WR quattro turbocharger remove & rebuild

[urquattr085]

I thought I'd share my experience of this job for those who may be needing to do the same at some point.

The turbocharger is a KKK K26, a fairly common unit of the era, also used on the 200, Porsche 944 and others, although there will be differences with each make & model.

I'll cover removal of the turbo in this post, then follow up with the stripdown & rebuild.

Bearing in mind most of these parts have been off before in the last 4 years, this was still a decent afternoon's work.

First job was to create access, so I removed

the front grill and offside headlight
offside undertray
intake & intercooler pipes


intercooler


engine mount heatshield


fuel distributor "relocated" with all lines still attached, but vacuum pipes & wiring to potentiometer removed


allowing air filter and airbox to be removed (only 1 bolt)


Next to be tackled was the exhaust downpipe. Firstly uncoupled from the middle exhaust section which can be left in-situ, then it's 4x17mm nuts on the back of the turbocharger


3 are straightforward enough but the 4th, the lower one next to the block, is a tricky bugger to get at !!
Having removed this before, I resurrected this 17mm C-spanner which hadn't been used for anything else since the last time this downpipe was off !! I was happy I could find it.


With a length of rope looped through the accessible end, it's possible to crack off the nut by pulling from above. It's the only way I could figure to get some purchase on it.


I can't quite remember but I may have given it some extra curvature at the 17mm end to make it work - and removing the other lower nut and/or stud seen in the above pic really helps to make room for a bit of swing.

Then off with the drivers side front wheel to disconnect the flexipipe between the wastegate & downpipe, accessed through the inner wing. Remove the bottom 3 bolts and yes you need to be a contortionist !!


A 13mm 3/8" drive socket, long extension and a short 13mm combination spanner will be your friends. I had to slim down the ring on my spanner so it would fit between the nut and the lower section of pipe. The screwdriver you see has been inserted into the first bolt hole to stop the pipe twisting round - this helps to get the other 2 out.

The downpipe can now be manoeuvred backwards out of the way.

Remove the 2 oil lines and gaskets from the body of the turbo (the oilyness in the photos is penetrating fluid)



then it's ready to be removed.

4 x 15mm nuts hold the turbo on the manifold. To gain straightline access with a socket & extension I had to remove the remaining lower downpipe stud


and 2 of the nuts/studs that secure the turbine housing to the central bearing housing


The turbo to manifold nuts were very tight and cracked off very suddenly - BEWARE - heavy gloves highly recommended !!

and bingo, out she comes from below

My downpipe gasket showed slight blow-by......


and this is why...............b*llocks, not good........


severely cracked turbine housing


Now that unknown quantity £20 purchase I made 6 months ago just became a life-saver.

I had bought another unit on spec, in an unknown state of repair, really just to pull apart & see if a self rebuild was do-able. It turned out the bearings were shot and the compressor wheel is damaged beyond belief - looks like it's tried to consume something heavy and metallic!!
But the turbine housing is fine.....woohoo!! Hope it's going to fit.......

As an aside, if you need to change the offside engine mount, you won't get better access than now.
Mine was ok but I did take the opportunity to tidy up the inner wing, treat a bit of rust around a (unused) grommet hole and give it a quick lick of paint.



Details of the rebuild to follow.

[Davids]

Looks like a good afternoons work so far

[tractor Dave]

Nice work. Can't wait for the next instalment

[luapkram]

I think exhaust nuts on older Audi are the reason I have my C Spanners 🤔. To be fair a lot of Modern cars are not any easier and you still need to be a contortionist! Looking forward to next update 👍🏻


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[4v6]

Can you post up a photo of the engine mount heatshield in its fitted position please?

Only asking as Ive made dozens of these in stainless and Ive still never seen where exactly they fit!

[vorsprung durch technik]

Looking good so far - waiting for the next instalment.

[mikes2]

Nice work, shame about the turbo. It's possibly been cracked for a while.

I always thought the difficult to get at nut had 15mm flats to aid removal. I have some spares if you want for re-assembly.

[urquattr085]

Cheers for the comments guys.

Hi Tony - I'll take a pic or 2 this afternoon when out in the garage

[urquattr085]

Originally Posted by mikes2

Nice work, shame about the turbo. It's possibly been cracked for a while.

I always thought the difficult to get at nut had 15mm flats to aid removal. I have some spares if you want for re-assembly.

Hi Mike.
Yes, probably been that way for years and may well have been ok (bar the slight blow) for some time yet, who knows?

Cheers for the kind offer, that would be great.
I'll pm you my details.
Will certainly make life easier.

The parts diagrams are ambiguous, but looks like KW & RR engines may have had 2 different types of nut, not so clear for WR & MB.

[Hanuman]

I’m 90+% certain that the original turbo* flange nuts had two unique qualities.

1. 15mm A/F instead of 17mm.
2. Made of titanium.

Access being a major issue. Correctly aligned, the whole thing could be a pig at best. Wrong size nuts go on very easily, under clean conditions. Getting the sods off after several years of heat cycling being a completely different story. I have used stainless steel 17mmAF.


*mine is a 85WR, and until 2005 still had the original turbo, albeit with a repaired exhaust manifold