Help with power steering fluid ?

**Joelchester** · 11-20-2013, 03:25 PM

Yup I did a search....think I need someone to show me how to do a search (Always gives random stuff not even e21 related ?) Anyways...my steering is making 'that' grumbling noise at tickover (Dead centre) I recognise this as low fluid from my old 740 days...so what fluid do I get ...is it Pentosin..?.and does it go in that brake like reservoir ?....sorry to be a dumbass.....Cheers,Joel.

**olinjohnston** · 11-20-2013, 04:15 PM

Originally Posted by Joelchester

Yup I did a search....think I need someone to show me how to do a search (Always gives random stuff not even e21 related ?) Anyways...my steering is making 'that' grumbling noise at tickover (Dead centre) I recognise this as low fluid from my old 740 days...so what fluid do I get ...is it Pentosin..?.and does it go in that brake like reservoir ?....sorry to be a dumbass.....Cheers,Joel.

The Pentosin (power steering fluid) has its own reservoir which is a black canister. DO NOT put it in the brake fluid tank. The Pentosin fluid is shared with the brake BOOSTER, not the brake lines.

Oh and only use the "search this forum" button from the E31 board and you will see the results you want. The main search feature is crap.

**Timm** · 11-20-2013, 05:09 PM

On the 840ci it is CHF11S which is available from most motor factors. A lot of the fluid is present in the 'bomb' which provides a pressure reservoir to allow the brakes to work if the engine stops, and the method of getting the correct level is as follows:

Switch the engine OFF and pump the brake pedal around 20 times until the pedal goes hard. Remove the lid from the reservoir, the level should be 10mm from the top. You will notice that the lid of the reservoir has a drain hole - the reservoir is not pressurised and excess fluid will be expelled from the drain if overfilled. I did this and ended up with oil all over the drive.

If the fluid is looking dirty, pump up the fluid into the reservoir and remove as much as possible with a turkey baster (don't tell the missus) and refill. Get the engine running and use the steering and brakes - stop the car and do the process over again. The reservoir is shown at the front here with the knurled knob:

**Joelchester** · 11-20-2013, 08:30 PM

- - - Updated - - -

Cheers guys....I will address this in the morning....nobody likes 'cavitation'....see I AM learning...ha,ha....ps Timm had no idea about the 'pump it up' routine...Thanks again...pps Where is the 'search this forum' thing ?

**mikeeb** · 11-21-2013, 02:23 AM

Is there a definitive answer as to what to do when the car has 7.1 and needs topping up? I've searched everywhere and you get very conflicting answers

1. ATF is fine
2. Never use ATF
3. Just top up with 11
3. You must drain and refill with 11
4. Citroen LHM I'd fine fit top up

So which is it? Citroen LHM seems to have similar properties to 7.1

**legoman67** · 11-21-2013, 02:48 AM

Originally Posted by mikeeb

Is there a definitive answer as to what to do when the car has 7.1 and needs topping up? I've searched everywhere and you get very conflicting answers

1. ATF is fine
2. Never use ATF
3. Just top up with 11
3. You must drain and refill with 11
4. Citroen LHM I'd fine fit top up

So which is it? Citroen LHM seems to have similar properties to 7.1

-If your just topping up use whatever is in it. NEVER mix 2 different fluids(general rule of thumb for ANYTHING, but pentosin has very specifically stated to never mix 7.1 and 11)
- NEVER EVER PUT ATF IN EVER. It will ruin the bomb and every single line. I went through this with mine when i bought it.
- If the system is EMPTY after a job like replacing the bomb. You can only 'upgrade' the fluid. IE you can run 11 in a 7.1 system, but you cannot run 7.1 in a 11 system. and remember this is only after the system has been COMPLETELY EMPTIED. NEVER MIX 2 different fluids

Ive never tried a CHF replacement. whats the point? not worth the risk for the slight cost savings. If the system is leak free and not contaminated the fluid should be fine for years. Ive had mine sealed for almost a year now, and the fluid still looks just as green and new as the day i put it in.

**mikeeb** · 11-21-2013, 03:59 AM

Hi

Thanks for getting back to me.

I'm replacing the pas box return pipe as it has a serious leak where the rubber hose is crimped the the metal one.

Quite happy to empty the bomb and reservoir and to refill with 11 but if 7.1 & 11 are so "unmixable" I cant see that I'll get enough of it out. I'm addition there are the two filters one in the reservoir and the other on the brake booster in the hose below the radiator.

So as Pentosin are happy for a drain and refill but not to mix I think they have given us as much "snake oil"as those that say ATF is ok.

So it can only be that 7.1 & 11 don't actually mix but stay separate. Which surely will cause problems if you don't replace the filters and repeatedly flush through with 11.

Hope my ramblings make sense. ???

Mike

**Joelchester** · 11-21-2013, 06:54 AM

Well... I did the pump the brakes thing..and...the level IS 10mm from the top.....should I do the turkey baster trick now and replace most of the fluid ? or is it a sign of more serious stuff...?.... Cheers,Joel.

**Ahmed303** · 11-21-2013, 09:16 AM

Originally Posted by Joelchester

Well... I did the pump the brakes thing..and...the level IS 10mm from the top.....should I do the turkey baster trick now and replace most of the fluid ? or is it a sign of more serious stuff...?.... Cheers,Joel.

How long has it been since you replaced the filter in the pentosin canister? One thing I did on my old car is to replace the filter when I did my Brake booster job (a few days before). When I did the brake bomb (accumulator) I did a flush of the fluid to replace with 11S. Now the car (Mike's) has fresh and clear Emerald green Pentosin flowing through its pipes. The turkey baser does a decent job but flushing it at the lowest point (by the accumulator) gets most of the contaminants and sedimentation out. Plus Thanksgiving is coming and the wife may not want to scream over where the turkey baster is.

**mikeeb** · 11-21-2013, 09:23 AM

The more digging I do the more it seems that 7.1 and LHM are virtually identical.

It's got to be better to have a mix of two very similar mineral fluids (LHM & 7.1) than a mineral and synthetic that the manufacturer say aren't miscible

It seems to me that mixing 11 & 7.1 is very similar to mixing Citroen LHM & LDS which not recommended at all.

**BBmatic** · 11-21-2013, 11:59 AM

I have enough trouble just working out what "knurled" means

**Ahmed303** · 11-21-2013, 12:27 PM

Originally Posted by BBmatic

I have enough trouble just working out what "knurled" means

**e31gixxxer** · 11-21-2013, 03:30 PM

The more digging I do the more it seems that 7.1 and LHM are virtually identical.

It's got to be better to have a mix of two very similar mineral fluids (LHM & 7.1) than a mineral and synthetic that the manufacturer say aren't miscible

It seems to me that mixing 11 & 7.1 is very similar to mixing Citroen LHM & LDS which not recommended at all.

Why not just put in what it states on the cap, and do as advised here and replace what you can with a syringe?

Well... I did the pump the brakes thing..and...the level IS 10mm from the top.....should I do the turkey baster trick now and replace most of the fluid ? or is it a sign of more serious stuff...?.... Cheers,Joel.

It can't do any harm...it's a quick, easy job and if you do it a few times, there will be virtually no old fluid left in the system. I bet the old stuff won't be emerald green.

Edit: You can clean the filter in the ressy with brake cleaner and an air line if you don't have a new one. There is also an issue with the part No. for this on our cars, you will get the wrong one at the dealers if you go by what they say. I will post the correct No. here for info. when I check.

For 97 840 sport UK: Filter cartridge - 324 111 28 167, Rubber seal - 324 111 37 778 . BMWfans, realoem and the dealers part numbers are wrong.

**mikeeb** · 11-21-2013, 04:04 PM

You can't buy 7.1 anymore. So an alternative has to be used.

If anyone including Pentosin have a definitive answer I would be researching one.

**Timm** · 11-21-2013, 04:21 PM

Thanks Gixxxer - I've ordered the parts from Coopers, it's about time I changed that filter!

**Ahmed303** · 11-21-2013, 04:23 PM

Originally Posted by mikeeb

You can't buy 7.1 anymore. So an alternative has to be used.

You still can if you are lucky. Some places have limited stock. But the limited availability was my reason to flush the system and replace with 11s.

**mikeeb** · 11-21-2013, 04:28 PM

Well if you can tell me where in the uk I'll order it........

**Joelchester** · 11-21-2013, 04:36 PM

Cheers Gixxxer,will order one....also...it does say on the cap what to put in ?....But I am glad I asked ...there is always more to these things than meets the eye....Cheers,Fellas.....