I think my A.I.R. pump is giving up the ghost....

[Steve W]

My A.I.R. pump seems to be making weird noises...just once in awhile at first, but now more and more. Kinda rattling, etc.  The shop manual says NEVER to lubricate it,,,,but I'm afraid it might seize up or something!
So, where would I find a replacement?

[The Tassie Devil(le)]

G'day Steve,

Are you sure it is the AIR Pump?

Get a 4 foot length of Garden Hose, put one end up to your good ear, and then move the other end around the nooks and crannies of the engine bay to locate where the noise is actually coming from.   Could be a loose bolt?

From what I have seen of the AIR Pumps I have played with (removes, pulled to pieces for scrap, and thrown the rest away), they are interchangeable.

But, you will need one if you aren't going to move the Alternator, as it is the AIR Pump that drives the Water Pump, and the Water Pump drives the Alternator.

Bruce.

[35-709]

 NAPA and Rock Auto have them, no doubt any auto parts store worth its salt will have them.  Checking NAPAonline, NAPA lists it at $87.49 plus $8.90 core, did not check Rock Auto's price which is often cheaper.   If it IS the AIR pump, seizing up is a common failure mode in my limited experience with them.
Geoff N.   

[TJ Hopland]

What usually happens is the check valve (where the hose goes to the metal cross tube on the 472) quits working so you get exhaust back flowing through the AIR system.   First thing to die after the valve is the diverter valve which on that is mounted to the top of the pump.   Depending on which way it failed it could then be letting exhaust into the pump which eventually destroys everything including the bearings.   Replacement is the easiest thing but make sure the check valve is good.  Just start the engine with the hose off and see if you get exhaust.  If you do its bad.   If the diverter is stuck off the system does nothing but hold the belt in palce.  If its stuck open it causes pops in the exhaust when you let off the gas.  Like someone else mentioned removing it is a pain because its what holds the belt to the waterpump and the alternator drives off the waterpump.   Some models over the years did not have the AIR pump so if you can find the correct parts you can swap the crank and water pump pulleys so you dont need it.   That is not as easy as it sounds because 74 they went from a dual AC PS belt to a single so its one more thing to have to get right.   No big deal if you no longer have AC but if you have working ac you need to get the right parts.  Most 70's did not have the pump.  75 and 78 also seemed to be common years to not have them but it seems to depend on when they were built and where they were planned to be for sale.  Any setup from 68-81 will bolt up its just the single groove vs. double you need to look out for.  Be sure to get the timing marker at the same time since those also changed depending on the lower pulley.

[RobW]

Just one thing to add to the above post. The change in the AC system occured in mid 73. Early 73's used 2 AC belts and a seperate receiver and TXV. In mid year 1973 they changed to a VIR (valve in receiver) system and 1 belt on the compressor.

[Steve W]

Thanks guys. Looks like I have a job ahead of me this weekend. As I was listening to these weird noises, it was hard to really tell EXACTLY where they were coming from...and everything being connected together thru the belts and mounted so closely, its difficult. I know it seems sort of primitive, but I have this long wooden dowel...its about 18" long, 3/4 in diameter...and with the car running, i find a safe place to put it (away from pulleys, etc) on the unit I suspect, and place the other end to my ear. Its kinda cool, I placed it on the different units...alternator, AIR pump, a/c compressor, even the power steering pump (even though thats on the other side of the car) and I can hear the rotating assemblies, just smooth running bearings, etc...except for the AIR pump of course...and the alternator sounds just a little off...but I THINK its picking up sound and vibration form the AIR pump.
So...I guess what I will do is replace the AIR pump, IF I can find a replacement, and put it all back together and give it a listen.
Wish me luck!

[Steve W]

OK, after much searching, I found a pump at Cadillac King here in the Valley. Bought the part, went home to start the process of taking the old one off, and the first obstacle is...the hose clamp on the pump. The hose is held on with that '3-prong' type clamp. I forget what the actual name is...and, OF COURSE, I don't have the right tool...so I went to NAPA, Kragen and finally to Sears....no luck! Grrrrrrrrr...

[The Tassie Devil(le)]

I just use a pair of pliers to release those clips.

Sometimes I use Multi-grips.   And also used a Shifter as well as a last resort.

Bruce.

[TJ Hopland]

Another thing that could be making noise on the front of the engine is the timing chain.  I believe even a 68 had a plastic covered cam gear.  They dont hold up well with age or mileage.   That will be easy to determine, just start it up without any of the belts on.  It wont hurt to run it a minute or so with nothing turning.   If the engine is fairly clean you can get a decent look at it by removing the distributor.  You cant see much but you can usually tell if its really bad.  When they are bad you can see the missing pieces and easily wiggle the chain. 

My 73 had the newer ac setup without the sight glass but still the dual belt.  I think it had the earlier wipers so it could have not been too late.   

[Ted in Olympia WA]

I don't think they changed to a single belt till mid-1974.  All the 73 I have seen are double belts.

I also think the main reason they changed it to allow more room for the HEI.  I have early and late 74 in the field; points have double belts and HEi was a single.

TED

[Steve W]

Single belt? Double belt??  Ha! I have FOUR belts...two to the a/c compressor, one to the alternator and one to the A.I.R pump....plus all the hoses that are directly in the way of everything I need to do...and the A/C hoses are NOT flexible, as they are part metal pipe with rubber hose in-between. Making it extremely difficult to even SEE what I have to do, let alone work on it myself.
And in struggling to get the clamp off of the hose, I broke the ground wire off of the back of the alternator.

I'm afarid the car is going to the shop....damn, I really wanted to do this myself....

[Steve W]

OK..done! I took it to my mechanic and it was a breeze, The tip is to remove the pump from under the car, you just have to get the car up high enough to work under. The pump I got was the wrong one anyway, so he went and got a rebuilt one. Car sounds great once again! 

[The Tassie Devil(le)]

Great news.

Bruce.