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Showing posts with the label Maintenance

Torque tube maintenance

I had to purchase a heavy duty circlip plier (Knipex 4811-J4, 320 mm) to remove the large circlip fixing the drive shaft in the torque tube. Inside, there was nothing to tell that this torque tube had been in service for 20 years and 110k miles. The rubber couplers looked and felt like new. There was no play in the bearings, but they had less preload and made more noise than their new counterparts* A curiosity is the "16/1/2004" date stamp on the drive shaft for a car produced and sold in 2003 (The black marks are from my oily fingers). To remove the rubber couplers the bolts have to be heated with a blow torch to break the factory thread lock. I initially tried without heating the bolts, which quickly broke the bits. Heating the bolts caused the rubber couplers to catch fire, so this method renders the couplers U/S. The torque tube rebuild kit includes new circlips, O-rings and bearings, and also the slinger. A hydraulic press is required to replace the parts. Not much force

Spec stage 2 clutch kit

Lightweight aluminium flywheel with steel insert Worn slave cylinder At 110k miles (178 000 km), the car had developed the "clutch pedal stuck to floor"  issue when shifting at high RPMs. This is caused by a worn slave cylinder, where worn seals allows dust to enter the circuit and cause the slave cylinder to get stuck by the high inertial forces and the increased friction. A sure sign of this happening is that the clutch fluid gets discolored again quickly after a change. State of stock clutch The OEM clutch from LUK is more than capable of handling the LS6 stock power. The car still had the stock clutch, which was in a surprisingly good state for the milage. Minimal surface wear and only a few small hotspots, one could even mistake the clutch disk for a new item.  However, with everything else disassembled, it would be dumb not to replace the clutch now, as it will probably not last another 20 years. Guess what happens when a flywheel, a pressure plate and a clutch disk bou

Built 4.10 rear differerential

Late April, and the spring finally arrived with temperatures making it possible to start on the pending repairs.   This is what the T-1000 Terminator is made of; liquid metal drained from a Getrag differential. A magnet picked up a lot of metal shavings.  The output shafts have significant play, which is an indication of worn clutch packs and belleville washers, and possibly broken output shaft stubs (I will find out when I disassemble the differential later). With all these issues, this differential needs a complete rebuild. It is hard to find specialists with the knowledge and the tools required to perform this work in Norway. The cost of shipping the differential to the USA and back for a rebuild is also excessive, due to the weight. Built 4.10 differential C6 Z06 output stub shafts C7 Z06 clutch packs Motive 4.10 ratio ring and pinion gear New bearings, carriers and seals To ensure that history does not repeat itself, I'm not on a track day again until a differential oil cooler

Replace pilot bearing

I decided to install a new pilot bearing together with the new clutch kit. Notice that the tip of the propeller shaft, which is supported by the pilot bearing, has turned blue. This is an oxide layer forming on steel heated above 205 °C (401 °F), indicating that the pilot bearing has worn and heated up due to high friction. The surface is perfectly smooth and runout is within specification, so I'm reusing the propeller shaft. A bearing puller is required to remove the pilot bearing. It is necessary to totally mangle the bearing, as the tool does not get a good grip on the outer bearing race. The internal bearing race is crushed and the steel rollers drop out (beware!), at this point the bearing puller can be reinstalled so that it grips the outer bearing race from the top. It took a few attempts to get a good grip, and then it finally came out. New bearing installed. Notice that the chamfered side is out, this side also has an O-ring to protect the needle bearings from contaminatio

Replace rear engine seals

I've previously replaced the front engine seals, the oil pressure sender, cam sensor and the oil pan gasket, but oil was still collecting at the back of the oil pan. I think I've identified the source. The seal lip has hardened and worn down. Signs of a worn seal is visible on the surface of the crankshaft, but it felt perfectly smooth. I'll locate the new seal further in, as the rear cover is designed to allow this. While it was accessible I also installed a new oil gallery barbell, which is supposed to increase oil flow and reduce the amount of unfiltered oil bypassing the barbell - and thereby the oil filter. I drilled a small hole in the OEM barbell and used a wood screw to pull it out. New barbell in place. It has a threaded hole, making it easier to remove if one should ever need that. I managed to sneak the mobile phone camera up to the cam sensor, hiding in a chamber on the top of the engine (used for a distributor on earlier generations of the engine) and right abo

Removing and reinstalling the drivetrain

Removal Removing the differential, gearbox and torque tube was not as difficult as I was lead to believe. I used a jack for the engine, a jack for the torque tube and a transmission jack for the rear subframe and differential. The torque tube slid out of the bellhousing easily, and I had adjusted the rear transmission jack so that it kept the whole assembly in balance as I removed it from under the car. I forgot the fact that the rear subframe  is attached to this assembly only by one single point - the differential mount. It is only a piece of rubber with 4 posts sticking out of it, so it was bent at close to 45 degrees. I need a new differential mount, fortunately I had a replacement ready. I disconnected the rear brake lines and removed them, as I found it stupid to bend brake lines this much to get past the drive shafts. I will reroute the brake lines before reassembly. I see no logical reason for the brake lines to run down and behind the rear differential, when they can simply be

Larger 330 mm rear brakes from C6 Z51

Don't drive with your nannies on! With active handling in competitive driving mode, yaw control is still active and using the rear brakes to correct excessive yaw on corner entry/exit. This causes the rear brakes to run hot, and in my case one of the rotors cracked as the car cooled down in the pit. I even heard the *PING* as it happened. 305 to 330 mm brake rotor After some research online, I found that the C6 with the Z51 option code uses a larger 330 mm brake rotor, but still share the same caliper and parking brake dimensions.  Plus Increased thermal capacity. The EBC Z51 rotors are ventilated on both sides, have a higher mass and increase the swept diameter of the brake pad Better looks, the brakes fill the 18" wheel and looks more in balance with the front big brake kit. Reuse of stock brake calipers and parking brakes Minus Change of brake brake bias. The increased rotor diameter causes a braking torque increase of ~ 10%, which could affect the front to rear brake bias.

Window regulator replacement

High up in the mountains in Norway, close to freezing temperatures, the driver side window regulator broke down. Perfect timing. Fortunately, I managed to pull the window up by assisting the motor. A broken piece of plastic was all it took I had to twist my brain to get the parts back in the correct orientation. Notice that as pictured, it will not work. The wire coming from left (door B pillar) needs to pass below the right wire, otherwise it will conflict with the window. Mounted incorrectly here: I also noticed that the regulator power cable and the door latch switch cables interfered with the mechanism as it moved up and down. so I used some high strength duct tape to move them out of the way. New window regulator in place. I ran the window all the way down so that there wasn't any tension on the mechanism before tightening the bottom nuts. I followed Chris Askew's guide to replace the regulator: