M109A4 brakes locked up!

[mactiredearg]

I tried searching but am on my phone and tapatalk only returns so many search results and none were of any help.

I've got an M109A4 with locked up brakes, they wont release at all. Started the truck up normally thus morning and drove it to a Vietnam Vet display about 10 miles from home. About halfway there the truck was having a little difficulty keeping up speed. Got to the next to last light before the event I noticed smoke so pulled into the event and shutdown. That's when we all realized there was smoking coming from all six wheels (lot more from the front two). Drained tanks and let the thing cool down for two hours and then started poking at it. Pedal has no play. Started back up and tried moving it back and forth but its acting like the driver is standing on the pedal. Shut back down again.

Can't towbar it like this. Need suggestions please! Help!!!

 

[gimpyrobb]

Crack a bleeder. It is not a fix, but might get you moving.

 

[caliber1]

Check the vent on your master cylinder too, might be blocked and not letting the brakes release.

 

[mactiredearg]

Status update: we bled both master cylinders and got it freed up. But when I moved it back and forth they started locking up again. We've hooked up the towbar and I'm headed to get my m35. I'll bleed again and do an adjustment gippyrob recommended and head home slowly...

 

[doghead]

Crack your glad-hand valve open a bit(and leave it open a bit), that will keep the air from building and forcing the brakes on.

This is assuming your airpack is the issue.

 

[Sephirothq]

Or if you have air wipers pull the hose off and open it all the way. You can control your air loss from the cab that way.

 

[doghead]

I did not mean, to create an air leak that will lower the air pressue in the tanks.

I meant, the driver side air line(glad hand). If it is left open a bit, the airpack will not build up from internal leakage(and self apply).

With it only cracked open a bit, you get no pressure buildup(on the air pack) and still get some boost to stop.

 

[steelandcanvas]

Mactiredearg and I had a wonderful day, more story line to follow.

 

[gimpyrobb]

Now is as good of time as any!

 

[steelandcanvas]

We'll let Mactiredearg "tell the rest of the story".

 

[gimpyrobb]

This ought to be good...

 

[mactiredearg]

made it home same thanks to a tow from steelandcanvas and a towbar borrowed from Oldfart and advice from gimpyrobb...
I will stand up in public and say these folks are "good people" of the best sort.

I was steering the truck while steelandcanvas was pulling, but we hadnt gotten a block before we had to stop and block a lane of traffic while I rolled under and bled the brakes again. Of course in the process my phone holster popped off my belt and I didnt realize it.

S&C is a master tow drive and we got to my LZ safe and sound, unhooked and pulled Thing2 into the back yard. And then realized the phone was missing. It had all the pics of the adventure (including the smoking) on it, so before someone me, below is the only pic of the entire adventure.

Thanks to gimpyrobb and doghead for the suggestion on the gladhand. We drained the tanks completely a couple times in playing with it. Even after that I tried the gladhand trick on one of them, but no joy. The only thing that would get it to release was loosening up the bleeders on the hydraulic side. So I'm going to run with it being that side that has the problems when I start digging through it. Just hoping that I didnt glaze the drums and pads on the run up to the event.

Thanks everyone!!!

 

[mactiredearg]

as for the rest of the story, I was gonna be nice but since "big bro" poked:

Seems that steelandcanvas perfectly fills his tank for each event. Taking into account windspeed and direction for the day and everything...

So after he towed my big butt home ("dragged a kitty cat home" as he puts it) he used just a bit more fuel than expected for the outing. Just the right amount extra so that he ran out on the off ramp to his house, less than a mile from his LZ...

I would have laughed harder when he told me but I felt just ever so slightly guilty about making his wonderful wife have to sit with the truck on the off ramp.

 

[gimpyrobb]

Thats AWESOME! It wouldn't surprise me if its the "compensation port" in one of the master cyls.


Glad everyone (almost S&C) made it home ok.

 

[73m819]

Well the good thing about this whole event was that you DID find your phone

 

[CanonNinja]

being an A4, what are the chances BOTH airpacks went bad and causing the issue on both sides?

 

[gringeltaube]

being an A4, what are the chances BOTH airpacks went bad and causing the issue on both sides?

Slim...

In his 1st post the OP said "pedal has no play".... Even being a dual circuit MC there is only ONE pushrod w/clevis, attached to the pedal crank and adjustable in length.
Internal pressure WILL build up if for some reason that tiny (rear)orifice in the cylinder stayed closed after releasing the brake pedal. Either the (rear) piston is not fully returning or it's rubber cup is swollen.

Gimpy might be on the right track...

G.

 

[steelandcanvas]

being an A4, what are the chances BOTH airpacks went bad and causing the issue on both sides?

In my humble opinion, not real good. I think I would put that towards the end of the troubleshooting list. Between SS, the Club's talent, and a TM or two, we'll get Mactiredearg back on the road again.

 

[Awesome Possum]

I don't want to hijack a thread but this is very similar to a problem I'm having with my bobber. I did finally make a power bleeder and this worked great for getting the pedal up, no play at all. Did back off the brake adjustments in the rear (after the brakes had heated up badly) and this gave me some pedal play, but now the rear brakes sometimes don't release right away. The vent line on my MC had been closed by double bending it (by someone else) and I think this is probably the problem. Is it? How can I go about restoring the vent? I plan on doing a remote reservoir; would this do the trick?

 

[SCSG-G4]

Remote reservoir will act as a vent.