Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing speedometer hell! 1983 +8

I've had my 1983 +8 since 1988. not much is original after 130,000 miles. It still has the original Rover 5 speed box.
The latest problem is the speedo that started to wobble at 50 miles an hour. It progressed to only reading a half of the true road speed (checked with tom tom!). last year I replaced the speedo cable to no avail, same problems.
I gather it is probably the speedo drive as it comes off the drive shaft. I've stripped out the seats and gearbox cover but don't know how to access the speedo drive. I'm terrified of pulling something out of the gearbox and reducing it to a pile of random cogs that need an expensive rebuild.
I have seen that the likely worn part is a plastic cog that takes the rotation from the back of the gearbox and then turns the speedo cable.
Any advice would be welcome-the more basic and idiot proof the better.

27 years and 130,000 miles, now your first TM posting. Welcome

I think Chunky 4/4racer is your man, come on Lawrie to the rescue superman.

Welcome to TM

This is from memory from a +8 4 speed to 5 speed conversion as well as a subsequent gearbox swap.

The speedo drive at the gearbox end has a plate with a single bolt. Remove the bolt and plate and the speedo drive cable. The speedo drive gear simply pulls out and unless it's disintegrated, you should leave nothing behind.

Hope that helps.

Have a look at the Gomog website - there is a section there on speedo gears of the LT77 gearbox, which may be of help.

Thanks Guys. A warm welcome. Have removed the speedo gear from the transmission. It looks in perfect condition with the cable seating into the gear and no evidence of wear. So connected the cable to the speedo dial and turned it with my electric drill, the dial and cable seem to work fine.
All in all no solution, any ideas?
I've read that the precise assembly of gear to cable and cable route can cause problems could this just be the problem.

Went to the local garage and have set the speedo off for service and calibration

I have a 85 and an 86 Plus 8 with the LT77 box and Smiths gauges. Ensure your cable is not binding as the pressure will cause it to turn inconsistently. Even if it is new, it may still bind if the routing is problematic. Also, both in the speedo and the cable, the older lubricants start to harden up causing resistance which can lead to erratic reading.

Cheers,

Had the speedo serviced all works fine now

Good news!