R134a Retrofit Question

[PeterInSTL]

I bought the retrofit kit from BMA. Are the new line adapters supposed to fit over the r-12 ports, or do the old ports have to be modified? I saw on the BMWE34.net that the pin had to be removed from the old r-12 port. Is this the case with all conversions, and if so how do i get the pin out of the valve. Thanks for your help.

[shogun]

http://shrubbery.student.utwente.nl/...con_R134a.html

[PeterInSTL]

What kind of mods need to be made to the after market fittings?

[Kalevera]

Peter, they shouldn't be aftermarket fittings. If the kit is what I think it is, it should have two new fittings - low and high side for R134a systems.

First thing to do is get your R12 system evacuated. Don't open it until this step's done, for all of the obvious reasons.

Once the system's evacuated, the R12 fittings can be removed from their respective schrader valves/r134's put on and the receiver/dryer can be changed. Make sure the system can hold a vacuum for at least 15 minutes before filling with freon. Also, FWIW, I don't think it's smart to use those stupid cans that they sell at wal*mark; a shop with the proper equipment should test and fill the system (again, for all of the obvious reasons).

best, whit

[PeterInSTL]

The pin in the schrader valve appears to be in the way of the new R134 fitting screwing on to the port. Does the pin in the r-12 valve have to be removed or should the new valve screw right on? Once the conversion is done I do plan on taking it to get it leak tested and filled professionally.

Thanks

Peter, they shouldn't be aftermarket fittings. If the kit is what I think it is, it should have two new fittings - low and high side for R134a systems.

First thing to do is get your R12 system evacuated. Don't open it until this step's done, for all of the obvious reasons.

Once the system's evacuated, the R12 fittings can be removed from their respective schrader valves/r134's put on and the receiver/dryer can be changed. Make sure the system can hold a vacuum for at least 15 minutes before filling with freon. Also, FWIW, I don't think it's smart to use those stupid cans that they sell at wal*mark; a shop with the proper equipment should test and fill the system (again, for all of the obvious reasons).

best, whit

[Kalevera]

If it's what I think it is, the fitting holds the schrader valve open.

If the car previously got some kind of "retrofit" kit (IE something that wasn't R134), there's a probability that the schrader valve itself is damaged...


best, whit

[632 Regal]

from what I remember when i was first certified the new valves screw right over the old ones and indicate to any shop that it was retrofitted. After you get the r-12 evacuated you should replace the drier and oil with the new oil, if you skip this step it will lead to a lot of problems down the road (should...not definite). The r-12 oil is not compatable with r-134 and wont lubricate the pump properly. I'm still trying to screw my head on here so some things might not be 100% correct.

[winfred]

the mineral oil that came in the r12 system is not designed to handle the higher heat and pressures of the system running r134, i like ester in my conversions as pag can react with the copper that most of the evaporators are made from. the best conversion fittings are steel and have their own valve, you remove the old valve core and screw the new fitting on, the crappy el-cheepo conversion fittings are aluiminum and just have a anvle that presses on the old valve core which probably will start leaking since it's old and now being messed with, and sometimes the cheep fitting is not machined just right and won't screw all of the way down which won't let you have full flow through the valve (takes a long ass time to install 3.4# of freon) a valve core puller is cheep and only takes a couple seconds to remove the old valve core

[PeterInSTL]

The fittings that I have appear to have their own valve. the pin in the r-12 schrader valve seems to be in the way (much the same way as the example on the BMW E34.net website http://www.bmwe34.net/E34main/Upgrade/AC_upgrade.htm.) I guess that I will have to remove the pin in the old r-12 shrader valve before screwing on the new fitting.

the mineral oil that came in the r12 system is not designed to handle the higher heat and pressures of the system running r134, i like ester in my conversions as pag can react with the copper that most of the evaporators are made from. the best conversion fittings are steel and have their own valve, you remove the old valve core and screw the new fitting on, the crappy el-cheepo conversion fittings are aluiminum and just have a anvle that presses on the old valve core which probably will start leaking since it's old and now being messed with, and sometimes the cheep fitting is not machined just right and won't screw all of the way down which won't let you have full flow through the valve (takes a long ass time to install 3.4# of freon) a valve core puller is cheep and only takes a couple seconds to remove the old valve core

[632 Regal]

crack