Makita MAC700 compressor leaking oil

[ronkan]

Changed oil the oil on my compressor. Used the correct oil and only filled it half way up the level indicator as specified in the manual.
Leaked oil from the drain plug/bolt.
Removed the bolt, cleaned it off and wrapped it in plumber's thread sealing tape, put it in and tightened.
Still leaking!!!
Any ideas how to fix this?
It was low on oil before I added oil, but it never leaked before.

[ronkan]

I know this is not a very exciting topic, but slip sliding away in my shop is not the excitement I need.
Any suggestions about how to seal this bugger?

[Banditt]

If it's leaking from the drain plug I would put a new o-ring or a copper washer on it. Think I would skip the teflon tape, don't want that in the crankcase.

[Jeremy s]

Are you sure you did not tighten the plug too tight that it cracked the housing?

[daddo]

I'm assuming it has a tapered drain plug.

Remove the plug, wire brush it clean and inspect the threads for any that are missing or damaged. Replace it if it has bad threads.

Using just a coating of oil, install the plug and pull it up snug, then loosen it, then snug it up again - work it a few times in and out.

Use pipe dope or tape and install it working it in snug.

I did make one for a friend by welding a heavy washer onto it and installing an O-ring. Perhaps you can find one somewhere.?

To add, that should be a plug and not a bolt- a bolt will not be tapered! Should be an NPT thread.

Too tight can crack the housing and there is no fix other than replacing the housing.


Mine has leaked (Old Campbell Hause) since it was new but it only seeps a little.

[ronkan]

Thanks guys for the suggestions.
The case is not cracked.
The plug seems to be a bolt not a tapered plug. Pulled one of the crankcase bolts and it looks identical to my eye.
The parts diagram call the plug an "oil draining plug."
Called Makita. Good news is they answered almost immediately. Bad new is he couldn't tell me if it was a tapered plug. More bad news - $11 for the plug plus $7 shipping. Aaarg Seems expensive for what might turn out to be the same part I already have.
Didn't see an O-ring or washer when I removed it, but maybe I missed it, but none is indicated on the parts diagram. I will try adding one to the bolt and see if that is the answer. If not, I will see if I can find a tapered plug.
What a pain that a simple effort at maintenance turned into such a slippery hassle.

[ronkan]

Cleaned oil off the plug (really a bolt).
Put some blue thread lock on it.
Let is stiffen. Screwed in the bolt.
Problem solved. WRONG
Checked every couple of hours and no oil appeared under the compressor.
Came into shop in the morning and found BIG OIL PUDDLE
See next post for new insight.

[ronkan]

I had been hesitant to order another drain plug from Makita for two reasons. First, I was afraid that I would get the same thing I had although mine looked like a bolt not like a tapered plug.
And, I didn't want to wait for the new part and spend $20 for something that wasn't going to solve the problem.

Having run our of alternative ideas for a solution, I went online to buy a replacement plug. Went to Ereplacement parts thinking it might be less expensive than Makita. It isn't less expensive, but what it did have was pictures of the parts.
The drain plug looks very different than what I have. What I have looks exactly like what is listed under the part number for crankcase cover bolts. Looks like I have had a crankcase cover bolt instead of a drain plug all along. Have no idea why it didn't leak before. Maybe it had leaked over the years and I just took it to be the nature of things until I added oil and a lot ran out at once.
I will post my experience when the drain plug arrives and is installed

[ronkan]

Wasn't the drain plug. Installed it and still leaked.
Spoke to tech support. He suggested pulling the crankcase cover.
Great idea! The rubber gasket was distorted - stretched with one of the bolt holes raggedy. No idea how that happened.
Ordered a new gasket. Arrived today.
Installed it. NO LEAKING.
The fix took about two minutes. Figuring out the fix took almost two weeks.
Just thought anyone who bothered to read this thread might want to know how it was resolved. Don't you love happy endings.

[PaulC]

Glad it's solved. Thanks for posting the follow-up. That's what make this forum useful.