I replaced the cylinders,pistons and rings on my 500L and I am almost ready to reassemble. One of my VW friends told me that once I take apart the push rod tubes that they need to be replaced like on the VW's. Mine have the little ribs on both ends. They appear fine. So do I really need to replace them?
Technical Do I need to replace them?
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Technical Do I need to replace them?
the hobbler
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The honest answer is yes, you CAN use them again, but for what the standard 'plain' (as against 'spring-loaded' version) tubes cost, I would fit new. The corrugations at each end of the push-rod tube impart some sealing pressure to the ring-seals at both ends of the tube. Once they have been compressed for some time, there is no guarantee that they will 'spring' again ----and stripping down the engine again to cure a 'push-rod tube' oil leak is a pain in the bum! When you refit the head, it often wise to have 2nd pair of hands who can 'aim' the tubes so they sit correctly both top and bottom--trying to locate all 5 tubes on your own as you lower the head onto them can be tedious, to put it mildly. When you remove the head, check which seals are on the old seals--there are 2 sizes (thick and thin). 
With the concertina type push rod tubes I have always "refreshed" them by inserting something like a piece of dowling in each end then winding it around to flex the concertina section at each end and give it a chance to spring back if necessary. You will know if there is likely to be a problem when you refit the cylinder head as the push rod seals should give a little resistance when to lock down and torque the head nuts. You can check the push rod tube seal then by checking for any movement. Most leaks are caused by using old seals or getting a seal out of alignment.
