Disco-1 Electric-hydraulic power steering conversion DONE!

[DiscoClay]

I recently converted my 1995 NAS Discovery 1 [14CUX, but that is irrelevant here) from the original belt-driven power steering pump to the Stellanis [aka: mopar] electrically driven pump.

I am posting here because I posted over in landroverforums and really want to get the word out to any D1 drivers (who've not seen that thread) trying to eek a little more usable life out of their disco.

***I AM NOT A RE/SELLER, THIS IS NOT AN ADVERTISEMENT *** I am just an astonished (and satisfied) DIY'er.

Tldr: for around $500USD you can transform the steering experience..and I do mean **TRANSFORM**.

This is the single best conversion I have done, insofar as Drivability BangForTheBuck is concerned.

No longer do pedestrians flinch or run away in fear of the banshee that is the stock pump at idle speed attempting to "service" the steering boost demand of a parallel parking excursion in town.

Now, I have max volume [ergo pressure] at idle/low speeds and minimal effort [with a nice slightly heavier feel] at highway speeds.. and with the turn of a dial i can customize the assist at any time.

This solution was only possible with the product support of the guy that makes the CAN bus emulator that enables the operaton and control of this pump: Mark, up in Canada at NMStec [NMSTEC.CA].

I will attempt to past the info I already added to the other forum's thread. I will also post the thread [admins please let me know if thats cool prior to banning me, as I am just trying to get the info that I created into this forum]:

GM Power Steering Pump Conversion Kit - Land Rover Forums - Land Rover Enthusiast Forum

Discovery II - GM Power Steering Pump Conversion Kit - I have spoken with a number of people over the last few months who have been having p/s pump issues, failures, groans and lack of pressure on both their D1's and D2's. Well I spoke with Rob this morning, the kits are ready and available in...

landroverforums.com

I will follow this post with the actual text.

 

[DiscoClay]

1/n

2015 Jeep Pump conversion: check!
As the guy who just went thru the conversation I can tell you: 100% WORTH IT.

I'll detail it here. And answer questions as able.
I'll start by saying Mark at NMStec is *the real deal*. He has been incredibly helpful through this process, hell, helpful isn't really a fair description. Anyone complaining about the price of his product clearly hasn't actually built it. Perhaps if you are a hard-core firmware and real-time OS coder with lots of CAN bus reverse engineering under your belt.. they're out there but I'll go out on a limb and wager most rover guys aren't that guy. The price paid for the product is more than worth the access to the expertise and assistance. I don't get a commission, I'm just a satisfied Customer.
Regarding the project, I recommend the dodge/jeep (stellanis?) Pump, at least for Disco-1's.. it fits perfectly in front of the airbox, where the jack and chock normally live. It required a horn trim and I am going to trim up the hoses proper.. I left them long during the install.

It drives like a different wagon.. I opted for the manual potentiometer control, no more loading up that POS stock pump at low rpm during a city parallel parking expedition and now it has a nice heavy-centering feel on the freeway.. and each driver can adjust to their preference.

 

[DiscoClay]

2/n

Here's a pic


More to follow..

 

[DiscoClay]

3/n

Regarding the build, once I got all the fiddlybits sorted it was remarkably smooth (for a land rover project anyways).

In regard to the pump:

• The Stellanis pump (Jeep/Dodge) lays horizontally, thus it fits nicely. If I had to stand it vertically like the FoMoCo (volvo) pump things would have been tighter and it would have involved routing the air inlet directly out the side (like some snorkels).
• The 2015 Jeep (3.6L engine version) is what I used.
• You should connect with Mark at NMStec.ca to obtain a list of known-compatibles.
• This pump will *not* work without the power steering controller made by NMStec (https://www.nmstec.ca/product/psc/) or an equivalent. I know there are other combinations that work, but as I wrote up there^ NMStec's PSC *works* great.

Things to keep in mind when pump hunting:

• If you are stuck with eBay, like me (not many wreckers in my area), then you will ***NEED*** to look into the details of each potential pump.
• Look in the detailed description for the VIN number of the vehicle from which the pump was salvaged; DO NOT BUY ONE WITHOUT THE VIN INDICATED!
• Check the *actual* model it was in (I used https://www.vindecoderz.com for which you can just paste the VIN into the navigation bar, e.g.: https://www.vindecoderz.com/EN/check...RJFBG1FC129832)
  • *a metric ****etonne of listings target Dodge Durangos and other models ...and worse: other YEARS than indicated in the auction headline (trust me on this one).
  • The added benefit of this is that the VIN may be useful for CAN bus ID purposes (ask Mark for more about that).
• Try to find a pump that has the high-pressure line STILL ATTACHED...and ideally also has the harness pigtails as well. The benefits are obvious, even if you just using them for mockup and plan to make shiny new ones.
  Picture of the pump I purchased on ebay (with two pigtails, one large, one small, and that black metal hydraulic line):
  
  

 

[DiscoClay]

4/n

Interlude..

I was trying to post this from my phone but the discoweb editor is..."not cooperative".

I'll post the rest when I am in front of a proper computer.

 

[p m]

Keep it coming!

 

[Stocksuspension66]

Interested. I have 35s on deck and my stock pump is a lil whiny

 

[p m]

I've used half-ton GM p/s pumps on two of my trucks. Steering is stupid effortless - but the box will blow the seals sooner or later.
The only way to keep that from happening is to shim the pressure relief valve in the pump, so it almost never goes beyond 1100 psi.
An electric would be an interesting alternative, in the same price range.

 

[nmstec]

I've used half-ton GM p/s pumps on two of my trucks. Steering is stupid effortless - but the box will blow the seals sooner or later.
The only way to keep that from happening is to shim the pressure relief valve in the pump, so it almost never goes beyond 1100 psi.
An electric would be an interesting alternative, in the same price range.

I'm the seller

My controller does have support for Pressure sensor inputs, which you can use to set a limit on the pump if you prefer. Usually with EHPAS this isn't a problem though, as it just produces flow, while the rest of the rack is what produces the pressure. Mazda/Volvo pumps do 1.91gpm @1200psi bypass, while the newer Charger/Jeep pumps (like OP has) are 1700psi bypass @2.5gpm.

Since the pumps technically never reach above 4k rpm, you aren't really cavitating the system (keeping the hydraulics cool), and the pressure is done on demand by the rack itself. Another customer did use the pressure sensor to activate the pump, so it would detect when theres steering pressure applied, and only then go through the mapped pressure curve to increase pump pressure: https://www.nmstec.ca/2023/02/27/johan-from-south-africa-and-his-insane-jeep/

Quick POC, is this Mazda pump on a drift car. Large front tires, and it basically lives lock to lock. No cooler, and temps stay well below above 10C+ambient.

S13 LQ4 Drift Car

On this car we installed everything we had for products we sell a while ago. He's running our ECU, Power steering setup, and a quick and dirty center console control screen! This year Spec-D will…

www.nmstec.ca

 

[DiscoClay]

I've used half-ton GM p/s pumps on two of my trucks. Steering is stupid effortless - but the box will blow the seals sooner or later.
The only way to keep that from happening is to shim the pressure relief valve in the pump, so it almost never goes beyond 1100 psi.
An electric would be an interesting alternative, in the same price range.

Yeah, it turns out (hah, pun) the Jeep pump effortlessly provides enough flow.. I find the happy spot is somewhere between 10-25% of max rpm.

 

[DiscoClay]

Don't know what happened there...

I meant:

Based on how well its working for me, this setup will own those 35's

 

[ERover82]

Neat. How much current is drawn when turning?

 

[DiscoClay]

5/n

Regarding hydraulic lines:

• The high pressure line, it is a 3/8" steel tubeand so if you have a stub of the original, just use a high pressure compression fitting (I can confirm this one fits perfectly, though I did not ultimately use it:
  Amazon
  )
• The specific details for the high pressure fitting (NOT the line which has a smaller OD) are indicated here: https://plews-edelmann.opticatonline...edelmann-92750
  • The relevant info: 11MM Male Captive "O" Ring x 18MM Male "O" Ring. The fitting has a larger OD than the actual line.
  • note: the closeup pic below shows the fitting without the O-ring..which is definitely necessary (unless you want to keep in the Land Rover tradition of marking your territory
    
• Ultimately, for the high pressure hydraulic hose that connects the pump to the steering box, I had the local NAPA shop make it using standard farm-type compression fittings (again... 3/8 of an inch OD) mated directly to a high pressure hydraulic hose which then mated the other end to yet another compression fitting which sealed to the original hard line end attaching to the steering box.
  • here is a shot of the land rover shop manual page for the high pressure line:

• For the low pressure side, I left it unmolested.. it is still connecting to the stock reservoir (from the steering box).
• NOTE: I can almost guarantee the stock O-rings (high and low pressure) on the steering box are frigging toast.. The part numbers for them are RTC-4825 and RTC-4826.. they are sized differently, they look like this:
  
• The Jeep pump has two nipples, one large and one small.
  • I connected the large nipple to the large nipple on the stock reservoir. It requires a step down in size from 3/4" to 5/8" (man, I forgot to note that down, but I believe those are the correct sizes).
    • It's not high pressure, so any fittings and hoses that can live with the hydraulic fluid is fine.
  • I plugged the small nipple on the pump.

The reservoir:

• I rigged the crap outta this, and I ain't proud of it.. but I was in a bit of a hurry and I will likely come back later and craft a proper mount and maybe a new reservoir.
• It is now mounted to the lower tub of the air filter box (the pre-filter side). I used a generic intake inlet (silicon) connector and it's hose clamps to affix it to the airbox. I drilled a hole in the hose clamp (where it is solid/not-slotted) and just used a flat head (chamfered shank) 1/4-20 bolt.
  
  Note the lack of detailed imagery for that reservoir mount
  

 

[DiscoClay]

6/n


The wiring:

• Primary power: Because of last minute rushing, I did not obtain proper heavy gauge (8ga copper / 6ga aluminum) wire and instead improvised: I sacrificed a set of "copper coated aluminum" jumper cables and harvested the 6ga wire. Not my proudest moment but it works. So far, it has not been detectably warm to the touch.. if I notice any heat I will swap it out with copper welding wire. [NOTE: you can see the breaker mounted forward and above the pump, just behind the headlight area, in one of those pics below]
• I opted for a circuit breaker rather than fuse/fusible-link.. because of the load/current draw on startup and under heavy use, I doubled the fuse size (60 amp fuse/fusible-link) and when with a 120amp waterproof breaker (
  Amazon
  ).
• The canbus and 12 volt (switch/relay power) wires are ran into the cab through a convenient hole (complete with rubber grommet) right between the brake vacuum booster (that's next on the list to go, btw) and the clutch master cylinder.
• I opted for the potentiometer rather than automating via speed sensor (though I may change this as we get used to the pump and how best to tune it).. In my case, there is a perfect potentiometer mount hole just next to the dashboard dimmer switch (lower left side of the steering wheel).
• Currently (hah, pun) I am using the ABS fuse slot (the small 'control' one inside the cab, not the big pump one which is under the hood) for the switching power.
  • I used one of those jumper fuses, which allows a separate fuse for the 'new' circuit. I am using a 5 amp fuse for this.
  • The PSC (Power Steering Controller.. At least I hope thats what it stands for) is also powered off of this circuit..with a downstream 2 amp fuse to protect it.

Regarding the serpentine belt drive:

• I found a 7-rib belt that actually fits the system without adding an idler pulley (see belt pic below). A note on this: the waterpump seems to be getting plenty of traction with this belt but it only has contact from about 6 o'clock to about 10 o'clock.
• Because of the less than ideal contact surface for the waterpump I obtained an extra (original/stock) tensioner pulley and will use it as an idler ..by crafting a mount for it to replace the original pump pulley. [note: in this pic you can see the extra tensioner pulley dangling roughly where the pump pulley used to be] [note: the belt looks really close to rubbing on the far side of the waterpump pulley, in this pic... it's an optical illusion; they are not touching ]

• Either of these cases, for the Disco-1 (with that pesky distributor) this opens up REFRESHINGLY easy access to the distributor. Bonus!

[the shortened serpentine belt is 66.2" (66.2 inches for the search engine) or 168.2 centimeters. It needs to be 1/4-1/2"...maybe up to an inch shorter..it's a little too loose; I got this Continental from autozone]

* After several highway runs at speed, it is clear there is some belt slippage; the belt had the telltale marks on the smooth side. I recommend going a quarter to a half inch shorter or, as is proper: install an idler and keep the stock belt. I'll update this thread with that bit when I do.

Regarding the actual mounting of the pump:

• I used one of the rubber and metal-sleeve mounts that came with the stock brackets as a pedestal mount on the bottom of the unit and drilled a hole in the webbing (right under then air inlet horn) for it to "grommet" into.
• I used the stock twin-mount with it's rubber and metal-sleeve mounts for the stabilizing mount.
  • This was attached to a modified stock bracket (I bent it in a vise to get the desired angle) which came with the pump.
    • I attached this under the front airbox mount and bolted it to the inner fender (see pics)

Don't judge me on that wiring.. I changed the routing up which gave me some slack i had to deal with (I will "optimize" it..someday). Note the 120 amp circuit breaker; this is because the fuse should be 60 amps (if you go that route) and to deal with starting/peak loading I doubled it.

(the 'extra' oily stuff around the bolt holes is anti-rust spray that I just blasted around)


Here you can see the original jeep OEM mount bracket' it is BENT back quite a ways, to enable this nice fit with the Disco's fender angle and it allows the machine screws and bracket to pass neatly through that central portal in the airbox bracket. I just put it in a vise and 'gently' ...'tapped' on it..the tested fitment..then tapped... rinse and repeat until desired angle is achieved.

[in the Carolinas here.. frigging pine needs get EVERYWHERE]

Some fender washers on the underside and button head bolts to avoid tire issues:


Let me know if there is a way I can upload an MP4 and I will upload a video snippet of it in action (with audio).

Regarding noise:

• When the engine is running, this thing is completely silent
• When the engine is not running and the hood is closed:
  • Full speed (95-100%) is audible outside the car but it is not loud.. it is very muted
  • Min speed (5-40%) is not audible outside or inside the car
• When the engine is not running and the hood is open:
  • Full speed (95-100%) is very audible outside the car but it is not loud
  • Min speed (5-40%) is audible outside but is muted

Thoughts on drivability:

• I cannot tell you enough, how much of a pleasure it is driving the Disco now.
• The power steering has ***ALWAYS*** been the bane of this wagon (not a truck, not a car...a true "Station Wagon" of the post-railway era).
• I am not familiar with the Disco-2 in this manner but I know the D1 was a polished middle class wagon when it came out, but it's pretty old school..and it drives like it.
• The complete lack of engine idle-loading when parallel parking is still taking some getting used-to!
  • Our disco is manual, not a slushbox, so the parking and low speed full-stop turning has the added challenge of not killing the engine (especially when its up at operating temps).
• It is now alarmingly (and refreshingly) mundane in town!
  • I cannot be the only Disco driver who has glanced around the sidewalks prior to slotting into a street parking spot... to avoid startling passersby with the power steering pump's banshee cry of anguish!
    • Now: no muss no fuss.
• On the highway:
  • Wow!
  • The ability to dampen the steering boost on-the-fly at highway speeds is *GREAT*! Now I can roll the boost back and the steering has this nice centered heaviness that is just perfect. No more flighty darting about the ruts.
  • As bad as the stock pump is at low engine rpm and low speeds.. it is an overboosting idiot at highway rpm and speeds. It's like Rover did it on purpose, just because.. like to stay up with the Lucas boys or something.
  • Our Disco has the emu ~1-3/4" lift and shocks and the bulletproof RoverTym steering links/draglink etc. It also has a rack (of course) and a winch, so it's slightly heavier than stock.

In conclusion: This conversion breathed new life into a vehicle that I was finding harder and harder to justify. Not any more; it's actually a pleasure to drive. If any of you are in the North Carolina (triangle) area and would like to experience it first hand, just DM me.

*I am curious to see if it picks up any economy or power; does anyone know how much parasitic loss was pulled by the original pump?

 

[Greg_M]

• ... right between the brake vacuum booster (that's next on the list to go, btw) and the clutch master cylinder.

Curious what"ll be replacing the booster?

 

[DiscoClay]

7/n

As I said up there somewhere ^ ...I chose to go with a potentiometer rather than speed sensing (and a map).. I may change this but damnit I love the control of rolling that dial to thicken up the steering based upon the road/trail and speed/conditions. So I'll probably stick with that. There is a pre-existing pot hole in the dash, next to the mirror control. I don't know what was there before I bought it.. but it's been empty a LONG time..just waiting for this upgrade:

The perfect spot (at least for the 1995 NAS 14CUX Manual trans 3.9L):


That is about ~30% of pump speed (= flow = boost assist). That is the most I use.. indeed most the time I leave it down around 10-20%.


Minimum speed (basically 0-5%)


Max speed (~95%):

Remaining tasks, to polish this up:

1. Shorten the hydraulic high and low pressure lines, to clean up the kit.
2. finish up the mounting bracket to attach a *stock* tensioner pulley to allow the original serpentine belt.
   1. This could also just be a non-tensioner pulley but I like the idea of a completely model-matching (NAS disco, pre-GEMS) part.
3. maaaaybe shorten up those main power cables.

I just gotta say that buying that controller from Mark over at NMStec is the best way to go; again, I am not paid nor an investor.. just a Customer; it would have been so much more of a headache (as well as not actually working) without his CAN bus emulator (PSC; Power Steering Controller) and especially his support with sorting out my issues and getting it dialed in. The money for the unit was just a complete no-brainer.

I apologize for the messy writeup; i was tired and in a hurry Feel free to AMA about it and I will answer as best as I can.

 

[DiscoClay]

Curious what"ll be replacing the booster?

eBooster Gen2 Or.... hydroboost. I have both here in the bin.

The eboost will be a GO if I can get the VIN from the car it came out of (attempting now). I am not interested in running in "limp mode" (I don't recall if it will even function in limp mode.. Mark will know) Otherwise, I will try to run the hydraboost with this jeep pump and see if it can keep up. Mark (NMStec) mentioned it may struggle but not sure; I can say it certainly doesn't struggle at 20-30% (not at all) for just the steering. I think it may possibly hold up.

 

[Greg_M]

eBooster Gen2 Or.... hydroboost. I have both here in the bin.

The eboost will be a GO if I can get the VIN from the car it came out of... Otherwise, I will try to run the hydraboost with this jeep pump and see if it can keep up.

Thanks. Very interested in how this works out. Excellent thread!

 

[DiscoClay]

Well, the current project I really need to get out the door are the new headlights. I have limited facilities and am pretty much inventing as I go..so it's a slow slog. DOT hella H4's .. the old school euro ones with metal (e.g.: hard chrome) reflectors which can be easily chromed if they get nastied up. The trick is, I need to make polycarb non-diffusing covers because the original (pitted) glass ones have the diffuser ribs cast into them.

Side note:
I am very interested in using SABIC's Extrite (Lexan brand) polycarb material but I can only get 10' sheets here Stateside and its currently ~$750 a sheet (it literally self heals from sand pitting and scratches; it was made for window glazing in the Middle East and is UV resistant ;-P). btw, here is the info on that stuff: https://ff.sabic.eu/en/product/lexan-solid-sheet/lexan-extrite-sheet

Here is the basic solution (I should probably put it in another thread, but it's just a bun in the oven at this point):

 

[DiscoClay]

Thanks. Very interested in how this works out. Excellent thread!

Talk to Mark about that ebooster. If you an get the VIN it is probably doable.

I really am torn: I really like the hydraboost.. I have it on an old Ford dually and it is incredibly strong and reliable. No vacuum issues and it fairly compact. The main issues to put to bed are:

1. Will the e-pump deliver enough volume for both the steering and the brakes?
2. If I use that single pump it will surely have to get cranked up to max/near max
3. I will loose the ability to manually modulate the steering boost (because it will also effect the brake boost)

That said.. the ebooster is my first choice. So long as the battery has juice the power brakes will work. Plus; i *really* like the idea of being able to dial in the boost, just like with the steering.