I am in the middle of trying to rebuild an old A.I.R pump that I was able to come up with. Appears that it fell victim of a bad check valve and was clogged up with exhaust carbon. Has anyone had any experience with this, or know where a "How to" rebuild proceedure might be found. I want to have it available for my 70 LT-1 if I get the urge to get it closer to original condition. I thought it would be worth while to replace the bearings. Also, I have heard of some dummy pumps that have had the internal mechanisms gutted. How is this done? What should I look for on the pump housing that would tell me the heritage of the pump
Any help is appreciated.

Bullshark

 

I think my 81 shop manual has a good description on this. Got one of those? What year do you need?

 

Not sure which year this one is off of. I believe it is the older style pump housing. By older I mean pre 78. I also have two 78 pumps but the case looks different.

Bullshark

 

ttt

 

Here's how I'd approach a rebuild project for a smog pump.

Step 1: Send it to Bill Hodel - he's the man!
Step 2: Wait patiently for a week or so
Step 3: When it comes back, bolt it on the car

 

there was an AIR pump in a 70 Vett? wow

 

Now that sounds like a plan I missed the part about cashing in one of my CD's to pay for the rebuild.

Seriously who is Bill Hodel? Can/will he provide any guidance if I call him?


Yep...70 LT-1's had them


Bullshark

 

Nothing too special about those pumps. A-1 Cardone used to have blue painted rebuilts available. Maybe you can find one of those and strip off the blue paint?

You might need to cash in one of those CD's to pay for a properly dated rebuilt pump. If you are not worried about the date codes they are pretty easy to find cheap used ones. 1969 and several years after that Chevy units are the same. Avoid the ones from Caddilacs or Buicks as they use the same casting but are machined differently so they do not fit Chevy brackets.

You can trash the pump vanes if you are dead set on having a gutted pump but I would suggest you keep it functional. This mod is not reversible.

I went to the trouble of building a correct appearance but non-functional system on one of my cars. The trees are plugged internally with pan head screws where they attach to the manifolds. I cut holes in the underside of the rubber hoses to bleed off the pump presssure to the check valves. It is not easy to replace the pump vanes if you trash them but the hoses can be replaced if needed in the future. I would have kept the whole system functional but the diverter valve was shot and they are not reproed as far as I know.

Hope this helps.

-Mark.

 

exactly! WOW !




__________________
*** Car Hydraulics Newbie ***

 

I looked in my shop manual, not much there, just a replacement on the impeller on the front.

 

Thanks for the input guys

Well I decided to throw caution to the wind and dig into the A.I.R pump I refered to at the top of this post. It has a casting that looks like the ones I have seen on 71 and 72 LT-1 vettes in shows. As I said earlier, it was seized up from exaust carbon build up. I removed the pully and carefully pressed off the plastic fan on the front shaft. I then removed the bolts on the rear plate and removed it. The rotating cylindrical vane assembly was then easily removed.



Thinking the front bearing needed replaced.....(since it was seized and did not rotate), I used a hydralic press and popped it out of the main housing. Here is where I am thinking I may have screwed up. If you look at the pic below, the bearing looked to be permanently set in the housing with ridges that captured the bearing. When I pressed it out it looks like the ridges were sheared off. Not sure?? Wondering how a new bearing would be pressed in ???




How is the rear bearing assembly removed from the rotating vane assembly? Not readily apparent to me. Need to do that if I want to get to the internal rotating vanes. I might just clean it up and pack it with fresh grease??



Here are some numbers I found on the casting and rear plate. Can anyone tell me what year they are date coded for? Pretty sure it is off of a Vette.






Bullshark

 

The assembly date code is stamped into the housing. You can almost see the stamp in the first picture you posted. From that you will know the date, shift and production plant.

-Mark.

 

Mark, I am not sure what to look for? By first pic are you talking about the one of the front of the housing where the bearing was pressed in, or the one with the whole pump spread out on the bench? I have looked all over the housing and all numbers are in the pics????

Bullshark

 

Ok, I did a little research on the old internet and was able to determine where to look for the A.I.R pump date code. Turns out it is stamped on a pad on one of the cast housing dog ears on the side of the pump. The date code format is DDDY#P, where DDD = the Julian day, Y = the calendar year, # = 1 or 2, and P = is assumed to be the plant code where the pumps were built.
The meaning of # code is unknown; it is not a shift code. 67 pumps were coded 1 or 2 and all 68 and later pumps were coded 1. So my pump looks to have the number 6021S. The 2 is barely detectable with only the top part of the number being stamped, so its a educated guess. That would mean it was assembled on the 60th calander day in (7)2 at the Saginaw plant.



I read somewhere on the internet that pre 72 had a white impeller and sometime in 72 they switched to the black impeller pictured below. Anyone have a white impeller they want to part with?



I plan to go to Bearing Headquarters here in St.Louis and get a replacement front bearing and press it back into the housing. The rear bearing and the vane bearings in the cylinder cleaned up pretty good, so I re-packed them with bearing grease. Everything turns free and easy.

If it all works out, I should be able to reassemble and have the proper vintage A.I.R system for the 70 Lt-1. I just need to pull the old NCRS trick and change the 2 to a 0.

Bullshark

Woops, I better change the 2 to a 9 since the LT-1 has a build date of Jan 22 1970

 

The impeller is available from Paragon. I am sure that it is a repo part so it may not be exaclty the same as an original one from the General. The paragon part number is 11491.

Regards,

Jay

 

Sorry that I can't help you with the date codes but I can tell you how the front bearing was held in place.

Look at the picture of the front of the pump with the bearing. The two small nubs that are located at the 2 and 8 o'clock positions on the front of the housing are plastic injection sprues. You can see a pair of rings on the outside of the bearing. The rings are plastic that has filled the two grooves on the outside of the bearing. I believe that there are matching grooves in the pump housing as well. The bearing was set in place and hot plastic was injected through the two sprue holes into the housing. The plastic flowed around the bearing and housing grooves and locked the bearing securely into the housing.

When you pressed the bearing out of the housing, you had to shear the plastic in the grooves. Obviously, this was not an operation that was servicable. You might get away with epoxy or JB Weld to reattach the bearing to the pump housing.

BTW, Saginaw was in the GM propeller shaft (driveshaft) business in the 1960s and 70s. (They didn't make any Chevrolet parts however.) They had a process to hold the bearing cups for the prop shaft universal joints in place that used the exact same concept. There were special injection molding machines that injected plastic through small holes into the prop shaft yokes to secure the universal joint bearing cups. You had to use a big press to push on the ends of the bearing cups to shear the plastic and service the bearings. Service bearing cups were held in place with snap rings. I can imagine that a lot of home mechanics cursed the engineers that invented this retention process.

Jim

 

Yup, and I watched (from a safe distance) many a "mechanic" heat those puppies with a torch to try to get them apart. Gave a new meaning to the term "explosion" when they let go. It's a wonder that more mechanics didn't wind up in the hospital from that technique.

Steve

 

Jim, Looking at the parts, I think you have hit the nail on the head.

I took the housing and bearing to Bearing Headquarters (a large bearing wholesaler here in the Midwest). They told me the bearing is an old bearing made by "New Departure" which was owned by GM and is now out of business. The guy behind the counter had not seen this type of bearing but agreed with Jim Shea's analysis of the design. We came to the conclusion it must have been a GM custom design since that type of bearing was not standard and it had no part number.

He measured the bearing and cross typed it to a NTN 6203LLBC3/EM which he said was a common bearing used extensively in many type of applications like this. It has no grooves, but indicated it was common design practice to apply Loctite 609 on pressed in bearings, implying that this is today's process, rather than GM's old approach. The bearing was $8 and the Loctite costs $13. Guess that's not bad for the bearing anyway He agreed that the rear bearings needed only to be repacked and looked good to go. It would have been a much bigger job if I had to get inside that rotating vane cylinder.

Stay tuned, I will post some pics of the completed project

Thanks Jay, for pointing out the Paragon impeller I think you got some numbers crossed though - should be #11491. $80 bucks!!!! I will probably keep the black impeller for now Those NCRS guys must be rich

Bullshark

 

What?? you don't need an antenna bezel . I must be dyslexic because I read that reply a few times to make sure it made sense.

Regards,

Jay