Title: How to fill the rear differential?
Post by: paul on October 30, 2008, 04:22:57 PM
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Hello
My 1st post here. I'm helping a friend with his 1951 170s Cabriolet. The axles boots were just replaced and I wa wondering what is the best method to fill the case with oil. Is it filled through the breather hole at the top of the case? or is there another access point my manual does not show much.
I was told 85w-90w should be fine for the gear oil is this correct?
Thank you
paul
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Title: Re: How to fill the rear differential?
Post by: Charles Adamson on October 30, 2008, 07:54:03 PM
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There should be a bolt on top of the diff. The bottom of the rear seat needs to be removed for access.
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Title: Re: How to fill the rear differential?
Post by: Stephen Dietrich on October 30, 2008, 09:37:41 PM
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And of course, there is the special tool used to open the access at the top of the case.
Title: Re: How to fill the rear differential?
Post by: John Ellis on October 30, 2008, 10:24:08 PM
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Back in 2004 I wrote an email to George Murphy, the technical director of MB Club of America, regarding current lubrications for our our era cars. Here are my questions and his reply:
Quote
I own a 1953 Mercedes 170Vb and looking for information about what current lubricants and oils are best for my vintage car. The following are the original specifications that are part of the service manual, but obviously some of the lubricants are no longer available.
Today's lubricants are much improved over what was available in 1953. I have a 1960 MGA which thrives on modern lubricants as opposed to the OEM 1960 recommendations. My experience with vintage cars of all marques is that the old cars will never suffer a lubricant-induced failure when maintained correctly. With that in mind here's what I would do if I had your car:
Engine Oil - normal or premium oil SAE 30
2005: Dino oil: any good brand - Pennzoil, Castrol, Kendall 10w-40 all give good cold start lubrication.
Synthetic: Mobil-1 20w-50 - not necessary to go down to 5w or 0w as you will probably not be driving the car in sub-freezing conditions
Water Pump Lubrication - Mobil Compound No. 5W; Renolin 2
2005: Shaft lube: EP gear oil 85w90
Seal lube added to coolant: There are several WP lubes available - Justice Brothers brand is used by many antique car owners and my local MB dealer.
Browse your local auto supply store for a good brand of WP lube . . .
Generator - Bosch oil 1 V 13
2005: Same oil as used in the engine would serve well . . .
Rear Axle - Shell transmission oil HDL; Mobiloil CW
2005: Any good brand of EP gear oil SAE 85w90 - I use Castrol or Kendall or Pennzoil or Redline or Mobil-1 synthetic.
Transmission - Shell transmission oil HDL; Mobiloil CW (?)
2005: My 1953 owner's manual calls for Shell Donax T-6 - which is an early ATF. My MB shop manual calls for ATF in the MANUAL transmission. Most MB manual transmissions use Dexron II or III ATF because the tolerances are so tight compared to most cars.
Steering - Shell transmission oil HDL; Mobiloil CW
2005: same as rear axle
Front Wheel Hubs - Mobil Compound No. 5W; Renolin 2
Use MB WB grease part # A001 989 23 51 10 - $6.50 per 150gr tube from me, be sure to observe MB shop manual procedure for bearing service. - see your owner's manual for quantities to be used - here's how:
Here's a few things to consider:
First, get the MB Chassis manual for your car so you can do the job right.
In my experience, the grease should be changed at the 90,000 mile service - I found my OEM grease was getting a little stiff by this mileage.
Use MB wheel bearing grease part no 001 989 23 51 10 or a good grade of lithium high temperature bearing grease - Kendall Blue comes to mind. Of course, buy new inner hub seals.
Pull a bearing cap and look at the grease - if it is stiff and wax-like, it is long past time for bearing re-pack. Anyway, I do bearing grease at 90,000 miles interval (third 30,000 mile service) since MB now uses that new green high temp grease in all cars since 1986.
If your bearings are OK, but if the hubs are coming off anyway for rotor change, change bearing grease and install new seals. Thoroughly clean the hub and bearings of ALL old grease. DO NOT SPIN BEARINGS at high speed with air gun to dry them - be gentle with the air. Some mechanics like to have fun by making that high pitched whine using compressed air to spin and dry out cleaned bearings - it is really hard on the bearings to do that.
If you are changing the bearing races, here's the easy way:
After cleaning the hubs of all grease, put them in the oven for one hour at 250-300 degrees F. Place the bearing races in your freezer the night before doing your bearing work.
When the hubs come from the oven, use a long drift to drive out the old races from the hubs. The new frozen races will practically drop into the warmed hubs with little force. Make sure the races are seated all the way around the groove they fit into.
Next, pack bearings by hand with MB grease - save all excess - weigh out correct # of grams and pack it into hub IAW the MB chassis manual. There's a reason for the specified grams of grease for the bearings and inside the hub. Too much leads to overheating and too little starves the bearings of grease. The grams specified for inside the hub and the bearings just fills the hub cavity such that centrifugal force during rotation forces the grease outward in both directions to continually pressurize the bearings and keep them lubricated. It has been shown that the grease actually "circulates" inside the hub and through the bearings to keep them lubricated - that's why properly-lubricated MB front wheel bearings can last so long, and that is the reason for that 45 grams of grease.
Use the rest of the grease to fill the hub cap. In this manner the inside seal stops the grease from leaving the bearing due to centrifugal force, and the cap, being full of grease, keeps the grease inside the hub/bearing area.
The 150 gram tube of MB grease will do both front wheels - about 60 grams per hub plus 30 grams for bearings - simply follow the MB factory chassis manual procedure.
Here's data from TD Manual:
For a 150 gram tube of MB wheel bearing grease, here's how it breaks down:
(From TDM Section 33 - All weights are approximate)
107, 124, 201.03 models: total 65 to 70 grams - 50 in the hub with bearing;15 to 20 in the hub cap
116, 123, 126: total 60 grams - 45 grams in the hub; 15 grams in the hub cap
201.02/1: total 50 grams- 35 grams in hub; 15 grams in the hub cap
your 1953 MB: book says 4.2 oz (115 grams) in the hub after packing the bearings - put excess in the wheel bearing cap
Be sure to maintain the specified charge. Suitably weigh entire charge prior to starting assembly of front wheel hub. Weigh quantity filled into hub. Fill roller cage of tapered roller bearing well with grease. Also provide roller faces with grease. Fill hub cap approx to beaded rim.
Starting 12/88 all models use 150 gram tube - green grease part no. 001 989 23 51/10
DO NOT MIX GREASE TYPES - unexpected results may occur.
As to setting the free play, certainly the dial gauge method is preferred.
Here's how I did it on A 107 before I bought a dial gauge: (N/A for 126 and those w/o washer)
Re-assemble the washer and adjust nut and tighten it about 25 to 30 Nm while spinning the wheel. Back off the adjust nut just enough so that you can barely rotate the washer behind it by hand - that should be as close as you can do it by feel. Tighten the lock bolt and check that the washer can still be rotated by hand - it should be a little stiff, by movable.
If you replace the bearings and races, you should repeat the above after a few hundred miles to assure that adjustment is correct. I've always had to re-adjust after bearing race change, so plan on doing it anytime you replace bearings and races. . .
Central Lubrication - Engine Oil (?)
2005: MB manual says to use same as for rear axle - SAE 85w90 gear oil
Hydraulic Brakes - ATE 1000 Original (ATE blue)
2005: I use ATE Super Blue alternated with Castrol LMA each change so I can see color change when fluid is flushed every 3 years
Distributor - Bosch grease ft 1 V 8 - where? On the bearing or rubbing block?
2005: Dist bearing - engine oil ... Rubbing block - any good chassis grease - Kendall Blue is good
Let me know if you need any more info . . .
Regards,
George Murphy
MBCA Technical Director
