Range Rover front diff in a Series?

[jp-]

Tell me if I'm crazy here, but why can't I take an early Range Rover front diff, cut off the coil spring bits, weld on spring perches, and have a disc brake front diff?

Assuming that I don't care that the ratio is now 3.54/1.

[enovey]

Your series diff will bolt in place of the range rover diff. There are some complications with steering and spring mounts, but I have seen someone else with range rover axles mounted under a leaf sprung 109". I am working it out to do the same to my 88".

[Mercedesrover]

Call me crazy but the brakes on the new 109 are great. I'm soooo glad I didn't bother with a disc conversion.

Why reinvent the wheel? Put 109 brakes on it.

[jp-]

I like reinventing the wheel, it's why I became an Engineer.

[greenmeanie]

It's the usual things
Coiler axles are wider so you end up either having to use wheels with an odd offset and really narrow tyres or have the tyres poke out from under the truck. While they are coil sprung you can look at either NCrover or Bluebomber's trucks and see how coiler axles look under a series body.

On the front axle there is an issue of interference between the linkage bars and the leaf springs that has to be addressed. All this has been dealt and made to work by others so it can be done.

As Jim points out the question then becomes why? Disc brakes have there place if you are building high horsepower trucks or spend a lot of time in water. A good oem drum system set up properly, however, will lock up the wheels very nicely if set up and maintained properly in which case it all comes down to rubber contacting the road. With this in mind disc conversions on stock trucks are a lot of hassle for little gain.

If you must have disc axles you could also look at some of the Toyota axles which I am assured will slot right under there with similar or less modification than the Rover coiler items.

[jp-]

Green,

What's the width of an early RR axle vs a Series?

[greenmeanie]

From the LRFAQ website:
RR track width - 58.5"
Series track width -51.5"
Series body width - 66"

I made a mistake earlier with my references. Look at pictures of NC Rover's swb and Blueboy's lwb for coiler axles under a series body.

[yorker]

I think they are ~6" wider.

[yorker]

Oh- IIRC that additional width is all added to the long side too.

[yorker]

If you wade through these you might find some info:

http://forum.landrovernet.com/showthread.php?t=109506&highlight=Range+Rover+axle

http://forum.landrovernet.com/showthread.php?t=112491&highlight=Range+Rover+axle

http://forum.landrovernet.com/showthread.php?t=131792&highlight=Range+Rover+axle

[TeriAnn]

As Jim points out the question then becomes why? Disc brakes have there place if you are building high horsepower trucks or spend a lot of time in water. A good oem drum system set up properly, however, will lock up the wheels very nicely if set up and maintained properly in which case it all comes down to rubber contacting the road. With this in mind disc conversions on stock trucks are a lot of hassle for little gain..
With an 88 I agree completely. You get better braking but not dramatically better and probably not worth the added expense & effort.

With a 109 in the flat lands I also agree. But 109 front brakes have two leading shoes which gives it good braking in the forward direction and really poor braking in the rearwards direction. Mostly you don't need good brakes in the rearwards direction.

Unless you happen to be nose up on a steep grade and needing to hold your 109 stationary. Held up by someone in front of you, a failed ascent, a broken axle (never with Jim's truck), gearbox or transfercase popped out of gear or for any of a number of reasons. Most people aren't strong enough to hold a 109 stationary in a steep nose up attitude for more than a few seconds. Disc brakes hold just as well in the forward and rearwards direction and holds better than the drum brakes.

For a 109 used in the mountains I consider a front disc brake upgrade to be a safety upgrade. If you don't do steep ascents in a 109 it is an upgrade not needed.

Maybe Jim has super strong legs. Or maybe he just hasn't been in the right place at the right time in his 109 to understand what I'm saying at a gut level.

Or maybe its just that girls don't have enough leg strength to keep a 109 stationary in a steep nose up attitude.

[jp-]

I'll tell you, I've driven on flooded out roads with water up to the door bottoms and I didn't like the feel of my new brakes after coming out of the water. It didn't matter how hard I pushed the pedal, it would not stop (and I have legs like Schwarzenegger), that is not confidence inspiring.

[greenmeanie]

I'll tell you, I've driven on flooded out roads with water up to the door bottoms and I didn't like the feel of my new brakes after coming out of the water. It didn't matter how hard I pushed the pedal, it would not stop (and I have legs like Schwarzenegger), that is not confidence inspiring.

Ah now then the solution is learning how to dry off the brakes afterwards by driving against the brakes to generate enough heat to get rid of the water. It is something well worth practising in a controlled environment on a quiet road. Mt confension is that I had to learn the the hard way that my idea of dried off brakes did not agree with physics.

While I do not disagree with you on your explanation Teriann I have always meant to ask why you don't use the hand brake if you have stopped on the hills?

[yorker]

Ah now then the solution is learning how to dry off the brakes afterwards by driving against the brakes to generate enough heat to get rid of the water.

I was going to say- that was what my dad taught me to do years ago when I started driving- After wading to drag the brakes a bit to dry them off before resuming travel at speed. I've never really had a problem with it.

I've experienced the loss in holding power on hills though with dual leading shoes in drum brakes- it becomes particularly fun if you have a brake booster and stall the engine and lose your vacuum. :eek:

I'm not sure it is worth the cost of the current series disc brake conversions though-it isn't to me anyway and I'd have to resort to other means like JP is considering or a complete TLC axle swap.

[SafeAirOne]

Unless you happen to be nose up on a steep grade and needing to hold your 109 stationary. Held up by someone in front of you, a failed ascent, a broken axle (never with Jim's truck), gearbox or transfercase popped out of gear or for any of a number of reasons. Most people aren't strong enough to hold a 109 stationary in a steep nose up attitude for more than a few seconds.

I can testify to the difficulty in holding the drum brakes in a 109 while stalled on a 50-or-so degree incline. It's do-able, but it's not fun! My approach would be to change out my little 65-horse 2.5diesel for a 300Tdi instead of changing the brakes. More HP would eliminate the 110mph running start and eventual stall 10 feet from the crest of the hill. Of course, I could just plan ahead and use low range:rolleyes:

[scott]

...109 front brakes have two leading shoes which gives it good braking in the forward direction and really poor braking in the rearwards direction. Mostly you don't need good brakes in the rearwards direction...

teri, what do you think of fitt'n 109 front brakes on an 88? i plan on doing a bit of trailering. is it easy? worth the hassle/expense?

[yorker]

teri, what do you think of fitt'n 109 front brakes on an 88? i plan on doing a bit of trailering. is it easy? worth the hassle/expense?

It used to be a fairly popular modification. Very simple to do once you have accumulated the parts.

[siiirhd88]

I have early 10 spline Range Rover disc brake axles under the wife's SIIA 109. The rear was easy, just cutting off all of the coil bits and welding on generic 3" tube spring perches at the desired pinion angle.

The front axle was more of a problem, as previously discussed. Unlike a Series, the RR axles have the steering arms on the rear side of the swivel housings. The location of the arms causes the tie rod to interfere with the leaf springs. By using two leaf parabolic springs, different thicknesses of spacers on each side and wedge pinion angle shims between the axle and springs I was able to get the heavy duty RTE tie rod to just clear the springs. The wedge shims allowed adjustment of the castor, but the castor and pinion angle is a compromise that fortunately has worked out fine. I used 88 rear shock mounting plates to mount the lower end of the front shocks.

The spacers and axle location caused a loss of some ground clearance, but that has not been a problem so far.

Since the wife's 109 is RHD I had to source a RHD RR swivel to mount the drag link from the steering relay. The drag link tube ended up needing to be shorter than the RR one, but longer than the Series. I had a machine shop shorten, drill and tap a RTE RR drag link to the correct size.

I might play around with moving the tie rod to the front side, since with RHD and LHD swivels now have steering arms up front. Using a tie rod with a drag link connection would eliminate the spring interference.

I did add small rubber wheel arch flares to the wings due to the tires on Disco steel wheels sticking out slightly. I kept the 3.54 ratio gears, and the 3.9 V8 and R380 5 speed make it a great cruiser. I used a stock 109 vacuum assist brake master cylinder and booster. The braking has been excellent, compared to stock drums.

I had bought the axles just for the 3.54 10 spline diffs, which I intended to put in my 3.9 V8 SIII 88. I will likely modify a pair of S1 Disco axles for the wife's 109 later...

Bob
'96 Disco SE7
'80 SIII 109
'75 SIII 88 V8
'68 SIIA 109 V8
'6? SIIA 109