LT77 Speedo Cable Location

codekiddie

codekiddie

Active Member
Just a quick one I hope :shock:

I have a 5 speed gearbox installed in my car, and as far as I can tell it is an LT77 gearbox. The serial number is 19A 01568260 if it helps at all.

The speedo is not particularly stable so I would like to see if re-lubricating the cable has any effect, so am removing it from the car. Unfortunately, being a conversion, the cable doesn't seem to end up anywhere near the cover plate in the tunnel as per the Workshop Manual. I also have no access to the nearside of the car at the moment, and just wondered if anyone can shed some light as to where the cable exits the gearbox so I spend less time fumbling :?
 
It's in the tailhousing of the LT77, on the passenger side. Personally as a first step I'd remove the cable at the top, pull out the inner cable and inspect and lubricate it.
 
harveyp6 said:
It's in the tailhousing of the LT77, on the passenger side. Personally as a first step I'd remove the cable at the top, pull out the inner cable and inspect and lubricate it.
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Thanks Harvey. I have already got the top off, but was unaware the inner could be pulled out :)

I will give it a go tomorrow. Should it go back in easily enough, or is it likely to be a PITA, and should the cable be oiled or greased?
 
codekiddie said:
I will give it a go tomorrow. Should it go back in easily enough, or is it likely to be a PITA, and should the cable be oiled or greased?
Click to expand...

It should go back in without problems, just twisting it a touch for the final bit to engage it into the drive in the box. Clean the inner and then lightly grease all but the top few inches. As said in the previous posting, check the route of the outer cable.
 
roverp5Bcoupe said:
you could also check if the speedo cable doesn't make short bents under the dashboard near the speedo.
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No nasty bends as far as I could tell when removing the dashboard end :) but thanks for the tip.

harveyp6 said:
It should go back in without problems, just twisting it a touch for the final bit to engage it into the drive in the box. Clean the inner and then lightly grease all but the top few inches.
Click to expand...
Thanks for that.

Next questions are:-

IMG_1497.jpg

Should the cable spin freely within this plastic end part on the speedo end of the cable, or should the plastic spin with the cable? Mine currently spins with the cable, but I can't decide if that is right or not.

IMG_1503.jpg

This is the only damage I can see, about 135mm from the gearbox end....

IMG_1507.jpg

....and a slight kink at the gearbox end.


Time for a new cable, or acceptable :?
 
codekiddie said:
Next questions are:-

IMG_1497.jpg

Should the cable spin freely within this plastic end part on the speedo end of the cable, or should the plastic spin with the cable? Mine currently spins with the cable, but I can't decide if that is right or not.
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The plastic part should be tight on the inner cable.

codekiddie said:
IMG_1503.jpg

This is the only damage I can see, about 135mm from the gearbox end....
Click to expand...


I can't see the damage clearly in the pic, but I'd say that if there isn't anything that could snag up on the outer cable it will be OK.

codekiddie said:
IMG_1507.jpg

....and a slight kink at the gearbox end.


Time for a new cable, or acceptable :?
Click to expand...

I'd just try straightening that out.
 
Hi,

The LT77 in a P6 speedo cable is a non-standard/hybrid part, i.e. it’s LT77 at the gearbox end and P6 at the dash. Is it possible someone has done some amalgamating of 2 cables here? Is that what the “damage” 135mm from the gearbox end is? When we fitted the LT77 to our car we just got speedy cables in London to make a new cable for us, LT77 at the gearbox …. P6 at the dash. Wasn’t very expensive and we have a nice stable speedo…. although still rather inaccurate as we never did get round to doing the calibration :shock: Gav is currently working on a digital speedo driven by the speed sensor in our Jag diff.

Tim
 
Kman1600 said:
Hi,

The LT77 in a P6 speedo cable is a non-standard/hybrid part, i.e. it’s LT77 at the gearbox end and P6 at the dash.
Click to expand...

It doesn't have to be. I modified the standard 3500S cable.
 
harveyp6 said:
I can't see the damage clearly in the pic, but I'd say that if there isn't anything that could snag up on the outer cable it will be OK.
Click to expand...

Kman1600 said:
Is it possible someone has done some amalgamating of 2 cables here?
Click to expand...

speedo_cable.jpg


A better photo of the 'damage'. It may well be that it is a join of two different cables, and as far as I can tell there are no 'high points' that may snag it in the outer sheath. If it is one cable made from two, then they made a very good job of it, as inspecting the coil from one end of the 'damage' to the other, (even with an eyepiece), I cannot see a join :shock:
 
I'd say that damage was most likely caused by the outer cable being tight up against something. I think I'd check the cable routeing, lubricate the inner cable, and then refit and test. If it doesn't work it's cost nothing other than a bit of time.
 
harveyp6 said:
I'd say that damage was most likely caused by the outer cable being tight up against something. I think I'd check the cable routeing, lubricate the inner cable, and then refit and test. If it doesn't work it's cost nothing other than a bit of time.
Click to expand...
I would agree with you there Harvey. Hopefully I will find some time over the weekend to have a look underneath and check the routeing, and guage where the 'damaged' area is on the outer sheath, and remove any constriction if present, and as you say it doesn't cost me a penny :D
 
chrisyork said:
If you should fail in your endeavours and decide you need a complete new cable, LT77 to P6 cables are available off the shelf from Speedy Cables - http://www.speedycables.com/

Chris
Click to expand...
Thanks Chris.

I had already seen their website and bookmarked it in case, but didn't realise there was a ready made cable to suit, so that's good to know :D The inner cable has now been cleaned, greased and back in place, ready for me to test drive later:- weekend chores permitting :(

I did have some trouble with the cable though. I did a test insert of the inner cable, to make sure I had no problems in getting it back in, and the only issue was getting the square end past what would be the 'damaged' area, but once past that it was fine and moved freely. At the time I had the cable coming out of the speaker grille area, so very few bends to deal with.

Since the test went OK, I took the inner cable out again, ready to be greased, but before re-inserting it I routed the outer part through the dash to where the instruments would be. This time no amount of trying would let me get the square end past the 'damaged' area, so I had to come back out of the grille, grease and insert the inner cable, and then route it through the dash. I assume the extra bends in the routeing were enough to cause me a problem :shock:

It took me a while to get what I thought was the best route for the cable, and the angle that it was coming in at the top of the tunnel was making it want to point towards the rear of the car, which was obviously no good, so the bend I have there may be an issue, especially once the speaker is put back in place. Is there any specified route the cable should take, or is it just what looks best with no tight bends, or restrictions when the drivers glove box is closed :?
 
Finally got a chance to do some more with this, so I wired up the instrument cluster and screwed it back in place, re-connected the battery and took her for a drive.....

Success :D

For the first time since I've owned the car, I have a rock steady speedo :D

Thanks again to Harvey and others for their words of wisdom 8)
 
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