Tuesday, November 26, 2013



 This is the instrument module from a '78 Mercedes Benz 450SL. It speedo's but it's speedo don't odo.  Drat! So 'twas time to get inside the bugger and work my magic on it. Out with the demon tweak tools!
 This is the flip side of the instrument module. Clearly, a whole lotta screws have to come out to get to just the speedometer.
 Here the speedometer is out of the module. If the speedometer was all that needed attention, that's as far as I'd have to go. But life ain't that simple. This critter was dirty and dusty INSIDE the plastic face plate, so it all had to come apart. In addition to the photos, I made a couple of pages of illustrated notes so I had some chance of getting it all back together on the first pass.....
Here is the bugger all apart. A lot of cleaning was necessary on ALL the internal parts of the module, and then I reconditioned the speedometer itself [lower left in the photo above].

 So, after a lot of cleaning, wiping, dusting and polishing--along with liberal amounts of questioning the ancestry of the designer of this conglomeration of parts--it's done, pretty and ready to go get dusty and grimy once again in a drop top Merc.    And...the odo now odo's---HA!


 This photo shows all the internal gubbins of an ANCIENT Bosch windshield wiper motor, as used in Saab 93/95/96 two-stroke models of the late 1950's and very early 1960's. It turns out that these early motors were quite high quality, with a lot of brass and evidence of a well thought out design. This motor, which is over 50 years old, showed little wear and tear, and required nothing more than a thorough cleaning, fresh lubrication with modern lubricants, and careful re-assembly.

These early motors did require a careful alignment of the brush holding "saddle" [bottom right in the photo] and even more careful alignment of the permanent magnet assembly [bottom left, in the photo], the latter to assure even clearance of the armature from the permanent magnet. 

The bean counters at Saab got busy after the first 20,000 cars  or so were built, and changed wiper motor suppliers to the German SWF company. Saved a few pennies, but the quality of the SWF motors was crap compared to those early Bosch motors.
I always bench test ANY wiper motor I recondition and this is the setup for this little Bosch motor. The interesting switch on the right is a Saab wiper motor switch, which incorporated the windshield WASHER.  You pulled the switch OUT about three inches and let go, and as the washer fluid began to spray on the windscreen, you turned the switch clockwise to start the wipers.

There were TWO different switches used by Saab, and they looked pretty much alike, but the second series switch had TWO "ON" positions, for the TWO speed motors that were used in the GT 750 and GT-850 Saab 96 cars.  The second series switch still used the same windshield washer setup.

This all worked pretty well unless the washer fluid froze and cracked the plastic pump portion.  Then washer fluid--when it thawed--pee'd on you leg.  Hmmmm....not cool.  So in 1967, Saab switched over to Lucas wiper motors, with an electric motor attached to the washer reservoir, which was now located in the engine bay. No more pee-ing on your leg.  What fun was THAT?

Sunday, November 17, 2013


 BIG RIGS have speedometers, too! This one is out of an 18-wheel Peterbuilt logging truck. It came to me dead as a hammer, with over 500,000 miles on the odometer. 500,000---that's not a misprint. Even Stewart-Warner speedos get tired, and it took parts from two old, dead ones to nurse this one back to health. The outer rings and the glass are on the left, the outer housing at the top, and the speedo internals plus the face and speed needle on the right.  I built the holding fixture [in red], a necessary thing when I'm working on the delicate "innards" of a speedometer. Even one from a Peterbuilt.... 
 A different view. The lower inner ring still needs to be painted in this picture, but everything else has been thoroughly cleaned---some parts in the ultrasonic cleaner---and are ready for reassembly.  The special Phillips screwdriver at the bottom is yet another special tool I built. Handy little bugger.
One down, one to go... On the left, the reconditioned and calibrated speedo, ready to get back to work in a big ass logging truck. On the right, all the parts of another Stewart-Warner speedo for a Peterbuilt. Note that the speed faces are different. I ASSUME that the face on the right indicates a later version, as it has speed ranges in both MPH and Km/h.  Except for the case, the parts on the right are ready for assembly and calibration.   See, I can have fun with TRUK parts, too---HA!


 BAD? Dead, too. This is typical of SWF wiper motors I receive for reconditioning. These were used in a TON of V W's, some Saabs and who knows how many other Euro cars--Borgwards, NSU's, DAF's, early Porsches, etc. They came in one and two speed varieties, though the only external difference was the contact panel [bottom left, on the unit].   This one is definitely dead. 
 Here are the [cleaned up] internal parts. From the horseshoe shaped permanent magnet [bottom left], clockwise: the armature, the aluminum base assembly, the brush assembly with wires to the contact plate assembly, the main drum gear and bottom plate assembly, the smaller intermediate gear, and  the cover bail + four bolts.  It is worth noting that these parts usually look like they've spent time at the bottom of a swamp when I take the motor apart. Except for the drum gear/bottom plate assembly, ALL of these parts have been through the ultrasonic cleaner.
 Assembly time. The green parts comprise a jig assembly that I built to steady the base as I install all the reconditioned parts. The cleaned up aluminum cover is at the right.
 SMOKE TEST TIME! At left, the reconditioned motor on the holding jig [green color]. A V W wiper switch is in the center and a 12 volt battery is on the right.  I like to leave the aluminum cover OFF for the smoke test, so I can....uhhh....see where the smoke comes from.... You can see the three brush holders at the top of the motor assembly. One speed motors have just two brush holders.    
This motor passed the test---no smoke and both speeds plus self park worked just fine.  I let these motors run for 10 minutes or so...just to make sure the smoke isn't just hiding out on me.
Ready to go.  Tested, serial numbered and eager to flop the wiper blades back and forth on someone's Beetle. Good stuff!