Thread: Series axle conversion

Tech issues:

D1 and D2 are basically the same, except that pre ~94(ish) D1s have 10-spline diffs and later model D2's swapped to P38 diffs. However the oem 24 spline are no stronger than 10-spline, and P38 diffs can have issues. No difference diesel-petrol, and they are all 3.54:1.

On the front, the track rod wants to be where the springs are. So you will need to (a) go SOA (spring over axle), (b) rotate the housing to a funny angle so the track rod clears - then index and rotate your swivels if you want correct caster, or (c) fit a double-arm RHS swivel housing from a post '99 model or a LHD vehicle, and move the track rod to the front using a toyota-style combined track rod and drag link. Note that option (c) will not give you proper ackerman steering.

Legal issues:

In most states converting to coiller axles on a series will be illegal as you will increase the track width by more than is allowable. Series are 55" drum-drum, coillers are 61" disc-disc.

Option (a) is illegal in many states.

Thanks mate! I bought a pair of complete D1 axles/diffs and brakes in good nick for ten bucks (bargain!) but I don't want to spend money modifying them for leaves until I know its a good option. I suppose my question should have been: "What is the easiest way to get disc brakes and stronger diffs on a IIa?" Any ideas?

Originally Posted by isuzurover

Tech issues:

D1 and D2 are basically the same, except that pre ~94(ish) D1s have 10-spline diffs and later model D2's swapped to P38 diffs. However the oem 24 spline are no stronger than 10-spline, and P38 diffs can have issues. No difference diesel-petrol, and they are all 3.54:1.

On the front, the track rod wants to be where the springs are. So you will need to (a) go SOA (spring over axle), (b) rotate the housing to a funny angle so the track rod clears - then index and rotate your swivels if you want correct caster, or (c) fit a double-arm RHS swivel housing from a post '99 model or a LHD vehicle, and move the track rod to the front using a toyota-style combined track rod and drag link. Note that option (c) will not give you proper ackerman steering.

Legal issues:

In most states converting to coiller axles on a series will be illegal as you will increase the track width by more than is allowable. Series are 55" drum-drum, coillers are 61" disc-disc.

Option (a) is illegal in many states.

Originally Posted by roadlegaltractor

I suppose my question should have been: "What is the easiest way to get disc brakes and stronger diffs on a IIa?" Any ideas?

You may want to rephrase that again... Easiest would be to buy one of the bolt-on disc conversion kits available, and buy ARB/Jacmac/Truetrac diffs, Ashcroft ring and pinions, and strengthened axles from Hytuff, rovertracks or mercesesrover/seriestrek (preferred option for a series http://www.seriestrek.com/axles.html).

But I suspect you may not wish to spend that sort of $$$?

Thanks again! That looks like expensive fun, and I like the idea of keeping the unis, rather than using CVs. I've looked into the disc conversions, supposing the rear Salisbury is pretty much as good as a disco diff, but I assumed I'd have trouble finding a good diff that fitted into the IIa front housing. Are the ones you mentioned bolt-on units or does the housing need modification?

Originally Posted by isuzurover

You may want to rephrase that again... Easiest would be to buy one of the bolt-on disc conversion kits available, and buy ARB/Jacmac/Truetrac diffs, Ashcroft ring and pinions, and strengthened axles from Hytuff, rovertracks or mercesesrover/seriestrek (preferred option for a series Extreme duty axles).

But I suspect you may not wish to spend that sort of $$$?

Originally Posted by roadlegaltractor

Thanks again! That looks like expensive fun, and I like the idea of keeping the unis, rather than using CVs. I've looked into the disc conversions, supposing the rear Salisbury is pretty much as good as a disco diff, but I assumed I'd have trouble finding a good diff that fitted into the IIa front housing. Are the ones you mentioned bolt-on units or does the housing need modification?

All the ones I mentioned are bolt-in centres which would completely replace your centre. They are many times stronger than either your series or a D1/D2 centre.

Keep in mind the D1/D2 diff centre is no stronger (and almost identical) than the centres you have now. Just the 3.54:1 D1 ring and pinion is stronger than the series 4.7:1 ring and pinion. 3.54's are far too high unless you want to drive most places in 3rd and never go offroad.

The strongest ring and pinions available for a rover diff are here:
Ashcroft Transmissions

I forgot they also make lockers which I left out from the list.

Cheers mate, I really appreciate your advice.

Originally Posted by isuzurover

All the ones I mentioned are bolt-in centres which would completely replace your centre. They are many times stronger than either your series or a D1/D2 centre.

Keep in mind the D1/D2 diff centre is no stronger (and almost identical) than the centres you have now. Just the 3.54:1 D1 ring and pinion is stronger than the series 4.7:1 ring and pinion. 3.54's are far too high unless you want to drive most places in 3rd and never go offroad.

The strongest ring and pinions available for a rover diff are here:
Ashcroft Transmissions

I forgot they also make lockers which I left out from the list.

P38 have 4 pinion diff heads which are much stronger than the std series ones. but are 3.54 and a different stud pattern, but the smaller stud pattern is more common making mags cheaper. just another line you could look at.

Originally Posted by boot

P38 have 4 pinion diff heads which are much stronger than the std series ones. but are 3.54 and a different stud pattern, but the smaller stud pattern is more common making mags cheaper. just another line you could look at.

Diff heads are on the other side of the P38 axles too.