Power Steering/Brakes Project

[Enemy]

Gentlemen,

Hope you are all doing well this morning. I have been working on my recently acquired 8er, sloooowly, over the past 2 months. It is a '91 850i 6-Speed and when it arrived had a major pentosin leak from between the master cylinder and brake booster. The brake bomb was also suspect.

I went ahead and purchased the brake booster rebuild kit from Max Lumens, a new brake bomb, and both Pentosin filters (canister filter, and the one which goes under the car). I also picked up most of the hoses that end up attached to the Pentosin canister and replaced the pipes that attach to the brake bomb. Lots of new stuff in there now.

Tonight, I was finally able to put everything back together and give the car a go. NO LEAKS! So this is the good news. The bad news is, I think my Power Steering Pump needs to be replaced.

Before I cranked on the car, I topped off the Pentosin in the canister, and also the master cylinder with some DOT4 brake fluid. I pumped the brakes a few times to get some of the stuff flowing. Turned on my car, let it run for a few minutes, but the car was GROANING something fierce, especially if brake pressure was applied or the steering wheel was turned. No fluid leaks though.

I shut it off. Checked for leaks. Topped off the fluids again. With the car off, pumped my brake pedal until firmness was established (about 7-10 pumps) and syringed out the ATF that is still in the system. Topped it off with Pentosin again, turned the car on, turned my steering wheel from lock to lock a few times and the car still GROANING something fierce. Syringed the ATF out, de-pressurized, turned on car, ... idling... no groaning now... but if brakes applied or steering wheel, groaning is back... but steering is easier. Did all that a few more times but ATF is still coming out (obviously turning greener, but I ran out of Pentosin after 4 cans) and I still get the groaning. Brakes still only pump about 7 times before they get stiff.

So... I'm still not finished

I have a few questions:

- Is the groaning a bad power steering pump? Could it be a loose belt?

- I'm getting the BREAK ASSIST INACT message, and I did in the process snap the wires off the pressure regulator switch, but repaired them. How do I know if I have the wires plugged in correctly or if it's time to replace those two switches?

- My car is running rich and smoking from passenger side exhaust. My MAF is broken on that side too. Is that the problem?

[mjrgroup]

Enemy, I'm not sure about the other issues you're having but when you pump the brake pedal about 10 times to depressurize the system and/or when you drain and refill the entire power steering system, you have to run the engine, which gets the power steering pump running and there will be a lot of groaning because the fluid hasn't circulated through the entire lubrication passages. With the engine idling, turn the steering wheel from lock-to-lock three to five times to get the fluid moving. Then stop the engine, depressurize again and check the Pentosin level.

Personally after that I'd even give the car a nice long drive and check again.

If the groaning continues you could have a compromised hose fitting or one of the metal pipe gaskets (o-rings, always replace those) which is sucking air into the system causing or aiding impeller cavitation.

There's no harm in checking the power steering drive belt, but it's most likely either working and driving your pump or not. You can get replacement gaskets to reseal the pump, and it might be worthwhile to disassemble, clean and inspect it too.

[m10n]

hey enemy,
i watch your posts as you got your 8 the same time i got mine. i noticed you were redoing your hydraulic canister. did you put a filter in it? is it together properly? take the filter out and see if it quietens. i know the slightest drop in supply to the pump will cause it to starve, and i'm worried you may be damaging it with starvation. i have also looked into replacing the pump as it is so important on this build.

[Enemy]

m10n - I have replaced both Pentosin filters and rebuilt the components of the oil canister with all parts as per realoem.com diagrams. I have then re-assembled as per Max Lumens' write-up.

MJR - I feel like I've already done what you are suggesting, but I will try it once more. I will let the car idle for a while, turn wheel lock to lock a few times again, de-pressurize and check.

Honestly though, I don't feel like I should drive it right now for safety reasons until I can get it to quiet down. Also, I need to bleed my brakes too.

Key things to remember here:

- Brake Servo Unit (booster) is rebuilt fully.
- All pipes and hoses related to booster are new.

- Brake Pressure Accumulator (Brake Bomb) is brand new.

- Pentosin filter at front of car, under the engine is new.
- Pentosin filter and all internal components of the oil canister are new and arranged properly.
- All hoses related to this canister are new.

Item #5 below is suspect: The wires were cut-off from terminals. I repaired using crimp-on spade terminals. I now have a BRAKE ASSIST INACT. message on the Mid. Would this have anything to do with the groaning?

[m10n]

the switches would be good to replace but i would see if the noise stops with no canister filter. from the drawings it appears the switches allow, and limit boost. i also changed fluid from my hydraulic system, but i didn't have the wrong fluid in it thankfully. but you shouldn't have needed to use 4 cans especially since you replaced the whole system basically. do you have leveling suspension? i don't think there's that much volume in it. maybe 2 full cans?

[Enemy]

Well, the system doesn't have 4 cans of Pentosin in it. Remember, I would add some, run the system cycles, and syringe it back out of there since it was redish/brown. It's still dirty, but getting more green, so I will pick up 4 more cans today and hopefully that will be the end of that.

I definitely plan to replaced the switches. I wonder if I have the wires backwards. Does anyone know the proper way to tell if they are on correctly or is it just trial and error (flip them just to see).

I do not have leveling suspension, I don't think anyway.

[m10n]

i know what you meant about the 4 cans, i suspect it is a beautiful clear green now? maybe the pump is shot? wouldn't be crazy. running while noisy certainly sounds like premature death, this "other" filter you speak of, i'm not familiar with. the one on the steering box? the little screen? i would get a pump, it is old.

[mjrgroup]

this "other" filter you speak of, i'm not familiar with. the one on the steering box?

IIRC, I think it is coupled between some lines on cars with ASC+T...

[Enemy]

Alright, here's the scoop. I think my pump is shot. Well, I shouldn't say it's shot as it does still help power the steering (it's smooth and I don't have to muscle it), but it's still noisy.

I switched the wires on my pressure switch. Turns out I had them backwards and now the BRAKE ASSIST INACT message is gone. So that was my bust.

I did a few more Pentosin bleed cycles. I've been thru 7 quarts of Pentosin It's not red anymore, but it's not clean green either. The fluid is like a muddy green still.

I get about 13 steady pumps at the break pedal before it goes full hard. The car is less noisy than it was last night, but the pump is still groaning when I press the brake pedal or when I turn the steering wheel.

I'm going to bleed the brakes next and go ahead and cautiously drive the car for a while. See if that does anything.

How does one test the power steering pump to make sure it is dead-dead???

First Cycle:


Dirty:


After 6 quarts, this is how it currently looks:


Fresh Pentosin. Straight out the can.


$100 worth of Pentosin all lost

[mjrgroup]

IDK how to check the pump, but I would remove and dismantle it: you might be able to check the impeller for cavitation damage, clean it out, and/or check and replace the gaskets too. I've seen gasket kits on eBay for a steal. This is largely conjecture but I imagine that since you're fluid was as filthy as it was, perhaps it may have contributed to pump damage...

Check your Pentosin radiator and #18 hoses that connect to the radiator as well. Did you replace the metal washers on the pipe connections? I still suspect that air might be getting sucked in from someplace.

If and when you remove the pump, please take pics of the removal process, pump, and pump internals. FWIW, IIRC AutoHausAZ has rebuilt units, at least for non-ASC+T cars, for about $400.

Thanks and good luck.

[m10n]

i would think that ATF might have damaged the pump. i forgot about the early years with that separate fluid circuit. i also forgot that those pumps are much harder to come by, i only found 1 and its on the bay.
http://www.ebay.com/itm/1991-1993-BM...ht_1683wt_1185
did you ever run it without the filter? noise to me means pump especially since all you have to do is break and hear noise.

[olinjohnston]

Everything you've said points to a worn out P/S pump. Any previously-neglected 20 year old car run nearly dry for who knows how long, then running the wrong fluid, would likely need a new pump (or a rebuild). I know it sucks to use that much CHF, but look at it this way: A proper fluid flush from a dealer or shop would cost much more than that!

[e31gixxxer]

I agree it sounds like your pump is shot, but was it "groaning" before you did all the work?
If it wasn't, how has it failed while in your garage?

Can't see on your pic. if the canister filter is removed (mine is different), but are you 100% sure nothing is obstructing the outlet?

[Enemy]

Check your Pentosin radiator and #18 hoses that connect to the radiator as well. Did you replace the metal washers on the pipe connections? I still suspect that air might be getting sucked in from someplace.

I replaced the #18 hose at the bottom of the pentosin canister, but not at the pentosin radiator. I still have enough of the hose to replace the smaller two at the radiator. I did not replace the washers at the #1 hose. Perhaps I should.

My Pentosin canister will not seal at the top. The bolt that holds everything together is pretty badly stripped, and so the lid wont seal when I apply the knob. Air would get in, I'm sure, but I don't think this would be the issue. I don't see how that air would get into the fluid that's being sent back down to the pump.

I'm currently looking for a replacement canister.

I agree it sounds like your pump is shot, but was it "groaning" before you did all the work?

Yes. It was actually worse before the repairs.

Can't see on your pic. if the canister filter is removed (mine is different), but are you 100% sure nothing is obstructing the outlet?

The filter is in there. It is set up exactly like this: http://bmw8.us/PSF%20Filter%20Replace2.htm

I'm pretty sure there is no outlet obstruction.

[e31gixxxer]

Quote:
Originally Posted by e31gixxxer
I agree it sounds like your pump is shot, but was it "groaning" before you did all the work?

Yes. It was actually worse before the repairs.


Quote:
Originally Posted by e31gixxxer
Can't see on your pic. if the canister filter is removed (mine is different), but are you 100% sure nothing is obstructing the outlet?

The filter is in there. It is set up exactly like this: http://bmw8.us/PSF%20Filter%20Replace2.htm

I'm pretty sure there is no outlet obstruction.

Ummm...Doesn't look good:~(

[Enemy]

Ummm...Doesn't look good:~(

What doesn't look good?

Can you guys think of anything else I should check or should I just go ahead and do the pump?

[olinjohnston]

Nah, do the pump. No sense in spending more time and money chasing ghosts to avoid this eventuality IMO. Worst case is you have a brand new pump and one less future repair.

Also, I don't see how this wouldn't solve your problem - it's the only part on the system that can cause a grinding noise when everything else has been fixed.

[Enemy]

I guess you're right. I'll try one more look-over and I'll drive it around once I bleed the brakes, see if that does anything. I've seen stranger things end with better than expected results before.

But I'm already sourcing my parts for the pump replacement (and a new MAF, and replacement canister).

[cartoonz]

completely REMOVE the filter cartridge and drive it around for a bit, see if it settles down. Those cartridges take more pressure than you might suspect... once it settles down, obviously put the filter in then.

Not sure what/how much/how long was put into the system before and run, but the pump *could* be damaged, yes... but if it was not making as much noise with the WRONG stuff, it sure would not be making it now with the right Pentosin. You've got an issue, but I don't think it is the pump.

[e31gixxxer]

Quote:

Quote:
Originally Posted by e31gixxxer
I agree it sounds like your pump is shot, but was it "groaning" before you did all the work?

Yes. It was actually worse before the repairs.


Quote:
Originally Posted by e31gixxxer
Can't see on your pic. if the canister filter is removed (mine is different), but are you 100% sure nothing is obstructing the outlet?

The filter is in there. It is set up exactly like this: http://bmw8.us/PSF%20Filter%20Replace2.htm

I'm pretty sure there is no outlet obstruction.

Ummm...Doesn't look good:~(

Originally Posted by e31gixxxer
Ummm...Doesn't look good:~(
What doesn't look good?

The pump.

[Enemy]

I want to clarify some stuff.

The pump sounded really bad before I performed any work on the car. I used to get no assistance in my steering before. I had to use a lot of muscle to turn the wheel.

The pump is much better now, but still makes noise. Also, the pump works because it makes the steering smooth and easy. So maybe, it's on its way out. Who knows.

I will try to run the system without the redish looking filter in the canister. Hopefully that works out.

[Enemy]

I had the car idle with the filter removed and did the lock to lock flush method. Not better.

Today I actually let the car warm up, took her out for a few miles, but not better. PWS Pump sounds off after every other brake pedal press and it was still loud when turning the wheel at low speeds. Braking power is weak, not firm. Brake pedal travels down kinda far before I get any braking so I obviously didn't go much faster than like 25mph. I didn't drive on any busy roads. Just stayed inside our subdivision.

Another observation is that my car seems to be running in... you guessed it, limp home mode. I do need a new MAF on the passenger and I do have CEL but haven't read the codes (no code reader yet).

So, I don't think there's any further doubt that my power steering pump is shot. I need to get around to bleeding my brakes. I need that MAF and I need to read those codes.

Lastly, on downshifts, she sounds like a Honda reversing. Any comments on this?

I don't think I'll be driving my car regularly anytime soon. She will definitely keep me busy this winter.

[BBmatic]

When she's finally done Enemy, she will reward you for your excellent hard work.

[Enemy]

When she's finally done Enemy, she will reward you for your excellent hard work.

That's what keeps me going

Is it wrong that I've already thought to myself "maybe I should just sell this thing", lol. I don't think I would sell it... I was just frustrated. Haha.

[mjrgroup]

Regarding your downshifts, is your car an auto? 4spd? 5spd? How many miles? Has transmission fluid level been checked (warmed up, engine idling), changed ever?