[Frost]

As stated, I need to remove the speedo cluster from the 75, the speedometer has not worked since I bought the car and I really want to get it sorted, I have replaced the control unit under back seat and this has not worked, so I am hoping that if I remove the entire cluster and send it to a speedo repair specialist he will be able to help, but I cant seem to find any bolts to undo to pull it out , help please!

 

[Gubi]

There are three components to check: the amplifier box under the seat, the hall sensor in the transmission, and the speedo itself. If you have the Cardisc there are a few TSBs that explain how to isolate the problem.

IIRC the Cardisc has the removal procedure for the cluster as well that shows where all the screws are. It's not very difficult technically, it just takes a while because there's a bunch of crap to remove (and then a bunch more crap to take apart in the cluster to actually get the speedometer out).

 

[oz3litre]

I just removed one from the wreck yesterday as it happens. First you have to carefully prize the covers off the switches on either side of the cluster, trying not to break the base which is screwed onto the cluster like a previous owner of my black car did. Then you remove the bases and you will see some screws inside on the firewall that hold the cluster on. There are also a couple on the other side under the computer panel or ARC so that will have to come out as well. It was a while ago that I removed the ARC from that car, but I think it just pulled out. The trickiest bit is getting those covers off because they are quite tight. Trying prising them off from the bottom first. I was hoping to swap the cluster into my black Potenziata because the tacho is way out, but the cluster from the burnt wreck suffered heat damage sadly. I hope this helps.

Guys, is there a common cause for tachos to read very low that is easy to fix?

 

[Frost]

Thanks, think this will help, or at least give me a starting point.
While Im at it , my arc and speedo lighting does all sorts of weird and wonderfull thing, Ive read on here somewhere its a common earth fault, can someone advise me as to where the earth is so I can clean it up and maybe get the car to work properly once more.
Many thanks

 

[oz3litre]

Thanks, think this will help, or at least give me a starting point.
While Im at it , my arc and speedo lighting does all sorts of weird and wonderfull thing, Ive read on here somewhere its a common earth fault, can someone advise me as to where the earth is so I can clean it up and maybe get the car to work properly once more.
Many thanks

Here is the link for the definitive fix for ARC problems:
http://www.alfabb.com/bb/forums/milano-75-1987-1989/69476-real-fix-arc-blinking-lights-7.html

 

[gtvpete]

Here's a link to a copy of Shiv Sikand's old Milano Resource Site (from the late 90s), it has, among other tech articles, step-by-step instrument cluster removal instructions:
The Alfa 75 / Milano Resource

 

[oz3litre]

Here's a link to a copy of Shiv Sikand's old Milano Resource Site (from the late 90s), it has, among other tech articles, step-by-step instrument cluster removal instructions:
The Alfa 75 / Milano Resource

Thanks for that. I have saved some very useful stuff as PDFs.

 

[Frost]

Thanks guys, have succesfully removed the cluster, going to take it to speedo specialist to see what is wrong, my only concern is, how do I know if the problem is A on the speedo, B on the control module under rear seat or C the pickup on the gearbox?

 

[Gubi]

If they test the speedo and it works then the problem is the amplifier module or pickup

If you want the answer before you bring the cluster in, you'll need to follow the directions in the Alfa TSBs. There are two: one tells you how to build a "digital" test light from an LED and a resistor, and the other tells you how to use it to diagnose the pickup and amplifier.

 

[oz3litre]

The funny thing is my tacho has suddenly appeared to be working better. It was running extremely slow by over 2,000 RPM but is now somewhere around the mark. I will need to check it against an accurate one of course. Can anyone tell me where it is wired to? Is there for example a wire on the coil or somewhere else that I can check? I did have the back seat out the other day but I would have thought the tacho would go to the front somewhere. I have not yet removed the cluster, but I did replace the fog light switch, so a wire might have been wriggled back there in the process.