Brake fluid leak, fix now or fix later?

[5ivepenny]

Still learning about my truck and this site, so much good stuff!! and good people so far too. Thanks. So my question about brakes: Background: When the truck sits for more than 2 weeks one of the rear drums and tire gets wet, no smell but feels like break fluid. Have topped off Master w/ DOT 5 twice but in never takes more than a couple oz's. I am a bit overloaded with projects now and already plan on doing a full PM in the fall before winter storage and after I have had a chance to down load the TM's and read through. Fall would be a better time of year for me to take apart my truck and learn more about it. From my automotive experience I am guessing a leaky wheel cyl of some sort resides in the drum.
So my question is: Does anyone think this needs immediate attention?? My solution so far has been to keep an eye on Master cyl level and drive truck more frequently as it only seems to leak when sitting for more than a few days. Also would appreciate links or good search terms to research on SS site. Thanks....now I am off to get a gallon of milk, deuce hasn't been driven in a couple of days...ha ha

 

[DeucesWild11]

I wouldn't chance any brake leak. It's a single stage system so one leak could mean no brakes period. If you know there is a leak then fix it ASAP and don't drive it till it's fixed. Just too risky in my opinion.

 

[73m819]

YOU HAVE TO BE KIDDING ME, BAD BRAKES ON A SINGLE CIRCUIT SYSTEM AND YOU ASK "should I keep running the truck" DA

You have a wheel cylinder leaking, your brakes ARE wet (no brakes on that wheel), a leak DOES NOT GET BETTER, at some point it WILL FAIL = NO BRAKES. NEED to THINK about what the truck HITS with NO BRAKES

After some thought, a KGR posted the above because a nonKGR was about to get a week off.

 

[Carl_in_NH]

I think he said it was an AF deuce in another post - so, it should be dual circuit brakes. That said, I wouldn't chance a brake failure. Whatever is leaking will fail - likely when you stomp on the brakes hard because you really need them.

 

[Warthog]

It is a '86 Air Force Deuce. As far as I know it is still a single circuit system. (87-89 had the dual circuit)

Park it until it is fixed.

 

[ke5eua]

Just drive to your nearest subway restaurant, they know what to do.

 

[FloridaAKM]

Just not funny to the guy who drove his, new to him, Deuce into the Subway building!

Fix your brakes before you cause yourself & someone else a very bad day!

 

[5ivepenny]

Yes, sorry should have said it's and '86 M35A2C from the AF and yes, appreciate the safety concerns, I drive the truck more off road than on and was thinking about it more from a maintenance stand point and how likely it is for a heavy duty wheel cyl to just "blow". With that said I still have to use the public roads to get to my property so you all are absolutely right in pointing out the safety concern. Assuming I keep it only off road for the time being will the seals hold with usage or are these things known to blow?? I have had other experiences with engine oil seals drying out from sitting and not leaking when in use and was assuming something similar was happening. But I also I don't want to be forced to emergency repairs like pinching off a perfectly good line or needing to use a large tree to slow me down....actually the more you guys make me think about it even off-road the risk doesn't seem worth the reward if I end up with a caved in tree shaped bumper or worse. We are already 6 month+ ahead on firewood so maybe I will spend some time soon downloading TM's and learning how to order seal kits and other parts on-line. I have had a lot of beater light duty trucks that I didn't care about in the woods but this isn't one of them. Thanks.

 

[Valence]

Unless it's really rusted out, the wheel (brake) cylinders are super easy to rebuild and hone out. I would venture a guess that what's going on is fluid is escaping from an old, tired cup inside the brake cylinder (likely the spring is the inferior kind w/o "cup expanders"). As said, it won't get better and could cause more damage to the brake cylinder. But you don't know what's going on until you get in there and look.

Like others have said, it's not worth the risk. Park it until you can get to it. You can still go periodically run the engine. While in neutral.

When I serviced my brakes I rebuilt all the brake cylinders. See my post here and the links in the post:
http://www.steelsoldiers.com/showth...ce-Questions&p=1727122&viewfull=1#post1727122

Also maybe useful:
http://www.steelsoldiers.com/showth...ce-Questions&p=1727409&viewfull=1#post1727409

Also, like everyone else, I highly recommend adding a remote reservoir for easier fluid level monitoring. Something like the following:
http://www.bigmikesmotorpool.com/products/remote-master-cylinder-reservoir-kit


Even though I had no indication of issues, I kind of wished I had also rebuilt the master cylinder and air pack at the time (saved on brake fluid).

 

[The King Machine]

When I bought my truck off of a private seller I was able to drive it home as the truck didn't look to be in terrible condition.
It wasn't until a few weeks later that I got into an assessment of the truck mechanically. What I saw when I pulled the drums off gives me nightmares to this day, If I had known the condition of the brake system I would not have drove it. Every wheel cylinder on the truck was leaking to some extent. The truck still stopped but it was just a matter of time before the MC ran dry of fluid then I would have had nothing for brakes. The chances of a wheel cylinder completely letting go is pretty low I'd say but not impossible. For farm use, with only yourself at risk you could get away with it. Your choice. However for road use this truck needs to be parked.

My experience put a scare into me, I have since rebuilt the entire brake system, new rubber hoses, wheel cylinders all around, new MC, rebuilt Air pack. I have spare parts for every component of the system also. The parts are relatively cheap.

 

[frank8003]

Everybody here likes pictures.
How about pictures of what may find in there.

A fact is one may not even see a tell tale leak from a wheel with non-functional brakes because the stuff is so crapped up the fluid can not get out.
There is copies of pictures here. I am going to leave it that way.
"reinforcement" so to speak.
no particular order or wheel. Lots of things to fix.

 

[The King Machine]

Yikes that's uglier than a can of smashed ******.

 

[Katahdin]

The leak will only get worse, the rubber cups are probably old, dry rotted, and cracked. Fix it now or park it until later.

 

[5ivepenny]

tiny pics removed

 

[5ivepenny]

Had week off work anyway, mostly to help my mom move (done) but also to catch up on house projects (no fun, too hot) so just got back about an hour or so ago...been trying to figure out how to upload normal sized pics to this site. My test pics came out like thumbnails. Anyway decided to err on the side of caution and do breaks sooner than later went to retrieve the deuce and bring it home to park on the maintenance pad I built for it this spring. BTW "ke5eua" Ironically I stopped (successfully) at subway for lunch on way back. Fluid was full but test stops on dirt reviled leaky wheel not locking up...probably wet shoes. Anyway will tear into it hopefully this weekend and if I get my digi camera working you guys want some pics of my 1st deuce break job?? if digital camera doesn't work can try my phone again. Thanks again all who gave feed back and links. These pics of my maintenance pad taken with my phone. Did they come out ok?

 

[5ivepenny]

Well that was weird.. Text was supposed to be included in the 1st post.... few quirks I am still learning with this site, guess I timed out while I was messing around loading pics. oh well.

 

[Valence]

Definitely take pictures anyway you can. The ones you uploaded are indeed like thumbnails (but better than nothing, but don't expect us able to help you "look at something" with them that size). When you login, check the box "remember me" and you won't have to log back in again until your web browser cookies are cleared.

 

[5ivepenny]

larger pics

think I figured out the zip file thingy. are these better??

 

[Katahdin]

Pics look good. You'll want some of these copper washers on hand for when you install the new/rebuilt wheel cylinder. Re-using the old copper washers don't work very well in my experience. One each per wheel cylinder. These are #16 and #14 on the diagram frank8003 posted.

http://www.eriksmilitarysurplus.com/cowaforbafio.html

http://www.eriksmilitarysurplus.com/cowaforbafio1.html

 

[saddamsnightmare]

August 3rd, 2015.

Wait until you HAVE to stop a 13,500 lb truck, you step on the pedal, and nothing's there. Your parking brake will not stop you, many small to medium trees will not stop you, the guardrail may not stop you, BUT the seatcover sucked up your butt while you're stepping on the brake...that WILL constipate you!

FIX IT NOW, Mac, before you give the rest of us a bad reputation (see the fool at the Subway noted in the above article)! Not shouting here, gents, just being emphatic! Anybody who questions the need to fix a leak in a single circuit brake system on a medium or large truck must be joshing us, right?