Crawls Backward (When Alarmed)

IconProjects, musings about guitar builds, guitar repairs, vintage tube amplifiers, old radios, travel, home renovation, and other stuff.

VDO Quartz Clock Repair on the Saab c900

I suspect this will be a long-ish post.  I just uploaded 16 pictures!

Here we see the back of the c900 instrument panel on the bench in The Dungeon.  I'm going to replace the electrolytic caps for the clock in hopes of getting it working again.

If you do a search for "repairing VDO clock" on the interwebs, you'll find quite a few posts about how to fix them in your vintage Yurrupean car.  It seems the electrolytic caps dry up over time (surprise) and replacing them will fix the clock.  Let's hope so.

The blue circuit board you see above is actually flexible plastic, and it's attached to the panel with plastic pins.  The board has mating holes that just slip over the pins.  I say this because I've seen some ads for used instrument panels on the interwebs saying "board is not lifting" as a sales pitch.  For one thing, I find that hard to believe, since the whole thing is flexible.  Second, it will lift in spots - it's just its nature.  Doesn't mean anything is wrong with it.  It's the way it was designed.

If it was glued down, it would be virtually impossible to service.  And here I am proving that if the car lives long enough, it will need to be serviced eventually.  (And many of these cars have very long service lives indeed).

The tachometer and clock are in the leftmost (from the front) position.  There are 4 screws (arrows) holding the whole assembly to the panel.

You can remove this now or later.  I opted to leave them until the end, since they hold the panel in place, which is handy while you undo the instrument and clock screws.

Obviously this is for a Saab 900,  but the same basic approach should apply for any VDO instrument panel you may have in, say, a Mercedes, Porsche, BMW, VW, or that other Swedish brand that shall remain nameless.

You'll need to unsolder the ground pin for the clock.  Here I'm using desoldering wick to get it off.  I'm pretty sure it's a ground; in any event it has to be unsoldered to get the clock separated from the panel.

See also the yellow arrows - they're the locations of the tach and clock screws which also must be removed.

This assembly is fairly fragile - handle it gently and put your screws in a safe place.

I also highly enourage you to wear vinyl or nitrile gloves when working on the instruments to avoid getting oils from your hands on them.  You don't want to put it all back together and then see a fingerprint you left on the tachometer!

This assembly also has another tab (again, I suspect it's an electrical ground contact) that needs to be pulled up.  This connector holds a copper tab onto an instrument contact.

See what I mean about the circuit board?  You can see a mounting pin to the right of the pliers, and you can also see how it lifts a bit up off the panel in places.  It's the way it was made.

This is a shot of that clock pin/tab I unsoldered and removed earlier.

Now we carefully and gently can tilt the tach assembly up off the instrument panel itself.

The circuit board material will flex enough to allow you to flip the tach up over the board backward.  But be gentle

The arrows in the picture show the three screws that hold the tach and clock face onto the white mounting piece.  We need to remove them to get access to the electronics.

This is the clock assembly, and the silver Phillips can is one of the electrolytics we need to replace.  Use solder wick to unsolder the capacitor.

One note:  the hands on the tach and the clock will shift some when you have it all opened up.  Don't panic!  They're just not mounted to anything now that the screws have been removed, so they will just spin around some.  No big thing.

Handle the assembly with care - don't sit the face of the tach on something that will scratch it.  I was able to sit it on the panel in a way that I wouldn't move while I worked on it, and it wouldn't shift and get damaged.

The value of this cap is 100uF at 16 volts.  I went searching through my bin of low-voltage electrolytics and found a 100uF rated at 25 volts.  Perfect.

Here's the old cap shown with the new one that will replace it.

The new one is a bit thinner - and it's actually rated for 25 volts vs. the 16 volts of the original. Be sure to use a cap rated at 16 volts or higher.

I suspect a 35 volt cap might fit, but anything much higher will probably be too large.

Here's the new cap in place.  Be sure to observe the correct polarity - the circuit board has "+" and "-" markings.

I suggest using a good quality cap here - a cheap cap may fail and then you're back to square one.  I try to use higher end Nichicons or Panasonic caps in stuff I build or repair.  They cost just a few cents more than the cheap junk.

The second cap to replace is this 47uF electrolytic on the small board above and behind the tach.

It looked like the board would slide out - there's a clip on the back.  However, I couldn't budge it at all, and rather than risk breaking it, I just removed it from where it was.  A little harder to get to, but not too difficult.

The second cap replaced.

Note the little 'bins' where the warning lights shine through.  Maybe I should pop the upshift (NOW!  UPSHIFT NOW!) bulb out?

Nah, I pretty much ignore it anyway.  :-)

Reassembly is pretty much the reverse of disassembly.  The only semi-tricky part is getting the gauge to sit back down from where it came.

I found that if you gently move it around, it will find its seat easily.

Then put all the screws back in and button it up.  Be sure to resolder the clock ground and put that tab connector back on.

One last bit of maintenance before it all goes back together.  The dimmer rheostat for the instrument lights is to the left of the speedometer when viewed from behind.  These have a reputation for going intermittent, so I figured I'd clean it while I had access to it.

It just unscrews from the panel.

The sides are open, so it's easy to squirt a small amount (small amount) of cleaner in there.

Here's the instrument panel back together.  I'm going to clean and polish the plastic cover before it goes back into the car.

Before I put the tach back in, I hit it with compressed air to get any dust off it.  I also noticed there were small piles of dust on the inside of the panel where the clock setting knob and dimmer knobs pass through the plastic.  (There's enough clearance that dust can get in.)

So I took a vacuum and compressed air and got all the dust out.  Now it's perfectly clean inside.

Hopefully I'll have it back in place this week.  I'm putting in a second, calibrated boost/vacuum gauge and will do that while I still have easy access to the factory hose behind the dash.  Said gauge has yet to arrive at The Dungeon, so I'm in a holding pattern for now. 


Instrument Panel Removal on Saab c900

With the fascia removed, it's quite easy to take the instrument panel out.

First we need to remove the left-hand side speaker assembly.  There are 2 screws holding it in.  Take them out and pry the grill up.

Disconnect the speaker wires, and also wiring to the alarm LED (if you have one).

There are two connectors to remove from the back of the panel.  These are the electrical connector on the speedometer, and the speedometer cable.  You can see these highlighted by the red arrows.

The cable is the white connector - squeeze the tabs and it will slide out.  If you car is turbocharged, there will also be a vacuum/boost line going to the panel - it will just pop off when you slide the panel out.

Then remove the 4 screws in each corner of the panel which hold it in place.  These are T10s I think.

Notice all my labels for the center pod switches and bulbs. 

There are 2 ribbon connectors on either end of the panel.  Push push, wiggle wiggle, and they will slide off.

Now we can remove the entire instrument panel.

Again, that turbo vacuum line will just pop off when you take the panel out. 

I'm going to put a boost gauge in, so I'm eventually going to put a T connector in that line and run one end to the factory gauge and the other end to my new gauge which I have yet to acquire.

The passenger seat is still in The Dungeon, although it's ready to go back in.

In the meantime, I have plenty of space to store all the pieces I've taken off the dash :-)

Here's what it looks like with the fascia and instruments removed.  Controlled chaos.

Now we'll retreat to The Dungeon with the instrument panel and fix the clock.


Saab c900 Dash Fascia Removal

Lots of projects in the wings in The Dungeon. But while I have reasonably good weather here and can work outside, I'm trying to fix some stuff on Saabmarine #2.

I wanted to take care of a few things at once: the clock isn't keeping time (losing 6 hours a day!), the trim around the fascia/dashboard has pulled away in a couple of places, and I also want to service the instrument light dimmer.

What this means is I need to take out the fascia and the instruments themselves.

This might seem like a daunting task, but if you're patient and label everything, it's very straightforward.

There are four long bolts that hold the fascia to the dash. Two are on the left side of the steering wheel; you see them here.

Later cars (this one is a 1991) use Torx fasteners - these bolts are T15s.

Keep the bolts in order as you remove them. They are 4 different lenghts - they are also marked with rings to identify them (I'll get some pictures later).

Third bolt is to the right of the steering wheel...
...and the fourth is behind the ashtray. Just take the ashtray out and you'll be able to access it.

You may read in the factory manual or elsewhere that the steering wheel must be removed. Not so. There's plenty of clearance with the steering wheel in place.

With the screws removed, you'll be able to pull the fascia slightly away from the dash on the left side.

You can see that trim piece I need to reattach. I'm tired of looking at it hanging off like that.

I suppose I should have mentioned you need to take the radio out of the dash. I forgot, mainly because I took the old radio out a month or so ago. I'm going to put a new one in soon.

Here's the view through the DIN slot for the radio.

The screwdriver is pointing to the heater control rod. That needs to be disconnected.

Pull and wiggle gently on the control shaft and the swivel connector will pop off. This is what it looks like when it's removed - there is a flat metal tab on the heater knob, and the rod just clips onto it.

Next we need to remove the connector from the back of the air direction control. You'll see all of the vacuum hoses that run to it. Don't touch them! If you disconnect any hoses, you will have a heck of a time getting them back on.

There's a gold-colored clip that holds the connector to the body of the direction control. Just push back the top of the clip.

Here's the connector end after removal. Mine has red paint to identify the top.

The vacuum direction control is one of the things I love about old 900s. It's so much fun to switch the knob and hear the 'click-whir-whoosh' of the vacuum in the lines and the different flaps opening and closing.

I love using it, but I wouldn't have to troubleshoot all the lines. Fortunately, in the four 900s I've owned, that system has been very, very reliable.

Now that the heater control and the air direction controls are disconnected, we can move the fascia out a bit and get to the switches.
This part is very straightforward. I'm not going through it bit-by-bit. Basically you need to disconnect all the wiring for the dash lights and various switches.

In the picture above, the red arrow points to one disconnected switch - in this case it's the fan speed switch. You can see the mating connector tabs below it.

The yellow arrows point to some of the other connectors that need to come off. The switches will slide out from the front if you need better access to their connectors.

The best advice I can give you at this point is: label everything! And gently but firmly pull and wiggle connectors to get them out. If they are hard to disconnect, you may be able to use a small screwdriver as a lever to separate them.

Don't forget the headlight, seat heater control, fog light switch, and mirror switch on the left side.

With everything disconnected, the whole fascia/panel comes right out.

Remember: this car was built largely by hand. Yes, it was put together on an assembly line, but it was hand-assembled for the most part. That means it's relatively easy to take apart!

Next we'll get the instrument panel out.


Sagging Car Seatback Pocket Repair on the c900 Seat

The last bit of repair on the c900 seat is the dreaded sagging seatback pocket.  The other three 900s I've had never had this problem, but this one does.  The fact that gloves were stuffed deep into one pocket and the heavy and large-ish owner's manual/paperwork 'purse' was stuck in the other one is probably why they sagged over time.

Here's what it looks like.  There just isn't any more tension left in the elastic that runs across the top of the pocket.

I've also seen this pocket-sag on older Mercedes and BMW cars, as well as the "other" Swedish brand which shall remain nameless.

I'd think the way I repaired this is applicable to any car that uses this type of pocket.  If you have a 'mesh' pocket, like the legendary Mercedes W123 cars, you'll have to take a slightly different approach, since the elastic is exposed and not hidden under fabric.

I'm just going to cut open the seams at either end of the top of the pocket, connect a new piece of elastic to the old one, pull it through, and sew it all back up.

This is the right side of the pocket.  You can see the stitching that makes a little 'tunnel' flap that the elastic passes though, holding the pocket tight up against the seatback.

With my new 'ergonomic' seam ripper (cost $1 more than the standard model...), I cut the stitches at the end of the flap.

The pocket and the elastic were originally all sewn into a seam at the edge of the seatback.  I'm just trying to undo enough to get at the end of the old elastic.

Here's the elastic on the right side of the pocket after I pulled some stitches out.  About 18mm wide I'd guess.

I'm going to attach a long piece of new elastic to this, then cut the old one on the side where it attaches to the seam on the seat - leaving a couple inches (maybe brain's Imperial-to-metric converter is working today) to work with to attach the new piece to.

It's not pretty, but it's functional.  I used 3 safety pins to hold the new piece (lower one) to the old piece.

Then I took a deep breath and cut the old piece.

Then I went to the other, uncut end, and pulled the old elastic through the little tunnel.

It worked!  In fact, it took 2 seconds for the thing to pass through.  And to think I was wondering it the pins would get hung up.  Worked like a charm.

Here's our seat with the new elastic passed though the pocket.

As an aside: the elastic I used was 3/4 of an inch wide - it pretty much matched the width of the old piece exactly. 

I cut the other side (left) and attached the new elastic to the short piece of the old elastic which was still sewn to the seat.

Then I pulled the other end of the elastic tight and fastened it to its respective old elastic end.

It took a few attempts to get it pulled up tight.  I used small safety pins to hold the two ends of elastic together - I tried sewing them but it went nowhere fast.  The thread just wouldn't hold together under tension.   The pins aren't visible - they're tucked under the leather flap at the top of the pocket.

Last step was to resew the ends of the flap back together.  In the picture you can see my new thread and the needle I used.  You can also see the original stitching I pulled out (on the left).

I didn't want to just cut the old stitching since I figured it might eventually unravel over its whole length.  So I ran my stitches over it to lock it down.

Here's one of the finished parts I did.  You can see my stitches - they're a lighter color thread than the original.  But note how I ran stitches over the original thread.  Not the best sewing job, but it's functional and from a foot away, you'd never notice.

This is the finished pocket.  Not perfect, but a lot better looking than it used to be (compare with the first picture above).

The bottom of the pocket is pretty stretched out from years of having stuff in it.  But overall, not bad.

Now I need to find time to get the other seat out and repair it.


Saab c900 Seat Bottom Repair Completed

I finished sewing the rod/frame and its new fabric cover to the seat.  I did it section by section over several nights so as to keep my sanity. 

It seems to be attached tightly to the seat cover.

Now to attach it to the seat.

I punched holes through the new material in the locations where the clips will attach.  I did double check the locations prior to making the holes.

Here's the seat cover with the clips attached to the rod.

I had to do this twice.  The first time I found that one of the clips pulled up off the rod, so I went back and squeezed the the ends tighter around the rod so they'd stay in place.

Now to attach the clips and see if all this work was worth it.

This is one of the clips (there are 7 total) poking up through the seat foam.  There were slits cut in the foam to allow the clips to pass through.

What we need to do is just pull the clip up and attach it over the seat frame.

Easy to say, not quite so easy to do.

The two rear clips were easy, as were two of the side clips.  I just pulled the clip up with pliers while pushing the frame down, and hooked the clip on the frame.

Whoo hoo!

The arrows in this picture point to two of the clips, just in case you didn't believe I actually did this!

Note all the obstructions in the way...and hold that thought.

I'm sure this was originally done before the motors, wiring and seat bottom frame that bolts to the car floor were on the seat.

The three clips on the semi-circular part of the rod were difficult to attach.

I tried pulling them up with pliers, but I couldn't keep enough of a hold on them - they kept slipping off the pliers.

I pondered this for a day or so, then I got an idea.  I put the top of the clips around a piece of small chain.  I could then really get good leverage on the chain (and the clips) and pull them up.

I also used a block of wood wedged between the seat frame and the cushion to push the cushion down for more clearance.  See the arrows in the picture above for the chain and wood block.

Here's one of the clips after attaching it.  I used a relatively thin chain, so I could just clip it with nippers after the clip was attached.

The center clip is under the seat tilt motor bracket, so it's virtually impossible to get to from above.  I slipped my hand under the seat cover from the front, clipped on the chain, and then passed the chain through the slit in the foam.  It worked!

I reattached the side clip rods (previous post), as well as the clips holding the back and front of the cover over the cushion.

Turns out I lost a clip somewhere, so I just used some 18 gauge picture frame wire as a substitute.  It's not like it will be visible when the seat is in the car.

You may also recall the two cable ties that held the cover onto the front corners of the seat.  I had cut those off during removal, and left the cut ends on the cover to use as a guide.

Now I was able to replace those ties with new ones (red arrow).

You may also recall my grousing when taking the seat tilt motor mounting bolts off.  I needed a ratcheting box end wrench for that job, so I got one - actually 3: 8mm, 10mm, and 13mm.  Probably the three most common sizes on a Saab 900.

The wrench was great to have and made the job of remounting the motor go much faster.  Here's the whole assembly back together with the replaced drive cables.

Now for the moment of truth.  Let's turn this puppy over and see how it looks!


Much much better.  The center part of the seat bottom now follows the contour of the foam.  The seat's still pretty dirty, but I'll clean it up shortly.

Those creases and wrinkles in the material from sitting flat for years which you see in the picture have already beginning to relax more than the picture shows.  It looks pretty good.

Too bad I have another seat to do...sigh.  But now I know what I'm dealing with, so it will go much faster.