Pretty sure my air packs shot.......

I installed a new master cylinder, built the power bleeder as yall suggested and it works great. I bled the air pack, then at the wheels, got lots of air at the wheels. My pedal still sinks to the floor 1st pump then 2nd pump its good BUT now its blowing fluid outa my slobber tube & i can hear a pssst from the air pack when pumping the brake. So, is my air pack shot? Internal seal blown or something? Any other way i could be getting brake fluid in the vent? I have a remote reservoir hooked to the MC cap vent.

Speaking of the MC cap, apparently there's 2 sizes and the my new MC is the big one & the spare i had for my power bleeder is the small one. Where can i buy just the cap? I really dont wana be changing the fittings in ny cap every time.

Thanks guys, i know i ask alota questions

You said you had a remote reservoir hooked up to the MC cap. If so, you can install a connector to hook up the power bleeder in the hose from the reservoir to the MC cap. Just put a shutoff valve above it, so the pressure goes to the MC and not to the reservoir. For normal driving, the shutoff is open, you only close it for power bleeding. That way you do not have to mess with the MC cap at all. Common plumbing parts.

Air pack: Here is a rebuild thread with pics: https://www.steelsoldiers.com/showthread.php?82753-MY-Airpack-Rebuild-with-Photos!

Id feel alot better bout doing that in a steel line. This remote kit is kinda mickey mouse. The hose dont fit the barb very tight & have to crank the fool outa the clamp to get the hose tight. I feel sure it would leak if pressurized. On top of that im not sure its not air locked or something. When i took the hose off the MC cap today no brake fluid came out & the MC was only bout half full. Reservoir on the firewalls full tho, right up to the line. Obviously not real stoked bout the remote kit. Great concept but i need to plumb up something decent.

Whats yalls thoughts as to integrity/longevity of new air pack vs rebuild?

sgms18 said:

Whats yalls thoughts as to integrity/longevity of new air pack vs rebuild?

Click to expand...

I had similar problems on an air pack on a truck I was selling recently. I went with new, mostly due to timeline.

There shouldn't be a big difference.

Will dot 3 cause air pack failure? I dont know how to tell the difference other than color but most of the old fluid i bled out was a clearish yellow color. Fairly clean looking but not purple at all. Does dot 5 loose its color w/age or water contamination?

Is it a short or long AirPak?

I’ve rebuilt both with success, but I did have a long AirPak last year that I rebuilt twice, and it suffered from the same symptoms you mentioned (blowing brake fluid out of the vent in engine compartment). There are parts inside that we cannot rebuild, so I removed it & replaced it with a NOS short-style AirPak....problems solved, it worked like a champ.

Member Rustystud listed a shop back east that does complete rebuilds on AirPaks; I need to send this extra long one off to get thoroughly rebuilt to have on hand as a spare. Contact him to get the phone number, as I don’t have it handy right now.

I have the long style on the truck. So the short long style are interchangeable? Whats the difference other than the size?

sgms18 said:

I have the long style on the truck. So the short long style are interchangeable? Whats the difference other than the size?

Click to expand...

I think only one or two air fittings, IIRC. Fairly easy to interchange.

I’d compare the cost of sending the long style off to be rebuilt against the cost of a NOS short style...if you send your long style in to be rebuilt, at least it will be a direct bolt-in when it’s returned.

silverstate55 said:

Is it a short or long AirPak?

I’ve rebuilt both with success, but I did have a long AirPak last year that I rebuilt twice, and it suffered from the same symptoms you mentioned (blowing brake fluid out of the vent in engine compartment). There are parts inside that we cannot rebuild, so I removed it & replaced it with a NOS short-style AirPak....problems solved, it worked like a champ.

Member Rustystud listed a shop back east that does complete rebuilds on AirPaks; I need to send this extra long one off to get thoroughly rebuilt to have on hand as a spare. Contact him to get the phone number, as I don’t have it handy right now.

Click to expand...

The company that rebuilds the air-pacs with new stainless steel liners is "Precision Rebuilders" . Phone number is 1-800-325-2690 . Ask for Tim.

Thanks Greg!!

rustystud said:

The company that rebuilds the air-pacs with new stainless steel liners is "Precision Rebuilders" . Phone number is 1-800-325-2690 . Ask for Tim.

Click to expand...

I would assume this companies rebuild is more complete than what we could do at home w/the $80 rebuild kit?

sgms18 said:

I would assume this companies rebuild is more complete than what we could do at home w/the $80 rebuild kit?

Click to expand...

Yes. They actually "reline" the main and side bore with stainless steel. The side bore is what allows the master cylinder pressure to apply the main pressure piston in the air-pac. This bore gets really worn over time and the pressure cannot build-up properly. This is also where a lot of people install the piston seals wrong. They think pressure is applied in only one direction. Forgetting the main pressure side.

rustystud said:

Yes. They actually "reline" the main and side bore with stainless steel. The side bore is what allows the master cylinder pressure to apply the main pressure piston in the air-pac. This bore gets really worn over time and the pressure cannot build-up properly. This is also where a lot of people install the piston seals wrong. They think pressure is applied in only one direction. Forgetting the main pressure side.

Click to expand...

Ok, thanks for the insight. I will call em today & see what they say.

Well, I talked to the guy at Precision Rebuilders & he said he couldn't really give me a price till he looked the air pack over but it would probally be $450ish. Looks like I'll be buying a new one.

sgms18 said:

Well, I talked to the guy at Precision Rebuilders & he said he couldn't really give me a price till he looked the air pack over but it would probally be $450ish. Looks like I'll be buying a new one.

Click to expand...

The cost to re-sleeve the bores is expensive, but it will never wear out again !

rustystud said:

The cost to re-sleeve the bores is expensive, but it will never wear out again !

Click to expand...

So do you think I'd be better off spending $450 on a rebuild than $400 on a new one?

You know what you'll be getting with the rebuild: an AirPak that you should never have to worry about again. With an NOS/"new" AirPak, who knows...unless you know the date of manufacture/rebuild and it hasn't been sitting on a shelf or in someone's yard for 20 years or more.

It all boils down to how much value you place on your peace of mind.

Hmm...... Good point.

silverstate55 said:

You know what you'll be getting with the rebuild: an AirPak that you should never have to worry about again. With an NOS/"new" AirPak, who knows...unless you know the date of manufacture/rebuild and it hasn't been sitting on a shelf or in someone's yard for 20 years or more.

It all boils down to how much value you place on your peace of mind.

Click to expand...

Totally agreement here ! A few years ago I bought two NOS air-pacs. I dissembled both just to be sure and found one was OK. The other one though had extensive rust through out ! It was almost unrebuildable ! So with anything being that old even if it is NOS your rolling the dice on the condition. At least with the rebuilt one you know it will last your lifetime if not longer. Just saying.