1978 speedo bouncing - ISSUE !!!
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 974
Likes: 0
From: Boca Raton Florida
1978 speedo bouncing - ISSUE !!!
I have been sorting things out on my 1978 L48 anniversary with cruise car for the past 10 months . Had the brakes checked today and they were good with 70 percent left . Thats the good news .
I bought a lower speedo cable thinking that the speedo guage was bouncing because of that . Turns out my mechanic tested both cables (upper and lower) and they are fine . He seems to think its where the speedo cables connect to . Looks like the cruise control box . From what I've seen here this doesn't seem likely . Or am I wrong . If I am wrong what's the best route to go . Thanks in advance .
I bought a lower speedo cable thinking that the speedo guage was bouncing because of that . Turns out my mechanic tested both cables (upper and lower) and they are fine . He seems to think its where the speedo cables connect to . Looks like the cruise control box . From what I've seen here this doesn't seem likely . Or am I wrong . If I am wrong what's the best route to go . Thanks in advance .
Pro
Joined: Aug 2007
Posts: 707
Likes: 31
From: Pitman NJ
When my car did this, it was the lower cable. I ended up putting in one long cable by-passing the cruise control box.
I could be wrong, but bet it's the lower cable. As the cruise control box wares, it will put more an more tension on the lower cable until it eventually breaks.
I could be wrong, but bet it's the lower cable. As the cruise control box wares, it will put more an more tension on the lower cable until it eventually breaks.
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
I have been sorting things out on my 1978 L48 anniversary with cruise car for the past 10 months . Had the brakes checked today and they were good with 70 percent left . Thats the good news .
I bought a lower speedo cable thinking that the speedo guage was bouncing because of that . Turns out my mechanic tested both cables (upper and lower) and they are fine . He seems to think its where the speedo cables connect to . Looks like the cruise control box . From what I've seen here this doesn't seem likely . Or am I wrong . If I am wrong what's the best route to go . Thanks in advance .
I bought a lower speedo cable thinking that the speedo guage was bouncing because of that . Turns out my mechanic tested both cables (upper and lower) and they are fine . He seems to think its where the speedo cables connect to . Looks like the cruise control box . From what I've seen here this doesn't seem likely . Or am I wrong . If I am wrong what's the best route to go . Thanks in advance .
Le Mans Master
Joined: Nov 2006
Posts: 7,215
Likes: 1
From: Orlando FL
The cruise control box is the most common area that causes a bouncing speed reading provided the cables are good. Since the cables are good I would remove the control unit. If you are ok with disassembly of the unit you will find a good cleaning on the discs inside will improve the speedo reading. It usually doesn't fix it for a long time, but will show you where the problem is.
Instructor
Joined: Jan 2013
Posts: 145
Likes: 1
From: Edwards CA
Ran my 78 silv anniv Saturday (ops checked the newly re-cored radiator) and it has started the "Bounce".
Anothe rproject to do, remove the "Control Unit"....(like WE dont have enough projects already, LOL)
Thanks!
Anothe rproject to do, remove the "Control Unit"....(like WE dont have enough projects already, LOL)
Thanks!
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 974
Likes: 0
From: Boca Raton Florida
On another note . When I drove the car home last night I let it out somewhat and when I did this the speedo started working . I noticed that after a good run it did get better . It's not fixed but worked a lot better for a little bit .
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Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 974
Likes: 0
From: Boca Raton Florida
So , if I bypass the cruise control does this mean I remove the upper cable and go right through the firewall to the cluster ? Sounds like I also need a longer cable . How long ? I think the lower is 49 inches .
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
Just replace the cruise control module. Remove it and cleanup the inside of the old unit and you will notice a big change until you get the new unit this would be a similar cost to getting a longer cable and your cruise control will still work.
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 974
Likes: 0
From: Boca Raton Florida