1978 Z28- Seee Ya!

Discussion in 'Project Progress' started by 8pack, Mar 8, 2014.

  1. Scott Sievers

    Scott Sievers Veteran Member

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    Nice set up! The serpentine belts are so much nicer to deal with.... Mine is still all original so it will stay that way for now... I forgot just how COLD that original style compressor could make the air.
    I flushed the system and filled it with 134a and WOW... time to take braless ladies for rides! Until the wife finds out........
     
  2. 8pack

    8pack Veteran Member Lifetime Gold Member

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    Did you convert everything to accept 134a?
     
  3. Scott Sievers

    Scott Sievers Veteran Member

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    The only conversion necessary is adapting the fill port on the low pressure side. Adding one to the high pressure side makes connecting both hoses possible but isn't necessary.
    The adapter literally screws onto the low pressure fill port after you unscrew the valve. Flushing the system and adding new compressor oil is recommended. I also usually change the accumulator, but in this case it is still the original one.
     
  4. 8pack

    8pack Veteran Member Lifetime Gold Member

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    I thought you needed to change the orifice tube and the o rings as well. I also thought the low pressure switch needed to be changed as they have different settings for r12 and 134.

    How did you flush yours. When I did mine it was a very messy and stinky process which I would never do again myself.
     
  5. Scott Sievers

    Scott Sievers Veteran Member

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    Yeah, I was working for Chevrolet when we started the switch over from R12 and the techs told us that R12 and 134a created a solid when mixed, that was not entirely true. I heard a LOT of false stories about how to convert back then. 1992 or 1993 iirc. The owner of the Chevy garage I was working at had a SWEET 68 302 CAMARO WITH ac, and he didn't want it to LOOK like it was converted over. So he cut and spliced hoses so he could use the r12 connector for the 134a, and only after he had it converted and working did he think to ask if it was compatible.... Thus, our education was totally hands on, because the "word" was proven to be unreliable.
    I had an 81 shortbed GMC 4x4 I pumped full of 134 to test it. My buddy filled his rabbit, and the paint guy filled his chevelle. They all worked, and as far as I know they are all still working.
    There are also other refrigerants that can be used in the system to replace the R12 if you didn't want to use the 134a.... etc, etc... A lot of it was hype, garbage and a means of making more money. I have, at the farmers request, warning him of the danger.. filled a system with 134a that still had R12 in it, because he needed the AC NOW in his 4230 John Deere. (I'll send a pictue when I get back to Iowa.) Every spring he refills it with 134a and it still works well for him all summer before leaking down in the fall when he doesn't need it anymore. I guess he is just too cheap to fix it when he has found a method that works. Same pump, o rings, accumulator etc, etc.. I can rattle off more than a dozen older tractors that were converted over with nothing done to them at all, and at least that many cars and trucks. I am NOT advocating such a method, I am just saying that i have never had one fail to work when doing an "emergency" switchover. Many of those old farmers I still deal with on a daily basis, and they talk and laugh about John Deere service refusing to help them without flushing, replacing parts, vacing the systems down etc, etc, etc. while they got it done the cheap way. There are few people in this world who can appreciate cheap like a good ol farmer.

    134a won't hurt the o rings or anything else in the system that I am aware of. I did hear that there WAS a compatibility issue with either ford or chrysler products, but understood it was the compressor oil they were using? Maybe someone else can elaborate, though it has been a few years since the changeover. I was certified at the time, but with the changeover they wanted us to go to school, and they wanted us to pay for it ourselves, so I let my cert drop.

    Flush... I unhooked the lines at the accumulator and at the compressor. I poured the flush into the line, and used compressed air to push it through the system, and out the other open end, without letting it go through the accumulator or the compressor. I blew both accumulator and compressor out with air only. I pulled the orifice screen tube out and flushed it out as well, put everything back together... Took the Shrader valve out of the low pressure switch (EDIT; SIDE not switch.) and screwed the adapter on it. I jumped the low pressure switch and charged the system with 134. I put in 2 cans and plugged the low pressure switch back in, and added another 3/4 of a can to top the system off. (Make sure to check on how much your system needs!)

    This system has not been charged up in 28ish years that I am aware of, (The prev owner cant remember when it stopped working) and now the air is flat out COLD coming out of the vents... I have put right at 900 miles on it since I charged it, and all of those miles were done with the windows up. It is hot as hades here in new england. I have heard it is the hottest summer they have had in thirteen years.

    Windows UP at the beach in Kennebunkport Maine.
    IMG_0350.JPG
     
  6. 8pack

    8pack Veteran Member Lifetime Gold Member

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    Ok...Long time no update...

    1. I still can get the ac working. The high side is way to high and I can’t get it to cool below 60*. I don’t think the shop I am using really knows what they are doing. Classic Auto Air thinks my reed valves may be bent from when he filled the system. He did it with the car running and CAA says it should be filled on a full vacuum within the car off....too cold now to deal with it. Will try again in the spring.

    2. I have a terrible vibration over 65mph. I thought it was out of balance tires but Think it is a driveline/pinion angle problem. I need to do some measurements. More on that after the measurements are done.

    3. Ready to put the new big brakes and front suspension parts in. TO do that I need to by the new wheels I have been pining for....BUT, see number 4.

    4. I have been getting feeds from Barn Finds. Some great cars and trucks come up. I have been on the lookout for a 50-75 Chevy pick up. One came up that I made an offer on but didn’t work out...shortly after a ‘55 Ford F-250 came up out of Wichita....95% rot free body....so much for getting new wheels...no new wheels, no installing new C5 brakes.... will be setting up a build thread over on the ford-trucks forum... see below..

    538C87E8-D5A8-4BB7-9E85-82B495F6AE85.jpeg 9C352A90-C4E4-469C-9ABC-A1AE3E7F6B9B.jpeg 01DB21AF-B332-405A-801E-ED27999B2097.jpeg A71A71BC-F67A-4F7D-AEB9-0845A37751A1.jpeg
     
  7. Scott Sievers

    Scott Sievers Veteran Member

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    Oh thats going to be fun!
    rebuilding an 89 checyhalf ton right now... plan to sell it, and use the money for the 434 lower end. welding in new rockers, not making much progress, harvest season, so am right out straight. will get back on it after harvest and deer season!
    New wheels!!!! yeah! Definately new wheels!!!!

    DSCF5002.JPG

    Parts for the ford can wait. GOT TO have the new wheels! :)
     
  8. Bandit723

    Bandit723 Veteran Member

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    Have to love that color - Nice buy.....
     
  9. 8pack

    8pack Veteran Member Lifetime Gold Member

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    Thanks. Waterfall Blue....

    When I get it back to the east coast I am going to try to clean it up with CLR and see how much of the paint reappears. Apparently that is a pretty effective trick to bring some of it back.

    Unfortunately, the money I had set aside for the wheels bought the truck ...so no new wheels until next year at the earliest....

    In the mean time need to get my pinion angle figured out. I also have an issue with the starter grinding that needs to be sorted....
     
  10. Scott Sievers

    Scott Sievers Veteran Member

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    Why would your pinion angle be different? Even if the rear end was swapped it should still be okay, unless the pads were removed from the housing and rewelded on incorrectly? TO make it vibrate the angle would have to be off quite a bit. Lifting lots of trucks over the years taught me that it takes a bit of an angle to make the truck vibrate. Are the rotors warped? Does it vibrate worse when you step on the brakes at speed? Bad u joints, bent driveshaft, balance weight fell off the driveshaft etc... OR yeah, the pinion angle is seriously wrong.

    Sorry to hear about the loss of the new wheels, but... in your shoes, I'd probably do the same thing.
     

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