Yes, I run an Air Pump because I have emissions testing in my state that requires it and it cooperates well with my RB header and presilencer the rest of the time. On leaving work the other day, startup caused an unbearable screeching/screaming noise and I found that the Air Pump Belt was spinning reluctantly over the pulley. Shut it down and spun each component to see what was binding. Air Pump pully cannot be turned but 1/4 turn forward or backward, effectively killing the belt on the way home (it was 115F out and I couldn't do much in the parking lot at work...).

got it home with minimal slip on the Water Pump pulley and watched engine temp gauge very closely to be sure it was pumping coolant. No problems there. I think I have a spare Air Pump in the garage, but was curious if these are rebuildable...?

For the expected replies of "just remove it", that's not an option. Thanks to all others for any suggestions,

 

It should be rebuildable. I've disassembled one and it seems to have a set of apex seals made of carbon and circuit board material, which are spring loaded. A set from a 12A or FC pump might be swappable.

 

I re built a spare air pump a few years back, but it wasn't seized. They are basically like big pneumatic die grinder. There is a central drum with OD slots that is connected to the external pulley. In each slot, is a rectangular, flat vein. As the drum spins, centrifugal force push the veins outward to the ID of the pump housing to seal off the spaces in-between the veins. The whole thing draws air in, compresses it and pushes it back out again. Kinda like the engine itself, just without the spark to drive it. The pulley drives the whole thing. I'd say that either a bearing is seized or maybe a vein broke is dislodged somehow to keep it from turning. It probably can be fixed but if you need a vein you may need to improvise to find a suitable material to fabricate a replacement from. They are a fiber or phenolic material.

 

Too hot to get out in the garage today to hunt for my spare pump. Good to know it can be rebuilt with some ingenuity. You guys who don't run an Air Pump, do you get pulley slippage on the Water Pump? How do you counter that? Thanks, again.

 

if you don't rebuild yours, the 12A and FC pumps are the same, just the hose fittings change, but they can be changed, so its straightforward to swap right over.

everywhere except CA and AZ should have plenty for sale cheap too, they just chuck em into the woods, as Chuck would say

 

Dual sheave alternator pulley,twin belts. No issue with belt slippage.

 

Turns out; not rebuildable.

The method of this air pump mechanism is basically 3 fiberglass vanes which travel inside of a cylinder each on roller bearings which pivot around an offset shaft such that as the cylinder turns, the vanes are forced outward during part of their travel (about 270deg), and pulled inward for the remainder of travel (~90deg) so that they can clear an internal baffle which creates the intake/output sides to the pump. All of this happens smoothly so that the vanes generate a constant force of air pressure to the output side (the Air Control Valve side). A large roller bearing at the rear of the Air Pump retains the vane assembly and shaft for pivoting the vanes outward. The forward pulley cannot be removed, and drives the cylinder in which the vanes articulate.



Failure mode is that the metal flat springs which hold the fiberglass vanes against the internal cylinder will eventually flatten out, allowing them to be released into the vane path. If you're very lucky, the spring remains flat and finds it's way out of the output side of the Air Pump, ending up in the rubber hose which goes to the ACV, and is held there as it's too big to get into the ACV port to the exhaust. The unlucky failure allows the flat spring to twist slightly, get caught in the rotating assembly and scissor off one of the vanes so that it cracks the fiberglass material, destroys the mounts to the roller bearings on the shaft, and then proceeds to detonate on the inside of the rotating assembly, locking up the Air Pump. That's what happened on mine.

I pulled out the offending broken parts, re-greased and reassembled the working 2 vane assemblies, and found that only 1 of the flat springs remained. I removed it, as it's likely to cause the same problem down the road. With only 2 working vanes, that means I'm down to 33% pressure output, as what would normally be 3 working chambers is now down to 1, much like having 1 of 3 Apex Seals blown, and the other 2 intact. Regardless, I couldn't find my spare Air Pump, so this is how it was reinstalled back into the car and is now awaiting a new belt to power it.

If anybody has a spare Air Pump, preferably in the Phoenix (AZ) Metro area, please send me a PM, as I'll need a 100% working pump for emissions testing next February. In the meantime, I'm unplugging my ACV electrical connector to avoid having it open the air vent in 4th gear, and have tightened up my Alternator belt to help compensate for slippage. I'll be watching my coolant temp like a hawk this next week. Thanks for the advice posted, and let me know what you have available,

 

Do you still have a cat in the exhaust? If so without the air pump it will destroy the cat.

 

No Catalytic Converter (unless it's being emission tested), and I run the RB header to RB Presilencer to RB PowerPulse rear muffler 99.9% of the time. The emissions exhaust system is installed only for the day of testing, and then removed to preserve catalyst function for future years.

At this point in time, I'm considering finding a used Air Pump and installing it where it belongs, but leaving the drive belt off of it until it's time to emissions test. I would run a dual-pulley alternator (as shown above by another poster) in the meantime to retain proper Water Pump function. This is more work to make the car ready for emissions testing, but would get the job done without unnecessary wear and tear on the Air Pump when it's only needed for emissions testing. Yes, I would be dragging around an extra 10+lbs everywhere I go,...

 

Is all of AZ emmisions this way or just in the urban areas like Pheonix?

 

If you don't already have one, I suggest getting a Banzai alt bracket. It makes keeping the correct belt tension very easy. You do have to drill out the threads on the one alt ear but it's easy.

 

Hmmm, must be different designs, mine was different internally.

 

Phoenix Metro area has vehicle emissions testing, as it all falls within Maricopa County. Most counties (*they are large in this part of the country) will have emissions testing requirements if they receive Federal Funding for road maintenance. Smaller towns in out of the way counties may not, as most of the desert southwest is considered rural.

Also, I had occasion to drive the car today without the A/C running for a bit, and found that removal of the Air Pump drag can be felt in the butt-dyno. The engine revs more freely (aluminum flywheel...) without having to turn the Air Pump, and when you're working with less than 150hp, the few you're wasting to turn that thing are noticeable.

Pushes me more toward the plan above to get a dual-sheave Alternator pulley, another belt on there, and call it a day until next February when I can hook up the Air Pump again for the test!

 

^^^ this #1 being parasitic loss #2weight loss(along with associated and attaching components)+yours in condition it is in may have had more drag than a healthy one.

 

^^^this #1 reason parasitic drag #2 reason weight loss(attaching and associated hardware)+ yours may have had more drag than an otherwise healthy one making its absence more noticeable.

 

I hate parasitic drag...

 

 

I live in California, which also requires this air pump. I found one at a salvage yard, so I wanted to test it before I bought it. I removed the hoses and belt, and hand-turned the pulley with a finger in the output hose fitting. Be sure to turn it in the same direction as the pulley does. It turned w/o excessive resistance & I could feel the pulses of air around my finger. The bare air pump (w/o brackets, etc) was like $25 plus a $5 core charge. It also had a warranty, but I can't recall the length of time.

Re-manufactured air pumps are also available, such as Rock Auto, which is an A-1 Cardone unit with a 1-year/18k mi warranty.

Ben