the nut lock yet. I've checked tightness monthly and it hasn't budged. I also have rolled up aluminum foil and stuffed it in between the nut and pipe to stop leaks. It's working too.
George n L.A.
A cheap stainless 1 1/4" radiator hose clamp tightened up on the pipe against the nut will stop this problem.
You may have an inferior pack nut. I've seen a few reproductions that have threads that are too shallow. I always use a Ford pack nut wrench, and they never come loose. Also, as you tighten, wiggle the exhaust pipe to help it seat against the manifold. And of course my last comment is, those horrible reproduction exhaust pipes they make. Too bad someone who owns a first rate tubing shop can't make them for use exactly like Ford did.
Ken K mentioned that if the pipe is clamped to the muffler, may cause this. Model Ts are supposed to rattle. Rattles don't seem to bother me. However, many people do try to quiet them down.
The problem with clamping the pipe to the muffler, is that depending on many variables in the muffler, pipe, mountings, manifolds, and clamps, if something doesn't give easily, something will break because of the normal and healthy-by-design twisting in a model T frame. With the muffler properly mounted, and not-properly clamped to the head-pipe, it is possible (and has happened a few times) to bend or break the exhaust manifold. The muffler and pipe can be clamped (or even rust seized) to not rattle, but be still loose enough to give for frame flexing. But that is tricky and not reliable (more rust seizure). If your muffler and pipe are tight, the muffler should be allowed some "float" on the frame mounting. Spring loaded bolts would probably suffice. Other creative mountings could also work. This is especially important on earlier cars with mufflers properly mounted on both ends.
Drive carefully, and enjoy, W2
Wayne - Excellent point. It's not proper, but when using muffler clamp to clamp muffler to exhaust pipe, I have used (successfully so far) a universal type hanger to support the muffler. The hanger includes a short length of reinforced rubber to allow flexibility.
That pack nut is a weird thing. You can drive a car for 30 years and never have it come loose. Then, all of a sudden, it works loose. No big deal, tighten it up. Drive 20 miles: loose again. and so on, and so on....
The little retainer device above works wonders. Getting the pack nut "real tight", as some above suggest, isn't such bad advice but, with the proper sized wrench, it's entirely possible to break off the end of the manifold. They're surprisingly thin, but you won't know that until you bust one off!
When I assemble the exhaust pipe to the manifold, I coat the threads and both mating surfaces with "Muffler Cement". It not only makes a leak-proof seal between both pieces, but keeps the nut from loosening. When hot, it is easily loosened with the proper sized wrench.
Wayne. As you said and I agree with, the Model T is supposed to flex, by design, but I don't think the manifold and exhaust pipe were ever meant to flex separately from eachother as you implied (if I misinterpreted that, I apologize). By saying so, you are implying that the packing nut should be loose enough to allow for them to flex, but that would allow exhaust gases to escape between the manifold and the exhaust pipe flared connection, which will allow the escape of gases and noise. Much better to have a good tight joint and allow the exhaust pipe to flex further down toward the muffler as it was designed to do. That way, there is no danger of becoming asphyxiated by exhaust fumes coming into the cab instead of being safely ejected out the rear. Jim Patrick
Wayne, I re-read your thread and I did misinterpret it. For some reason, I misread muffler as manifold . Please disregard my thread. Sorry. Jim Patrick
I use the Ed method on all my Model T's. It works very well except when the threads are worn out. The threads on the manifold must be clean and sharp, and same with the nut. If the threads are stripped, the Ed method will keep it from completely backing out, but it could still slip somewhat.
My worm drive hose clip is a nut retainer only. It prevents the loose nut migrating right off an letting the pipe loose. This present nut is the first in forty years which I have not been able to keep tight. It will be replaced when the exhaust needs working on.
Allan from down under.
No problem. And I always look forward to your comments. Thank you.
Yes, the manifold nut should be tight. After putting a manifold nut back on, I always run the engine good and hot, then re-tighten the nut. It usually will turn a bit more hot and reshape the head-pipe to seat tighter. WARNING! You cannot put nearly as much pressure on the nut with a wrench or any other implement when it is hot (as you would cold) because if you try to, you WILL break the manifold (brittle when hot).
The muffler end, I let rattle to its heart's content.
If I had a manifold nut that kept backing off, I would use one of the clamps suggested above (me, would probably be the home-made version). But I have never had a recurring problem with one.
Drive carefully, and enjoy, W2
hey all you guys with the loose nuts should check out my fix with the cut on one side. With the hose clamp tightened around it clamps to the threads and doesn't slip back.