One Brake Upgrade To Rule Them All - D1 1995 (pre-GEMS, pre-OBDII) Stopping Power Brake Fix

DiscoClay

Well-known member
Mar 18, 2021
433
85
Chapel Hill, North Carolina, USA
Hi folks,

I am sick and tired of the incredibly dangerous brakes my early NAS disco has been shod with. Shoddy indeed.

After replacing *everything* and still finding them *not even the equal* of the drum brakes on my old '68 Goat... I've decided to take the matter into my own hands.

If this works out, I will likely offer the brackets and conversion fiddlybits for sale somewhere (off road use only, of course).

Here is the project:

  1. D110 vented (actual vented, not cross-drilled) disks and their "extended" calipers on *all four corners* of the disco.
  2. Conversion brackets for the rear axle from some Spanish company (I forget the name atm).
  3. Wilwood adjustable proportioning valve, enabling bias adjustment for the increased aft stopping power AND to allow *much better* trailering brake bias adjustment.
  4. Delco hydra-boost brake booster... replacing the very poor performing (and off-throttle, deceleration idle killing) vacuum boost canister.
  5. Stainless steel direct adapter for the brake pedal attachment.
  6. Conversion/mounting plate for said booster (I designed it in solidworks and have it cnc machined from an online service).
  7. Wilwood or other 1" piston master cylinder.
  8. Complete delete of the useless ABS system.
  9. New Cunifer hard lines all around (https://cunifer.com/).
  10. Replace the wooofully inadequate hydraulic pump with a 00's era Corvette power steering pump (ball bearings, not bushings).
  11. Conversion/mounting plate for said pump (I designed it in solidworks and have it cnc machined from an online service).
  12. Custom 5" pulley enabling the stock serpentine belt.
  13. Dual inlet, single return remote reservoir.
  14. Hoses all around...
  15. All the other fiddlybits necessary.
I have used the hydraboost in my 2002 Ford F-350 dually 7.3l powerstroke and it is incredible. I have directly spoken with guys that have converted their old broncos, IH scouts, various GM A-body musclecars... and there is simply no way else to obtain modern vehicle stopping power in the D1 without this kind of dramatic intervention....IMO.

I already have *most* of the parts (no hoses or reservoir yet) and I have the cad designs almost done.

Who's with me? ;-P
Who thinks its stupid (and why)?
Who has already done this?
Who has seen it done (and ....LINKS!)? :)
Who has advice, thoughts, and prognostications about this conversion? Please expound :)
 
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p m

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P/S pump conversion has been adequately addressed. Almost adequately - you need to shim down the pressure regulator in the pump to bring the output down to ~900-1000 psi, otherwise you'll eventually blow the seals on the POS steering box.

Brakes... 110 front brake calipers and pads improve braking considerably, even with non-vented rotors. I haven't gotten around to upgrade the rears as well - not sure that the stock master cylinder has enough capacity for those.
Never, not once, had issue with vacuum servo killing the idle - if you do, you definitely have other problems.

Other than that... every single thing you mentioned has been tried and done.
 
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discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Post up a picture of your rotors. I want to see the surface the pad presses against. I've fixed a ton of brake fade issues by rebuilding calipers. Just a picture thru the wheel should work.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I think that the brake problems these things always seem to end up with are mostly due to the calipers. When these things were new I don't recall people bitching about the brake fade. Rich people bought them for trophy wives and what have you. The brakes worked or we would have heard about it.
 

Tugela

Well-known member
May 21, 2007
4,754
562
Seattle
Are you conflating D90 and D110 rotors? The former are vented, the latter are not.

You don't mention this in your post so we don't have the context, but how much mass are you trying to stop? If you have aftermarket steel bumpers, a roof rack, tent, awning, large tires, hi-lift, winch, jerry cans, sliders, or other hefty mods on your Rover, carrying a lot of extra stuff will adversely affect braking performance.

I put D110 front calipers on my D1 along with braided SS brake lines and that increase in stopping power has been all I need. For context, my truck wears 245/70/16 tires, a Safety Devices roof rack, and a factory brush bar for extras. Before you go to the time and trouble to do all 15 things on your list, start with the calipers and see how you like them. You may find the other items are a lot of work for diminishing returns.
 
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robertf

Well-known member
Jan 22, 2006
4,781
358
-
There are multiple front 110 calipers. The 300tdi era and newer are the same parts as a 90 of the same era. Vented, same rotor as a range rover classic.

I did hydroboost on one of mine a long time ago. Took it off soon after. It was goofy.

what tires do you have?
 

JohnnoK

Well-known member
Mar 19, 2017
190
19
Cape Town, South Africa
I think that the brake problems these things always seem to end up with are mostly due to the calipers. When these things were new I don't recall people bitching about the brake fade. Rich people bought them for trophy wives and what have you. The brakes worked or we would have heard about it.
I wonder if rebuilt Disco 2 calipers wouldn't be what he needs to start off with?
Any bracket/mounting differences will be cheaper by comparison to the proposed fix.

My old Td5 D2 with 380k km on the clock stops on it's nose if it has to and that is on the original untouched calipers.
 

terryjm1

Well-known member
Jan 23, 2011
1,486
375
D90 front calipers/pads and vented rotors are a simple option that is not more costly than stock D1 stuff depending on where you buy. My thought was if the rotors needed replacement anyway, why not upgrade considering the cost is close to the same. However, cheers to you. Please post your work as it should be an interesting project.
 

nickhand

Well-known member
Jan 18, 2018
47
14
Oklahoma
D90 front calipers/pads and vented rotors are a simple option that is not more costly than stock D1 stuff depending on where you buy. My thought was if the rotors needed replacement anyway, why not upgrade considering the cost is close to the same. However, cheers to you. Please post your work as it should be an interesting project.
That's what I did and added 110 calipers in the rear
 

DiscoClay

Well-known member
Mar 18, 2021
433
85
Chapel Hill, North Carolina, USA
P/S pump conversion has been adequately addressed. Almost adequately - you need to shim down the pressure regulator in the pump to bring the output down to ~900-1000 psi, otherwise you'll eventually blow the seals on the POS steering box.

Brakes... 110 front brake calipers and pads improve braking considerably, even with non-vented rotors. I haven't gotten around to upgrade the rears as well - not sure that the stock master cylinder has enough capacity for those.
Never, not once, had issue with vacuum servo killing the idle - if you do, you definitely have other problems.

Other than that... every single thing you mentioned has been tried and done.
Thanks for the reminder! Indeed, I intended to include a pressure reducer on the input to the (POS) steering box. Those valves are crap. That said, the lower seal seems to fail
Post up a picture of your rotors. I want to see the surface the pad presses against. I've fixed a ton of brake fade issues by rebuilding calipers. Just a picture thru the wheel should work.
I am not asking for pad to rotor mating optimization. :)) I am building this to have modern and *much* more effective braking.

The pressure-reducer shim is a known and very valid point that I should have mentioned :) The steering box in the disco uses a *poor* design with those balancing valves (imo, and sorry for the non-technically correct terminology on those valves :)

The 110 brakes, as far as I can tell are the same as the stockers except for the vents and the thickness..and the corresponding spacers in the calipers and the dual brake lines coming into both sides on the ones I have.

The 1 inch piston is adequate for balanced rotors (same used in many other vehicles with similar master<>caliper volumes) **BUT** it 100% **needs** an adjustable proportioning valve... otherwise there'll be a whole lotta rear brake lockup :p
 

DiscoClay

Well-known member
Mar 18, 2021
433
85
Chapel Hill, North Carolina, USA
P/S pump conversion has been adequately addressed. Almost adequately - you need to shim down the pressure regulator in the pump to bring the output down to ~900-1000 psi, otherwise you'll eventually blow the seals on the POS steering box.

Brakes... 110 front brake calipers and pads improve braking considerably, even with non-vented rotors. I haven't gotten around to upgrade the rears as well - not sure that the stock master cylinder has enough capacity for those.
Never, not once, had issue with vacuum servo killing the idle - if you do, you definitely have other problems.

Other than that... every single thing you mentioned has been tried and done.
Thanks for the reminder! Indeed, I intended to include a pressure reducer on the input to the (POS) steering box. Those valves are crap.

That said, the lower seal seems to fail due to the eccentric wear in the top plate in which the shaft pivots. It is a soft iron cap and it actually wears an obloid pocket, this appears to cause the shaft to level the lower seal, causing it to be pinched (and ultimately fails). A friend of mine used to machine the pocket and press a bronze bushing into it...and swears that seal really won't fail again. I have not researched this beyond his advice but I have seen that obloid wear myself.
 

DiscoClay

Well-known member
Mar 18, 2021
433
85
Chapel Hill, North Carolina, USA
Here is the basic brake kit I used, with a bunch of other fiddlybits:


I also ordered non-crossdrilled rotors. Crossdrilled may be great for racecars and throwaways but if you crawl through mud, dirt, sand, clay... them crossdrilled rotors eat pads (and themselves).. IME. :)
 

p m

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Apr 19, 2004
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proportioning valve... otherwise there'll be a whole lotta rear brake lockup :p
Not as much in a Disco - it is so ass-heavy.

As far as steering box leaks - sector shaft seal fails most frequently, but the others do, too. Meridian Automotive has practically taken over the market of rebuild boxes, and I don't believe they care to even look at the wear of the shaft surfaces before they slap down new seals. My own success rate with them is now 2 leakers out of 3.
 

DiscoClay

Well-known member
Mar 18, 2021
433
85
Chapel Hill, North Carolina, USA
Not as much in a Disco - it is so ass-heavy.

As far as steering box leaks - sector shaft seal fails most frequently, but the others do, too. Meridian Automotive has practically taken over the market of rebuild boxes, and I don't believe they care to even look at the wear of the shaft surfaces before they slap down new seals. My own success rate with them is now 2 leakers out of 3.
I share your opinion on the weight bias / braking :)

A steering box rebuilding told me those valves blow out and flood the low pressure side (bottom) of the box...which is where the upper (interior) side of the lower seal is located. Thus when those valves fail and start leaking (high pressure) fluid.. the seal is put under pressure, ultimately causing it to fail. When you add that "pinching" of the seal to situation, it is very plausible this combination lends a *lot* to the reputation of this steering box.

Regardless, the pressure reducer is sage advice, as I understand this new pump caps its pressure off near 1500psi.
 

p m

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Apr 19, 2004
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A steering box rebuilding told me those valves blow out and flood the low pressure side (bottom) of the box...which is where the upper (interior) side of the lower seal is located. Thus when those valves fail and start leaking (high pressure) fluid.. the seal is put under pressure, ultimately causing it to fail. When you add that "pinching" of the seal to situation, it is very plausible this combination lends a *lot* to the reputation of this steering box.
Interesting, thanks for the insight. I wonder if one of my boxes is salvageable.
 

DiscoClay

Well-known member
Mar 18, 2021
433
85
Chapel Hill, North Carolina, USA
I think that the brake problems these things always seem to end up with are mostly due to the calipers. When these things were new I don't recall people bitching about the brake fade. Rich people bought them for trophy wives and what have you. The brakes worked or we would have heard about it.
I am not even talking fade... the lack of simple stopping power is step one, along with effort. Then fade comes into play.. for me :))
 

DiscoClay

Well-known member
Mar 18, 2021
433
85
Chapel Hill, North Carolina, USA
Are you conflating D90 and D110 rotors? The former are vented, the latter are not.

You don't mention this in your post so we don't have the context, but how much mass are you trying to stop? If you have aftermarket steel bumpers, a roof rack, tent, awning, large tires, hi-lift, winch, jerry cans, sliders, or other hefty mods on your Rover, carrying a lot of extra stuff will adversely affect braking performance.

I put D110 front calipers on my D1 along with braided SS brake lines and that increase in stopping power has been all I need. For context, my truck wears 245/70/16 tires, a Safety Devices roof rack, and a factory brush bar for extras. Before you go to the time and trouble to do all 15 things on your list, start with the calipers and see how you like them. You may find the other items are a lot of work for diminishing returns.
Quite likely :)

When I was talking to this Spanish company about their conversions, I swear they said they were using [D]130 brakes and somewhere between that conversation and a bunch of calls with RimmerBros I got [D]110 stuck in my brain. Mea Culpa. :)

You are not the first person to remind me they are most likely D90 brakes. Rimmer doesn't list them one way or the other, just as a part number.

In any case, they are finned, like most disks for cars and trucks weighing more than 800lbs :cool: That is the only real difference. The diameter is the same or very close (I don't have the specs handy, atm).
 

p m

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Apr 19, 2004
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Quite likely :)

When I was talking to this Spanish company about their conversions, I swear they said they were using [D]130 brakes and somewhere between that conversation and a bunch of calls with RimmerBros I got [D]110 stuck in my brain. Mea Culpa. :)

You are not the first person to remind me they are most likely D90 brakes. Rimmer doesn't list them one way or the other, just as a part number.

In any case, they are finned, like most disks for cars and trucks weighing more than 800lbs :cool: That is the only real difference. The diameter is the same or very close (I don't have the specs handy, atm).
The D90 vented rotors are exactly the same as RRC - https://www.roverparts.com/brakes/rotors-drums/LR017952/
 

DiscoClay

Well-known member
Mar 18, 2021
433
85
Chapel Hill, North Carolina, USA
Are you conflating D90 and D110 rotors? The former are vented, the latter are not.

You don't mention this in your post so we don't have the context, but how much mass are you trying to stop? If you have aftermarket steel bumpers, a roof rack, tent, awning, large tires, hi-lift, winch, jerry cans, sliders, or other hefty mods on your Rover, carrying a lot of extra stuff will adversely affect braking performance.

I put D110 front calipers on my D1 along with braided SS brake lines and that increase in stopping power has been all I need. For context, my truck wears 245/70/16 tires, a Safety Devices roof rack, and a factory brush bar for extras. Before you go to the time and trouble to do all 15 things on your list, start with the calipers and see how you like them. You may find the other items are a lot of work for diminishing returns.
I have all upgraded calipers (see the links in this thread, the rimmerbros links). The entire brake system is new and larger. None of this provides a modern, satisfying, effective, robust braking experience.

My 2002 F-350 powerstroke dually hauls to a stop vastly better than the disco1 does. ;-P

Thus I insist upon a redo :)

I have a set of 911GT2 brakes collecting dust.. have thought about using those but I really don't want to upsize the wheels. That said, those shorter tires have a lot to do with braking response. Have any of you modified your hubs and mounted the newer smaller pattern wheels? Just curious.