Strange disc on my propshaft

[hipplew]

Right this may sound daft but I have a strange disc on my propshaft now please remember that this is a monterey 3.1 with LSD

looking at the rear of the transfer box there is a plate that links this disc to the propshaft the disc is about 8" dia by 1" thick it looks like some sort of composite stone the center is solid as that it is fixed to the propshaft by a plate either side the outer of the disc it held to the center disc by rubber bushes

yes I will get some pics up but it will be tomorrow

any ideas

Howard

[Rifleman]

Sounds like a doughnut joint. Hard to say without seeing it, but on some cars they are there instead of a normal type UJ joint.
They are supposed to stop vibrations.

[Rifleman]

This is the kind of thing i'm talking about.
http://www.alibaba.com/product-gs/21789 ... shaft.html

[hipplew]

Kieth, I will get some pics up in the morning but yes it does look some thing like that but circular so you mention that is for some sort of joint or to stop vibration but must have labottomised myself as I cannot think how it would reduce vibration because of the outer held by these bushes if anything I would have thought it would have created more vibration

defo. a confused dot com momment

Howard

[Rifleman]

A lot of the old Fords were fitted with them, especially the larger automatics. (Granada and Cortina MK3 onwards)
They do away with the traditional front UJ and fit these rubber doughnuts.
The rubber doesn't allow as much movement in the joint, as a UJ would, so the rubber acts as a damper.
I hope that explains a bit better, what i'm trying to say.

[jontera]

my understanding of it is, that it reduces the harmonic vibrations caused when the prop is rotating. it does allow a little flex as half the bolt holes connect to one end (i.e the rear section) and the others to the other end..it's sort of a like a very basic universal joint, but with a more limited range of angles.

problems occur when one (or more) rubber section split sending the prop into an un-even rotation (can't remember the proper term, but it's like one of those spirograph pictures you used to try and make as a kid)..basically the weight and acceleration/braking forces cause it (the prop) to wobble off center

my old MK5 Cortina had one, when it went i got one off the shelf (after being sold compleatly the wrong one..long story, let's just say it was a Ford dealership that would argue your Ford didn't have certain parts that you wanted)..

(damn, my last bit was posted by Keith, just as i was typing)

edit* many thanks to Big Dav..centrifugal force was the term i was looking for..

[Drift]

Is not the rubber doughnut Howard is talking about, look at the gearbox in this link

http://www.ebay.co.uk/itm/ISUZU-TROOPER ... 1c197c24ca

[Sir-Doris]

Some sort of gearbox flywheel perhaps?

With a bit of fiddling I bet you could use it as a handbrake with a set of old calipers or summat. Similar toy a landy rollover

[Ajsymes]

Transmission handbrake I reckon

[Drift]

Nope, later trooper handbrakes are incorporated into the rear calipers

[adyclemo]

I was also going to suggest some sort of brake. May bo it could be turned into some sort of PTO.

[robbie]

Is the doughnut not there to help reduce judder when pulling away as the troopers run a solid flywheel with a sprung clutch ??

[Drift]

Nope, the Trooper have a straight through prop

[Fatbaz]

If the item in question is the same as that shown on the ebay link for the Trooper gear box, your looking at a harmonic balance weight. Their main purpose is to minimise/eliminate propshaft drone and vibration. We use them on a particular model of van that can suffer "prop harmonic acoustic issues".

The photo of the big rubber thing with the steel spacers is a "flexible coupling". It takes the place of a conventional UJ, the flanges either side of it are 3 legged affairs, each leg bolted to an individual hole and bush in the coupling. This arrangement was used at the prop flange of mark 1 Disco's (I've change quite a few and in some cases converted them to conventional UJ's). They also go some way to reducing drive line vibrations being transmitted from the axle back up to the transmission. Obviously they are maintenance free and will last near on as long as a UJ, especialy one that gets a regular dunking in the gloop we all love to play in.

Hopefully this cleared up the mistery.

Regards

Stuart

[Drift]

Ta Stuart

[Rifleman]

Told ye
Good info there bud.

[Sir-Doris]