Hi Folks, can you help? The metal cap and spring that sit over the pressure valve on top of the vessel has flirted off as I undid the cap to refill. Now , of course,being a complete klutz I cant get it to go back on! Have I lost an important piece? could someone give me a quick overview of how it goes back together and is supposed to work? It's a 4L from '79 I think.Thanks in anticipation.
- Thread starter marstan
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angel
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Inside that metal cap should be a spring and a disc valve. The valve goes first, rubber ized side downwards, then the spring and finally the cap. As the assembly is held by solid rivets, I'm puzzled how did it came off that easily...anyway, if the cap is not perforated by rust, you can fix it with small self-tapping screws (seal them with RTV afterwards).
Obviously, the point is to have an airtight seal there, otherwise there will be no pressure in the cooling system.
Obviously, the point is to have an airtight seal there, otherwise there will be no pressure in the cooling system.
Thanks Angel, that makes a lot of sense, but I still don't understand what happened. The plate with the valve assembly in it and which the pipe passes thro' is sound.The metal cap that sits over the spring and valve assembly has not been riveted or fixed in any way, there are 3 tiny marks that look like they were made when the cap was manufactured.That's why I thought I'd lost a piece when it sprang apart! I thought perhaps there was a spring clip that went over the top of the cap, held in place at either side by the screw-down top that you remove to open the vessel. So what function does the spring have if it isn't holding anything in place? It doesn't touch the valve which is built into the plate. Can you can shed a little more light? Unfortunately the car is in Toulouse and I'm in Lancashire! Thanks, Marstan
angel
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Yours must be spot-welded. Simply drill two holes and hold it with screws.
The spring presses the disc valve to hold it against the holes on the metal cap, thus sealing the expansion bottle. When pressure in it reaches a pre-determined value, the valve opens and pressure is released to the atmosphere. That simple. :-)
The spring presses the disc valve to hold it against the holes on the metal cap, thus sealing the expansion bottle. When pressure in it reaches a pre-determined value, the valve opens and pressure is released to the atmosphere. That simple. :-)