Could this knock be anything other than the propshaft?

[jonmillard]

Hello, new Humber owner, good to find this resource.
I bought a Mark II recently as a day to day classic. It runs smoothly up to 50 mph, but then develops a rumble in the boot, which turns into a vibe under the back seat at 60 and a thudding under the front seats at 70.
Everything says propshaft to me. I'm not used to leafsprings though, and I don't think the rubber bushes are in very good condition. Is there a chance if a stripped the springs and rebuilt it all with new bushes it would clear, or shall I go straight for having the prop looked at?

[BeJay]

get underneath and try to twist the prop against itself, e.g. hold the yoke that goes into the diff and try and twist the prop against it, you shouldn't get any play in the UJ between the two halves, then do the same gearbox end, you'll soon see if the UJ's are knackered, (don't confuse the normal play in the drivetrain with play in the UJ's though) if there's play you can get the UJ's for approx a tenner if you can change them yourself, either way it's not a big job, HTH, Jack.

[SegaSceptre]

Yep that definately sounds like the prop shaft, as mentioned check the UJ and check everything is secure.

[jonmillard]

Thanks. It's always good to know where to start!.