Brake Fluid Leak Around Master Cylinder Cap????

[trider]

This past weekend I added a remote brake fluid reservoir to my deuce and a half. I now have a brake fluid leak from somewhere on the master cylinder. It appears to be coming from the top and looks like its coming out around the threads of the master cylinder cap. I dry the top of the master cylinder off them when I go back and check it I have fluid around the master cylinder cap. Has anyone else had this happen when adding a remote reservoir? Do you think I should add teflon tape to fix it?

 

[Jeepsinker]

I use only Rectorseal pipe thread sealant. Teflon tape is a pain.

 

[welldigger]

The best thread sealant I have ever used. Use anywhere standard pipe threads are used. Use sparingly.


http://www.permatex.com/products-2/...ants/permatex-thread-sealant-with-ptfe-detail

 

[Jeepsinker]

Dude, do you ever sleep? I know you work ummm... Today....

 

[rustystud]

Dude, do you ever sleep? I know you work ummm... Today....

Well your still up too ! and so am I !!! LOL !

 

[Woodsplinter]

I had the same problem and sealing the threads of the m/c cap will not help. You need to put a thin washer under the cap. I think I used a thin copper washer from a hardware store. My leak was coming from where the bottom edge of the metal cap meets the m/c, just above the threads. Hope that makes sense- it's past my bed time.

 

[Katahdin]

Yeah, the cap on my MC came with a copper ring/gasket, it sounds like yours is missing.

 

[cattlerepairman]

A copper washer is great; a flat plastic washer from the plumbing section (the ones used for sink traps; 1 1/4 inch I think) also works very well. I had the same problem after adding the remote reservoir...constant loss of brake fluid.

 

[trider]

In the small town I live in we have one parts store and an Ace Hardware. Th best thing I could find is a rubber o-ring so I am going to give that a shot if it doesn't work I will have to find a copper washer in a different town.

 

[doghead]

Why not look up the NSN and Google search it?

 

[steelandcanvas]

In the small town I live in we have one parts store and an Ace Hardware. Th best thing I could find is a rubber o-ring so I am going to give that a shot if it doesn't work I will have to find a copper washer in a different town.

Your Ace Hardware ought to have that 1 1/4" plastic washer and it won't deteriorate like the rubber O-ring.

 

[trider]

I went theough ever little plastic bin with washers, o-rings etc couldn't find anything so I asked the guy and he said they didnt have anuthing lile that. The o-ring stopped my leak so im leaving it alone until it start leaking again then I will look in another town.

 

[cattlerepairman]

I went theough ever little plastic bin with washers, o-rings etc couldn't find anything so I asked the guy and he said they didnt have anuthing lile that. The o-ring stopped my leak so im leaving it alone until it start leaking again then I will look in another town.

Murphy says: "If it ain't broke, do NOT fix it". Good plan.

 

[rustystud]

Murphy says: "If it ain't broke, do NOT fix it". Good plan.

The only problem with that is if it's the wrong part it will fail in time due to incompatibility with the brake fluid, and usually the time it fails is the worst possible time !

 

[gimpyrobb]

Yes but where its leaking, it will still leave him with a full master cyl, just like a stock truck.

 

[jbayer]

It really depends on what that O-ring is made of.
I think the DOT 5, being Silicone based Is not as harsh on plastic/rubber like DOT 3. (Assuming it is DOT 5)
Not meaning it wont ever deteriorate rubber/plastic.
Just my

 

[doghead]

Why not just get the correct seal?

 

[trider]

It is DOT 5 brake fluid and I will continue to use the o-ring until it starts leaking then I will get a plastic or copper washer.

 

[rustystud]

Yes but where its leaking, it will still leave him with a full master cyl, just like a stock truck.

My comment was towards the "don't mess with it if it's not broken" idea. Not this fix in general . In the Marines and here at work I have been required to make field expedient repairs. Some turned out to be a real good fix, but in general it is better to use the factory part as they are the ones who have spent the money and time to research what will and will not work.

 

[MyothersanM1]

Try these...

I did the remote MC reservoir mod on my M818. Mine seeped at the cap with the copper washer. I replaced it with this...Double Seal Buna-N O-Ring...from McMaster-Carr. Buna-N , AKA Nitrile, is compatible with silicone. Mine is holding fast for now.

I believe, therefore I don't know , the Deuce MC cap may be smaller diameter. If you go this route, do not over tighten as the o-ring will bow out on one side.