Disk upgrade on a 90, can you swap front discs to rear?

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RustHater

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Have just bought a 1985 90 which had been converted from a V8 to a 300tdi Auto. Solid discs front, drums rear. Years ago I experienced very bad brake fade taking my solid front discs 110 down Cradle Mountain in Tasmania, despite using the brakes as little as I could.
Being an Auto I worry that I might get a similar problem with the 90. Ideally, if money was no object, I'd upgrade both axles to 24 spline. But it seems I could just upgrade the 90 to larger 110 calipers and get vented discs for the front.
Two questions: What year did 90s get the larger 110 calipers (to widen my search) and ... can I reuse my solid front discs on my drum brake rear axle?
 
The 90's went on to the so called 110 calipers with the introduction of the TDI models, J plate on. You need the right calipers to go with vented discs but it is just a nut and bolt swap. Done it on my 1990 TD with solid discs. [ if used in muddy conditions a lot one may as well stay solid disc as the grooves just fill up.]
As for swap front discs to rear that is a big NO. A stamp on the brakes would soon see the vehicle swapping ends.
The job of brakes on the rear axle is to stabilise the vehicle. Most of the braking force is done by the front wheels.
Whether drum or later disc on the rear axle makes no difference provided they are in good condition. To have discs on the rear [ they are smaller than fronts] a compleat axle from a later model is what's needed.
 
The 90's went on to the so called 110 calipers with the introduction of the TDI models, J plate on. You need the right calipers to go with vented discs but it is just a nut and bolt swap. Done it on my 1990 TD with solid discs. [ if used in muddy conditions a lot one may as well stay solid disc as the grooves just fill up.]
As for swap front discs to rear that is a big NO. A stamp on the brakes would soon see the vehicle swapping ends.
The job of brakes on the rear axle is to stabilise the vehicle. Most of the braking force is done by the front wheels.
Whether drum or later disc on the rear axle makes no difference provided they are in good condition. To have discs on the rear [ they are smaller than fronts] a compleat axle from a later model is what's needed.
Thanks, very helpful. That's one less job for the rear then! It will go in mud, but not too often as I don't enjoy that as much as rocky track laning in Wales. So now I need to find out when the upgrade to vented discs happened for the 110. I know Discos got it fairly early (1990 or so?) but think the 110 has larger calipers, so would prefer a 110 set up (having the auto box)
 
I've done similar on mine - 110 vented disks & calipers on the front, really easy swap. On the rear, I've now got a discovery axle which was also a nut & bolt swap, which gave me rear disks too.
It was impractical to upgrade the old drum hubs to disks, easiest way was to just switch the axle. Vaguely recall I had to put a new UJ plate on the axle, but it was no problem.
 
I've done similar on mine - 110 vented disks & calipers on the front, really easy swap. On the rear, I've now got a discovery axle which was also a nut & bolt swap, which gave me rear disks too.
It was impractical to upgrade the old drum hubs to disks, easiest way was to just switch the axle. Vaguely recall I had to put a new UJ plate on the axle, but it was no problem.
Thanks. At present 110 24 spline axles seem in short supply, certainly with vented discs. Will keep looking as seems 110 have larger calipers than Disco. Could fit 110 brakes to Disco axle I guess, but new a pair is about £200. Should not be too hard to get Disco rears. Frustratingly can't yet place a Wanted ad as don't have enough posts, and can't beat that by subscribing to this site as the PayPal link has been reported broken si ce at least Oct 22. Luckily not I a hurry !
 
Have a look on the Flea bay, complete set available, discs, calipers, pads, seals and small bits for about £ 200.
Yes, I found that. Sadly I have a 10 spline axle and would rather, if possible, have 24 spline. In my ideal world complete axle, used, at about that price. But if that doesn't work out I could buy that lot, bolt it to my 10 spline and then if a 24 spline comes along later could move the kit across again. Life gets in the way so it'd be nicer to buy a complete set at the off, seeing its not a critical upgrade just nice to have.
 
Are you really sure you need the 24 spline? I did consider that path myself, but certainly the rear brakes don't do much at the best of times, so any disks on the rear along with the vented fronts is good. I tow a max weight trailer behind my 90 and I've never found the rig wanting for brakes. Shame yours has been converted from a V8 to a tdi. I converted mine from a V8 to a slightly bigger V8 - they make a nice noise.
 
Are you really sure you need the 24 spline? I did consider that path myself, but certainly the rear brakes don't do much at the best of times, so any disks on the rear along with the vented fronts is good. I tow a max weight trailer behind my 90 and I've never found the rig wanting for brakes. Shame yours has been converted from a V8 to a tdi. I converted mine from a V8 to a slightly bigger V8 - they make a nice noise.
No, not really sure. The tougher one part is, the more likely a dearer part will fail instead! I think my 90, having been a V8, might have a tougher diff from standard than other engines. Have found Salisbury F and R for sale, 24 spline but solid disk and drum....rare but not sure I need 2 huge diffs really. Would also need shorter props. If I can get 24 spline, complete, with vented front at a reasonable price, may well do so. Otherwise I may just add vented to my front 10 spline, carry a spare set of hub end thingies and be done with it.
 
If you see those Salisbury axles in the flesh you will realise what brutes they are. Mostly from military trucks and they are darned heavy.
Strength wise there is not a lot of difference between 10 or 24 spline normal rover types.
Your 85 model will have hubs lubricated by oil that migrates from the axle and so your hub end thingies:p [ drive flanges ] get some lube on the splines. Later hubs are grease lubricated and the flanges can run dry and wear. Just check the condition of the axle you have [ spline wear ] when fitting discs/calipers. Its only a few more bolts when you get that far to be able to pull the shafts and check the splines at the diff end as well. How many miles on your truck?
 
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If you see those Salisbury axles in the flesh you will realise what brutes they are. Mostly from military trucks and they are darned heavy.
Strength wise there is not a lot of difference between 10 or 24 spline normal rover types.
Your 85 model will have hubs lubricated by oil that migrates from the axle and so your hub end thingies:p [ drive flanges ] get some lube on the splines. Later hubs are grease lubricated and the flanges can run dry and wear. Just check the condition of the axle you have [ spline wear ] when fitting discs/calipers. Its only a few more bolts when you get that far to be able to pull the shafts and check the splines at the diff end as well. How many miles on your truck?
Thanks. Almost 200,000 allegedly but no history to prove that. MOT history indicates chassis swap to a 300 galvanised in 2016/2017 which is probably when the Disco auto was fitted. No idea of its mileage. Maybe the engine was from a manual as the kickdown lever looks homemade
 
My 1990 Ninety is a genuine 180k plus [ a hard working farm truck but well maintained, tat body though.] and is still on original axles with original shafts, flanges ect.
The original box with the V8 in yours would have been a 4 speed so likely the engine and auto box would have come together from a Disco.
Various mods are needed. [ like your kick down link to do this]
 
Are you sure? I thought the 4 speed manual was the old LT95 box that the Stage 1 V8 and Range Rovers of that age had.
I think the 90/Defender has only ever had the LT85, until the 50th Anniversary model that was auto?
 
Are you sure? I thought the 4 speed manual was the old LT95 box that the Stage 1 V8 and Range Rovers of that age had.
I think the 90/Defender has only ever had the LT85, until the 50th Anniversary model that was auto?

You are probably right MattYorke, The 85 model I remember one member of our 4x4 club having could have been a conversion.
 
Just one point to note with your brakes. The thread on the bolts holding your calipers may be course or fine thread. If you are replacing these bolts make sure you know which you have. I found out the hard way - well the previous owner of mine decided to fit fine thread bolts into a course thread which cocked it up!
 
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