What would cause my speedometer to bounce at low speeds and also around 55-60? the car is a 85 gl hatch

Usually a little fluid in the speedo cable itself. The seal in the transmission lets it suck up into the speedo head.

Can also be a bad cable.

how hard is it to replace the cable \seal

Its kindof a pain. If you pay attention to how it comes out of the speedo head while unrouting it and are careful with the threaded end its pretty easy. Allow an hour for it and be happy if it takes 20 minutes.

hrm sounds like more of a pain then its worth ill change it if need ie: it breaks

You might want to make a little note of how fast your speedo says you're going at certain RPMS

 

if you have an auto trans:

 

65 mph - 3950 RPM in 3rd gear or

 

if you have a manual trans:

 

85 mph - 4,000 RPM in 5th gear.

 

 

Write down the RPMS for various speeds, 25, 35, 50, 60, 70 and keep it for reference, that way if your speedo cable does snap and you lose your speedometer, you still have a way to keep track of your speed.

 

lol 85mph it reads corectlyish if need be i just use my gps for a speedo and im only a four speed still