I have just rebuilt my T25 turbo, using a T25 rebuild kit I got from Ebay and alot of care. And getting the shaft balanced by Garrett themselves tommorrow for $77 bucks!
Original writeup by - Jason_G200t (Jason Broadhurst)
... its a T25 .48 and .48 AR's and the power band is good on it. mild lag but its a VERY small price to pay for top end power, which the STD RHB didn't really have. has done 30 odd km now without a puff of smoke or a leak so i think it may be fixed with any luck
very good learning experience. 4psi feels like 12 did on the std turbo btw. and spool up is very mild.
Here's how to rebuild the T25:
1) remove turbo from engine. read type cb manual to find out how
2) clean the turbo. using carbi cleaner or degreaser clean the turbo very well
3) take the wastegate actuator off
4) TAKE EXTREME CARE Remove exhaust housing (the big cast iron side) by removing the 4 retaining bolts from the cartridge side of the housing. these hold the housing to the cartridge. to fully remove these bolts it may be necessary to push them into the cartridge. If the all the bolts are loose and the housing still wont come off, apply CRC or RP7 every 10 minutes for an hour, then lightly tap with a hammer with the housing facing downwards and the cartridge in your hand. tap different spots around the housing as to not jam it on, working around the housing. That way the housing falls down straight away from the blades of the impeller wheel. exhaust housings are also sometimes held on by a big circlip. take the circlip off and then if the housing does not fall straight off, read above how to remove.
5) remove the compressor housing (the silver alloy side) this is done in the same manner as the exhaust side, there is normally 4 bolts or a circlip holding it on. this side rarely is jammed on. remove the big rubber O ring which seals the housing to the cartridge
6) Remove the locking nut on the compressor wheel, the compressor wheel nut is left hand thread. This is done by using a T piece socket arm and another T piece in a vice holding the shaft on the exhaust side. T25's have a 8mm 16tooth socket piece compressor side and a 13mm on the exhaust side. I expect it to be different on every other turbo. The tee bar socket arm is so that a uniform torque can be applied so as to not bend the shaft. i used a ratchet and the breaker bar (but i have warned you!) Once the nut is loose, remove it and then the compressor wheel and put the wheel somewhere safe and clean.
7) remove the shaft and impeller wheel (the exhaust side) slowly and avoid damaging the bearing surfaces on the shaft as it is then useless. put the shaft and wheel with the compressor wheel safely away somewhere.
8 ) There will now be a plate over the compressor side, this is held in with a circlip. remove the circlip and the plate should fall out. if it doesn't, don't be afraid to pull it out, just don't damage the cartridge/housing as yuo get a new plate with the rebuild kit, just not a housing. If the little piece didn't come out of the middle of it, then try get two blades either side of the lip half way in the plate and lift it out that way. New rebuild kits come with two pieces where the old ones had 1. The pictures show the 1 piece and the 2 piece as i have both lying around. if you have the 1 piece bearing then its frustrating because as you can see there is a piston ring sort of seal which really holds that plate on tight. remove the rubber O ring seal which seals the plate to the cartridge
9) now there will be the 270degree retainer to remove, you will need a size 15 or 10 tek bit to remove the 3 screws holding this in.
10) you will be able so see a brass bearing now. it will fall out, if not there may be a circlip holding it, that is rare.
11) remove the circlip which was holding the last bearing in.
12) now right down the end of the shaft (looking from the compressor side to the exhaust side) there will be another circlip on this side and a real mongrel clip on the other side. remove them both and take out the bearing.
13) clean the inside of the cartridge with carbi cleaner and then spray ample RP7
14) remove the "piston ring" type seal from the exhaust side of the turbine shaft and remove the big plate from behind the exhaust wheel, this is known as the dog dish.
rebuilding is a reversal of this procedure. wheels will need to be balanced, so take the shaft, compressor wheel, new nut and new 2 piece bearing into a turbo shop. This was 55 AUD for me. ( EDIT - I paid $77 for my balance. Prices may have changed since he wrote this, ALSO - I basically needed to have my turbo put together without the housings to get it balanced, as they hook the cartridge up and run fluids through it during the balancing.)
I'll let you's know how mine goes!
Note:- there are a few different versions of the T25, some have retainer clips where others dont, dont be affraid if you have any left over, just be sure 100% you put all the bits the same as what you pulled out back in where they go! It really isn't overly hard providing you take your time and be patient.
# #1: JOURNAL BEARINGS (2 sets narrow & wide)
# #2: RETAINING RINGS FOR JOURNAL BEARINGS
# #3: RETAINING RING FOR OIL DEFLECTOR
# #4: OIL DEFLECTOR SEAL/WASHER
# #5: PISTON RING FOR TURBINE END
# #6: THRUST BEARING
# #7: BOLTS FOR THRUST BEARING
# #8: SEAL RING FOR SEALPLATE
# #9: THRUST COLLAR
# #10: PISTON RING FOR COMPRESSOR END
# #11: SEALPALTE
# #12: RETAINING RING FOR SEALPLATE
# #14: LOCKNUT FOR TURBINE SHAFT, 0.264"/6.70mm
# #16: O-RING FOR COMPRESSOR HOUSING
# #17: RETAING RING FOR SWING VALVE
# #18: RETAING RING FOR TURBINE END
# #19: BOLTS FOR TURBINE END
# #20: CLAMPS FOR TURBINE END
Recource - http://www.dairally.net/daihard/chas...JasonTurbo.htm
T2T25info.pdf(unauthorised copy of melett document)