Brake fluid coming out of drip tube at turbo

[cowboyballer]

I got a 1972 m35a2 and I just done 2 back wheel seals and I got in the truck fired it up and was pumping the brakes and brake fluid started coming out of the big drip tube at the turbo anyone have a ideal what it could be

 

[cowboyballer]

And when you press the brake pedal air comes out the drip tube

 

[daytonatrbo]

If air and brake fluid are coming out of the same place, you likely have an issue with your master cylinder and airpak.

However, I can't think of any reason why either would be coming out of the slobber tube. Unless its coming out of the master cylinder vent, and it just looks like it coming out of the slobber tube.

 

[cowboyballer]

Yea that is the only way it would be. I had just put fluid in the master cylinder but I didn't hook the vent back up on the lid pain in the butt. But my wife pumped the pedal about 6 times and a cup full come out. But I then hooked the vent back up and It stopped coming out but when u pump the brakes you can hear air coming out the slobber tube

 

[cowboyballer]

That's with the truck on or off you can hear it... but let me back up a second the air comes out when you left off the pedal. But the brakes work great they are tight and stop good

 

[Recovry4x4]

On the original design, the air assist cylinder was vented into the slobber tube. At some point an MWO was introduced where it was removed and simply had a check valve installed on the line after it was bent like a J. Yours obviously hasn't had that MWO. The brake fluid is a sure sign that your air assist cylinder needs rebuilt.

 

[cowboyballer]

Yea like I said the vent line was unhooked when that happen and I hooked it up and it stopped so idk what the deal was. Anyways would over filling the master cylinder cause fluid to come out the slobber tube??

 

[cowboyballer]

On the original design, the air assist cylinder was vented into the slobber tube. At some point an MWO was introduced where it was removed and simply had a check valve installed on the line after it was bent like a J. Yours obviously hasn't had that MWO. The brake fluid is a sure sign that your air assist cylinder needs rebuilt.

Where abouts are you talking about is the check valve? Are you talking about off the J tube on the back of the air pack? If so I would have to go look I was talking about is the vent line that is hooked on top of the master cylinder cap

 

[jatonka]

yes,over filling can send some fluid out the vent tube

 

[cowboyballer]

Ok well that is what happen then it was about to over flow. But being I was bleeding the brakes. I figured I could use a little extra Lol.

 

[daytonatrbo]

Good info coming from this thread!

 

[gimpyrobb]

Good info coming from this thread!

You mean...
Good info being re-posted in this thread

 

[rmgill]

I performed the MWO which separates the Master Cylinder Vent from the common fuel tank vent and which connects to the Slobber tube. This is a good thing to do as it avoids dumping brake fluid in your fuel tank or contaminating your master cylinder with fuel.

The fact that you have BFS coming out of the slobber tube is likely indicative of a problem with your Air Pack. I just rebuilt mine because I had the same issue, except in my case it was dumping BFS out on top of my air filter housing because that's where my vent comes out. The seal on the air pak around the air piston's push rod will begin to fail and will leak. This works it's way up the vent line every time you step on and release the brakes.

I strongly suggest you fix the Air Pak and effect the MWO. There's a PS that covers the MWO.

 

[daytonatrbo]

I performed the MWO which separates the Master Cylinder Vent from the common fuel tank vent and which connects to the Slobber tube. This is a good thing to do as it avoids dumping brake fluid in your fuel tank or contaminating your master cylinder with fuel.

The fact that you have BFS coming out of the slobber tube is likely indicative of a problem with your Air Pack. I just rebuilt mine because I had the same issue, except in my case it was dumping BFS out on top of my air filter housing because that's where my vent comes out. The seal on the air pak around the air piston's push rod will begin to fail and will leak. This works it's way up the vent line every time you step on and release the brakes.

I strongly suggest you fix the Air Pak and effect the MWO. There's a PS that covers the MWO.

...

On the original design, the air assist cylinder was vented into the slobber tube. At some point an MWO was introduced where it was removed and simply had a check valve installed on the line after it

Well, now I'm confused.

 

[Flyingvan911]

Originally the vent tube for the master cylinder was T'd into the vent line for the fuel tank. Which then ran to the slobber tube. I need to seperate mine.

 

[cowboyballer]

I'm pretty sure mine is run together like that I need to separate mine as well

 

[cowboyballer]

Well I just went and looked and my brand new wheel cylinder is leaking going to wait a few days and see if it stops

 

[rmgill]

At this point if it stops, you'll probably be low on BFS/DOT5. Fix that cylinder.

 

[rmgill]

...

Well, now I'm confused.

BrakeVentFix1.jpg
BrakeVentFix2.jpg
PS magazine issue 364 (Mar 83), p18-20Brake vent line modification