British-Cars.org

Welcome to the DMR Site for British Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - TF speedometer cable problem

All;

I just came back from the first drive of my 'new' old 1955 MG-TF. What was immediately apparent on the road was that my speedometer was 'waving' rather than the needle holding steady. Do I have a speedometer cable lubrication issue or perhaps a more serious issue with the instrument itself? Anyone have this experience?

As always - THANK YOU for the advice!!
TStac

Our '55 TF has always don this; had the speedometer rebuilt and... It still does it. It swings back and forth 3-5 MPH

D. Sander

Mines been waiving at me for more than 10 years.
I confirmed with a gps how accurate it is and found mine is very close at the "hi" end of the wave.
(Even after rear-end change and running oversized tyres)
I just live with it.
Cheers,
David
David Sheward

Hi,
Look back a few days to "TF Speedo cable - over or under?" We got a bit off the question and talked about this same problem. It could be the inner cable, either it might have a slight kink, or might need lubrication (dry, graphite, not oil). My TF speedo swang wildly until I replaced the inner cable, now it's only around 5mph swing.
Al
A W Parker

My cable must be good ...about 5MPH here as well.
David Sheward

My 55 TF speedo did the 30mph swing thing, so I bought a whole new cable assy - that improved the swing, but not much. I noticed that the pulses were timed to the trip odometer advance, then the odometer stopped. Hummmm...
I pulled the speedometer and opened it up. Carefully remove both the gears driven by the main spindle worm gear by pulling the end clips. You will see that all the old grease has dried out and is dragging things down or in the worst case, has frozen the shaft causing the fiber gear to strip. The gear drives an eccentric that advances the counter, all the dead grease pulls down the works causing the needle pulse. Clean the shafts and bores with alcohol and use some light grease and non spreading oil to slick up all the monkey motion.
Speedometer is rock steady now. GPS shows it about 3mph fast on a car with a 4.3 rear - go figure!

Dick Lambert

Other end of shaft showing the eccentric that pushes the odometer. A little fiddly, but not too bad.

Dick Lambert

THANKS for the quick response guys! As usual - interesting and informative. Not certain how I'll proceed at this point....jump into the speedometer OR try a new cable insert. Sounds like the gears in the speedometer may have 'dried' up and need a good cleaning and careful lube -
TStac

Dick, thanks for the additional info. I'll get into my speedo one of these days and hope for some further improvement.
Al
A W Parker

Had the same problem with the TD, and replaced the cable....VOILA! Fixed.
Edward
E.B. Wesson

I had the same problem with my TF 1500. The needle of my speedometer fluctuated wildly. First I checked the speedometer: I took a M4 threaded rod of about 10 cm length that I filed on one end so that it fitted into the speedometer and put the other end in a drilling machine. You need to run it anti-clockwise. In my case the needle was stable in the complete range up to 70 mph which was the maximum for my drilling machine. So I bought a complete SPEEDO CABLE from BROWN & GAMMONS. It works fine! Almost no fluctuation.
CM Mayer

I did that drill trial also, but the drill drastically overpowers the dragging gears. The fluctuations are formed by the drag of the gear shafts actuating the counters causing the the 5ft long cable to wrap up a little each time for a needle slow down, then releasing the energy causing a tiny over speed. A new cable is undamaged and stiffer than a 60 year old cable. My cable was unwound in 2 places.
I believe every speedometer should be relubed, pulses or not. Even if you don't tear into it like I did - light oiling of the 2 odometer shafts without disassembly will smooth them out and reduce chances of a stripped gear and odometer failure, to say nothing of a smoother needle. Both of my gears were stripped of teeth and the shafts firmly seized in the bores.
Dick Lambert

This thread was discussed between 01/08/2011 and 02/08/2011

MG TD TF 1500 index

This thread is from the archives. Join this live forum now