Part 3: Reassembly

1. Lube (with engine oil) a new bearing and insert it into the compressor side.
2. Place the new bronze seal plate spacer on top of the new bearing
3. Install the new bronze seal plate. This should sort of snap into place. There’s only one proper orientation.
4. Install your replacement o-ring.
5. On the “snout” of the compressor seal insert there is a “piston ring” style ring. Remove the old one and replace it with a new one from your rebuild kit. I removed the old one forcefully by separating the ring at its gap until it came off. Installing the new ring is not that difficult when lubed; just push it down over the snout. You may have to seat a small portion of the ring at first and work around the circumference to get it seated. Here’s a picture of the ring replaced.
6. Reassemble the compressor seal insert and compressor seal.
7. Install the appropriate snap ring to hold the compressor seal in place.
8. Replace the piston ring on the turbine shaft. This is almost identical to the piston ring you replaced on the snout of the compressor seal insert. I removed the old one the same way — just pry it apart until it comes off and throw it in the trash. Installing this one is a little tricky due to the groove just above the ring. I got clever and filled that groove with thread, then oiled the thread to stop the ring from seating in that groove as I pushed it down to the proper groove.
9. Reassemble the turbine side by lubing (oil) the outside perimeter of a new bearing, lubing (oil) the turbine shaft itself, sliding the bearing onto the turbine shaft, and inserting the turbine shaft with bearing into the turbine side of the CHRA until it snaps into place. You should be able to freely spin the turbine at this point.
10. Slide the compressor wheel back onto the shaft. Line up the marks you made on the compressor wheel and the CHRA (with paint or white-out) so that when the nut is tightened, everything is lined up properly. it took me 10 tries. Tighten the nut so that it stops, then give it a little snug tighten of no more than 1/4 turn. Ideally you’d have a precise torque wrench and I’d know the torque specs for you, but I don’t. A reader has submitted his ideas for this step. They can be found on the last page of this article.
11. Clean the oil return line’s gasket surface well and remove all old gasket material. Clean the gasket surface on the CHRA in the same manner.
12. Reassemble the oil return line with the new gasket. Torque the bolts to 3-4 ft-lbs.
13. Reassemble the coolant line with the new copper washers (one between the pipe and the CHRA, another between the bolt head and the pipe). Torque the bolts to 22 ft-lbs.
14. Reattach the wastegate actuator/controller and vacuum hoses. Give the bolts a “good snug” but don’t overtighten them, as they are threaded into the semi-soft aluminum compressor housing. Remember, it’s just a bracket to hold the actuator in place. ∞

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Reader Input

Reader “Steve” submitted the following information from his rebuild. He can be contacted about the following at steveSEVENSIXTWOus@yahoo.com (replace SEVENSIXTOO with the numbers 762).

Balance-Marking and Final Reassembly Ideas.

I marked a vane on turbine side with a paint marker
(less likely to “disappear” with cleaning agents, oil
pre-lube, etc), and marked the edge of the sheet metal
cover (beneath the turbine wheel)with a needle file to
provide an index for the very tip of the marked vane.

On the compressor side, I used the needle file to
scratch an index mark on the compressor wheel, across
to the housing. I don’t think the miniscule loss of
mass from the needle file will upset the balance.

The advantage of using the needle file to mark, is the
marks won’t disappear in handling, cleaning, etc.

For reassembly, I indexed the turbine wheel and
temporarily immobilized it with a piece of duct tape.
I then applied a small glob of hot-melt glue to each
vane tip (except the index vane, to maintain
visibility of index), between the outer tip and the
sheet metal cover.

I put a 12mm ratchet wrench, socket up, on a towel on
my bench, and stood the CHRA up in it. With 12mm
ratchet set to “unscrew”, it will hold the turbine
wheel steady when the reverse-thread compressor nut is
tightened. Set up this way, you hold the 12mm socket
with one hand, and torque the compressor nut with
other…keeping the torque centered along the shaft,
to avoid bending it.

The compressor wheel tends to rotate a bit with the
nut, and I kept “overshooting” my index mark as I
approached final torque. I made a pencil mark on the
compressor housing to use as a my next start-point for
the wheel index mark—backing it up each time, by how
far I overshot the mark on the housing on the last
attempt. In this way, I was able to get my desired
torque, with the compressor wheel indexed, on my
fourth try.

In between each “tightening”, lift up the CHRA and
re-set the 12mm wrench to “tighten”, replace the
turbine end in it, to un-do the compressor nut…then
reset the 12mm “loosen”. This way, there’s never any
torque applied relative to the housing, and the
turbine wheel stays indexed the whole time, but double
check to make sure, anyway.

Removing the glue globs from the turbine side is
easily done with a fingertip, and any residual bits
come off with a toothpick.