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. :-)
CWJH
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I found this old thread when researching how to reattach the cap on the expansion bottle lid. As this is the circumstance I’ve just encountered.
Hopefully my lid valve is still there and functioning?
I can see evidence of four spot welds but presumably the buildup of rust has eventually caused the cover to detach.
Reading this thread I’m not sure if the cap fit has to be 100% airtight? But was thinking would a cleanup of the the lid and cap to remove the rust; then superglue a gasket to lid; then superglue cap to gasket.
Hopefully my lid valve is still there and functioning?
I can see evidence of four spot welds but presumably the buildup of rust has eventually caused the cover to detach.
Reading this thread I’m not sure if the cap fit has to be 100% airtight? But was thinking would a cleanup of the the lid and cap to remove the rust; then superglue a gasket to lid; then superglue cap to gasket.
mr-reno-139
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Very observant of you I would have simply replaced the component rather than attempting a repair
JdeW
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I agree, this is what you need
Renault 4 5 6 12 16 Alpine Α110 A310 Pressure relief valve – 7701348022 or 064 | Vintage French Car Parts
Pressure relief valve - Element for Renault 4 5 6 12 16 Alpine Α110 A310 Brand New Original Renault Product.Made in France. Part Number: 7701348022 or 7701348064007 Intake and exhaust valves - Rocker arms -Push Rods
www.vfrenchcarparts.com
And how the spring assembly should look like, well basicly it's a cap, spring and valve which opens at a certain pressure.
The higher the pressure the hother the coolant gets;
0,70 bar-114,1°C
1,00 bar-118,9°C
1,20 bar-121,7°C
1,40 bar-124,4°C
CWJH
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As a result of the gentle teasing I did decide to buy a new part. Successfully received from vfrenchparts.com and now fitted.
I do feel happier that the expansion bottle setup is working as designed. I did also replace the last remaining sardine can clip on my car with a fuel pipe clip. Sad to see something that’s been there since 1979 in the bin, but I could not put it back on in good conscience, seeing I was aiming to get the system working properly.
Annoyingly, and as often happens, the day after I’d ordered the new lid. The missing spring makes a miraculous reappearance.
I was thinking I’d take apart my previously repaired lid and add the now rust free spring. Then re-glue as before and pop it in my spares box. Is this worthwhile or just a fool’s errand?
I do feel happier that the expansion bottle setup is working as designed. I did also replace the last remaining sardine can clip on my car with a fuel pipe clip. Sad to see something that’s been there since 1979 in the bin, but I could not put it back on in good conscience, seeing I was aiming to get the system working properly.
Annoyingly, and as often happens, the day after I’d ordered the new lid. The missing spring makes a miraculous reappearance.
I was thinking I’d take apart my previously repaired lid and add the now rust free spring. Then re-glue as before and pop it in my spares box. Is this worthwhile or just a fool’s errand?