73 CJ5 Master Cylinder Leak

My master cylinder just started leaking out the bottom when brakes are applied - I've lost about half the fluid from the rear-most reservoir. The cylinder has less than 50 miles or so on it, and is the second to leak from the very same location upon installation. Is this like a "freeze plug" designed to release pressure in the event of an internal problem? It looks like it has some sort of bolt, and has been covered over with an epoxy type material that has pulled away from the metal on one side.

Both cylinders were ordered from the same online major Jeep distributor, but the actual make is unknown. I am now reluctant to go back to them to get a third potential piece of c___!

Any help appreciated.

Mike

 

Nothing at all like that on a master cylinder. Got a picture?

 

Packrat - Thanks for responding. I have enclosed a pic. The leak (if you look close you can see a drop of brake fluid) is out of the bottom of the round portion in the middle of the case (not a real clear description, but hopefully you can decipher it). Every master cylinder I have ever had on this Jeep had this feature. However, I never had a leak here, except for the last two, both of which were Crown Automotive.

Negative on the pic - I will try to send it to you directly. I am new to the forum, and it seems I don't have attachment posting permission. Not sure what the big deal is, but it certainly limits free and open communication.

Mike

 

Packrat - I finally figured a way to get the pic online where you can see it. Go to my profile and pull up the public album I created, if you are still interested. I looked at the forum info re: attachments, and none of it made sense or worked. Might just be a "headspace and timing" issue on my part.

 

I believe that would be the port for the brake light switch. Maybe it actually has one or not, but mine has the same thing except its sort of a threaded on cap with a prong on it. Mine also leaks about about a drop a day or two.

Probably the best bet would be go to the local auto parts store and check theirs out and see if they have one that does not have that port cast in. Good luck man!

 

Here's what the MC looks like on a 72. That location is where the brake switch is located on the 72. I got mine at Autozone, cheaper than the well known replacement supplier.

 

Thanks, guys. Now I know what the opening is for. On the '73, the brake switch is located on the brake pedal. It may be that during the remanufacture of these cylinders they are not getting the opening plugged properly.

Mike

 

I would tend to think that if those are 'new' master cylinders from China then they're using the old casting with the brake light switch port or they have a lot of old masters with the switch they're using up. Not 100% sure but 72 should have been the last year for the MC mounted switch, at least it was for Commando.
OTOH they may be using the wrong type plug and need to be aware of the problem. I've run those MC's before and seen a lot of then with a plug and they were never a problem.

 

my 73 has that type of master cyl. also and it is plugged and no leaks as of yet. i purchased mine from oreilly's.

 

Just an FYI. No one has permission for attachments since the site was hacked a while back. There is a post about it I believe in the announcements section or similar

 

Nickmil - Thanks for the info re: posting attachments. Since I am new, I figured there was an explanation that I had not found. Is there another way (such as what I did by creating an album in my profile) to occasionally share pics, especially when they contribute to the understanding of a technical issue? How was Roadhog able to post a pic of his mc in this thread? I'm not looking to make waves, just want to know how best to send and receive info.

Thanks, Mike