Project car - 1989 75 3.0 V6 [Updated 12 November 2021]

[ARQ164 Shane]

gday mate,
Hmmm that sounds like it mite be a good trip ,going via the coast road you would cruze right passed my front door
you would be welcome for a coffee.

I have rego on the car today took it out for a spin and blew the clutch salve cylinder hose, so that will need to be fixed. asap

cheers

[shiny_car]

For this update, I worked on several different areas around the engine bay. Lots of little details which take plenty of time, but will be worth it in the end.

One design weakness in the 75 (as if!) is the cabin air inlet area. Firstly, no grill over the intake aperture means debris enters the fan blower housing which can be hazardous (hot fan resistor + debris); future job is cleaning out the ventilation unit under the dash. I'll make up a mesh grill to cover the opening. Also, water is meant to flow out the drain outlet; however, debris also blocks this area, resulting in damp crud = RUST. Indeed, my car was not immune to this, and there was a lot of crud blocking off the outlet. gergory had warned me about this, from his experience.



Time, moisture, engine heat...whatever...the foam gasket between the outlet hole and pipe had perished and leaked water. I drilled out the rivets to remove the pipe.





The area is hard to access and photograph, but after the initial cleaning, you can see the areas of rust in the thin-walled air inlet aperture frame. Debris and water sits infront of the aperture causing grief over the years. Fortunately, the main firewall structure (the bottom section and where the drainage outlet is) seems intact with no obvious rust.





After crunching away as much rust as possible, I painted the whole area liberally with Cold Gal rust proofer. Next task will be patching the holes with fibreglass and plenty of resin.



Reworked the powerwiring again. As per the wiring diagrams in the workshop manual, I located the two main powerwires feeding the fusebox under the steering wheel. These originate from the terminal board in the engine bay that I had attended to previously; the wiring diagram denotes the wires as 4mm^2 each (approx 10~11awg). I don't know why Alfa chose 'two smaller wires' rather than 'one thicker wire'. I can only postulate that the 9mm (wide) spade terminals that connect the wires to the fusebox are not rated high enough to carry the current to supply all the electrics; that is, if the electrics require 60A of current under full load for example, a single connection could be a weak link. So the load is shared across two connections, and thus two wires. Meh, I can improve on this setup.



From the engine bay, I located the powerwires in the loom, cut them, and removed entirely.







After removing the two wires, I filled the vacancy in the firewall grommet with silicone. Also, change of plan! I had previously upgraded the main wire feeding the terminal board from the starter motor, to improve power delivery to the fusebox and engine bay loom. However, I have since decided to relocate the battery to the boot, so that upgrade has become redundant. I will run a new powerwire from the boot to the fusebox in the future. Thus, I removed the upgraded powerwire, and reinstated the original wire by joining a short length of 8awg wire to where I cut it short. This wire now only needs to feed the engine bay loom, and no longer supply the fusebox/electrics.







The terminal board is now simplied. It has the 8awg feed from the starter motor connection, a wire to the starter relay/solenoid (an upgrade I did earlier), and a wire to relays at the front of the engine bay.



I stripped the wiring loom on the R-hand side of the engine bay of all the tape. You can see the red powerwire for the relays dangling down loosely.



Another upgrade will be rewiring the headlight (low + high beam) wiring to something thicker and feeding directly from the battery supply. Thus, the green/grey (and black ground) wires were cut from the loom to reduce the bulk.



There are two small 'branches' coming off the loom. First are the wires to the coolant expansion tank 'coolant level sensor'. I covered these with new pvc tubing. The neatest tubing was narrow diameter, too small to slide over the existing spade terminals. Rather than cut off the terminals, I cut the wires proximally, added the tubing, resoldered, then insulated with heatshrink. The other branch is the red powerwire to the relays.





Another minor change in plan: I had bought plenty of new corrugated split conduit to replace the original. However, I prefer the cleaner look of smooth pvc tubing; this also doesn't gather dirt/grime like the corrugations do. So, larger diameter tubing was used to cover the main loom. I measured and cut out side holes for the two small wire branches. It was a tedious job, feeding through a metre of wires through the tubing, but I got there! I first had to unclip all the wires from their plugs on the ends, itself a tedious job (I also took reference photos to ensure I reinserted all the wires into the correct holes in each plug).



All the wires/branches at the far end were then covered with new pvc tubing and heatshrink for a fresh new look. The groundwires will be fitted with new lugs/ring terminals and connected to a new grounding bar.





Here's an old photo as a reminder of how it used to be:



This is another smaller wiring loom that connects to the main loom (via 4-wire plug); it connects relays for the AC compressor clutch, and radiator fan power supply, with power connections to a small terminal board (which is supplied by the powerwire branch discussed earlier). This loom also has wires for the radiator fan thermal switch (ie: the radiator fan is turned on/off via this switch which is screwed into the radiator and senses when the coolant approaches 90 degrees celcius), and AC trinary switch.



Loom stripped of corrugated conduit and tape, then overhauled with pvc tubing and heatshrink (yes, another time-consuming task! ).





The arrows highlight the exposed ends to show wire colours for easy identification. Whilst this is in keeping with the factory design, let's just say it's now a bit neater!



I retrofitted OE-spec relays. A previous owner had fitted aftermarket Bosch relays, but these were 'unfused'. The replacement relays are secondhand, but work fine; they are fused (30A for radiator fan; 10A for AC clutch), and from research they are the same colours as original (though no actual difference in design). I discovered that the pin layout was different: pins 30 (main power) and 86 (coil ground), which I have circled in the photo. What's more, the AC clutch relay wires had not be changed to cater for the Bosch relay pins! The fan relay wires had been appropriately changed, but it may explain why the AC was not working (hopefully it's as simple as that)! I have obviously reverted the fan relay wires to suit.





The relays and wiring loom, and power supply terminal board have been refitted to the car.





New engine oil filter fitted. More compact than the existing one.





The other task I finished was re-attaching the AC compressor. The belt tensioning pulley had a 'rough-feeling' bearing, so it wasn't going to last a lot longer. The original bearing is cast within the pulley, and thus the bearing alone is not replaceable. I bought an aftermarket pulley+bearing from ebay but alas, the inner diameter of the bearing was not the right match for the spacer it fits over. However, this version has a simple snap ring securing the bearing which was removable; so I sourced the correct size bearing from a local supplier and pressed it into position.









I cleaned then sprayed the mounting bracket.



To clean up the compressor main pulley and clutch, I bought a cheap clutch-removal kit from ebay. The handle attaches to the clutch face via 3 supplied bolts (the model compressor on the car is a Sanden SD508, version 8390); using the handle to prevent the clutch rotating, the lock nut is removable.





Then a supplied adaptor added to the handle to convert to a puller, to remove the clutch from the spindle.



Removed a small snap ring, then used a conventional 3-prong puller to take off the main pulley with its bearing.



Behind the pulley is the coil. This is energised by +12V, which then magnetically pulls the clutch against the pulley to lock them together, thus spinning the compressor. Removing another snap ring allows removal of the coil.







The coil had an excessively long powerwire, so I cut this short, soldered and insulated with heatshrink.



All components were cleaned. I sprayed the pulley and clutch (masking off the clutch mating surfaces). Then reassembled in reverse order. The 'air gap' between the mating surfaces was within spec, checked with a feeler gauge (0.4-0.8mm). Then I used a +12V power supply to test, and confirmed the clutch engaged with the pulley - works perfectly.









Service guide for Sanden compressors can be downloaded here: http://www.sanden.com/originals/images/SD_Service_Guide_Rev.2.pdf

That was a productive month. I continue to really enjoy it. I particularly have this weird fascination with wiring: wiring diagrams, rewiring, and making things neat and tidy    . I can't wait until I put the battery in the boot    .

[gergory]

richard another great post...............with all this electronic upgrade I was wondering if you were going to consider looking at the lethargic power window syndrome?
If you can come up with an upgrade it would be fantastic.

[shiny_car]

Cheers Greg. Come time, I'll definitely assess the power supply to the windows. Have you modified the groundwires for the rear windows?
http://www.users.on.net/~craigf/rearwindowgrounds.htm

I haven't yet, but will get to it once I'm working in the cabin.

[Sheldon McIntosh]

richard another great post...............with all this electronic upgrade I was wondering if you were going to consider looking at the lethargic power window syndrome?
If you can come up with an upgrade it would be fantastic.

Have you tried relaying them?  I had that issue with my GTV6, but connecting 12v directly to the motor showed that they were more than quick enough with a decent source of voltage.

[GTVeloce]

I have just had a go at trying the method of grounding the rear wires suggested on craig's place. However, I couldn't get the wire back into the plug once I had attached the second cable - there just wasn't enough room no matter what I tried. In the end I just cut and spliced into the cable about 20mm after the plug (instead of soldering at the plug end) and the result was still a significant improvement.

[VeeSix]

Great work, that 75 is going to be like brand new when it is finished, yes that area under the windscreen is a downside on the 75 as for the reasons you have mentioned, not so much the design fault but without reguler checking maintenace a 75 that has been kept outside will usually have rust in there, if you are lucky it will just rust thru on the engine bay side and simply run out down the back there but if not you will also have it running into the interior usually ending up on the drivers floor but sometimes also going over to the passenger side sometimes soaking electrical parts on the way down, if you have never checked this area on your 75 do it now, you may save yourself a bit of work, quite a hard area to access as well if you do not remove the plastic cover   

[ARQ164 Shane]

gday blokes,
Shiny_car well done, If you ever have had to ever remove the brake peddle I have a few tips on putting back in (learned that hard way) and the steel bar from the brake to the booster is solid steel bar and it's very heavy.

all the best with the rest m8

[shiny_car]

Thanks guys.

if you have never checked this area on your 75 do it now, you may save yourself a bit of work, quite a hard area to access as well if you do not remove the plastic cover   

Yeah, removing the wiper cowl trim is a little tricky; I had to loosen the bonnet and of course remove the wiper blades, to jiggle it out. And removing the wiper mechanism wasn't easy either; awkward access and needed to disassemble much of it.

If you ever have had to ever remove the brake peddle I have a few tips on putting back in (learned that hard way) and the steel bar from the brake to the booster is solid steel bar and it's very heavy.

Hopefully I won't need to do this, but I'll hit you up for advice if I need to in the end!

[ARQ164 Shane]

Hi Shiny car,
How is your clutch pedel is it one smooth action or two part action?
Because if it two part action your clutch pedel may look like this:

[shiny_car]

Hmm, I haven't driven it for well over a year, but I vaguely remember it felt ok. I'll be sure to check the connection for signs of wear once I start working in the cabin. Thanks for the photo.

[ARQ164 Shane]

gday m8,
I am having trouble with the 3 relay on the right ,I have seen your photo on the 1st page of (two small one big)
my'n are (small ,big, small)?
Would you know to buy new relay ;low,high beam.

cheers

[shiny_car]

Hey alphie

Indeed, the relays in my car are fitted out of order. When I start overhauling the wiring on the passenger side of the engine bay, I will fit them properly, 'small-big-small'.

Which one do you need? In the correct order, it should the 'horn relay' (small, at the front), 'headlight wiper timer' (big, middle), and 'brake fluid level switch relay' (small, rear). I have not inspected mine yet.

The description of each (pin layout) is in the workshop manual (Group 40 Electrical System / pages 75-40-10 to 75-40-12).

[ARQ164 Shane]

Howdy,
Would you have any photos of the top's of the 'horn relay' and 'brake fluid level switch relay' so i can see what written on the top please.

I think prev owner has messed up the relays.

cheers

[shiny_car]

I'll try and take photos tomorrow, and confirm what each relay is.