[DeTomaso] Cruise control again--you how one project causes something else to break...?

[MikeLDrew at aol.com]

In a message dated 9/13/09 19 55 30, chrisvkimball at msn.com writes:


> Before I start trying to strong arm the turnbuckle nut to move, is there 
> anyone out there who can give me some help and advice on what I'm looking 
> at to get the ZF device to work?  I was also told that if I do the wrong 
> thing, a piece (maybe an inner nut) might fall into the ZF which wouldn't be 
> good.
> 

I just went through this exercise on Markus Woehler's car a few weeks ago.

The ZF angle drive is not supposed to be loose on the gearbox.   There is a 
threaded pipe that exits the case at a 45-degree angle; the speedometer 
gear passes through this pipe.   The angle drive is threaded onto the pipe.   
The end of the speedo gear is shaped like a flat-blade screwdriver and 
engages a slot in the angle drive.   Bevel gears rotate the motion 90 degrees, 
ending in a square-shaped protrusion that the speedometer cable engages.

You should not be able to rotate this protrusion by hand, given that it's 
directly geared to the speedometer gear.   In your case, something is wrong.

The good news is it shouldn't cost too much to repair it.   It is probably 
just a bad angle drive and Dennis Quella (along with some of the other 
vendors) have good new and used ones available.   Dennis said a new one is $176 
and used is $100-120.   

The other potential problem is that you could have broken the gear that 
emerges from the transmission and turns the angle drive.   That would be a bit 
more challenging.   

Here's a photo of the part:

http://www.panterapartsusa.com/cgi-bin/detail.cgi?prod_id=07801b

The geared end goes into the transmission, the other end has what looks 
like a flat-blade screwdriver.   That engages the angle drive and turns it.   
What could have happened is that the screwdriver blade broke off.   If that's 
the case, then you have to do some gearbox surgery.

Look at this drawing:

http://www.panterasbywilkinson.com/webpages/catalog/ill11a.html

You can see that the gear (part number 801) enters the transmission at a 
45-degree angle, and is retained by a 17mm bolt that rides at a 90-degree 
angle to it (part 804).  If the end of your gear is broken, what you have to do 
is remove the bolt while retaining the gear with a pair of needlenose vice 
grips or whatever, and then carefully withdraw the gear from the 
transmission.   It has an O-ring that seals it against the inside of the sleeve to keep 
it from leaking oil, but if you goon it up, clink clank you'll drop the gear 
down inside the transmission.   Then you'd have to fish it out with a 
magnet which would be a major problem!   In the worst case, you'd have to take 
the gearbox out, and remove the bottom cover to extract it.

You can see from the first link that this gear is a pretty spendy part, so 
I hope you haven't broken it.   However, if you have, the good news is that 
I've got a brand new replacement gear in my NOS parts stash, still in its 
original Ford box, and I'll make you a better deal than the vendors ever 
would. :>)

You may have difficulty getting the angle drive off.   The nut threads onto 
the sleeve on the gearbox with a regular RH thread and is threaded onto the 
angle drive with LH thread.   Hopefully you can turn the nut and back the 
angle drive off.

Once it's in your hand, it's easy to test--just insert a screwdriver into 
the gearbox end, where there's a slot, and turn it.   If there's no 
corresponding turnage on the output side, then you have found the problem.   On the 
other hand, if it works, then look carefully at the end of the drive gear and 
you'll probably find a broken-off screwdriver end.

So, do the troubleshooting by removing the angle drive, and then let us 
know what you find out.   Thankfully most of the time the problem is the drive, 
and not the gear!   So it's a simple fix. :>)

Mike