Tachometer and Speedometer Repair

[Gary Miller]

Gene,

The tach sending unit is on the front of the CAT in the area behind
the engine fan mounting bracket. It comes off the front of the
engine and makes an immediate turn toward the roadside. Two bolts
holt it to the front of the engine.

The unit is a combination direct drive and electronic drive type and
contains some nylon gears at the right angle with a couple drive
tines on each side and some magnetic pickups I think.

On mine, I took it apart, cleaned and lubed it with speedometer cable
graphite and it began working again. Problem was, on the end of it
where a cable would be attached, there was a rubber cap which had
long ago crumbled away leaving the end exposed and open. After
reviving mine I found a new cap for it (NAPA #660-1696).

Removing it is a tedious job best done with the fan off, and be
careful not to force it. Taking the whole unit off at the block is
the best way since getting wrenches in there at angles to take parts
of it off may snap something off. As an alternative, try to keep
working some lubricant into the end of it and see how it goes over
time with that new rubber cap. And look for broken wires. The
electronic tach has adjustment screws recessed into the back of it.

Haven't had my speedo apart, but did replace the sending unit at the
rear curbside wheel after some road debri pulled out the wires. On
your year, I believe the pickup is on the driveshaft.

Gary Miller
83 FC 33
Wauwatosa, WI

--- In WanderlodgeForum@yahoogroups.com, "woodland_builders"
wrote:
> Hello all, it is great to see the new group on track and doing
well. I
> would like to go after the broken Tachometer and Speedometer on my
77
> FC Diesel. Has anyone been down this road? Where is the pick up on
the
> engine for the tach? I do not have a book that covers a test
procedure.
> Does anyone know of one? My tach in the coach is electronic. I had
a
> 3208 in a truck awhile back that was mechanical which makes me
question
> if the current tack is OEM. Are parts still available? The
speedometer
> runs up to about 35 mph and then stays there reguardless of higher
> speed. I think the internal weights may be restricted. Does the
guage
> come apart and has anyone been in there? Thanks Gene
>
> Gene Chaude
> 77 FC33
> Connecticut