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Showing posts with the label Maintenance

Fuel pump not priming

Having reinstalled the drivetrain, I wanted to start the engine to check for any issues. It fired up once, then died after a few seconds and would not start again. I noticed that the fuel pump was not priming when I turned on the ignition, the fuel pressure meter I've installed on the fuel rail also confirmed zero fuel pressure. Additionaly, the starter motor did not turn over, all I got was a blackout of all lighting when I turned the key. I erased a long list of fault codes, removed the fuel pump relay and jumped the 12V supply, but the fuel pump would not run. I started thinking of possible causes; fuel pump faulty due to car being stationary for a whole year, clogged fuel filter, wiring passing over torque tube damaged on removal or reinstall of torque tube. Oh no... removing all of the drivetrain again?! A new $250+ fuel pump assembly?! A Google search for "c5 corvette fuel pump not priming" gave multiple hits on , and in one of the threads the gro

Reinstalling the drivetrain

"Assemble in reverse" New rear engine seals and gaskets, new flywheel, new clutch, new slave cylinder, rebuilt torque tube, transmission leaks fixed. The drivetrain is finally ready for reinstall.  I decided to reinstall the drivetrain in three steps. This makes it easier to get the clutch splines and the torque tube lined up correctly, as there is less mass to move around: 1) Torque tube 2) Transmission and differential 3) Rear subframe with suspension Again, the bellhousing bolts caused troubles, with no space for my hands or any socket tools to get the threads engaged. The solution I came up with was to loop a wire around the bolts, which I could use to guide the bolts in place. Transmission and differential assembled and ready to be installed on the torque tube.  By using only hand force to install the torque tube, the chance of damaging the pilor bearing is close to zero. I stretched out under the car and lifted the torque tube up by hand, and then slid it in place. If

Skip shift solenoid delete

A skip shift eliminator  has made the skip shift solenoid itself obsolete. The previous owner had cut off and blanked the electrical connector, but that did not stop oil seeping through. While the solenoid was accessible, I decided to replace it with a simple plug (saves some weight too!). The skip shift solenoid thread is M20x1.25, which happens to be the same size as a Subaru EJ oil drain plug. Unfortunately a bit too short, but I solved that by some DIY machining, allowing the bolt to seat on the chamfered edge in the transmission. I also applied a thread sealant. Disable skip shift in ECM Instead of a skip shift eliminator, the skip shift can be disabled in the ECM using HP Ttuners. By setting "Disable TPS" to 0%, the skip shift is effectively disabled. This also stops the "1 TO 4 SHIFT" indicator in the speedometer from lighting up. What is skip shift/CAGS? CAGS is short for computer aided gear selection. Shift blocking or “skip shift” is a feature of six-speed

Slave cylinder shimming and Hinson remote bleeder

  I installed a Hinson remote clutch bleeder line, which makes it easy to bleed the clutch line later. Ideally, the bleeder should have used the stock design with a tapered fitting, instead of a crushed washer. To avoid leaks, I used Loctite Form-A-Gasket on the threads and washer, and then secured the line to the fitting using threadlocker. I measured the A and B dimensions as illustrated above, with A-B = 3.7 mm (0.146") which is within the  3.18 - 5.08 mm (0.125"-0.200") clearance required for bearing travel and clutch wear, so I did not have to shim the slave cylinder. Avoiding the shim also maintains the self centering of the slave cylinder on the torque tube / input shaft, so I was happy that a shim was not required.

Rerouted and shorter rear brake lines

The stock routing of the rear brake lines looks completely illogical (probably due to factory assembly procedures). The brake lines run from above the transmission, down to the rear of the differential and then back again across the rear subframe. By re-routing the brake lines, the driveline can later be removed and reinstalled without touching the brake lines. To make the correct bubble flares, I used this method:  Make a Bubble Flare with a Double Flare Kit My plan was to straighten and reuse the original brake lines, but my flare kit quickly failed as it couldn't handle the hard steel. I can't spend a fortune on a tool I'll use once, so with "Made in China" I switched to nickel copper brake lines, which are softer and easier to form. New shorter brake lines in place. I used a steel wire to make a template for bending and cutting the new brake lines. This works for both sides, but the length of the top section depends on how you bend the brake lines in the car (

M12 extension housing oil leak

ATF transmission oil (red color) accumulating between the transmission body and the extension housing (This is where the 5th, 6th and reverse gears are located). This leak is caused by a failed RTV seal between the two housings, and the only way to repair this is by removing the extension housing and resealing the flanges. The failed factory RTV sealant. The earlier effort to seal the leak from the bottom/outside was only a partial success, but who wants to remove the transmission only to stop this leak? The two magnets seen trap metallic particles produced as the transmission wears, which would otherwise be circulating in the oil and cause further wear. I wanted to remove the magnets to clean out all the particles, but I had to use more than sensible force, so I cleaned them in place. I found no large particles or shavings, only fine metallic dust that disappeared into the cleaning cloth.  A good sign. Another source of oil leaks are the inner and outer rear seals of the extension hou

Torque tube maintenance

To pull the driveshaft out of the torque tube the large  ~ Ø110 mm circlip has to be removed. I tried using a regular circlip plier, but the circlip only laughed at my effort. I did not want to remove the circlip with screwdrivers etc., which could ruin the machined slot in the torque tube. I purchased a heavy duty Knipex circlip plier (4811-J4, 320 mm), which made the removal easy (Wear eye protection, the circlip stores significant energy when compressed). Inside, it was hard to tell that this torque tube had been in service for 20 years and 178.000 km (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 driveshaft 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 to break the factory thread lock. I first tried without heati

Spec Stage 2 lightweight 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 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.  So the OEM clutch from LUK is more than capable of handling the LS6 stock power.  However, with everything else disassembled, it would be dumb not to replace the clutch now, as it will probably not last another 20 years. Spec Stage 2 clutch kit I had originally purchased a LUK OEM clutch ki

Pilot bearing replacement

I decided to install a new pilot bearing when replacing the flywheel and clutch. 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 contam

Rear engine seals, gaskets and barbell replacement

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 found 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 above the rear e