Valve Stem Seals 93 Astro

[Rupesy]

Has anyone replace valve stem seals before? I got everything ripped out except for the springs and seals. I went to the store to buy seals and there were two different types. I understand that the umbrella type are better. When I got the springs off it appears that there are two different types of seals. Can I use the umbrella type on both??

Thanks,

Jon

[Rupesy]

Well for everyone's information, I finished changing the seals and thought I would share some of the details. I took me about two days (about 8 hours each day). The first day it took me about all day to get everthing cleared out so I could reach the valves. The second day was mostly changing all the seals and putting it back together.

There are two different kinds of seals for the intake and exhaust and there is also an o-ring that has to be placed on each valve stem as well. I did not have access to hook up an air compressor to the cylinder chambers so I had to move each cylinder to TDC before working on each set of valves. I found this to work just fine and I was able to remove and install the seals easily even though they would slide down a bit. Here was the procedure if anyone wants to know:

1. Move cylinder to TDC of set of valves you want to work on. This is extremely important as the valves may fall completely into the cylinder at which time you are completely screwed.
2. Plug up any openings in the head where stuff may fall down.
3. Remove the two rocker arms and push rods. I almost lost a pushrod down the pushrod hole so I definitely think you should remove them (thank goodness for magnetic tools!)
4. Gently tap the outside of the top plate of each spring. In the middle of the plate is where the two half clips are located and you want to loosen them up a bit. No need to hit hard. A few gentle taps will do.
5. Work on one valve at a time. This way you will not get confused.
5. Compress spring with spring tool as far a possible (this is probably the most important part of the job to be successful and efficient. I bought one from Advance Auto and I used it with three springs and it broke into pieces. I returned it and bought a much more robust one from O'Reily)
6. Allow the compressed spring and valve to fall until the spring bottoms out on the head. You will notice that you can pull the valve and spring up and down a little bit and that the spring assembly is still stuck to the valve stem. I know the clips have a name but a I can't remember right now. You may think it will be impossible to get the spring assembly off of the valve since it keeps sliding down, but there is a very easy solution. After allowing the spring and valve to lay at rest, gently tap on the top of the spring compressor tool. As you do this the valve stem will rise up in the air (I just love Newton's laws of Physics).
7. Use a magnetic tool to pull the half clips out. There may be other methods but this is hands down the easiest method and you don't have to worry about dropping the half clips.
8. Pull/yank the spring assembly off of the valve stem. It may be difficult becasue there is a small oring that is typically hardened after years of use. It will probably break anyway.
9. Clean up the area with some lint free rags. Make sure you find all of the pieces of the broken oring or seals to prevent this from getting into your system.
10. Lightly lubricate the valve stem with oil and the inside of the seal that will touch the valve stem. Do not lubricate any where else on the seal.
11. Slide the small plastic tube from the installation kit over the end of the valve. This is to help slide the seal over the small indentations/grooves on the end of the valve stem and prevent damage to the seal.
12. Slide the appropriate seal (intake or exhaust) onto the valve stem and push it completely down.
13. Pull the valve stem up and take off the tube that came in the installation kit. Make sure you hold the seal down while you pull the stem up. The valve stem should stay up because it is a new seal.
14. Take the spring compressor tool off of the spring. This part is important. Reclamp the spring, but try to compress as many springs as possible. (Sometimes this is difficult when removing the spring because of clearance issues.) The reason that it is more important when putting it back on is because there is an oring that needs to be installed after the spring is put back over the valve stem.
15. Gently slide the compressed spring over the valve stem. You should be able to see both grooves on the valve stem. If you can't see the lower groove then you may need to recompress the spring.
16. Gently place the oring over the end of the valve stem and push it down. The valve stem should not move if you are careful. If it does just use a flat blade screwdriver to move it back up or use a magnetic tool. Once it got the seal to the first groove I had to use a small screwdriver to gently push it down to the second groove. Make sure it is not twisted and make sure the backside is in the groove as well before proceeding to the next step.
17. Place a small amount of grease on the inside of each half clip. This will keep it is location when you are releasing the spring. Use as littel as necessary to keep it in place.
18. Use your magnetic tool to put each clip in place. This takes some time and finagaling to get them in place, but it is not difficult. I put the first one on and then rotated it to the back and then installed the second clip.
17. Release the spring compression on the spring assembly.
18. Gently tap the top of the spring assembly to make sure everything is seated.
19. Move on to the next valve of the cylinder. When both valves for each cylinder are complete, re-install the pushrods and rocker arms. Torque to manufacturer's recommendations.
20. Go to step one and start on the next set.

Please do this job at your own risk as I may have omitted a step or instruction. These steps are a few notes from my experience working on a 93 chevy astro. They are to serve only as a suppliment to the original manufacturers instructions on changing valve stem seals. Please follow manufacturer's instructions first. Manufacturer's instructions supercede any instructions given here and above all use common sense (there seems to be a shortage these days).

I hope this can be a help to someone some day. One time I was changing the universal joints on an Isuzu Rodeo and got stuck becasue i didn't know the "trick". I searched for a bit on the internet and found that someone had step by step instructions with pictures. I was able to complete the job once I read the instructions. I also set an email to the web page owner thanking him for his detailed page. I took lots fo pics and plan to put the instruction on the internet some day.

[drew300]

Interesting. It only took 1 day to strip it far enough to work on it? I don't envy you that job.
Out of curiousity, did you get a quote from a garage for that work? Or are you just easily bored?