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MG TD TF 1500 - Speedo Cable Question

I have my rebuilt engine back in the car and hope to have it back on the road again before too many more weeks or months pass. It's been almost 31 years.

I've got the speedo cable off to examine it and clean it but now I’m not sure if I’m putting it back together correctly. I can’t find an answer in the archives and of course none of the photographs I took while taking things apart show what I need. I think I put the split washer back where it came from, as it shows in the picture, but I’m wondering whether I’m right and whether it is needed. It seems to me that the washer only makes it easier for the cable to leak at the transmission housing. It doesn’t show very well in the picture but the washer is marked “Smiths”.

What do you think? Thanks for any help you can give.

Joe


Joe Olson

Joe-- I may be way off base on this but it looks to me as if the split washer serves two functions: (1)it allows the cable to be remove for new lubrication or replacement and (2) it keeps the cable centered so it doesn't wobble as it spins.
If I am in error I am sure someone will correct me.

Larry
LD Kanaster

Hi Joe,

It would seem you have an original Smiths Industries cable, a type that was fitted by the factory. A washer is always fitted here, for the reasons set out by Larry, but without going out to the garage, I can't check whether a split or solid washer was used on later replacement cables.

At the speedo end there is a small split washer, which when removed, allows the cable to be pushed down and out into a dismantled gearbox end, as per your photo. With this slack it is then easy to rotate the large end with the 'rib', so it engages with the slot in the gearbox drive shaft. Absolutely no need to remove floorboards etc, (as you sometimes read!) to change a cable using this technique.

You seem to have a remnant of felt? behind the washer - if replaced with a new thicker piece, this is quite successful at stopping oil going up the cable.

Cheers,

John
J C Mitchell

Larry and John: Thanks for your thoughts. I still have a few questions, though. Isn’t the cable kept from wobbling by the fit of the keyed end where it fits into the gearbox? And doesn’t the washer keep the brass collar from fitting snugly over the end of the gearbox fitting? Also, doesn’t the split or opening in the washer make it easier for oil to work its way into the threads of the fastener and make it more conducive to leaking?

Somewhere I vaguely remember reading that the coupling is supposed to leak so that excessive oil won’t find its way into the cable shaft and then eventually up into the speedometer. Any thoughts on this?

As John mentions, there is a split washer at the speedo end, too, and it’s not a problem. The felt visible in the photo is a felt bushing which fills the whole raised collar. I do remember that it was oil-soaked when I removed the cable.

Sheesh, I’ve learned yet another lesson about the importance of pictures, more pictures, and notes instead of relying on my faulty aging brain for every small detail. For now, I think I’ll go ahead and replace the cable as shown in my photo and deal with any problems or leaks if they happen.

Joe
Joe Olson

Hi Joe,

I've been out to the garage and can confirm that both of my later cables have a split washer similiar to yours. It has to be slotted to avoid complicated manufacturing issues. It does have a centralising effect - the 'rib' is quite a loose fit in the drive shaft, especially in one radial direction!

More importantly the washer stops the cable from slipping back up into the large brass outer cable end. As I said before, this should be filled with as deep a 'home made' felt washer as possible, with a small pierced hole in the middle, around the cable itself, to reduce oil passing through.

Hope this helps.

Cheers,

John
J C Mitchell

Finally..... that's what i am missing! The felt washer oil seal. Mine must have deteriorated to invisibility. Another oil leak solved! Thanks for posting the picture.
C.R. Tyrell

This thread was discussed between 17/01/2014 and 18/01/2014

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