View Full Version : Main Drain Caps - Brass vs Lead

12-03-2008, 05:22 AM
This is a follow up question to my other post "Best way to remove lead cap in cast iron main trap" http://www.terrylove.com/forums/showthread.php?t=24926

I went to Home depot and they have caps made from brass, lead, pvc and of a rubber/plastic expansion design. What is the plus and minus of each?

Also upon closer examination, one of the existing plugs is not lead which I assume means it is brass. Is removal of a brass cap different than a lead one? I am thinking, if it is stuck to go at it with a pneumatic cut off wheel to make it easier to break apart.

I am going to do the job this weekend.

Thanks again the help is much appreciated.

12-03-2008, 05:26 AM
A lead plug is used when the opening's threads have deteriorated to the point where a brass or plastic one will not work. The proper way to install them is to screw them in so the lead conforms to whatever thread is left, but many users just pound them in. You do whatever it takes to remove a brass plug. The final method, after all else fails, is to cut them out with a hammer and chisel, or a saw.

12-03-2008, 07:23 AM
As for the final method I usually cut part way aruond the center with the chisel then beat the threaded section inward until it is loose enough to remove.

12-03-2008, 07:35 AM
So why doesn't every one use a PVC cap which can easily be cut out or the expansion cap which all you have to do is loosen the wing nut?

12-04-2008, 11:45 AM
Because as my Dad used to say, "They make the brass ones thin so they are easy to cut out."

12-04-2008, 03:37 PM
I've only removed a couple...the one that had a brass plug had the square nub ripped right out when I tried to unscrew it. Didn't have to cut anything! I then used a hammer and chisel to get the rest out. Dont' remember how long a cheater bar I had on the plug...I'm fairly big and strong, but couldn't do it with the small wrench I have without one.

12-05-2008, 07:19 AM
Well plastic plugs work awesome in plastic pipe. As long as you do not glue it on. Yes I know some people that did that. Plastic plugs in cast iron fittings do not work as well. They freeze on at time requiring me to use a saw to cut them out. Brass plugs are preferred in cast iron threads. But like with anything you buy there is many different qualities of brass plugs some are die cast brass. They shatter when you try to make them budge. Then you have the thin brass Chinese made ones they tear away from the threads which is a pain. Then you have the nice heavy machined brass plugs. These can take a beating, best way to remove these is take a 15 inch crescent wrench and a 3 pound hammer put the wrench on and as your pushing down on the handle take the hammer and hit the wrench right where the handle meets up with the thumb screw. This gets 99% of them to turn with ease. The other 1% I use a chisel to cut along the threads to get the chisel under the plug then pop it right off.

12-05-2008, 07:42 AM
I am thinking, if it is stuck to go at it with a pneumatic cut off wheel to make it easier to break apart.

Ya know on second thought, after reading the exploding dishwasher thread, the sparks created by a cut off wheel may not be such a good idea :eek:.

I think I will stick to a hammer and chisel.

12-07-2008, 07:04 PM
First, thanks again for the help. Here is what I learned:

The expansion plugs that Home Depot (2 red discs with a rubber ring in between that expands when you tighten the wing nut and bolt through the center) do not fit.

The lead caps are a bitch to remove as compared to the brass ones.

To remove the brass caps I scored an "X" with my cut off wheel and broke through with a chisel. Using an old tire iron as a wedge I made the hole bigger and using the hook on the other end of the tire iron under the cap below the square nub it popped right out. If you do these regularly you should consider buying one, mine is a Kent Tool T25. Sure beats using a hammer and a chisel.

The the casting of the Chinese brass caps are half the thickness of the better ones and have about one third as many threads, which as a result sit flush when installed as opposed to being proud by 1/8 to 1/4 of an inch. Went with the cheap ones because they should be easier to remove next time.

The job went well, perhaps too well. I found a easy to clean clog at the end of the pipe near the cesspool. A little back and forth and it fell into the pool, which leads me to think that the heavy use over the Thanksgiving weekend raised the level enough so the flotsam and jetsam got into the pipe. Will have to wait and see, but if I am right I guess I will need to have it pumped.

12-07-2008, 09:08 PM
These are all the tools I have ever needed to open a cleanout...




10-17-2011, 10:44 AM
Old thread bump. Plumber reused old cap when he redid/added the check valve - moved cleanout, etc back.
I noticed that there is a slight air gap in both where the thread meets the CI as well as the *liner* ontop of the plug. Both small holes which are suspect to water infiltration.

Off to get new caps. Is Lead or a Better Quality Brass the way to go on a CI main trap ?
In theory, the trap caps will never need to be opened as the check valve cleanout is the *one in front* and that would be the cleanout they tap into should they need to...