Rebuilding a turbo?

[1stbenznc]

I've been searching around without much luck. I think my turbo seals are bad and leaking a good amount of oil through the intake manifold (wet). I can't really see any blue smoke but the oil consumption is high.

I know it's the turbo as it started when I swapped out the entire exhaust manifold with turbo.

My old turbo had a chipped fin or I would throw it back in

Not sure I want to attempt rebuilding and balancing myself. Anyone know of a forum member or good shop that rebuilds them? I have an Air Research by Garrett.

[dude99]

You could always swap the impeller on your leaky turbo onto your old one. Mercedes source has a several different kits. Some with parts, instructions and tools. Haven't checked peach-parts, but they probably do to.

Here's a video on it http://www.youtube.com/watch?v=pYN7dUXop60&feature=player_embedded

[greazzer]

Try GPopShop in Arkansaw .... Great customer service, and they sell the kits for the DIYers and a rebuit starting at $350.00 plus postage. Not a bad deal.

[Diesel911]

People have said it is easier to buy a used one.

Rebuilding the Turbo is not hard but there is a not good info available.

The various do-it-yourself threads on the internet cannot agree on how the Shaft Nut is to be torqued and there are no specifications for the Bearing Bores or Bearing Journals on the Turbine Shaft.

Some of the Threads at least speak of balancing the Wheel & Shaft.

[jef d]

I have a fresh rebuilt 3.5lL turbo ! for sale ! uf you need it ! thanks Jeff

[1stbenznc]

I PM'd you Jeff. So it looks like DIY for a rebuild is not that bad. Seeing I have the hard parts from two turbos, I can swap internal parts if needed.

What about measuring tolerances and balancing the shaft/turbo when complete.....or are these turbos not as sensitive as some of the truck and high performance turbos? The thing spins at what, 15,000 rpm or something? You'd think it should be balanced if you do it yourself?

[babymog]

30,000rpm stock according to the FSM.

[Bob Albrecht]

I just finished rebuilding my turbo. It is a Garrett T3 with an Air Research compressor.

Before you take the turbo apart score the compressor to back-plate and the turbo to oiled section as these will rotate 360 and can go back any way you want.

The job wasn't too hard, but I did break 1 encapsulated carbon seal by assembling it wrong, and Ron broke another installing it.

I used Ron's Turbo Service for the parts and balancing (free).

You need to make sure you get the T3 encapsulated carbon seals.

I have a tool that was made by a friend on this site that allows you to put the carbon seal in without damaging it. You need a big socket on the other side when you are tapping the new seal in.

You will need some special snap ring pliers to put the snap rings back in that hold the journal bearings in.

You can use the shaft and turbine from another turbo and have it balanced.


Oh, yeah. You will want to completely clean your intake manifold and crossover. It will be full of the the nastiest stuff you have ever see. On Shop Forum it is called "devils food cake". I dug about a pint of the stuff out of my intake and i bet that stuff is capable of killing engines. To prevent future devils food cake you your EGR vacuum line might spontaneously injest a BB. Mine did that, and somehow a plate got installed across the place where the exhaust goes into the intake.

[1stbenznc]

Thanks for the input and will check into those carbon seals!!

Still deciding to do it my self, get a used one or exchange one of mine in.

[Diesel911]

Originally Posted by Bob Albrecht

I just finished rebuilding my turbo. It is a Garrett T3 with an Air Research compressor.

Before you take the turbo apart score the compressor to back-plate and the turbo to oiled section as these will rotate 360 and can go back any way you want.

The job wasn't too hard, but I did break 1 encapsulated carbon seal by assembling it wrong, and Ron broke another installing it.

I used Ron's Turbo Service for the parts and balancing (free).

You need to make sure you get the T3 encapsulated carbon seals.

I have a tool that was made by a friend on this site that allows you to put the carbon seal in without damaging it. You need a big socket on the other side when you are tapping the new seal in.

You will need some special snap ring pliers to put the snap rings back in that hold the journal bearings in.

You can use the shaft and turbine from another turbo and have it balanced.


Oh, yeah. You will want to completely clean your intake manifold and crossover. It will be full of the the nastiest stuff you have ever see. On Shop Forum it is called "devils food cake". I dug about a pint of the stuff out of my intake and i bet that stuff is capable of killing engines. To prevent future devils food cake you your EGR vacuum line might spontaneously injest a BB. Mine did that, and somehow a plate got installed across the place where the exhaust goes into the intake.

What proceedure and or Torque did you use on the Shaft Nut?

Any, other specs you could share would be helpful.

[Bob Albrecht]

Make the nut as tight as you can. I did not use my torque wrench.

The correct position of the nut relative to the compressor wheel is marked after balancing.

[Diesel911]

Originally Posted by Bob Albrecht

Make the nut as tight as you can. I did not use my torque wrench.

The correct position of the nut relative to the compressor wheel is marked after balancing.

Some people have the Turbine and the Compressor wheel balanced separately.

There is a Factory Torque Proceedure. Someday I will find a site that has the correct one.
Below is the closest I have come to any real documentation. (I was uable to locate any info on the Book mentioned.)

http://www.gnttype.org/techarea/turbo/turborebuild.html
Search= garrett t3 shaft nut torque
“As for the tension of the compressor nut i quote from the Normalair-garrett TO3 TO4 overhaul manual, "on oil threads, after bottoming the lock nut, torque to 18 to 20 inch pounds above the drag of the lock nut. Tighten lock nut through an angle of 90 degrees. This additional tightening will result in stretching the shaft 0.0055 to 0.0065 inch, which is required for proper installation of the compressor wheel"
Turbo Shaft Nut torque see post #12

This is from another internet source:
Turbo Charger Nut torque = Line up the mark on the compressor wheel with the mark on the turbine wheel. Torque the compressor nut to 18-20 in-lb (that's INCH-pounds NOT foot-pounds) Then continue to rotate the nut an ADDITIONAL 90 to 110 degrees. DO NOT use any sealers on the nut or shaft threads--the nut is self locking.

These are the only 2 sets of info from different sources I have found that coincide.
I have not ever posted this info before because I am still not 100% certain it is correct.

[Bob Albrecht]

The link isn't a very good set of instructions. I would not re-use the inner journal bearing snap rings or any of the hardware. The carbon seal on the Mercedes Garrett T3 turbo is probably encapsulated, not 4-part as in the instructions. There are some good T3 rebuild instructions on YouTube, and on a few other web sites that include nice pictures. The G-Pop shop has a nice exploded diagram.

I believe thread lockers will throw off the balancing on the shaft nut.

The rebuild kit I got from Ron's Turbo Service included all new hardware including the new shaft nut. The e-clip fastening the waste gate actuator to the waste gate was not included.

The bolts that hold the turbo together already had a dot of red thread locker on them. I put a little blue Loctite on too.

One mistake I made was to NOT mark the position of the compressor and turbo relative to the middle section before I took the thing apart. It took some time to get it assembled at exactly the correct angles.

The special snap ring pliers need to have .035" straight tips that are 1 1/8+". Sears had the right tips that went with another set of snap ring pliers. But the Sears snap ring pliers would not have worked, had I used them, because the clamping mechanism for the tips took too much of the tip to work right. I think it would be impossible to insert the inner snap rings for the journal bearings without the correct pliers.

One of the compressor clamp plates is the waste gate actuator and is not used. The other two plates can only go in one way.

Be prepared for a huge mess if you clean the intake manifold yourself. The repair shop with a solvent tank took one look at my intake and said "no way, it will contaminate our whole tank".

I ended up cleaning it first scraping out the devils food cake with a big screwdriver, then with some brake cleaner which didn't work very well. Then I filled it up with purple degreaser and let it sit for a day, It made an bunch of bubbles and loosened up the cake. Then I took it to the "wand" car wash and blasted it out as much as I could. Then I scraped and wire brushed the remaning scraps of cake and used brake cleaner again.

All in all, it was one of the most horrid jobs I have had to do on this car. The actual turbo rebuild part was easy and fun.

I noticed that one of the bolts connecting the drain tube bracket had stripped the aluminum threads. Someone had used a bolt that was too short, or used a short bolt from another part of the turbo bracket. I purchased a longer bolt to catch the threads that were left.


If I were running a shop I would charge $400 for the turbo rebuild, but $1400 for removal intake cleaning, and installation.

[Diesel911]

Originally Posted by Bob Albrecht

The link isn't a very good set of instructions. I would not re-use the inner journal bearing snap rings or any of the hardware. The carbon seal on the Mercedes Garrett T3 turbo is probably encapsulated, not 4-part as in the instructions. There are some good T3 rebuild instructions on YouTube, and on a few other web sites that include nice pictures. The G-Pop shop has a nice exploded diagram.

I believe thread lockers will throw off the balancing on the shaft nut.

The rebuild kit I got from Ron's Turbo Service included all new hardware including the new shaft nut. The e-clip fastening the waste gate actuator to the waste gate was not included.

The bolts that hold the turbo together already had a dot of red thread locker on them. I put a little blue Loctite on too.

One mistake I made was to NOT mark the position of the compressor and turbo relative to the middle section before I took the thing apart. It took some time to get it assembled at exactly the correct angles.

The special snap ring pliers need to have .035" straight tips that are 1 1/8+". Sears had the right tips that went with another set of snap ring pliers. But the Sears snap ring pliers would not have worked, had I used them, because the clamping mechanism for the tips took too much of the tip to work right. I think it would be impossible to insert the inner snap rings for the journal bearings without the correct pliers.

One of the compressor clamp plates is the waste gate actuator and is not used. The other two plates can only go in one way.

Be prepared for a huge mess if you clean the intake manifold yourself. The repair shop with a solvent tank took one look at my intake and said "no way, it will contaminate our whole tank".

I ended up cleaning it first scraping out the devils food cake with a big screwdriver, then with some brake cleaner which didn't work very well. Then I filled it up with purple degreaser and let it sit for a day, It made an bunch of bubbles and loosened up the cake. Then I took it to the "wand" car wash and blasted it out as much as I could. Then I scraped and wire brushed the remaning scraps of cake and used brake cleaner again.

All in all, it was one of the most horrid jobs I have had to do on this car. The actual turbo rebuild part was easy and fun.

I noticed that one of the bolts connecting the drain tube bracket had stripped the aluminum threads. Someone had used a bolt that was too short, or used a short bolt from another part of the turbo bracket. I purchased a longer bolt to catch the threads that were left.


If I were running a shop I would charge $400 for the turbo rebuild, but $1400 for removal intake cleaning, and installation.

I only Posted the Thread to show where I found the Comment on how the Shaft Nut should be Torqued.
I have looked at as may Threads as I could find and have not found any that I consider good Turbo Rebuild threads.