Tachometer and Speedometer Repair

[woodland_builders]

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

[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

[woodland_builders]

Gary,
Thanks for the information.
Just did belts, hoses, filters and fluids about a month ago, but the
tach was not high on the priority list. I guess I will get another
look at the Cat from the front side.
Gene Chaude
77 FC33
Connecticut
--- In WanderlodgeForum@yahoogroups.com, "Gary Miller"
wrote:
> 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

[Jeff Miller]

Gene:

Your tach is unfortunately obsolete, and I've found it hard to get
parts. I might have a working used one out of my '77, will have to
look to be sure, if you need parts.

The 90degree tach and sending unit are unusual, the sender is a DC
unit made by Autometer to match that Teleflex tach. The newer FCs
used an AC sender, which is a fairly common cruise-control sender,
easier to find (but doesn't really help you). The angle-drive unit on
my '77 went out twice, last existing of those I believe are at
Holland Motorhomes, and the short drive-tang from the fuel pump to
angle-drive broke once. The drive-tang would be the simple and cheap
problem to fix.

The tach can be replaced with an alternator-driven unit, the sender
wire moved from the old sender to the alternator (if the original
Motorola an AC output wire will have to be added). BlueBird can
probably still supply the 270degree alternator-driven tach for the
later 3208s and it is compatible.

As far as the speedometer, does your cruise-control work? On the '77
the speedometer is cable-driven from the output shaft of the allison
transmission, through a "ratio adapter", a cable to the Dana cruise-
control box under the driver's floor, another cable to the
speedometer. The ratio adapter on the transmission can fail, it is a
relatively cheap (Stewart-Warner) part, can even be rebuilt by some
speedo shops. Disconnect the cable at the transmission, spin it to
see if the speedometer jumps.

Also, if the nut on the yoke of the transmission loosens, the
speedometer drive gear will not spin full-speed and the needle
readings will not be consitent. If this is the case (was once on
my '77), not to be ignored as a loss of this nut can cause
transmission damage. If it is loose, a VERY cheap fix.

I believe that I also have a take-out '77 speedometer, and a new
ratio adapter for 11Rx22.5 tires on 4.63:1 gears, email me if you
need something.

- Jeff Miller
http://www.wanderlodge.net
http://www.millercoachworks.com



--- 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