1976 eldorado transmission speedometer driven gear

Started by 76 cadillac bob, June 20, 2018, 07:14:05 PM

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76 cadillac bob

My speedometer cable wound itself around the outer shielding, I replaced it it worked fine, then died.
I replaced the cable from speedometer face to cruise control which is not currently working) and cruise control to transmission. Still does not work, only difference the cable from CC to tranny is longer than it should be, could this cause the lack of funcationality. I twisted inner wire and speedometer does work from CC to face.
questiions
1) cable from cc to driven gear is longer than old one could this be a problem
2) could CC have a gear issue freezing up the speedometer
3) is it difficult to change speedometer gear on side of  transmission that is abell housing with clip holding top on and where the lower cable attaches? I know nothing about this.

bcroe

Those Cruise Controls are quite troublesome and short lived.  It
could well be your problem.  I don't think cable length is at all
critical. 

You might try inserting a different CC, or a cable direct trans to
speedometer as a test.  good luck, Bruce Roe

Scot Minesinger

Agree with Bruce, probably the cruise is the issue, and the longer cable should not matter at all. 

I restored by my cruise control on my 1970 Cadillac (same type of unit as yours) and it has been working for five years now, although it has only been driven about 1k miles per year and operated once a month.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

"Cadillac Kid" Greg Surfas 15364

Bob,
To test the cruise control for mechanical functionality, disconnect both cables at the CC unit and (with a square drive of some sort) turn the input to the CC (from the trans).  If the output turns then the gears are free.
If you find you actually need a replacement CC "transducer" Auto Zone has them at reasonable prices with a decent warrantee.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

TJ Hopland

If the cruise gearbox dodad doesn't feel smooth you can take it apart and at least clean and lube the gear part to keep your speedo working.    Getting the cruise to fully work is a bit more tricky but its not that hard to get apart and you can remove one part that will basically separate the cruise part from the gear part which makes it super easy to get back together.   

If you take the 2 screws off the housing section that the cables attach to you can carefully pull that cover assembly straight out.    You will then see that shaft and spring assembly that is held by a small bolt holding the spring.  You remove that spring bolt and you can carefully lift up on the shaft and the disc below it will come out with it.   You can just store that assembly somewhere till you want to really get into fixing it.   That will leave you with the gear section you can sort of access now to clean and lube.  Once you do that you can easily bolt it back on the main unit and it should drive your speedo just fine.   Getting it back together with that inner assembly in there without damage to anything and so it works is the trick. 

StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

TJ Hopland

And I should add if you get it apart and the plate you remove has been scuffing on the gear disc plate like in my photos its pretty much shot and won't ever work right again.   

Its some sort of magic magnetic no contact coupling action going on there so if things wear to the point where it starts making contact you are done.   The wear will occur if you use the cruise or not.   The shafts appear to be fairly hard and decent quality but they ride in what appears to be some sort of a plastic bushing so its not something GM ever expected to run for 100K+ or be serviced.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

76 cadillac bob

Disconnected the speedo cable from transmission, left it  screwed in at CC and CC to Speedometer face also in place. Used a drill, and had someone check speedo it did register at different speeds. so CC gears are working. Reattached cable to transmission driven gear and speedo jumped once and did not work. Should I try CC or a new speedo gear at transmission? The original cable, tangled at the transmission and really twisted, it may have stripped the gears at the transmission side, any thoughts? I am determined to get this fixed!!

bcroe

I'd take off that metal retainer on the trans and slide the speedo
driven gear out, with the cable still attached if possible.  Look over
the driven gear, it should turn smoothly and easily. Spin it and you
should see a reaction at the speedo.  Bruce Roe

76 cadillac bob

ok i was going to but was n ot sure if i was going to get in over my head i can do that

Glen

When you get the governor out look at the socket where the speedo cable connects, the white plastic piece in there should have a square hole where the tang of the inner cable goes in.  Sometimes that hole gets rounded and the cable slips in the hole. 
Glen Houlton CLC #727 
CLCMRC benefactor #104

bcroe

Quote from: Glen on June 23, 2018, 01:43:25 AM
When you get the governor out look at the socket where the speedo cable connects, the white plastic piece in there should have a square hole where the tang of the inner cable goes in.  Sometimes that hole gets rounded and the cable slips in the hole.

I was hoping this could be done without removing the governor,
which is a pain to get back in place.  Bruce

76 cadillac bob

I will keep you posted when engine cools off and i can spend some time on it in the next day or so. I suspect either gear or governor are worn from original mess with cable wrapping itself around itself and turning into a complete pretzel. More to follow.