Momo Super Indy Steering Wheel

Momo v35 Steering Wheel

The previous owner of our BMW Bavaria put in a Momo V35 steering wheel. It felt great when driving in a sporting manner. But now the leather by the top spokes is worn, so I bought a Momo Super Indy on eBay – probably because I remembered my parents’ Bavaria had the OE wooden steering wheel (the diameter of which has been likened to a bus steering wheel). The Momo steering wheels are a nice 350 mm (~13.78 inches).

Momo Super Indy Steering Wheel

I’m not sure if the Super Indy looks right, with the polished aluminum spokes. At least the color of the wood on the steering wheel relates to the color of the wood on the dash (like the color of your necktie should relate to the color of your socks – ask Egon von Fürstenberg).

Maybe I should have looked for a Nardi steering wheel.

BMW Fuel Sender Repair

BMW fuel sender

The fuel gauge on the Bavaria stopped working.

I was hoping that it was only a bad ground connection on the instrument cluster. On my first repair attempt, I hit the top of the dash above the instrument cluster to jostle the connections and take out some frustration. When only the latter worked, I looked at my BMW repair CD.

To test the fuel gauge, the repair manual said to connect the brown-yellow wire on the fuel level sender to ground and to switch on the ignition momentarily. The gauge deflected to full, so I knew the gauge and grounds were OK. But that meant the sender was broke. lists the price of new sender at $261.40 (USD), so that was a good reason to try to fix it.

BMW fuel sender sensor wire routing

After I moved all the crap in the trunk to one side, I lifted the carpet and unscrewed the floor panel covering the gas tank.

The gas tank was full. When I tried pulling the sender out of the tank, (it’s a bayonet mount) gas poured out into the trunk. I decided to take a drive down Highway 1 a little south of Point Lobos to lower the fuel level.

The fuel sender is basically a variable resistor. The float moves up and down a guide rod and is also connected to a wire of known resistance. The change in resistance (by the position of the float) is translated by the fuel gauge as the range from full to empty.

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One end of the sensor wire had broken off its terminal connection so the wire was now too short to connect to the terminal. I used a piece of 22 gauge solid copper wire (looped and soldered to the connector) to extend the connection so the sensor wire would reach its terminal. Since the sensor wire is a continuous run from one terminal to the other, I had to figure out the routing around the bottom of the sender. It seemed to just wrap around – at least that’s how I did it.

The repair manual says the resistance between the G terminal and minus should measure 3.2 & 73.7 ohms at the extreme positions of the float. I measured 3.4 and 84.7 ohms so at least my repair sorta worked.

Flex-a-lite Fan Failure

Five years ago, when I had our BMW Bavaria‘s radiator re-cored, the radiator shop said a two row core would be enough. I’ve never had any cooling problems.

Instead of replacing the water pump mounted cooling fan, I bought a Flex-a-lite 116 Trimline Fan. It’s a 16″ fan that is 3.5″ deep. The airflow is 2215 CFM (62747.8 LPM) and it draws 11A.

Flex-a-lite says there should be “at very least 1″ from the closest part of the fan to the radiator“. Because I didn’t have that much room, I mounted the fan in front of the radiator, as a pusher.

To switch it on, I mounted a thermostatic switch (61 31 1 364 872 82D) on a bung on the radiator lower hose connection. The other part of the switch was connected to a relay for power.

Because the climate is cool here, the fan rarely switches on. But yesterday when it switched on, I heard a grinding noise. I was hoping a leaf got stuck in it.

I had to pull the radiator to remove the fan. It made a grinding noise when I turned it by hand. I disassembled the motor by removing a couple of Torx screws and a pin retaining the motor shaft to the case. Inside I found a DC motor, not unlike the ones I used in my slot cars, except this one had 4 magnets and 16 poles. I have used Koford quad magnets in my slot cars.

One of the permanent magnets had become unglued from the case. The armature’s poles had distorted slightly from turning against the loose magnet. I used JB Weld to glue the magnet back onto the can and a large screwdriver to straighten out the armature poles.

When I pulled the armature out of the casing, the four brushes and the springs shot out. While wondering how I was going to hold four spring loaded brushes in at once, I noticed two holes at the end of the brush holders. I put a piece of copper wire in each one so I could reseat the armature end bearing and connect the brushes.

After I reassembled and tested the fan, I ordered a new one. I figured $100 USD for a new fan is better insurance for preventing an engine meltdown, even though a 5 year life span for the old motor seems just OK. Maybe when I get the new fan, I’ll put some dielectric grease between the motor covers and the casing to seal it a little better from moisture.

BMW Starter Replacement

Old BMW Starter and Bosch SR71X Remanufactured Starter

Our BMW Bavaria exhibited the symptoms of a faulty solenoid on the starter. The battery was fully charged and I re-tightened the positive battery cable connection on the solenoid. Turning the key didn’t produce a click out of the starter. After I tapped the solenoid with a breaker bar; the starter cranked and worked normally.

I used the Bosch Vehicle Part Finder, which specified a SR71X Remanufactured Starter. I ordered it from my local NAPA store ($109 USD).

I wasn’t looking forward to removing the old starter, though it turned out to be easy. I managed to remove the two bolts holding the starter to the block using only the box end of a straight 17mm combination wrench. A 17mm half-moon wrench would have made it a little easier.

BMW ignition switch minus 2 parts I didn’t see at first

The smaller diameter of the new starter made it simple to use a socket wrench to reach the bolts when I installed it. It took about 5 minutes. The car started on the first turn of the key. The next turn of the key did nothing.

I removed the steering column cover and looked at the ignition switch. The half of the switch soldered to the wiring harness was falling out of the steering wheel lock housing, leaving about 5mm between contacts that needed to touch.

In retrospect, I probably could have repaired the old switch, had I seen two of the parts that fell into the bottom dashboard cover. Since I’m apparently on a replace 36 year-old car parts jag, I ordered a new switch from Mesa Performance. The switch is actually an E21 part (61 31 1 358 932), about $100 USD. They told me it was cheaper for them to buy a complete E21 switch and sell me just part I needed rather than buying an E3 ignition switch.

I had to reuse the Molex connector from the old switch and grind off an alignment pin on the new switch.

BMW E21 Ignition Switch 61 31 1 358 932

After I installed everything, the car still wouldn’t crank. I measured 12v+ on terminal 50 on the solenoid when I turned the switch to start, but it just clicked. Then I shorted the cable from the battery to the motor windings connection on the solenoid and the starter motor didn’t turn.

I took the starter back to NAPA and it tested OK. Frustration escalated. The starter motor wasn’t getting enough current – I measured the voltage and it was OK. Before reinstalling it again, I used a wire brush around the starter opening on the block to remove the surface rust. Then I removed and cleaned the ground strap between the block and the frame. As a precaution, I also replaced the positive battery cable; the old one seemed a little too flexible in the middle for 4 gauge copper wire.

When I put it back together and tried it, it cranked, ran for a few seconds and shut off. I tried this several times because it seemed like the fuel bowls in the carburetors were empty. There was smoke coming from the resistor next to the distributor. In the wiring diagram, the second small wire went from the solenoid to 12v+ on the ignition coil. I disconnected that wire from the solenoid and everything worked normally.