Air pack question

[Jim145]

I had searched the site before posing this question......

today I started up the deuce and went for a drive I noticed the brake pedal was a little spongey at first then it tightens up good, if it sits for about 4 or 5 min without touching the brakes it feels spongey and goes about half way down.

I checked the fluid level and its good, no leaks, and for the hell of it I bleed the lines,no air bubbles.

Is this a sign of an air pack problem? i

I had read that there is a nut on the back that can come off to lput wd40 into, But on mine there is no nut on the back
would you recomend I just take the line off the back and spray it there?

as always thanks,

Jim

 

[ken]

When you step on the brake pedal the fluid moves a air valve witch pushes the big piston from the back. The air valve is probally sticking or the big piston sticking. The big air piston is lubed with grease. If the air tanks haven't been drained of water then water can collect in the big piston's bore. causing rust and sticking. I don't know if NJ has high humidity, but it's a real problem in Houston. I would dissemble the air pack and clean and lube the pistons. Be careful when removing the cap off of the back where the big piston rides the spring can send objects great distances!!!!! Don't forget to drain the airtanks each time you get the tuck home.

 

[Jim145]

Ok Ken, I will try what you said.
as far as draining the tanks, I do it daily and some mist comes out.

when I do press the brake pedal and release I hear the air go psssschhh (you know what I mean )
would a faulty air pack do that?

 

[cranetruck]

Jim, what you hear is the airpak venting and is normal. The venting tube connects with the vents from the fuel tank and brake master cylinder. It should be separated and be vented on its own to keep fuel fumes from entering the system.
As far as lubing the airpak, I would not use grease, use an oil, I would recommend a pneumatic lube oil. It gets into the large cylinder bore, mixes with the air and provides lubrication for all valves within the airpak.
You can check your brakes and bleed them without the air. There is a bleeder valve right on the airpak, which should be bled first, then do the wheel cylinders.

 

[Jim145]

Well, so far I squirted air tool oil into the airpak and I put some into the compressor too. started it up, drove it it brakes good (just as good as before my squishy brake pedal) I bleed the air out of the tanks( very small amounts of oil).

The pedal is still going almost to the floor but stops the truck fine, if I let up and press again the pedal is half way down before it is stiff.
I guess for now I will run like that maybe it will fix itself :smilewinkgrin:
I've been working on this on and off all day, I've made some progress with the fuel system too but I'll talk about that on the other post.

 

[MVtrucker]

Crane Truck said it, I'll say it again, bleed the system and keep the master cylinder full. Bleed the WHOLE system. I do it by myself, but a helper is good.

 

[ken]

You can use oil instead of grease. Ive rebuilt a few of these at the fire dept and they all were lubed with white grease. So when i reassembled them i went back with the grease.

 

[rdixiemiller]

Try adjusting your brake shoes. When brakes "pump up" hard, it usually means the shoes are loose. The first stab runs the shoes out til they touch the drum, the second quick stab gives you a high pedal and good brakes. Pumping up brakes and having them feel really spongy usually means air in the lines.

 

[MVtrucker]

If/when you bleed the system, do not pump the pedal rapidly. DOT 5 makes air
bubbles, so I've been told.

 

[Jim145]

Ok guys, I'll let you know what happens when I get a little time to work on her( more than likley this weekend) going to work really cuts down on my quality time with my truck not to mention the weather here went from nice 65-70 deg to well into the 90's.
My job has me outside all day with no A/C so when I do get home its hard to get me out of my cold house :eyes:



How's the weather around the rest of you guys? I know MVtrucker his more than likely in the same boat as me with the exception I get an ocean breeze once in a while.

 

[Recovry4x4]

Here is S Fla it rains a couple of inches every afternoon. Humidity hovers at around 150% and its around 90 every day. Fortunately, I work at night and it cools off to around 85. I might be exaggerating on the humidity but it doesn't feel like it.

 

[Jim145]

I hear ya Kenny, I once lived in the panhandle about 10 years ago in Mariana Fla in Jackson county. I remember rain everyday at around 1 or 2 in the afternoon and the humidity.....I dont miss that and I dont miss the fire ants either :yeah:


Kenny, Did you get the envelope I sent?

 

[Recovry4x4]

Jim, I sure did and thank you very much. You're quite a gentleman. I'm sorry I didn't let you know.

 

[MVtrucker]

Yes, Jim, conditions here are about the same as yours. Hot and very humid July and August. I get an ocean breeze too, when I go to Ocean City (NJ)

 

[Jim145]

We are getting hammered right now with the down pours lightning and of course THUNDER.

 

[MVtrucker]

Same here, been doing it for a few hours. Hail up north.