Hi folks,

The power steering pump on my R50 is continuously running even with the key in the off position. I’ve disconnected the battery to stop the pimp from running. Anyone know what the root of this problem would be? I’m assuming the circuitry in the PS pump has failed somehow, but I don’t know. Is there a control module for the PS system?

Thanks!

 

A likely reason is the carbon dust from the motor brushes builds up and shorts out the internal circuit board/control module. I’ve read posts about taking the pump apart to clean the dust out with circuit board cleaner, but replacing the pump is probably a lot safer.

The first thing I would do is run the VIN on the MINI website to see if your car qualifies for the power steering pump recall:
https://www.miniusa.com/owners/tools...rt/recall.html
https://static.nhtsa.gov/odi/rcl/201...5V660-2372.pdf

If the car is new to you and had the recall done, or a genuine MINI pump installed, it should still be under warranty warranty from MINI if it was done within the last two years.

 

Anyone else have any ideas? My car doesn't qualify for the Canadian recall as it is way to old (2002) and the service records from the previous owner do no show the pump being replaced.

Any chance that removing the pump and blasting it out as well as I can with electronic cleaning spray will help in any way? Getting a new pump right now is proving to be difficult! The Dorman pump seems to be sold out everywhere and all the other options are pretty pricey. I'm planning to sell the car ASAP once the new pump is in, so splurging on a high end pump isn't necessary.

Is there a chance that some problem with the PS fan could be causing the PS pump to stay powered on?

 

Not sure how to diagnose it , but I would def have it looked at or replaced . If I am correct this issue has contributed to engine fires. Here is a link on the forum u should read if u have not yet and perhaps it can help you out..https://www.northamericanmotoring.co...bay-fires.html

 

Interesting link! I disconnected the battery on my car, so no issues with a fire starting I think, but I will certainly refrain from driving it. Doing a manual steering conversion is tempting, but I won't be able to sell the thing with manual steering haha. I put a Condor Speed Shop manual steering conversion block onto my old R53 a couple years ago and the steering feel was amazing (100x better), but the effort required at low speeds was ridiculous.
I'll be replacing/fixing it myself. I'm not going to pay $1000+ to have shop deal with this. Changing the pump is easy, but if the fault were to lie outside of the pump or if there are other avenues to explore before replacing the pump I'd like to investigate those alternatives myself.

 

you mean the pump is running or the pump fan?

 

It is only the pump running. The PS cooling fan is not running.

 

You can get the pumps rebuilt instead of buying a new one.

 

Gonna need a wiring diagram and meter…

or pump

allmagautoparts.com for used
fcpeuro.com for new (lifetime warranty)

 

Does it still run if you disconnect a smaller 3-pin connector? If yes - the issue is in internal electronic circuit. If not - the issue is external to the pump (wiring, or control module).

 

What I would do (other than the test I proposed above): I'd remove the pump, disassemble it, clean it thoroughly from the carbon dust and checked once again. You can see some pics here: https://www.instagram.com/p/CYS81Wtr5Pw/ or even a video:

 

I have a rebuilt pump on the way from RockAuto now. Hopefully the issue is inside the pump and replacing it successfully solves the issue. Additionally, I really hope RockAuto’s inventory was actually correct this time around and they ship me the pump this time! I will update you guys on my progress once I put the new pump in.

 

If the pump keeps working when engine is off, then one or both of the MOSFETs inside the pump stuck in the opened position. I've done full rebuild of my pump, documented here: https://www.instagram.com/mini_bmw_mechanic/, more precisely these posts:
https://www.instagram.com/p/CYS81Wtr5Pw/

The last post has a video of benchtesting the pump.

Here are the MOSFETs you might need to replace (2x 2N04H4; can replace by IRF3205 (TO220)):

 

Thanks Nervos! Now that is what I call in depth advice. Great info in your Insta account there. I found some old posts on the Mini2 forum yesterday about replacing the FETs and your info corroborates the advice in those posts. i went down to my local electronics shop and they didnt have any IRF3205s, but they did have IRF3206s which have 8mohm of on resistance rather than 4, so I’m a bit worried they will burn out, but I will give them a shot and see what happens. I don’t have much knowledge of electronics so getting into this stuff is pretty interesting. I’m going to tear the pump apart tonight or tomorrow morning and have a look. Hopefully the brushes and commutator aren’t too worn out, but we’ll see! I’m really hoping I can repair this thing myself as the prospect of saving $500 is very appealing to me! Hahah

 

In the case if you need new brushes and rotor - the only place I found them is on ebay, seller name 'mtec-autoparts' (https://www.ebay.com/usr/mtec-autoparts, search for "Power Steering Pump BMW Mini R50 R53 R56 One Cooper Induced Rotor Replacement" and "Power Steering Pump BMW Mini One Cooper Holder"). But the ship from Italy, so, it will take some time.

I couldn't find IRF 3206, surprisingly, but 3205 is pretty much the same, just 55V vs 60V (with original ones 45V). Technically, speaking you can use original 2N04H4 too. I ended up not replacing mine, since the pump works fine with the original ones.

 

I cracked the pump open and had a look tonight. There isn’t anything obviously wrong with the circuit board and it wasn’t even all that dirty. Lots of brush left too. I have no idea if its possible to troubleshoot a transistor by checking continuity, but I put the probes onto the FETs anyway just to see what happened.
the big issue I saw if that the commutator looks to only have a fraction of a millimeter of material left on it. So, even of I do replace the FETs this thing won’t last long. Might as well just get a rebuilt pump from Rockauto since it’ll have new bearings and everything. Anyone know if its possible to have a commutator replaced? I saw the Ebay link to the new aramture of course, but its nearly the price of a Dorman rebuilt pump!

 

Also, can I just take a second to complain about the disastrous engineering of this pump? This motor is very obviously totally under spec’d. The guys doing the design of this thing were WAY off. 100,000km lifespan is just abysmal. Obviously a brushed motor will never last forever, but that means to get to the end of life of the car you’ll need four PS pumps. Insane.

 

 

By "commutator" you mean rotor, am I right? Yes, I did replace it, yes, it is not cheap and I found only ONE seller on ebay who sells them. However, I bet you won't be able to find Dorman pump for reasonable money nowadays, I failed to do so.
As to testing transistors - definitely possible to test mosfets by multimeter (search on youtube, plenty of videos about it), however, you'd need to de-solder them first. I'd just recommend to benchtest the motor ( ) and if it is not working then MOST likely it is because of the mosfets and it would make sense to start de-soldering them and testing. Just make sure your power supply is powerful enough (it consumes 4 amps) or if the battery is fully charged (if you use battery).

 

I’ll check some videos on youtube on testing transistors. I think I can rig up a power source for testing using a 12v battery.

Commutator is the segmented copper part the brushes run on. The rotor is the iron bit the windings are wound on.

Dorman is out of stock everywhere! Supply chain issues permeate every facet of life in 2022.

 

I found a source for a replacement commutator! Only $25USD. Now I just need to find replacement brushes and bearings.
https://store.eurtonelectric.com/11b...-4-1-1-14.aspx

I also made an offer on Ebay for a complete armature unit from M-Tec autoparts. If he rejects my offer I'll order up this commutator and see if I can manage to replace it myself. There are some videos on youtube...it doesn't look terribly difficult (famous last words!).

 

Wow, cool! As to MTEC - they are not super interested in low ballers, ask me how I know Keep us posted with your progress!

 

Update: I ordered a complete armature from Mtec as the vendor I posted earlier no longer carries commutators.

I tried bench testing the motor with the new MOSFETs installed and a 12V battery as the power source. All I’m getting is a short circuit and sparks from the main power leads when I hook them up. Not too sure what is going on.

 

BTW, if you want to replace the O-rings - I found them on ebay too.
The O-ring for sealing electrical motor housing is: 244 Silicone O-ring 4-1/4" ID x 4-1/2" OD x 1/8" thick
The O-ring for sealing the oil pump cover is: 234 O-ring 3" ID x 3-1/4" OD x 1/8" thick. Buna-70

Seller: swint101

I am also looking for the new shaft seal:


Seems like it is 15mm x 10mm x .... (4mm?). I've ordered this one to check: https://www.ebay.com/itm/264498881286

 

You might want to see if there is a recall on your Mini. My daughters 05 and my sons 04 have a PS Recall. We just got hers back and got a new pump and fan. No charge. They also inspect the wiring.
my 06 was not included in the recall.