AIR Pump disassembly

[Joe L.]

Re: AIR Pump disassembly

Here are some pictures of what I have. This pump was not coming apart in one piece. I bought this pump knowing it was siezed but I thought I'd at least be able to get the back off it.

My car is a October 4 1968 build date and the pump is dated 23881S, late August 1968. Too much earlier and the dates were going to be for the 68 style with the relief valve so this was a litttle hard to come by.

Michael------


This is a pump that experienced exhaust backflow due to failed check valves and, likely, seized up as a result of that. It's probably been sitting around for a long time, too, which has allowed the corrosion to get worse.

Many years ago, Don Dorfman, proprietor of the old "ASL Company" which specialized in rebuilding smog components and aluminum refinishing, told me that rebuilding of seized up pumps was no problem for him. So, it's apparently very do-able.

With a pump like this one, though, your best bet might be to consult with Bill Hodel before you do anything else. You are going to have to get rebuild parts (carbon vanes, bearings, etc.) from Bill or someone like him, anyway. Given the difficulty in finding a pump with the correct date for you, this might be a job that's best left to Bill. There's no substitute for experience, especially for something like this.

[Jim T.]

Re: AIR Pump disassembly

Here are some pictures of what I have. This pump was not coming apart in one piece. I bought this pump knowing it was siezed but I thought I'd at least be able to get the back off it.

My car is a October 4 1968 build date and the pump is dated 23881S, late August 1968. Too much earlier and the dates were going to be for the 68 style with the relief valve so this was a litttle hard to come by.

Michael from your post information above, are there two different pump configurations for the 1968 model year? My original owner 68 built in FEB has pump with the relief vavle in the aluminum housing.

[Michael B.]

Re: AIR Pump disassembly

Jim,

Mine is a 69 model built in Oct 68. All 68 models had the relief valve. In 69 the relief was moved to the diverter valve, internally. The 69 L88/ZL1 did continue with the relief valve on the pump.

I have had the discussion with several members, including Joe, about the possibility that "left over" 68 pumps made there way into early 69 production. Although the judging guide mentions this I'm leaning towards not.

[Joe L.]

Re: AIR Pump disassembly

Jim,

Mine is a 69 model built in Oct 68. All 68 models had the relief valve. In 69 the relief was moved to the diverter valve, internally. The 69 L88/ZL1 did continue with the relief valve on the pump.

I have had the discussion with several members, including Joe, about the possibility that "left over" 68 pumps made there way into early 69 production. Although the judging guide mentions this I'm leaning towards not.

Michael------


The fact that you have found a 1969-75 style pump that has the correct date for your car indicates that this style pump was being manufactured at that time and, therefore, it could have been originally installed on your car.

I think you would have a LOT harder time finding a 1968 style pump with a date that would work for your car. They were, of course, still being manufactured for SERVICE and for the 1969 L-88/ZL-1 applications, but I doubt there were large numbers being produced.

By the way, for those that are not aware, when the pump configuration changed for 1969, that did not just apply to Corvettes. The same pump was used for most other Chevrolet applications, too, and they all changed at the same time. The reason for the change was that most 1969+ diverter valves incorporated an integral relief valve, so the pump's relief valve became superfluous. 1968 diverter valves did not incorporate a relief valve function, so they must be used with a pump with relief valve.

There is no functional reason why a pump with a relief valve cannot be used for 1969+ applications but I doubt that much of this occurred in PRODUCTION. They could not have used the 1969+ style pump with a 1968 diverter valve, though.

[Kenneth H.]

Re: AIR Pump disassembly

I'm gradually gathering the components to replace the missing A.I.R. system for my '70 LT1. I was just getting ready to purchase a pair of restored check valves on Fleabay. Thanks to this thread I now know that that isn't a very good idea. I was wondering, does anyone know where I might be able to get a pair of new check valves that will pass muster for flight judging?

Thanks.

[Terry M.]

[Joe L.]

Re: AIR Pump disassembly

I'm gradually gathering the components to replace the missing A.I.R. system for my '70 LT1. I was just getting ready to purchase a pair of restored check valves on Fleabay. Thanks to this thread I now know that that isn't a very good idea. I was wondering, does anyone know where I might be able to get a pair of new check valves that will pass muster for flight judging?

Thanks.

Ken------


I agree with Terry; buy the restored valves for judging. However, these valves are easily removed and replaced. So, keep the original valves for judging and, if you otherwise drive the car very much, simply replace them with NEW SERVICE valves for driving. Always check them before re-installing, though. It's very simple: you should not be able to blow through them from the threaded end but you should be able to blow through them from the hose nipple end.

[Kenneth H.]

Re: AIR Pump disassembly

Terry,

There are a few pairs out there that are purported to be OEM with correct numbers and configuration, and they seen to come up for sale pretty regularly. But they ain't cheap. Maybe I'll just get the OEM correct valves and hold off on installing the A.I.R. system until I'm ready to have the LT1 judged, which won't be anytime soon.

Thanks.