Hey everyone. This is a pretty good explanation of how to rebuild your stock turbo. The example is an early 99. The build is similar for the OBS style turbos too.
First, spray all bolts and clamps down with WD-40 or other type of penetrating oil.
Let it sit overnite and work.
Remove the intake assembly from the turbo. Take off the driver's side intercooler pipe by loosening the 3/8 nut on the turbo clamps at the Y pipe and the Intercooler
Removing the passenger side intercooler pipe is the same way you removed the drivers side pipe. Its just a little bit tighter fit.
Then loosen the turbo clamp from the turbo to the Y pipe, as well as the gear clamps on the boots going to each head.
Also you will need to remove the electrical plug and the lines going from the map sensor.
Now you should be able to remove the Turbo Y pipe.
Now you should have this pile of parts laying in your driveway or garage.
Loosen and remove the turbo clamps that are holding the downpipe to the exhaust side of the turbo.
Then, there is also a turbo clamp on the back side of the turbo that mounts the up pipes to the turbo. Remove this clamp.
After that, there are only 2 more bolts holding the turbo in place. They are 13mm bolts and they are on either side of the turbo.
Late 99 and up owners might have trouble getting to the back one as the turbo mounts higher and allows less clearance under the cowl.
You may have to knock the turbo with a rubber mallet or piece of wood to knock it loose from the pedistal.
After you remove it, this is what it should look like. Also this view lets you see the placement of the up pipes comming into the turbo. You can also see if the up pipes are leaking on the gaskets. Mine are not luckily, but if yours are, you may see loss in boost. A good way to tell if they are leaking is if you se black sooting next to the flanges up top.
Ok, first there are seven 13mm bolts holding the downpipe mounting flange to the exhaust housing. Once you remove them, the flange plate will come off. Also, remove the 2 nuts holding the Wastegate on, and the snap ring holding the arm of the wastegate on.
The wastegate actuator and arm will now come off.
On the intake side of the turbo, there are four 5/16 twelve point bolts holding the outer compressor housing on.
You MUST use a 12 point socket, or the bolts will round off.
This is the compressor wheel. Removing it takes a drill, a socket adapter and a 16mm socket. You have to stick a screwdriver(wrap it with a rag as to not damage the fins) in the turbine(exhaust) wheel to keep it from spinning.
As you can see, I had horrible end play in my shaft and my compressor wheel had been hitting the housing for quite some time. This will also cause a loss of boost and non-efficiant cooling of the turbo EGT's.
Once the Compressor wheel spins off, you have 4 more 5/16 twelve point bolts to take off underneath it.
When you remove this back plate, pay attention to the way the thrust washer and front bearing are positioned. There are oil passeges on the thrust bearing that face the CENTER of the turbo. The front bearing is just lightly snapped in place on the compressor housing backing plate.
NOTE: My Thrust washer and bearing were still on the shaft of the turbo after I removed the compressor housing backing plate. My piston ring had broken, adding to the endplay of my turbo shaft. Both of these will be replaced with new parts.
After removing the thrust washer and front bearing there will be a gasket in the center of the turbo that needs to be removed. There are 4 more 5/16 twelve point bolts to remove.
Two of them are in the lower part of the picture. They are removed on this picture.
The other 2 are directly across form the other 2 and are recessed. You will need an extension on your socket to reach those. Once you remove them, the center section of the turbo will come off.
As you can see here, I have pulled the center section up, and have left the shaft assembly in place. If any of the brass oilers come off the shaft, dont worry, the rebuild kit has new ones.
You can now remove the shaft assembly and it should look like this. Remember the order in which the parts on the shaft were in, as it is important.
There is a brass oiler, and spacer, and then another brass oiler.
Here is a turbo rebuild kit. I ordered mine from Beans Diesel. The parts are listed from top to bottom, left to right: 4 new 5/16 bolts(Above the paper), Spacer, Front shaft bearing, the 2 brass oilers, Thrust Washer, Small piston ring, Large piston ring, and the gasket that goes in the center of the turbo.
The large piston needs to go in this groove, next to the turbine wheel.
Mine didnt have one here, and allowed the shaft to have end play. It is kind of hard to get in the groove.The ring will expand once you put it over the shaft and fit it in the groove.
Once you get the ring in the groove, take some pliers and compress the ring to make it fit tighter in the groove. Just make sure the two ends of the ring are meeting evenly.
Then, put a brass oiler, the spacer and the other brass oiler on the shaft in that order.
You may lube the shaft with some oil to make the slide on easier. But they should go on very easily.
Ok, you should now be able to slide the shaft assembly into the center of the turbo. You should hear or feel a slight "click" when that large piston ring goes into the groove thats in the center portion of the turbo.
Make sure you do not let the piston ring come back out of the groove. If it does, it will warp and bend causing problems. If this does occur, take the piston ring back off with a small screwdriver and straighten it and put it back on. Make sure to compress it to make it fit tighter in the groove. This was the trickiest part of the rebuild for me, as mine was giving me some trouble.
After it is assembled in the center section, you might give it some light taps on the nut of the turbine wheel with a hammer to make sure its set in place. The turbine wheel should be about 3/16 of an inch away from the plate when it is fully seated in place.
Then place it back in the exhaust Housing. Put the 4 new 5/16 bolts back in place. Be sure to put locktite on them and tighten as much as possible.
I am putting on a non-wastegated 1.0 A/R housing from Beans on mine. So I will not have to worry about putting the wastegate on.
You should be able to spin the turbine wheel pretty easily once it is assembled.
If not, something is wrong, so disassemble and see where the problem is.
On the back side of the compressor housing back plate, you can now get ready to assemble the front bearing and thrust washer.
On the bearing there is a small groove that takes the small piston ring. Compress the ring once its on again with pliers.
The thrust washer goes around the bearing and is inserted in the center of the plate. It only goes one way, and you will have to fit it in place.
REMEMBER: The grooves of the thrust washer go towards the CENTER of the turbo. If not the turbo won't oil properly and will fail in a very short time.
Also, oil the rubber gasket and place it in the groove in the backing plate.
Once you put the backing plate on, you can then put the 4 bolts back in using locktite and tighten them securely.
Then you can install the compressor wheel. Spin it on until it is just hand tight. Be sure to put a rag over the compressor wheel. The edges of it are RAZOR sharp! Take a 16mm socket and tighten it just a bit more, while you are holding the turbine wheel as you did earlier with the rag and a screwdriver. The spinning motion of the turbo will tighten the wheel from there.
Look on the backing plate around the outer ring and you should see a O Ring that is around the bottom of the flange. Inspect it and if its ok, spread some oil on it and place the other half of the housing on. If the O Ring is not there, use a thin layer of silicone as gasket material. Just dont get any on the inside of the compressor housing.
Put the outer compressor housing on, and tighten bolts securely. You do not need locktite on these bolts.
Then, you can install the mounting flange on the exhaust housing of the turbo using the bolts you took off.
At this point you can reinstall your wastegate if you are putting it back on, or if you are using an aftermarket wastegated exhaust housing.
Now, you are done with the turbo rebuild. Install of the turbo is reverse of the removal. Be sure to clean both surfaces of the pedistal and center section of the turbo, and use new Vitron O rings.
Relace the Intercooler pipes along with Y Pipe and make all connections with the correct turbo clamps or gear clamps. This is also a good chance to clean up around your engine bay under your turbo pedistal, to paint or clean, or do a foil delete mod on your intercooler piping. I also did the CCV mod to my truck while I had the intake off.
If you should have any questions about the rebuild or install of the turbo or components, feel free to PM me. I will help you all I can. It is a very simple task. I was surprised at how easy it was considering, I had never even thought about taking apart a turbo before this happened. Hopefully this was a helpful writeup.