W124 Power Steering Top-Up

[MattFatPanda]

Hi all,

Short Story: I think I need to top up the power steering fluid on a W124. Can I just take the top off the reservoir and fill it up, or do I need to take anything out of the reservoir first e.g the filter?

Long Story: I've got a power steering leak and it's not been an issue until a day or two ago when the car started making a funny noise when I turn the steering wheel for the first couple of minutes after starting the car cold (doesn't do it if the engine's hot). I'm guessing the power steering fluid level has dropped low enough that the pump is running empty at start-up until I turn the wheel a couple of times and it effectively primes the system with the remaining fluid in the system. I've got the car booked in to have it fixed in a couple of weeks but I don't want to ruin the pump/make it worse before then, so figured keeping the system topped up for a couple of weeks would be the answer?

Thanks!

 

[carat 3.6]

No need to remove the filter, just top up the level.

 

[MattFatPanda]

No need to remove the filter, just top up the level.

Awesome, thanks!

 

[Pontoneer]

Hi all,

Short Story: I think I need to top up the power steering fluid on a W124. Can I just take the top off the reservoir and fill it up, or do I need to take anything out of the reservoir first e.g the filter?

Long Story: I've got a power steering leak and it's not been an issue until a day or two ago when the car started making a funny noise when I turn the steering wheel for the first couple of minutes after starting the car cold (doesn't do it if the engine's hot). I'm guessing the power steering fluid level has dropped low enough that the pump is running empty at start-up until I turn the wheel a couple of times and it effectively primes the system with the remaining fluid in the system. I've got the car booked in to have it fixed in a couple of weeks but I don't want to ruin the pump/make it worse before then, so figured keeping the system topped up for a couple of weeks would be the answer?

Thanks!

As Carat says , just top it up .

However , do be aware that on the 300TE , including the 4-Matic , actually any 6 cylinder W124 estate , you have a tandem pump which has separate chambers for the power steering ( uses standard ATF ) and the self levelling ( which uses ZHM mineral oil ) and the common fault is for the self levelling pipes at the back to corrode and cause a loss of ZHM fluid ; this then causes the bearings in the pump to run dry and loss of both fluids .

Generally the self levelling will stay at the correct height unless you load or unload the car significantly , so the first thing you will notice is loss of power steering .

The thing to check on , besides the fluid level in the PAS chamber is to look at the reservoir for the self levelling ( just next to the pump , on the nearside inner wing ) and ensure it isn't empty ( it should be about 3/4 full ) . If you have only lost power steering fluid ( unlikely ) then it is probably the seals in the steering box ( it can be rebuilt ) .

Those tandem pumps are scarily expensive and when I had to replace one over 20 years ago it was about £1300 , plus I had to replace the hydraulic pipes due to corrosion ( I've had this twice , given I've had five W124 estates , but I now know to keep an eye out for these things , and caught the second one before the pump was damaged ) . I wouldn't like to guess what one of these pumps ( made by Vickers ) would cost now !

PS , damage to the pump will happen quite quickly ; I spotted the second one due to a pool of fluid on my driveway , where the back end of the car usually sits and on checking , the loss of fluid was obvious .

 

[MattFatPanda]

As Carat says , just top it up .

However , do be aware that on the 300TE , including the 4-Matic , actually any 6 cylinder W124 estate , you have a tandem pump which has separate chambers for the power steering ( uses standard ATF ) and the self levelling ( which uses ZHM mineral oil ) and the common fault is for the self levelling pipes at the back to corrode and cause a loss of ZHM fluid ; this then causes the bearings in the pump to run dry and loss of both fluids .

Generally the self levelling will stay at the correct height unless you load or unload the car significantly , so the first thing you will notice is loss of power steering .

The thing to check on , besides the fluid level in the PAS chamber is to look at the reservoir for the self levelling ( just next to the pump , on the nearside inner wing ) and ensure it isn't empty ( it should be about 3/4 full ) . If you have only lost power steering fluid ( unlikely ) then it is probably the seals in the steering box ( it can be rebuilt ) .

Those tandem pumps are scarily expensive and when I had to replace one over 20 years ago it was about £1300 , plus I had to replace the hydraulic pipes due to corrosion ( I've had this twice , given I've had five W124 estates , but I now know to keep an eye out for these things , and caught the second one before the pump was damaged ) . I wouldn't like to guess what one of these pumps ( made by Vickers ) would cost now !

PS , damage to the pump will happen quite quickly ; I spotted the second one due to a pool of fluid on my driveway , where the back end of the car usually sits and on checking , the loss of fluid was obvious .

It had the rear SLS pipes replaced by the previous owner (still needs the rear leveler adjusting as it’s riding super high but that’s on the long list of things to do).

Last I checked I could clearly see lots of blue liquid in the front tank but I’ll have another look while I top up the PS fluid (assuming it does need topping up).

 

[optimusprime]

All in here Mercedes Benz Model 124 - M103 Maintenance Manuals

 

[Will]

Not sure on the setup on the 4-Matics but I’d suggest checking the ball joints in the front arms also - just in case the sound isn’t from the pump itself!

 

[MattFatPanda]

Checked the power steering reservoir today. Was bone dry. Topped it up with some Power Steering fluid from Halfords (says is an okay substitute for MB236.3) and no more noise turning the wheel on startup.

Hopefully that’ll keep it going until I get it into the garage for them to find/fix the leak in a couple of weeks.

 

[MattFatPanda]

All in here Mercedes Benz Model 124 - M103 Maintenance Manuals

Thanks! That’s great, seems I filled it up to the line stated in the service manual instinctively as that seemed the natural place to fill to.

 

[MattFatPanda]

Not sure on the setup on the 4-Matics but I’d suggest checking the ball joints in the front arms also - just in case the sound isn’t from the pump itself!

It was definitely a pump cavitating noise rather than a knocking.

 

[Pontoneer]

Checked the power steering reservoir today. Was bone dry. Topped it up with some Power Steering fluid from Halfords (says is an okay substitute for MB236.3) and no more noise turning the wheel on startup.

Hopefully that’ll keep it going until I get it into the garage for them to find/fix the leak in a couple of weeks.

Good - when you do it , turn the steering fully from lock to lock two or three times - that will cause the fluid to be fully circulated through the system .

Depending how much you drive the car , worth keeping the bottle of fluid in the boot , so you can top up anytime the noise returns - I'm presuming you're hearing the usual 'groaning' type noise when you turn the steering , it will also feel heavier when you are losing power assistance .

If you run out of fluid and are stuck , it is basically just automatic transmission fluid with Dexron 3 , which you will get in practically any filling station .

 

[MattFatPanda]

Good - when you do it , turn the steering fully from lock to lock two or three times - that will cause the fluid to be fully circulated through the system .

Depending how much you drive the car , worth keeping the bottle of fluid in the boot , so you can top up anytime the noise returns - I'm presuming you're hearing the usual 'groaning' type noise when you turn the steering , it will also feel heavier when you are losing power assistance .

If you run out of fluid and are stuck , it is basically just automatic transmission fluid with Dexron 3 , which you will get in practically any filling station .

Will do the lock to lock thing if it crops up again. Had to buy quite a big bottle as that was all they had in stock so got plenty of spare PS fluid just in case. I’ll keep it in the boot until the leak is fixed.

 

[alabbasi]

Top it up with ATF.