P6B S Project Car

Radio - I had an aerial amplifier fitted, and it has partly died - took it oput of circuit and all is well again.
 
Getting ready to swap out the notchy LT77 for the old unit - swapping in the black 8 tooth speedo gear, rear seal. Box was on top of its wooden carry case, and it slipped off...broke off the front tube that the throwout slides on! Bugger! Might be able to braze it back together, but its cast iron..??
 
I've had broken cast exhaust manifolds brazed back together and they were fine afterwards. It will just need to be jigged accurately and machined true afterwards
 
Found on Rimmers....on the way. Hopefully it will go on without having to change bearing shims?
 
That might be something to consider, although I think you'll have a job getting the appropriate shims if it does need changing. It would be worth checking the current amount of play before fitting the new part.
 
Sometimes I wonder why I post some stuff, but you never know when somebody might learn from my mistakes.
Changing the speedo drive gear in the rear housing of an LT77- always pull the rear housing off, dont try to drive the gear and the bearing out by going in through the speedo driven gear hole - it can wreck the speedo drive gear. Thinking the gear was home, fit the spacer, then the bearing. It quickly became obvious the bearing was not going in far enough to get the seal in as well, so I had to drive it all out again. Not fun at all! Anyway, having got it all out and cleaned up the damage to the gear, now to reassemble. I found it difficult to see clearly what was going on inside, so I mounted the box upright on a 20L drum, with the input shaft inside the drum. The gear didnt want to go in easily, and required persausion to bottom on the shaft. The test is that with the spacer behind it, that there is enough space for the bearing and seal in the housing. Got there in the end, oiled the seal drove that in. Applied some sealant to the rear nut washer to prevent oil that wicked down the splines from getting out, then applied the 150lb/ft to the nut with a length of square steel tube bolted to the flange, with some difficulty - at least my long (2ft) torque wrench makes that possible with a gearbox unrestrained on the floor. And it still turns easily!
Now to replace the damaged front cover.
 
Update - I have both a full SD1 workshop manual and a 2300/2600 supplement (much smaller). Both cover the LT77, but there are curious differences. The SD1 manual specifies layshaft with 0.0002 to 0.002 PRE-LOAD and mainshaft 0.002 endfloat - not explicity stated, but thats what I infer. The supplement, as I read it, specifies end float 0.002 on both shafts - will check, dont have it in front of me now. Doesnt make sense to me. The set up of the remote change is also different in these manuals, which makes no sense.
I removed the damaged front cover, and the gasket survived intact on the box. I cleaned up the cover and measured the depth of the shim surfaces - the layshaft is EXACTLY the same as the new(used) one, so thats a win. The mainshaft needs an extra 0.024" , so I am on the hunt for a single shim of the total thickness - 2.5mm.
Not moving well now - lifting the box has given me a somewhat sore hip.
 
Found a local source of shims so sorted in that area - actually had a suitable shim on the shelf! The older LT77 does not have the oil catcher (TKC5779L) that catches oil inside the case and delivers it through the front to oil the primary input shaft, so I thought I should get one while I can fit it easily. Found several outlets listing it...this is smaller than my little finger, in plastic. First try they wanted .......GBP100 for postage. Found a better postage from a US site eventually.
Another thing... the book lists the rear flange nut as 18mm - the thread maybe M18, but the nut is 27mm (1-1/16")
 
Last edited:
Measuring the initial mainshaft end float - I had a new front cover gasket (0.015") so I fitted that to the old front cover with its shims and bolted it up. After a bit of messing around I got the dial indicator mounted to the box front face and probe resting on the primary shaft - almost dead on 0.015" free play. Will remeasure the gasket , which may have compressed a bit, but I think the free play was very close to zero, or at least < 0.002". Next is to try with the new (to me, but used) front cover with the new shim and see how close it is.
 
I would imagine the supplement is correct - 0.002 would allow enough for clearance and things to tighten up a little when they get warm.

M18 / 27mm sounds about right. I had one box where someone had used an imperial nut and that caused all kinds of problems.
 
Went out in Rover to get what I hope is the last shim needed for the LT77 - she went extremely well I have to say - because they ask $15 postage for a few grams , from about 10kms away. As I got close to home, what do I see parked up at a shop but nice shiny black Mk VII Jag! Been a long time since I saw one of these ! Had a lengthy chat with the driver - my age Scotsman. He admired the P6 at some length, so all around it was a good days outing.
 
Gearbox is now all buttoned up - almost dead on the 0.002" end float. I thought I was done untill I realized I hadnt fitted the oil catcher - off with the cover again, insert catcher, close it up again.
Now its ready to swap back into the car....when it gets a bit warmer..but not actually hot!
 
You must log in or register to reply here.
Back
Top