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-   -   S3 heater fan R/R & drain holes (https://www.alfabb.com/bb/forums/spider-105-115-series-1966-1994/132059-s3-heater-fan-r-r-drain-holes.html)

ghnl 10-28-2008 07:39 PM

S3 heater fan R/R & drain holes
 
4 Attachment(s)
The heater fan in our '84 Spider started to squeek and eventually it stopped working. I could turn the fan by reaching in the bottom of the unit but it didn't spin easily so I knew it was time to service or replace the fan motor.

I had removed the whole heater unit a while back which included removing the dash board. While that is not as hard a job as it may sound I had read that some have been able to unbolt the bottom half of the heater unit (which houses the fan & motor) without removing the whole unit. I had my doubts but decided to give it a go. It still took some struggling and cursing but I did it!

I took some new pictures to add to those I took way back when.

If anyone wants/needs to do this, here's some info that may help.

First I removed the center console and the side panels. Four screws, a bunch of electrical connectors, undoing the heater control levers and removing the shift knob gets the center console out. A small nut at the rear plus clips near the floor gets the side panels out.

The cable that controls air flow (off/floor/windscreen) attaches to the cockpit side of the heater unit. With the center console & side panels out it can be easily accessed. Loosen the screw holding the cable to the heater and unhook the end of the cable from the arm of the air flow flap.

On each side of the heater are plastic ducts to direct air up to the windscreen. A pair of hex head screws secure those ducts to the unit. Remove those screws and the ducts can be moved out of the way.

There are two wires on the left underside of the heater - low speed and high speed. Un-hook those (yellow and yellow w/ black trace IIRC). The ground wire (black) exits the front of the heater (closest to the firewall) and grounds to a screw way up under the dash to the right side of the heater. Remove that, too.

The bottom half of the heater unit is bolted to the upper half with four bolts. The heads of these bolts are inside the upper half and inaccessable. The good news is the heads fit into a hex shaped recess in the upper half so, if you carefully remove the nuts & washers the lower half should be removable leaving the rest of the heater in place. This is where I had some doubts but decided to try.

The bolts hang down and must be pushed upwards enough allow the bottom half to move sideways. Don't push the bolts up too far because if they get out of position they may be difficult (or impossible) to get them back into place without removing the whole unit. I moved the carpet directly underneath the heater out from underneath so that the lower half could move down a fraction of an inch. It was still a snug fit but I was able to squeeze the lower half with the fan & motor out towards the right side.

Once I had the lower half out it was obvious there had been some water in the bottom of the unit allowing the bearing to rust & seize. (I bought a 'good used' fan motor on eBay to replace the old one.)

I decided to drill a couple of drain holes in the very bottom of the lower half so any future water will have a way to get out. The picture below also shows the resistor that allows two speed operation (direct 12V = high speed, 12V + resistor = low speed). My estimation is that there is plenty of clearance between that resistor and the inside of the housing to carefully drill a drain hole or two without taking the unit apart. I'd suggest a 1/8" dia drill bit and drill only enough to go though the thickness of the plastic housing - say 1/8" to 1/4". (a piece of masking tape around the drill bit as a depth flag would work fine) Obviously with the lower half on my work bench and the motor removed, it was easy to drill these holes.

Assembly, as they say, is the reverse of the above. Of those four bolts holding the two halves together, the front two (nearest the firewall) will be re-installed by feel only - no way you can see what you are doing. What I did was stuff a piece of paper towel inside a socket to keep th enut at the end of the socket. Then I used a piece of masking tape wrapped around trhe socket to hold the washers on top of the socket. Thusly, I was able to maneuver the washers & nut into place and catch the bolt.

andytitterton 10-30-2008 09:43 AM

I did exactly the same modification after experiencing similar problems, although I had to remove the dashboard for other reasons anyway. I put a couple of extra holes in as well though, inline with the brushes that sit at the bottom of the motor. The additional holes are there to give a squirt of WD-40 or similar whenever I can to keep the motor free. That was several years ago, and it's still going well. To see the motor when I took it out made yours look comparatively new...........

Not the best Italian idea to have the brushes sitting in an inch of water!

cabikefreak 12-12-2009 07:10 AM

This thread proved very useful this morning as I just pulled the bottom half of the heater out without removing the dash. These instructions were most helpful. Mine came out toward the left - driver's side. My motor is rusted up just as described here.

mbb 12-12-2009 11:08 AM

Eric's method of removing the lower fan housing is a timesaver. Helps to remove carpet and padding below the housing for as much vertical room as possible. That area is hidden by the side panels so the carpet can be cut and peeled back.

Once the lower housing is removed, the fan and motor can be removed from the lower housing by compressing the two rubber bumps at the sides and pulling the motor out.

My spider housing held water very well and apparently for long periods. The lower bearing was frozen and the low speed resistor was deteriorated to almost nothing. Also the springs behind the brushes were almost totally gone.

Added drain holes.

Bent tabs and tapped open rear of motor. Cleaned and polished commutator. Cleaned brushes and added small hardware store springs in place of original springs. Cleaned and lubricated bearings. Reassembled motor. Tested with battery.

Note- with fan removed from motor it is possible to chuck the motor shaft in a drill and polish the brushes and commutator in place.

The fan has been replaced with the low speed resistor bypassed (removed). At a later date an in-line resistor will be added so that it has the proper speeds, (now has two high speeds).

The moral is that even rough units can be made to function.

cabikefreak 12-12-2009 01:19 PM

Hey thanks for the additional information. I was just going to buy a replacement as I figured it would be a loss. Now I will open it up and take a look!

Alfa_Rover 08-15-2013 07:26 AM

Can you remove just the bottom portion on a AC equipped 89 Spider? It looks like I should have some room to bring it out the driver side.

This past winter I had removed the entire interior for a number of reasons. This included rebuilding the AC system which is working wonderfully so I would hate to disturb it. The old fan/blower motor had stopped working, but I was able to get it operational with new brush springs and some lube. BUT it has now stopped working and must be replaced. So much for being cheap. I tried to relube it and can get it to spin with a little push, but it is obvious one of the bearings is completely shot.

SteveB2175 08-15-2013 12:18 PM

I've been reviewing this because I would really like to have a functioning heater blower. I've checked and mine is not frozen, it turns freely with a pencil, so it must be something else (worn out brushes ?).

There is one thing I don't understand about the write up and pictures. After loosening the 4 bolts and pushing them up slightly, the instructions are to slide the lower half of the blower assembly sideways to remove it.

The pictures indicate that the actual blower squirrel cage is significantly higher than the bottom half of the assembly, so doesn't the squirrel cage stop the bottom half from sliding out of position ?

Maybe it is intuitively obvious how to handle this once one is actually doing it.

Thanks !!

ghnl 08-15-2013 01:08 PM

Quote:

Originally Posted by SteveB2175 (Post 4744610)
I've been reviewing this because I would really like to have a functioning heater blower. I've checked and mine is not frozen, it turns freely with a pencil, so it must be something else (worn out brushes ?).

Before proceeding with removal of the heater unit I suggest checking that electrons are getting to the terminals on the left side rear of the heater unit. There are three connections - a black wire for ground that goes up to the underside of the dash. And the two left side rear terminals for slow speed & less slow speed.

Quote:

There is one thing I don't understand about the write up and pictures. After loosening the 4 bolts and pushing them up slightly, the instructions are to slide the lower half of the blower assembly sideways to remove it.

The pictures indicate that the actual blower squirrel cage is significantly higher than the bottom half of the assembly, so doesn't the squirrel cage stop the bottom half from sliding out of position ?
It is actually both - lower the bottom half and slide it sideways. There is barely enough room so that is why I pushed the bolts up, too.

SteveB2175 08-15-2013 01:33 PM

Thanks Eric, I failed to mention that I did check for voltage at the motor, but I will recheck my work before starting in on this major project.

I like your description of "slow and less slow" blower speeds :) :)

I used to drive a 1966 Citroen DS21 and I told my friends that it had a 2 speed blower, On and Off... :001_rolleyes:

Alfa_Rover 08-16-2013 02:35 PM

SteveB

Does your graduate have AC? There is a considerable amount of carpet am
and isulalation under the fan. I removed all that when I redid the interior, only reinstalling thin sound deadening like dynamat. Hoping that will help my cause. Keep us informed.

bongju 11-24-2013 07:48 PM

Eric,

Thanks so much for the detailed instructions. I was able to remove the heater fan motor on my 87 Spider. I had to remove the A/C which wasn't working anyway. I don't think it is possible to follow these instructions with the A/C in place. I found the springs in my motor had disintegrated and I was able to replace them to get my fan working again. I'm looking forward to having heat again.

SteveB2175 11-25-2013 09:11 AM

Bongju,

Before you started this task was the bottom of your heater assembly pushed down firm against the carpet over the transmission hump, or was there some clearance ?

As I read about this repair I gather that removing the blower from the bottom of the assembly works for some cars and not for others.

On my car the bottom of the assembly is pushed firmly into the carpet. I tried to force a 3 x 4 note card under the blower and could not do it. I can't imagine how the blower can be removed with zero clearance.

I'm just trying to gather data in order to determine if I should attempt this repair on my car.

Thanks !!

ghnl 11-25-2013 09:17 AM

From reports I've read the amount of clearance under the heat seems to vary quite a bit. I suspect that Alfa hung the heater then built the car around it.

SteveB2175 11-25-2013 09:23 AM

Eric,

Was there clearance between the transmission tunnel and the bottom of the heater on yours ? Do you remember how much ?

Thanks,

-Steve

ghnl 11-25-2013 10:19 AM

Perhaps a finger's width. There was just barely enough room to get the bottom half out. I had doubts when I started but thought it was worth a try. The only alternative is to remove the center console & the dash to remove the entire heater unit.


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