1984 Mercedes 300SD W126 - Front Hub, Bearings, Wear Sensor and Brake System Rebuild Finished

#impalamansgarage1
Bearing and bearing race removal and replacement. New rotors, pads and brake wear sensor cabling. The brake calipers (Bendix calipers) were rebuilt in the previous video. This car does not have anti-locking brakes. It was optional in 1984.
Notes:
In the video I stated that I packed some extra grease down in the hub before inserting the outer bearing. There is really no need to do this. There is no advantage in having extra grease inside the hub BETWEEN the inner and outer bearings.
Yes one of the rubber caps is missing from the brake reservoir.
Parts:
Brake Disc - Zimmermann 1264200005
Wheel Seal - Corteco 12012696B
Brake Pad Set - Pagid 0004205920
Brake Pad Wear Sensor - Genuine Mercedes 1265408107
Brake Pad Wear Sensor - Genuine Mercedes 1265408207
Brake Pad Wear Sensor (230 280E 300D 400E) - Genuine Mercedes 1405401217
Brake Hose - Corteco 1294280035
Timken SET3 Bearing Set
Timken SET5 Bearing Set

[@robertdurff1490]

Just wanted to say thank you for your video! I'm doing my bearings and rotors on my W126, and having your example as a reference has been super helpful.

[@LizpolygigiBG]

I’ve had two ‘79 f-150s that I do almost every repair job on myself. Picked up my first Mercedes, a 1990 560sel and although they are new to me my intention is to keep this one running myself too. Starting brakes today... this is a good video and I like your channel... liked, subbed, thanks.

[@ImpalamansGarage]

It's a mixed bag on ease of repair. Some things are like falling off a log but others are quite challenging due to age related problems.

[@DinahIsMyGal]

Thank you for making this video. It helped me realize I can do this myself. I watched a couple other videos and resigned to thinking I would just take it to somebody who had the right tools. After watching you do it and your methods I am confident I can do it. 1986 300SDL

[@ImpalamansGarage]

Go slowly. If you're not sure about something, research the issue and ask questions.

[@onariff]

Hey just wanted to say thank you. Just completed all new rotors, pads, shocks, bearings on my 1990 420sel. Watched, studied and followed your vids. Thanks for making it possible!!!!

[@ImpalamansGarage]

Thank you!

[@cal48koho]

nicely done with some nifty tricks like using the old races. Lots of forum discussion on whether to use a dial indicator or not. Some do, some don't mercedses does. I think I will try both methods. I have always done it old school like IM does here. One thing is certain. Too tight on the spindle nut is bearing failure.

[@ImpalamansGarage]

In the video I stated that I packed some extra grease down in the hub before inserting the outer bearing. There is really no need to do this. There is no advantage in having extra grease inside the hub BETWEEN the inner and outer bearings. Also putting extra grease in the dust cap is useless as well. LOL..... No need to do this either.

[@greenagoo]

Your channel is a godsend. I just started tearing down to do the front steering and suspension, and decided to do bearings and rotors while I'm in there just because. Nice to know the hub and rotor bolt together like that. I was trippin trying to look for parts lol.

[@ImpalamansGarage]

Thank you for the kind words and good luck on your rebuild!

[@dlwst44]

Top notch quality work!!! Definitely will use this video when I need to do mine.

[@Davran2742]

Using the old race to drive in the new one is old-school smarts :)

[@ImpalamansGarage]

Works on Chevys. Why not Mercedes. LOL

[@Davran2742]

Showing how to adjust a steering box correctly would be another good video. Few people seems to know how anymore and buy new/rebuilt ones, when being adjusted properly is often all that's needed.

[@ImpalamansGarage]

Agree. Good idea foe a new video!

[@Davran2742]

@@ImpalamansGarage -- When I bought my '84 manual-trans Benz 240d, the steering was so sloppy, and it was so slow, that other people wouldn't buy it. I immediately adjusted the steering box (on benzes the adjusting screw gets turned out to tighten, unlike every other manufacturer), and after adjusting the valves and replacing both fuel filters and air filter under the hood, it was like a different car. Fuel tank screen is next.

[@drewkeenan1]

Great video! Relieved not to use a press...dont have one anyway.

[@ImpalamansGarage]

You can pick up a small one at harbor freight for a reasonable price. It's fine for occassional use but for every day work a better quality one is needed.

[@marjangeh]

excellent again and again. Tnx.

[@matan6737]

Thanks boss. Big help. Too many videos talking about a dial gauge. Sometimes a hoss doesnt have time for that shit.

[@wernerdanler2742]

That spindal nut was so tight on the threads on my 85 300d that I had a hard time turning it off and back on even with the lock bolt loosened. I ended up overtightening it after replacing the bearings and eventually after a few months I burned up the bearings and swole the hub on the left side but managed to sve the right side, and had to replace the whole left assembly. Wish I had never thought about replacing the bearings when doing the brakes.

[@ImpalamansGarage]

On most cars an initial tightening followed by backing off and hand tightening works well. If your locking nut was difficult to remove, you can pry it open just a little with a screw driver since it has a split in it. The mercedes manual says there is supposed to be a little end play although I cannot recall what it is without looking it up.

[@wernerdanler2742]

@@ImpalamansGarage I actually tried that and it is so solid on the 85 that it would not budge. It looked like a pretty solid block of steel that had been machined. The main problem of course was me simply overtightening it. I don't know what possessed me to keep cranking it down on the spindle. Oh well. I no longer have that car but actually wish I did. It had a lot of miles on it but I had fixed it up and it ran like a top.

[@DScottDay]

I followed your path and now, at the point of putting the completed hub and rotor back on. It seems like you hand press the whole assembly snugly home on the spindle, and then, after checking the outer bearing, use the locking nut to snug it all up. My question is: Is the locking nut actually pulling the inner bearing into position on the spindle? I have a full quarter of an inch still to nestle the inner bearing (and the whole hub) far enough IN to be home. Am I missing something? I feel like I need to smack the whole assembly at least 3/16th" before asking the locking nut to achieve the final 1/8". To ask the locking nut to pull it a full quarter inch seems be asking too much of the locking nut. The sound ring should just barely clear the electronic reader, right? Like no more than 1/16th"? I feel like I need to seriously shrink the diameter of the spindle under the inner bearing to fit on it. Before I complain to FCP that they sent me the wrong bearing, let me ask for some clarification:how tight should it be before any locking nut effect? Thanks, Doug Day, Rockport, Maine

[@ImpalamansGarage]

The bearings should be a snug slip fit over the spindle. Sometimes it can be a little stubborn and might feel like it is sticking. That happens. When it does, back off, wiggle it, spine it.... try again. You could also just take one of those bearings by itself and try to slip it over the spindle to make sure they are in fact correct. The locking nut is used to set the bearing preload, not to pull the assembly onto the spindle. The hub assembly end play is .01mm to .02mm (.0004 to .0008), which is a little less than one thousandth of an inch. To take the measurement place a dial gauge on the rotor (magnetic base) with the measurement taken from the end of the spindle. Here is the procedure. drive.google.com/file/d/1fjMYZiPJqBgWFJKRFSdHJJFNIaAq398R/view?usp=drive_link

[@charlestimmis273]

Great job. I'm about ready to change my bearings. Two questions. When you are punching out the races. How do you make sure you don't kink the hub wall? Also do you put grease on the whole inside of the hub, where the races sit and else where? Thanks much...

[@ImpalamansGarage]

If you slip and nick the inside of the hub with the punch, really it's of no concern. Nothing that is moving touches that part. But be careful nonetheless. Sloppy work is sloppy work. LOL Use a flat-ended punch. This old fashioned method of removing a race can be done on all makes of car. Really there is no reason to pack the hub full of grease in the void between the two bearings. If you put too much in there, as heat builds the grease will ooze out of the dust cap and make a mess on you wheel. It won't hurt anything but it will make a big mess as you drive. Just put a moderate amount in there. Of course pack your bearings well. That is the most important part.

[@charlestimmis273]

@@ImpalamansGarage Thanks the reason I asked, is some people say install races first (no grease), then grease bearing and race and hub...

[@charlestimmis273]

@@ImpalamansGarage I guess the reason could be if the bearing failed and got stock the race would not turn and damage the hub. But in this case it would probably turn on the spindle, not sure which one is worst...

[@ImpalamansGarage]

A bearing race is a press fit but it's not THAT tight. If it were you'd need a press. In retrospect I think applying a film of grease before installing the race really does little if any good. Sometimes a race will spin in the bore and I think that is caused by either corrosion or heat.

[@ImpalamansGarage]

When a race does spin, you have to stake the inside of the bore prior to installing the new race. This happened to my right rear wheel on this car. I made a video on replacing it and I staked the bore and also used a compound to help keep the new race in place. Check out the rear wheel bearing video. That one was a challenge.

[@123works]

Video Well Explained thanks very much

[@ImpalamansGarage]

Cool! Thanks for stopping by!

[@johnbower5732]

Where did you order the new brake wear indicator cable from, and the new soft brake lines?

[@ImpalamansGarage]

The part numbers are in the video description. I use fcpeuro, pelican, autohausaz, rmeuropean, ecs tuning and parts geek mostly. One of those usually has what I want.

[@bmpvw]

What happens if the seal goes in and is flush with the hub? Mine bottomed out flush with the hub. Should I continue? Help!

[@ImpalamansGarage]

Well every car is a little different to a degree. I would stop where you are and continue with your work.

[@bmpvw]

@@ImpalamansGarage Thank you. I think I will continue with it as it is (flush) because I've also come across directions for this job that say to tap it in evenly till it is seated all the way (or bottomed out) and there isn't any mention of it needing to be up to an 1/8th inch above the lip of the hub. I hope I'm not screwing this up. First timer.

[@ImpalamansGarage]

@@bmpvw Yeah just follow the directions. No worries.

[@ImpalamansGarage]

I was expecting mine to be flush actually but I bottomed out everything and the seal was still slightly up. It will work fine as long nothing is cockeyed. That would be bad! lol

[@bmpvw]

@@ImpalamansGarage Ok good, it's definitely not cockeyed...it's in there evenly all around ..just flush. Thanks again!

[@Davran2742]

Did you make a video of replacing the rear wheel bearings on your Benz wagon? I looked through your videos and didn't see it.

[@ImpalamansGarage]

No I left those alone. Hopefully it will not come back to bite me later!

[@tisoy909]

Thank you!

[@igoriakoven3665]

Thanks!

[@sas8403]

I have just done my front bearings when i spin the disk i get a very slight hum i s this normal

[@ImpalamansGarage]

Well I suppose it depends on what you mean by a "hum". When you turn the brake disk the amount of noise you should hear should be analogous to lightly rubbing your hand over your T shirt. I would not categorize this as a "hum" however. More like a rush of air. If you hear a low pitched hum, i would say they are too tight.

[@sas8403]

@@ImpalamansGarage yes its a light sound even if i loosen the nut the sound is still there when i spin the disc

[@marjangeh]

cool

[@رافعليث]

❤

[@Tigerfire75]

I got a baring a race tool from Harbor Freight

[@ImpalamansGarage]

That will work just fine.