Vac trunk cylinder not working? Try this....
July 12th, 2010, 01:25 PM
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Vac trunk cylinder not working? Try this....
I found one of these from around the late 1960's in the shop and it did not work. It is a TRICO P-40951-19. I played around with it and found...
They can be dismantled and reassembled but there is really no need. There is not a rubber diaphragm in there but there is a big rubber 'cup' that looks like a giant master cylinder cup. There is a gasket around the cup that is soaked in grease and this is what makes the seal when the vac is applied.
There is also a large spring inside that makes the shaft push back when the vac is turned off. The little spring you can see on the outside shaft is also important, but it is not the spring that does the real work of returning the levers to the resting position.
To get it to respond to vac again I put some penetrating oil, like Liquid Wrench, on the part that fits over the lock so I could get it to moving easily. After it is free then apply some light oil, like 3 in 1, to all the surfaces that move and work it back and forth until it is free. Make sure to apply the lube to the inside and the outside of the lock shaft slot and also to the pivot on the spring shaft. When you pull it off the car you will see what I mean.
You can, and should, spray some lube down the hole where the vac hose connects so the rubber cup will not hang up on the sides of the vac chamber. This will also allow the gasket around the cup to seal better since the grease it came with has likely dried out. I used a white spray grease here since the light oil did not seem to be thick enough to form a good seal on the cup gasket.
You can buy a working one used for about $60 or you can spend 15 minutes and $1 worth of spray lube to make yours start working again. It is up to you.
Just don't let anyone tell you the diaphragm is ruptured since there is no such thing inside one of these.
They can be dismantled and reassembled but there is really no need. There is not a rubber diaphragm in there but there is a big rubber 'cup' that looks like a giant master cylinder cup. There is a gasket around the cup that is soaked in grease and this is what makes the seal when the vac is applied.
There is also a large spring inside that makes the shaft push back when the vac is turned off. The little spring you can see on the outside shaft is also important, but it is not the spring that does the real work of returning the levers to the resting position.
To get it to respond to vac again I put some penetrating oil, like Liquid Wrench, on the part that fits over the lock so I could get it to moving easily. After it is free then apply some light oil, like 3 in 1, to all the surfaces that move and work it back and forth until it is free. Make sure to apply the lube to the inside and the outside of the lock shaft slot and also to the pivot on the spring shaft. When you pull it off the car you will see what I mean.
You can, and should, spray some lube down the hole where the vac hose connects so the rubber cup will not hang up on the sides of the vac chamber. This will also allow the gasket around the cup to seal better since the grease it came with has likely dried out. I used a white spray grease here since the light oil did not seem to be thick enough to form a good seal on the cup gasket.
You can buy a working one used for about $60 or you can spend 15 minutes and $1 worth of spray lube to make yours start working again. It is up to you.
Just don't let anyone tell you the diaphragm is ruptured since there is no such thing inside one of these.
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