View Full Version : Falcon Axles! HELP!!

04-10-02, 03:11 PM
So I broke an axle in the rally car the other week. Spoke to previous owner about which axle to use and he said "I'm not certain, but I'm pretty sure you just need a XD drum brake axle". Sweet, I thinking, until today I go to buy one, and they're too long... So far today, i've pulled apart half a dozen various model Falcon diffs and looked at a zillion other axles, but to no avail.


The diff is a Falcon (no, I don't know which model, otherwise I could just go get one!), with un-modified axles, which I can see the following:

25 spline.
Drum or late disc type bearings (tapered roller)
One access hole in axle flange.
About 670mm measured from flange to the end of the alxe (ie not allowing for triangulation).
Big centre boss on axle (apparently XYs have a smaller one).

Any suggestions? I am loathe to just go and get one re-splined, seeing as a replacment axle should be $SFA, whereas a resplining job will cost $170ish...

My guess is Centura?

04-10-02, 03:17 PM
Do you have the brakes that would have gone on the axle (though they wouldn't be on your car)? :| if you could, you could perhaps ring up DBA and give them the dimensions, then they might be able to say "oh, that's an XY Falcon" or some crap..

04-10-02, 03:38 PM
Nah... there's several types of rear brakes for Falc's out there - not vented, vented rear-mount (which I have), and vented top-hat. As best as I can tell, you can mix and match discs with no drama.

Futher confusing the issue is there are a couple of different types of caliper mountings - there's an integral steel one, and another type with a alloy bracket that bolts onto the end of the diff housing (appears to be the same as drum brake diff). I have seen the alloy bracket type with both rear mount and top-hat discs.

My diff has a home-made caliper bracket welded to the housing, so that doesn't tell me anything.

04-10-02, 10:28 PM
So is this a BW78 diff? According to an old copy of Street Machine, Ford diffs from Xa 'til quite recently had the same overall width - yeah, it's a quality info source I know....
Apparently VH-CM valiants, VL to current commodores, 86-90 rwd australian nissan skylines also had them. It lists widths at 1560mm for VN-VS, 1520mm for VL, 1410mm for skyline (though it may be transposed with track which is listed at 1470mm - or 8cm shorter than the Falcon) and Falcon Xe-EL 1550mm.
Is there a metal tag or label on the housing? Apparently the codes can be used to identify the vehicle model and the diff specs.
BorgWarner were taken over by BTR Engineering about 5 years back, so they are now known as BTR78 diffs.

08-10-02, 02:13 PM
Spac, dunno if you are still looking but...
I measured up an XP Falcon diff today and it was about 1430 wide - the old man reckons the centura diffs were about an inch or two wider and a common swap into these early Falcons. So at around 1480 wide, 7cm narrower than the XD types, the Centura could well be on the money.