996 Cabriolet Hydraulic cylinder rebuild

Vitals: 1999 / 996 Cabriolet 116K Driver side hydraulic slave cylinder is leaking fluid. Can I rebuild the cylinder with a kit? DYI video available? I found a few guys who will rebuild the cylinder for a little over $200 but I'm guessing new "O" rings etc. might be $25? I'm a die hard DYIer. Any help would be greatly appreciated, Thanks Bob

It can be rebuilt but it's a pain in the butt. There are a couple of threads here that detail it. If you don't choose to go that route I got my replacements from cabriolethydraulics in FL. I've had them installed for 2 years now. No issues

+1 for cabriolethydraulics. They rebuild to a higher quality that the original. The other option I considered was buying them from FCP Euro with their lifetime warranty. Their prices seem to fluctuate significantly on this part. Ended up going with CabrioletHydraulics and they've held up nicely. Note: It's recommended to do them both at the same time. You can reach both ends of the rams with the top in the service position but it's a lot easier if you remove the speakers in the rear seats.

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If you've ever rebuilt a shock absorber, its a similar disassembly. I've done 2 sets of 996 hydraulic top cylinders so far, with the ebay $20, o-ring kit. Guess the consensus is the oem seals are a nylon type material that has a 5 year shelf life. Ebay kit Orings are suppose to be more durable, time will tell.... Been about a year or so for the 996.1 and 6 mo for 996.2, both are working perfectly still, no leakage. And I used ATF, would easily see the red fluid seep or leak. I am not recommending ATF fluid, its just what I had in my garage and Ford uses it on their very similar hydraulic top design. Think the top might work a little faster with the ATF,,, iirr. The disassembly of the cylinder is what some complain about, and 1 guy even drilled a notch in the cyl body to get access to the c-clip. I found that not necessary. But I've pulled out similar c-clips many times. Takes some patience and the right pick or tool to get in behind the clip and pop it out. One tip, if clip removal is difficult, push down the white plastic bushing to get more room to get out the c clip. After the clip is removed its all downhill from there. If the shaft doesn't come apart easily, pressurize the cyl from the hose end. Be gentle, don't need high pressure, and wrap it with a rag or old towel to catch possible mess. If you have to, try cobbling up some fittings/connections/banjo bolts/etc, to connect your air line. Doesn't have to be airtight leak free. Or suck some hydra fluid into the cyl, and then It will push the shaft/seal keeper white plastic bushing out and give access to the oem quad seal. Cut off old seal carefully as in the pics... Thread the new o-ring over the hydraulic line and stretch it carefully over the shaft hose block. Reinstall the C-clip, Rinse, repeat... The pics of the cyl are ones I saved from a forum member years ago...

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Thanks for the tips! Allcool's pictures were a great help. I took the cylinder to a local hydraulic shop and they removed the snap rings. On another thread they showed how to use compressed air to expose the guts. I didn't cut out the old ring seal yet (that's were I am), I ordered the "O" rings and I'm moving forward on the rebuild. Thanks again!

All went well with the rebuild and I would repeat on the other side when needed. The rebuild itself was about an hour, hardest part is getting the snap rings out. I was able to tap the white collar down just a wee bit to get the snap rings out (can't go crazy on the tapping as to not crack / damage the collar). After the reinstall I went to cycle through an opening & closing of the top. That did not go so well, I'm stuck! I close the top but the rear convertible cover is not finishing the cycle, closing! I do hear a motor working but the cover does not move. If I reverse to open all I get is silence / no movement either. The motor closing sound lasts for 5 seconds and then the dash light blinks and everything goes silent (fault code). Is the top out of sync and needs to be reprogrammed or do I have issues with the cover drive motor (996.624.122.00) / transmission - cables? Any ideas? I'm a die hard DYIer, trying to avoid the dealer! Let me know what you think. Thanks Bob

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Did you reinstall the potentiometer arm correctly..? Usually both cylinders are done at the same time since when 1 leaks the other is usually not far behind it. Might have to cycle the top a few times up and down even if it doesn't go all the way to get the air out and match sides up, maybe....

If the potentiometer is a plastic arm (driver side only) that connects to the back side nub of the cylinder - jackpot ! Just after posting I went to the garage and kept going over and over the assembly (couldn't leave it alone) and noticed this plastic arm for the first time (that I missed!). I hooked it up and during the reassembly I disconnected the battery thinking I could clear the codes? Anyhow I started the car and another shot at closing and sure enough, success! Thanks for the tip! Now I'm a much happier 996 owner.

Where can I order the O rings?

I just rebuilt both cylinders on the 02 Cab last month. these are the seals that I used and got them from McMasters, one other thing I did to make it easier to remove the bushings and snap ring. is drill 1/8 hole on the side into the snap ring area to push and remove the snap ring, also found some bushing will not come out on air pressure to the cylinder by itself, I drilled another hole on the opposite side and used to 2 picks to push the bushing out. McMaster-Carr part 1302N738 Buna O-ring 4.5 mm thick , 18mm I.D. , 27mm O.D.

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Thank you sir! do you know where can I find step by step instructions?

Thank you it works great!