W123 Most neglected maintenance points: Power steering fluid & Filter

Rather than sucking the power steering fluid out, or removing the return line and running the pump dry, why doesn't anyone use the drain plug on the steering box?
I'm very confident the fluid and filter have never been changed on my w123.
This will take a couple changes before all the residue and remnants of nasty 38 year old atf is flushed out, but that would be the case with any method you choose to use.
I would HIGHLY suggest not using any modern ATF as they have friction modifiers to help the clutches in a transmission grip, and you really don't want grip in your power steering system, other than only needing a light grip on your steering wheel since its so effortless to drive.
Many of, if not all models of similar age, especially those with OM617 and OM616 engines will use the same exact process, W116, W123, W126 for sure, possibly some W124 and newer as well.
Key points in video:
0:00 Introduction
1:15 Everything you need
2:30 Pump location and filter removal
4:05 How to find drain plug
5:00 Nasty old fluid draining
5:25 Drain plug has crush washer
6:05 Use screwdriver to get filter fully in
7:00 Turn wheel side to side after refilling pump
7:40 Top up as needed
8:30 Residue coming out from old fluid remnants
9:30 Testing with car running
10:30 Old fluid opacity test
11:30 Concluding thoughts
All the stuff you need to do this:
➡Power steering fluid (probably better deal at your local autoparts): amzn.to/3kRCSC7
➡OEM Mercedes fluid (if you want to refill after flushing with cheaper fluid): amzn.to/2TOLFIY
➡Mann h85 filter: amzn.to/3kTCliT
➡12mm wrench: amzn.to/3mQqhjf
➡Screwdriver: amzn.to/3mKs0X3
➡Rags: amzn.to/323gCh1
➡Jack: amzn.to/2HXcrfE
➡Jack stands: amzn.to/2GlLnGu
➡LED Bar light: amzn.to/2I1IOKq
➡Drain pan: amzn.to/34O8N0K
(These links may be affiliate links, which earn me a small commission at no additional cost to you if you choose to purchase from one)

[@trythistv]

All the stuff you need to do this: Power steering fluid (probably better deal at your local autoparts): amzn.to/3kRCSC7 OEM Mercedes fluid (if you want to refill after flushing with cheaper fluid): amzn.to/2TOLFIY Mann h85 filter: amzn.to/3kTCliT 12mm wrench: amzn.to/3mQqhjf Screwdriver: amzn.to/3mKs0X3 Rags: amzn.to/323gCh1 Jack: amzn.to/2HXcrfE Jack stands: amzn.to/2GlLnGu LED Bar light: amzn.to/2I1IOKq Drain pan: amzn.to/34O8N0K (These links may be affiliate links, which earn me a small commission at no additional cost to you if you choose to purchase from one)

[@dormantsuperhero]

Great videos, love the way George has to be part of it as well, Our old cats love hanging out in the garage, offering advice 😂

[@trythistv]

He's the brains of the operation for sure, Always has some input on whatever I'm doing, usually that I'm doing it wrong, and a nap would be time better spent. Some days I think he's right 😂

[@trixie9867]

George is so cute, so cuddly

[@trythistv]

He's gotta be included or he just screams at me! Best helper though! and the goodest boy.

[@danielporras9006]

What a great video, thanks for the info!

[@ebutuoyebutouy]

Thanks for sharing.

[@livin4today132]

I really enjoy your videos, well done,,always learn something new,,,thanks,,,

[@trythistv]

Thank you very much! I've got more in the works, got a few other random projects I'm finishing up and then I'll have some real whoppers of videos coming out

[@kuldipdhak7972]

Very good knowledgeable video

[@franklabbrador9279]

Thanks for sharing.......

[@DeltaStar777]

Great video, much appreciated!!!

[@trythistv]

Glad to help! Little maintenance points like this often get overlooked!

[@dieselbenzrevive6820]

i had no idea thanks

[@MrRjnr]

just did this today; ridiculously easy!!

[@trythistv]

Your power steering pump will thank you!

[@scottj12]

Very helpful video. Same deal on a W126 if anyone is wondering. The fluid kinda drip,drip,drips out but eventually gravity does its thing!

[@trythistv]

I figured it would be similar or the same, thanks for reporting that it is indeed the same on a W126. Turning the wheel one way or the other seemed to slightly speed up the draining on my car.

[@CatLady999]

I have a 1990 W124. My return line is weeping. and i have the ps filter ready to order. I was going to service ice the power steering fluid and filter as I re/re the return line. Going to visit my MB dealer, get a gallon worth, do all this at one shot.

[@chandima60]

10milian thanks.very good video.i am from srilanka

[@trythistv]

You're very welcome! Happy to hear these cars like mine are being loved and cared for all around the world!

[@bmpvw]

Excellent tutorial. Thank you!

[@stevesugulas9941]

Excellent video! Have 1982 W 123 SD 300 diesel; fix'n to duplicate, without cat. 450k miles. Thank you from Texas.

[@trythistv]

Without a cat how will you know if you did it wrong? Good luck with your maintenance, I'm about to do some more essential repairs on my car real soon.

[@stevesugulas9941]

My 90# GS will bark once!@@trythistv

[@stevesugulas9941]

Took passenger seat out so K'Moe can sit properly and get half out window. he rather ride than eat. Can see us coming a mile away with 40# head neck hangin out.@@trythistv

[@livium2002]

Thanks for sharing ! Didn't know about the drain plug. This is the asiest way to do it.

[@trythistv]

For sure! I've done them the "turkey baster" method before, and its a bit messy, while this way is absolutely foolproof. (as long as you remember to turn the wheel all the way to the left)

[@johnkahrs9706]

Thanks for this tip! Just did the drain-plug fluid change on my 300D- never would have thought to try this and really appreciate the guidance. (would have been struggling with a siphon for an hour had I not known). Used MBZ power steering fluid instead of ATF.

[@trythistv]

Good deal! I'm sure your car will thank you, and using any good power steering fluid has got to be better than the modern atfs in my mind, I figure I'll flush this a few times to get as much as I can out then switch to MB fluid in a while

[@secondopinion6654]

@@trythistv In fact, even at this late stage, Mercedes calls for using power steering fluid in these boxes. They used to indicate ATF and noticed an unusual number of these steering boxes wearing early. Alot of W123's have worn out steering boxes at 200,000 miles when they shouldn't. Part of it can be attributed to owners/mechanics using the adjustment on top of the box to reduce play in the wheel without getting the rest of the steering gear into spec. Here's an interesting upgrade. The steering box for 560SL's used both a 3.25 turn box, like the W123, and some got 2.75 turn boxes referred to as "quick ratio" steering boxes. The upgrade is they will 100% bolt up directly to the W123. Check years. For sure it mated flawlessly to a 1983 turbo diesel. It is EXACTLY 2.75 turns of the steering wheel from lock to lock. If it's ever time for a new box it might be worth chasing if the cost is similar.

[@trythistv]

Good to know that the spec has been changed, I constantly see people saying that the manual calls for atf and that's what they'll use and I know for certain that atf formulation has changed in the past 40 years from when that manual was written! Also very interesting tip on the 2.75 box, I'll have to keep my eyes peeled for one of those, that could completely change the feel of the car!

[@secondopinion6654]

@@trythistv They even accepted my W123 core. I assume for a rebuilder it's no different. Since you might be looking do a search for BAP:82-00116 Q3. The best reference number for general searching is just 82-00116 Q3 or 82-00116Q3 but the BAP takes you to a site with good info on part compatibility. I didn't buy from them though. I went on either eBay or Amazon because those sites favor the buyer if there's any drama. On most parts websites you're often at their mercy as to what they feel like honoring. The Q3 box feels great. I also switched to a direct swap Mercedes Sportline steering wheel which is a little smaller in diameter. It all adds up. These cars needed things like this back when they were being made. I still think that a great mod for all W123's is to add 2 more brake lights to the empty fog light sockets. Those plastic sockets just pop into place. Then just solder a wire to the adjoining brake light and you've got 4 brake lights coming on.

[@trythistv]

I'll be looking into that at some point for sure. I've been trying to figure out what steering wheel I could get that doesn't change the look a ton, but is smaller, as being 6'4" makes the wheel a tad close to my legs even with the seat all the way at the lowest and furthest back option. Do you know what yours is from? all I've found is wheels with airbags, $800 zebrano wood ones, and the aftermarket "racing" wheels that require adapters and such I'll take a peek and see if I can find the spare brakelight sockets, I recall seeing that idea somewhere and thinking that was a great idea!

[@vintage76vipergreenBeetle]

👍

[@faressh772]

Good jop

[@trixie9867]

@10:26 skip here for the best part 🐾

[@denisebetts27]

This was a super informative video, you describe everything perfectly. I just had my power steering pump/reservoir in my '82 240D replaced as it was leaking horribly. However, the "new" pump (well, new to me via Ebay) has my car making that kind of "hush" noise when you turn the wheel, and it just doesn't seem to turn as easily. Fluid seems to be holding steady, though--is there anything I should check out, perhaps a missing filter (I had no idea those suckers were down there at the bottom of the pump)? Appreciate your thoughts, and thanks! P.S. I have George's twin, Shadow!

[@trythistv]

I'm not super familiar with the pumps insides, I do know these are a rotary vane pump, so any air could cause some terrible sounds, or too thick of a fluid as well. I'd be curious to peek under the lid with the engine running, in theory it shouldn't make a mess, I had to bleed the power steering system on my very first Mercedes (a W116 1980 300SD) and did it by topping up the fluid while the engine was running, it spat a little when the air came out of the lines and was replaced by fluid but didn't really make a mess. If yours looks like its being whipped into a froth then something is askew, either air intrusion through a crack in a line or seal somewhere, or perhaps the fluid doesn't have the right properties? I'm not sure if I'm just rambling or if any of that will be helpful, hopefully the latter!

[@ZachAscot]

Thanks for the informative video, very helpful. Would a lack of fluid / filter change cause heavy steering? My steering is heavy. The steering belt was recently replaced and the tyres are fine. Best wishes!

[@trythistv]

It might. If it isn't getting pumped well, or has worn parts due to the fluid getting nasty and abrasive, or the filter is clogged up with grunge, it would restrict flow, which would make the power steering less effective.

[@brandon_duh]

Great video! Thanks for posting. I had a question about the pump position…is it required for the pump to be straight up and down? My power steering pump is slanted slightly left towards the engine.

[@trythistv]

The pump will rotate slightly depending on the belt tension and thus length of the belt. Nothing to worry about as long as the belt isn't slipping or overtightened.

[@Mrrefreshyourmind]

Great video, first I've heard about this. Do you know if the w201 also has a drain in the same location?

[@trythistv]

I think it should, but I've not personally checked.

[@user-jc7tc8qu5n]

Really helpful , i have w123 230 , 1976 , seems streeng box is same as yours but my car engin type is petrol would be so appreciated if share any link regarding my car ,unfortunately i dont have any even user manual 😏

[@trythistv]

It should be identical. The steering boxes were interchangeable between petrol and diesel models, some of the rarer ones had less turns lock to lock for a little quicker steering and only came on certain v8 petrol models, but are a popular upgrade for the diesel models. I think www.tonk.ca/models/w123/Index/115index.html should be what you need as far as a manual goes, If I'm correct you'll have a m115 engine, which looks a bit like a 617 or 616 with its SOHC arrangement and valve cover design. the M110 was very different looking as a DOHC engine.

[@LucianKel]

Great video. Thank you for sharing. I would like to be your neighbour, many afternoons would be lost under the car's....but we are to faraway.

[@trythistv]

No doubt! Its always fun to get some time to spend tinkering!

[@solsol1624]

Great stuff been meaning to do this a long time. Seen videos before ant they never mentioned the drain plug, is it on a 280ce?

[@trythistv]

It should be on nearly every Mercedes power steering box up until sometime in the mid 90s if I recall correctly.

[@solsol1624]

@trythistv thank you! Mine is 83, I'll be under it this weekend so will check.

[@trythistv]

I'm sure you'll have the drain plug.

[@dglenister]

1:08 Can George believe that all fluid drains out?

[@trythistv]

George said after doing a CAT scan on the power steering system, most of the fluid drains out, far more than just emptying the reservoir, but a little could remain in the lines and such. He also demands more cat food as payment for his services.

[@dylandog541]

Sweet little engine, is there a drain on the 300 sl 107, I will take a look

[@trythistv]

I'm fairly sure there is, I haven't had a 107 body yet though so I can't say for certain, but I do believe the steering boxes interchange so there should be.

[@allenying]

does anyone know if the crush washer is the same size as on the oil drain bolt plug?

[@trythistv]

I feel like it is smaller slightly. Its been a bit, but the oil pan is a 12mm thread size, and I feel like the power steering drain is like a 8mm or something. I'm not confident at all in those, hopefully someone can report back when servicing their power steering system!

[@westhavenor9513]

Lol black cats are perfect for working on cars. I had a white one once and the poor fellow always ended up with black smudges on him!

[@trythistv]

Sometimes George shows up with oil or grease all over him and I have to go on a hunt for what has started leaking, or where is there grease that he could rub on, and with the equipment and boats we work on, theres always something dirty for him to get into 😂

[@ЭтоДрючинский]

Woooow! How can your diesel be SO QUIET? How did you achieve that?

[@trythistv]

... Mostly because I turned the volume down when I made the video, past that it sounds like about every other decent running 617 I've heard, whisper quiet compared to my cummins work trucks, but significantly noisier than a modern gas or diesel engine. Sorry to disappoint, no secret for silencing a 617 that I'm aware of I'm afraid

[@michaelarmellino8334]

Is it fine to put power steering fluid or should I put ATF dexIII as I believe the manual says?

[@trythistv]

Getting actual dex3 is basically impossible now, the modern "dex3 compatible" formulations have changed from what the original fluid was and often have friction modifiers and other additives that can increase wear in the pump and steering gear, I choose to run standard power steering fluid that is clear and have had no issues yet over thousands of miles, only time will tell for sure, but ATF is not the same as it used to be for sure.

[@combosucks]

The FSM uses the term ATF, but it actually calls for fluids which are MB standard 236.3 compatible-most contemporary fluids compatible with this standard are power steering fluids. Like most fluid guidelines for Mercs, it is the standard, not the title you should be concerned with as far as compatibility.

[@bikeman123]

I tried to do my w123 230e today. Its got a full mercedes service history and guess what? No filter and no spring, boy am I pissed. Anyway, turned left full lock and it took an age to drain. Not easy to refill despite turning wheel, the pump howled for a bit. I tried starting the engine and the oil whipped up into a foam and spewed out everywhere.

[@trythistv]

Well that's not a very nice surprise!

[@MrRjnr]

Is the jack placed under the cross-member that's behind the oil pan?

[@trythistv]

Yes, it's very important to jack up the car somewhere safe, that crossmember is a good solid point that won't damage the oil pan or other stuff, I also used a couple jack stands on the control arm mount points as those should be plenty solid as well. I had a W124 Mercedes fall off a jack and nearly crush me a few years ago, changed how I lift vehicles forever.

[@MrRjnr]

@@trythistv wow, ok thx!

[@muhdaminuabdullahi8601]

I have drained the fluid but i there is no filter and even after refilling the pump resevoir the steering is still stiff. Get me thinking maybe the pump is dead. Any idea pls. Thanks

[@trythistv]

I thought I'd responded to you, But its not showing that I did. Weird. Must have mentally responded and didn't actually type anything. Some early pumps didn't have a filter, but you can put one in I believe. Also, double check that you got all the air out, I have had weird issues with entrapped air in power steering, but you may be right, the pump or steering gearbox may be on its way out.

[@muhdaminuabdullahi8601]

@@trythistv thank for the reply. Any suggestion about online store that sells w123 parts that ships to Nigeria? Cos getting good or new parts here is near impossible. As always thank you for taking your time to educate us.

[@Heve62]

Wonder if this could be done the same way in a w126 300se

[@trythistv]

I do believe the steering boxes are very similar if not the same, I would highly suspect it would be nearly identical. I've not done as much with the W126 bodied cars, nor the gasoline engines, but there is a ton in common between your car and mine.

[@Heve62]

@@trythistv thinking the same, jist havemt seen any videos/topics about doing the fluid change this way. The box may also be in a less accessible placement

[@Altanox]

what is a safe way to work under the car? Should i press very firmly on the parking brake? Or should i put the car in gear?

[@trythistv]

Either one would be sufficient, I would do both just for extra safety while under your car, and ensure it is raised in a safe way too, ramps or jack stands with extra safety like putting a block of wood under the car or such, I had some jack stands fail on me a few years ago and it absolutely terrified me, I'm very lucky that it wasn't far worse.

[@Altanox]

@@trythistv Damn.. I guess you can't be too sure... If you don't mind, i would like to ask you one more question. My first gear and second gear (manual4w123) feel a bit hard compared to 3th and 4th. I have to be strong and slow to shift smoothly (does that make sense? weird to explain), I really hold and slide the gearknob along the outer left side to have a smooth shift. Otherwise it's abrupt and clunky. Do you think it's bushings inside the gearbox or what they call shifter bushings under the car? Thank you for the amazing videos, i'm 26 and learning a lot

[@trythistv]

@@Altanox Sounds like your Syncros are geting worn a bit. I swapped a 4 speed into my Grey 300D, and 2nd is a little crunchy if you don't shift it just right. Probably yours has a little more wear and 1st gear syncro has started getting a little worn too. I probably should have made a video about the swap or at least should do one now about the car in general but I have focused on the blue car a lot more.

[@Altanox]

@@trythistv synchos... I don't know what that is. Does it mean somthing inside the transmission that I won't be able to easy DIY? Damn it... :D

[@trythistv]

Yeah, I have not dared dig in that deep, from my understanding they are made of brass and attach to the gears and make contact to slow down or speed up the gears when shifting. The better you can get at rev-matching shifts the less work the syncros have to do, and if you're real good at it, you can shift a transmission that has bad syncros without crunching or grinding. I am not that good at it.

[@deuvanas8008]

My power steering fluid has been leaking since i got my w123, basically the only problem. I cant see where it leaks , any ideas??

[@NouveauxReis]

There is a gasket between the pump reservoir and the pump itself. Take a look on the back side and replace as needed

[@trythistv]

I've seen hoses weep ever so slightly, you should be able to locate the leak if you clean it all real well, or look for a clean spot somewhere, if there is a patch of clean on or around the pump and hoses, that is likely the source of the leak

[@note_finger]

how much fluid did you use?

[@trythistv]

It seemed like a little over a quart per flush, I flushed it a few times, ended up using just under a whole gallon, the fluid looks fairly clear now with just a slight reddish tint. Cost me less than $30 for the filter and a gallon of the PS fluid

[@MartinLopez-ys5dm]

Didn't you defeat the purpose of the filter when you lifted it out the reservoir? (Removing reservoir cover, draining fluid while filtering old fluid from going thru the pump and then removing discarding filter...)

[@trythistv]

Perhaps slightly, there shouldn't be much if any debris in the ps system, and most any of it would have gotten caught in the filter, either way it's better to get that ancient fluid out

[@MrRjnr]

how often should this be done?

[@trythistv]

It is not specifically listed in the service manual that I can see, but I would check it at each oil change, personally I'd change at around the same interval as ATF, 30,000 miles or maybe a little longer with a good quality synthetic fluid, or when I notice it starting to look dirty or smell off.

[@MrRjnr]

@@trythistv ok, thx!

[@MrRjnr]

so any PS fluid will do?

[@trythistv]

Right, any decent power steering fluid is going to be nearly identical to what the old ATF that was recommended back in the 70s and 80s was, the new ATFs all have additives to add friction, which isn't ideal in a steering box, wears parts out super fast

[@MrRjnr]

@@trythistv cool, thx....how much fluid comes out with draining it that way? I'm going to buy 1 gallon of Prestone, & am wondering how many drainings I'll do to use it all up. (old fluid looks very dirty)

[@trythistv]

@@MrRjnr I got somewhere around a quart, maybe a hair more out, you should be able to get at least 2-3 good flushes with a gallon I would think

[@MrRjnr]

@@trythistv cool, thx

[@kuldipdhak7972]

Very good knowledgeable video

[@trythistv]

Thank you very much! I appreciate the kind comment!