Loose turn signal switch housing – A quick fix

Every time our bus goes in for her annual safety inspection, I wonder what quirk of this 40+ year-old vehicle might trigger the dreaded pink sticker of failure.  Let’s face it, after so many years parts and pieces do not always work as they should and while we owners often find ways to live with these imperfections, safety code says the part or piece must work as intended.  So far, knock on wood, Moby passes her inspection each year, but I give some credit to the inspectors at our garage and their acknowledgment of Moby’s age.

As a prime example, the turn signal switch is a bit finicky and has been that way since we got the bus.  Now when I say finicky, I do not mean the signals sometimes work and sometimes not.  The switch is very reliable in working the lights which is what probably saved us each inspection to date.  The problem is the switch housing and the fact it no longer mounts to the steering column properly.  Because of this, the housing rotates around the column, making it difficult to activate the switch lever and killing any hope of the self-cancelling ring (on the steering wheel) turning the signals off after making a turn.  The issue is not new to me, in actuality, every bus I owned had this issue at some point and I understand it is a widespread predicament with buses.  Before each inspection, I promised myself I would fix it and after each inspection, I would find the housing jammed in an odd position so as to eliminate the rotation (however, there was never any helpful effect on the self-cancelling feature).  Happily, the inspectors were flexible and found a fix that satisfied them and I just returned the housing to its normal position and drove away while manipulating the switch lever close tothe housing so I could keep it from spinning around the steering column.  With no self-cancelling of the signals, I just had to remember to turn them off after completing a turn.

Several years ago, I read a comment on The Samba which said something to the effect of “Just because we drive old buses, does not mean we should be OK when things don’t work as they should.  I’ve seen too many people driving around living with problems and excusing them because of age. FIX THEM!”  That was, and has been, me, – well to a point. After passing last year’s inspection in the fall, I decided to do something about that signal housing and stop living with it just because it is a tired, 40 year-old part.

The housing is made of two parts; one fits around the steering column, while the other holds the turn signal switch and screws into the first piece.  When fitted together, the housing pinches the column between the two halves and locks everything in place.  In this case, the culprit is not the housing itself, but rather the clamps (see #4 and #10 in the first picture below) that are actually doing the pinching.  Over time these clamps wear or might flatten a bit causing a loss in clamping ability.  There are a couple of options to correct this, replace the clamps with new (I have only come across a few vendors that sell replacements, mostly in Europe) or NOS clamps.  One could also source a good clamp from a junkyard, but that will be hit or miss.  Or, and I read about this after I finished this project, one could put the old clamps in a vice and bend them a tiny bit so they grab the column once again.  This latter option seems interesting, but relies on feel more than measuring and I figure I would probably ruin a few clamps before I got it right.

However, in addition to the clamps, the column might also wear to the point the clamps no longer grip.  This might become problematic when trying to bend the clamps (and keep them straight enough to fit into their slot within the housing).  The only solution for column wear is to build the column back up, making it wider.  I am sure I good welder could handle the task, but it is beyond my very limited welding skill, so I opted instead to build the column out with some tape, as it seemed the best (and fastest (and cheapest)) solution.  Only time will tell if the fix will last, but for now it works very well and I have not burned or ruined anything (well, on the bus anyway).

Signal switch 71 (5)

Exploded view of the signal switch and housing from the Bentley manual. Turn signals come in several varieties and, as I understand it, there are ’68-’71, ’72 only, ’73-’74, and post ’75 versions. Note the clamps (#4 and 10). All pictures of the ’71 switch I’ve seen only show one clamp. I don’t recall the other ’71’s I’ve owned, but Moby only has one as well. Not sure if the clamps frequently get misplaced or if Bentley is too general in this Figure for the early bay switch (feel free to chime in in the comments).

Signal switch 71 (3)

The housing is held in by two screws along the sides. The two screws next to the switch lever hold the switch in place (you do not need to take these screws out for this issue).

Signal switch 71 (1)

The top of the steering column is flared to accommodate the switch housing. The wear along the column is evident in the picture. Who knows how long the housing has been rotating, but it seems it’s been a while. The red arrow notes the self-cancelling ring attached to the bottom of the steering wheel. This ring hits two prongs (see green arrow two pictures below) on the switch and kills the turn signal by knocking the lever back into the neutral position after making a turn.

Signal switch 71 (2)

The tape I used is a rubber tape, similar to electrical tape but softer and thicker. It came with a bunch of tools and such I inherited from my Grandfather, so I am not sure what name correctly applies. This tape worked well because the sides of the clamp could easily cut through the tape and come into contact with the column (I’ve read that the signal housing must be grounded to the column, but am not 100% sure on that point) while the curved part of the clamp bites down on the tape and holds the housing securely in place. Regular electrical tape might prove to be too tough and require too many layers for the clamps to cut and, therefore, prevent proper grounding.

Signal switch 71 (6)

Due to its thickness, I only used one layer of tape around the column. Red arrow points to the solo clamp; green points to switch prongs for the self-cancelling feature.  The housing needs to be mounted high enough for the self-cancelling ring to touch these prongs when the signal is on, but if mounted too high, the ring will constantly hit the prongs regardless of signal lever position causing premature wear and constant signal lever problems.

Signal switch 71 (4)

When reinstalling the housing, tighten the side screws by alternating between the two screws until the housing halves come together.  Test signals and emergency flashers to make sure they work, and test drive to check the self-cancelling function.  With my my housing staying put, I still find myself operating the signals the same way I always did and turning them off manually.  Habits are easy to form, but getting rid of them…not so much.


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