Monday, December 21, 2009 - 10:43 pm, by: Cameron James(Dinosoarer)
I got the valve out and disassembled on the bench and its clear how the leak is occurring
There is a diaphragm that is clamped between the valve body and the spring cap - the spring cap has a machined groove for the diaghragm seal to locate in (see below)
With the diagphragm in place the sealing edge sits slightly proud of the spring cap face and when clamped to the valve body achieves a tight seal (see below)
My theory is that by machining a couple of thou off the spring cap face this will reduce the height of the machined groove making the diaphragm seal sit further outwards, thus squashing tighter against the valve body - hopefully resolving the leak...
Tuesday, December 22, 2009 - 12:38 pm, by: Cameron James(Dinosoarer)
Machined the spring cap down today
With a straightedge across the sealing surface, the machined groove had a clearance of 0.63mm - this has not been reduced to 0.34mm - with almost 1/2 the clearance removed the diagpram should clamp up a fair bit tighter between the housings and hopefully stop the leak....
Thursday, December 24, 2009 - 06:40 am, by: Cameron James(Dinosoarer)
HAAAHAHAHA! I would not be alive to write this post if my missus found out I'd bought a laith, but now you mention it... all i would need to do it take her for a ride on a baking-hot day and say "baby, its gonna cost me $10,000 to fix this air conditioning problem"
Nah I have a specialized tool room at my work full of equipment that doesn't get used very much - laith, drill press, grinders, press, etc. Its a hard life.
Thursday, December 24, 2009 - 08:10 am, by: Cameron James(Dinosoarer)
Fitted the valve yesterday arvo with new o-rings - stopped by the air-con mechanic this morning and got him to pressure test the system.................fixed.
Now I just have to wait for him to open next year so I can get it gassed.
I've made some enquiries about Hychill (thanks Boris) and searched the forum - most of the feedback seems positive but I have asked a couple of air-con mechanics and they run from it. Apparently its a thinner gas (compared to R143a) and will leak more easily.
Thursday, December 24, 2009 - 10:57 am, by: Miles Baker(Milesb)
Everything I've heard says propane (Hychill) is less likely to leak than even R12. I would much rather have propane burn than a refrigerant burn. For example, burning R12 produces phosgene which will straight up kill you. Propane is also a lot better as a refrigerant than R134a, and doesn't have the problems playing well with others either.
In my opinion there is a lot of A/C Mechanics which don't know a whole lot about the job they do.
You must mean R134a not R143a.
Hydrocarbons such as Propane/Butane mix found in Hychill will leak out much slower than R12 and R134a, and the molecules are not smaller than the R12 or R134a molecules.
It uses the same gasses as LPG (Butane/Propane) if you want to look at it that way, but possibly more refined, different proportion of Propane/Butane compared to LPG for better cooling efficiency, also contains a UV Dye.
However many people have used LPG, or just Propane from their BBQ Cylinders in their cars without a problem.