Valve stem seal replacement
written by: maxAbout this Guide
Valve stem seal replacement for 8 valve A2 Volkswagens, with specific focus on the "rope trick". Cylinder head removal not required. Compressed air not required.
Step 1: Background info
Valve stem seals on your 8 valve A2 Volkswagen are not as difficult to replace as you might think; however, it does take plenty of patience, skill, and care... as well as a good shop manual. I highly recommend the Bentley manuals for Volkswagens. Dealership garages use the Bentley books, and they aren't terribly expensive. The first time you do this it will be a learning experience, so take your time. Valve stem seals are there to keep oil from leaking into the combustion chambers where the valve stems come up through the cylinder head. To gain access to these seals the valve cover, camshaft, cam followers (lifters), and valve springs must be removed. The only thing that makes this procedure tricky is that once the valve springs are removed, there is nothing to keep the valve from falling into the combustion chamber. If a valve falls far enough, the cylinder head will have to be removed to retrieve it. There are two methods used to keep this from happening. The most common method is to adapt an air hose to fit into the spark plug hole in the cylinder head, and inject the combustion chamber with compressed air to keep the valves pinned against the cylinder head. The less common, but equally effective, method is to stuff rope into the combustion chambers through the spark plug holes. Obviously, you can't feed the entire rope into the hole - you need enough sticking out so that you can pull it back out. In this example, I'm using the rope method (or "indian rope trick", as it's sometimes called).
Step 2: Preparation
Since the camshaft has to be removed, it's a good idea to align your timing marks prior to starting disassembly. See your Bentley manual for specifics, as the timing marks vary. Note that just because you see timing marks such as notches and "0T" on certain pieces doesn't necessarily mean those are the timing marks you will use for your vehicle. Volkswagen's parts sharing led to lots of VWs with parts that have timing marks stamped onto them which aren't actually used for that vehicle. Check your book. For parts, you will need a valve cover gasket kit (should contain 3 pieces for the 8 valve engines we're discussing here) and eight valve stem seals. Now is also the time to consider replacing your valve lifters (cam followers) if they need it. You'll have them out anyways, so give it some thought. For tools, you'll need a valve spring compressor (in this example I'm using one that I made myself), a valve stem seal puller (in this example, I'm using a pair of needle nosed pliers that I modified to do the job), a valve stem seal installer (in this example, I'm using a deep 1/4" drive 8mm socket), and a valve stem cap to protect the new seals when sliding them over the valve stems (in this example, I used a random little rubber cap that I found laying around - I got lucky). For personal qualities, you will need plenty of patience and stick-to-it-ness. In this picture you can see my needle nosed pliers which have been modified to server as valve stem seal pullers.
Step 3: Getting to the "meat", so to speak
Okay, if you're doing this job yourself then you're probably already familiar with nearly everything in your A2 VW's engine bay. For starters, let's remove the airbox, remove the valve cover, and disconnect the throttle body and intake boot enough to move them out of the way a little bit (they don't need to be completely removed). If you are going to completely remove your timing belt, you will also need to remove your v-belt(s), v-belt pulleys, and lower timing belt cover. If you really want to live on the edge, you can just remove the timing belt from the camshaft sprocket and clamp it in place to keep it's position on the lower sprockets (In this example, that's what I'm doing - trust me though, doing that is best left to experienced VW mechanics). With the timing belt removed from the camshaft sprocket, the camshaft can be removed. See your Bentley manual for the procedure, as it varies depending on whether your cylinder head has 4 or 5 camshaft bearing caps. In general, the procedure is to completely remove all but 2 of the bearing caps and then gradually loosen the remaining 2, keeping even tension. Once the camshaft is out, the lifters can be easily pulled out with your fingers. Store your lifters upside down so that the little pistons don't bleed down. And now your valve spring compressor can be mounted to the cylinder head. In the picture here, you can see the bridge of my home made valve spring compressor mounted to the head after I have removed the camshaft and lifters.
Step 4: Compressing the springs
Now you will need to arrange something to keep the valves in place while you operate. Either use a compressed air hookup, or use the rope trick. In our example here, I'm using rope. I used good, flexible nylon rope with a cord core. I like nylon because it's flexible and you can singe it to stop fraying if necessary. You'll need something to help pack the rope into place, such as a long and thin screwdriver (but be careful not to damage the spark plug threads!). If you aligned your timing marks before starting, then cylinders 1 and 4 will be at top dead center and cylinders 2 and 3 will be at bottom dead center. In my case, cylinders 2 and 3 took roughly 12 feet of rope (because the pistons were at the bottom of the stroke). That amount will vary based on bore, stroke, rope diameter, and luck. With your first cylinder stuffed full of rope (or compressed air, as the case may be), you can operate the valve spring compressor on the intake and exhaust valves for that cylinder. In this picture, you can see the rest of my valve spring compressor in action. As you can see, it's a lever that hooks under the "bridge" (the part that mounts to the cylinder head) and presses down on a cylinder that has a window cut into it.
Step 5: Removing the valve keepers, part 1
In this picture you can see a closeup view of valve spring compressor pressing down on the upper spring retainer to compress the inner and outer valve springs. Now you can see why I have that window cut into the cylinder of the spring compressor - it's to allow access to the valve keepers, which you can see forming a collar around the top of the valve stem in this picture.
Step 6: Removing the valve keepers, part 2
A slim pair of needle nosed pliers works well for remove the valve keepers, but a small telescoping magnet works even better. In this example, I'm using a telescoping magnet. Each valve has 2 valve keepers, each of which is half of a collar shape that fits into grooves in the top of the valve stem. With the upper spring retainer pushed down far enough, these keepers will come out with little effort. In this picture, you can see one of the keepers on the end of my magnet.
Step 7: Removing valve springs and upper retainer
With both keepers removed, you can uncompress the valve springs and you'll notice there is now nothing holding the upper spring retainer and springs in place. You can simply lift the pieces out (needle nosed pliers work well, since it is a pretty small space). In this picture, you can see one valve's worth of hardware: 2 keepers, one upper spring retainer, one inner spring, and one outer spring. There is a lower spring retainer (or spring seat, whatever you want to call it), but it is wedged underneath the stem seal so you won't need to worry about removing it.
Step 8: Removing the old stem seal
This part takes patience. In this picture, you can see down into the lifter bore, where your valve springs were before you removed them. At the bottom (sitting in that pool of oil) you can see the old valve stem seal. You need to take your valve stem seal pullers and grip the base of the stem seal. Get a firm grip and make sure you're on the base of the seal and not the top of the lower spring seat. It can be difficult to distinguish between the two, but the base of the stem seal has a small metal lip that sticks out a little bit. Work the seal free by twisting and applying upward pressure. The moment you feel the seal come free, or the moment you feel the pullers lose their grip, then immediately relax to try and avoid wild movements. I say this because you do not want to put any scrapes or nicks in the valve stem. Be as careful as humanly possible during this step, I can't stress that enough. A nick in your valve stem can easily destroy your new seal. It's fairly common for the old stem seals to get a little bit torn up during the removal process, but try to keep them pretty much in one piece. If you do tear pieces off, make sure you don't lose them down into the oil.
Step 9: Inspecting the old stem seal
If you're a curious person (as I am), then the first thing you'll do after removing the old seal is inspect it. Mine were really shot in this example. The rubber was hard and brittle, and the inner lips of the seal were splayed upward - they weren't sealing at all. In this picture, you can see one of my old seals in the grip of my modified pliers.
Step 10: Prepping for seal installation
Now you'll need to prepare for installation of the new seal. Apply a thin coat of clean motor oil to the inside and outside of the new seal, and install whatever you're using for a valve stem cap (they sell inexpensive caps specifically for this, I just didn't happen to have one). In this picture you can see a new stem seal before installation.
Step 11: Stem seal installation
In this picture you can see one of my valve stems with a cap in place. Slide the new stem seal over the cap (making sure it's well past the grooves in the top of the valve stem) and then remove the cap. Now use your valve stem seal installer (in my case, I used a deep 1/4" drive 8mm socket) to press the seal down and firmly into place. Valve stem seal installation is now complete. Wicked, eh?
Step 12: Valve spring/retainer/keeper installation
I hate to say it, but installation is pretty much reverse of removal when it comes to the valve springs and associated hardware. Pop the inner and outer valve springs back into place, set the upper spring retainer on top, and then use your spring compressor to push the retainer down over the valve stem. Installing the keepers can be tedious, but be patient and you'll get the knack eventually.
Step 13: Repeat 7 times
You've done one, so there's 7 more to go. You'll have to move your rope (or compressed air) to the other cylinders as required.
Step 14: Install lifters
With all the seals replaced and all the springs reinstalled, you can place the lifters back where they belong. In this picture, you can see the brand new lifters that I installed.
Step 15: Install camshaft
You made life easy on yourself if you lined up the timing marks before disassembly, because now you have a reference point when reinstalling the camshaft. Set the camshaft into place, with the sprocket lined up roughly where it should be and refer to your Bentley manual to see which 2 bearing caps you need to install first (again, gradually tightening them in turn to maintain even pressure). Also refer to the Bentley manual for torque specifications - that's something you definitely don't want to guess. In this picture, you can see my camshaft set in place over the shiny new lifters.
Step 16: All done, except for finishing
You've made it this far, so I think you know what to do from here. Do take note, however, that if you installed new hydraulic valve lifters (all A2s with the exception of some of the earlier diesels used hydraulic lifters in the U.S.) you need to give them 30 minutes from the time the camshaft is torqued down to bleed down. Without that time, they will push the valves down further than they were meant to, so this could cause valve and/or piston damage if you're not careful. Depending on what you did with your timing belt, and whether you left your marks lined up, you'll need to do whatever is necessary to make sure valvetrain timing is correct and then reinstall the timing belt. The other miscellaneous re-assembly should be a cake walk for you.