Rear axle failure w123 - PeachParts Mercedes-Benz Forum

macdoe · #1 09-08-2012, 06:28 PM

Hello, I have ALMOST certainly determined the rear drivers side axle is failing, but am not 100% sure. I was wondering if someone might know how to tell if the axle is bad?

macdoe · #2 09-08-2012, 06:34 PM

I just thought of another thing it might be but I sure hope it is'nt. There is a bearing that is just behind the axle seal on the diff. It is a large bearing. I wonder how common it is for that bearing to fail? If that bearing has failed then I would probably need a new differential. How to test that bearing? I had a full diff meaning that I had not had any fluid leaking out of the diff, so it is not like it was starved for oil. This car is our 1985 300TD with 568,000kms.

barry123400 · #3 09-08-2012, 06:37 PM

Possible of course as are many things. I would first of all drive the car a few miles and either feel the wheel temperatures carefully or use a temperature gun.

Dragging brakes are quite common. The rim will rise in temperature if the individual one is. Try not to apply the brakes when stopping as this gives false results. Just coast to a stop.

Your overall milage is quite high so choices are greater. I can see no way a badly worn cv joint especially one not clunking can affect slowing down by producing an additional dragging effect on the highway.

macdoe · #4 09-08-2012, 06:52 PM

I have actually been keeping an eye on the temperatures of the wheels with a laser temperature gun for the last few days. I get about 32 degrees celcius at each wheel, give or take 1 or 2 degrees. That is actually aiming the laser through the holes on the wheel and the laser beam on the rotor disc itself. I have moved the laser closer to the hub with not really any increase in temperature worth considering.

I am with you Barry, in that I originally thought I had a dragging caliper or an intermitant collapsing brake hose, but I can easily push this thing back and forth in the garage with one hand. It seems like it occurs at higher speeds, now that could still be the brakes I guess but it does not explain that skipping type of feel I get when turning the hub by hand with no brake assembly on the hub. The other axle does not produce this skipping feel when turning it by hand...and having such even temperatures on the gun leads me to rule this brake thing out.

I guess I could throw this other axle in and find out for sure, but this is messy and I would rather not have to open the diff up again and would like to rule out anything with regards to the diff before I seal it up.

Thanks

macdoe · #5 09-08-2012, 07:01 PM

Got any temps. of your rotors after a drive with a temps. gun? I am curious to compare? I have the big brake upgrade on the front of this one. Vented rotors and matching calipers off a 1988 420 sel.

t walgamuth · #6 09-08-2012, 08:50 PM

I thought it might be a cv joint. The axle should slide back and forth but not up and down.

If it clunks if moving from forward to reverse is also a sign of cv failure.

Stretch · #7 09-09-2012, 02:56 AM

There's a good video made by Kent over on mint sauce for checking axles - I think you can also find it on youtube too.

macdoe · #8 09-09-2012, 05:36 AM

O.k Thanks guys...It is all put back together now and seems to be a bit better on initial testing by hand. I am going to wait for the silicone to dry overnight and then fill it with oil and check it again.

I guess I made it confusing as I meant that the shaft between the joints moves back and forth when pushing/pulling it towards the diff and the hub and not up and down on the suspect axle. I think they are suppossed to move a little but I am wondering if movement as much as this one does is normal. With the other axle installed I cannot push or pull the shaft at all which makes me think it is not a normal amount of movement on the suspect axle.

As I was under cleaning stuff up for the reseal I noticed quite abit of old oil with a crust of light dust over top that I had to scrape off. I did not notice it before cause of the dust on top which camoflaged it. I think something has sprayed the oil out and it is not the diff cause it was completely full before I started. I think I may have lost all the oil out of one of the joints on that possibly bad axle which may explain alot. I will check that explaination on axle testing
Thanks.

gatorblue92 · #9 09-09-2012, 08:37 AM

Quote:

Originally Posted by macdoe

O.k Thanks guys...It is all put back together now and seems to be a bit better on initial testing by hand. I am going to wait for the silicone to dry overnight and then fill it with oil and check it again.

I guess I made it confusing as I meant that the shaft between the joints moves back and forth when pushing/pulling it towards the diff and the hub and not up and down on the suspect axle. I think they are suppossed to move a little but I am wondering if movement as much as this one does is normal. With the other axle installed I cannot push or pull the shaft at all which makes me think it is not a normal amount of movement on the suspect axle.

As I was under cleaning stuff up for the reseal I noticed quite abit of old oil with a crust of light dust over top that I had to scrape off. I did not notice it before cause of the dust on top which camoflaged it. I think something has sprayed the oil out and it is not the diff cause it was completely full before I started. I think I may have lost all the oil out of one of the joints on that possibly bad axle which may explain alot. I will check that explaination on axle testing
Thanks.

The boot may have failed at some point in the past and was just replaced. If the boot does fail then the joint will get road dirt inside and kill it even if it is rebooted. Sounds like its time for new axles. Not a fun job but not too bad either.

t walgamuth · #10 09-09-2012, 10:04 AM

If the boot is good and the bearing or cv is good the grease can be added with a needle fitting on the grease gun.

I would be concerned about the axle which will not move back and forth.

macdoe · #11 09-09-2012, 12:28 PM

Quote:

Originally Posted by t walgamuth

If the boot is good and the bearing or cv is good the grease can be added with a needle fitting on the grease gun.

I would be concerned about the axle which will not move back and forth.

uhoh, so I may have just installed a bad axle? I don't know, it feels smoother when testing it by hand. I''l try moving it again... I was weak last night.

I was going to use this synthetic AMSOIL 75W-90 gear lube. What does the book call for? Anyone else tried it?

What type of oil is needed for the boots? Would a person be able to use something like a needle and then fill the hole with silicone? I wonder how much oil in those boots? Thanks

macdoe · #12 09-09-2012, 12:35 PM

Quote:

Originally Posted by gatorblue92

The boot may have failed at some point in the past and was just replaced. If the boot does fail then the joint will get road dirt inside and kill it even if it is rebooted. Sounds like its time for new axles. Not a fun job but not too bad either.

Funny you should mention this. The axle on the good (pass.)side looks to have been rebooted at some point. The side I am having trouble with looks to be oem and never touched. The boots are very dry and cracked. I could not see any cracks all the way through but that does'nt mean they are'nt there...I just can't see them.

The oil/dust film came from somewhere and the SLS is not leaking and like mentioned the diff was totally full....as soon as I pulled the fill plug oil came out. ....The more I think about it the more I think maybe one of the boots ran dry. My next question is....how long have I been driving it this way?

macdoe · #13 09-09-2012, 12:38 PM

So, if a guy was to fill a boot with oil does the oil travel through the shaft to the other boot or does each boot get filled separately, meaning a hole in each boot? I never took one of these "to bits" Thanks.

charmalu · #14 09-09-2012, 01:57 PM

Iam using the Amsoil 80w90 in all my vehicles differentials, and in the Datsun`s 5 spd trans.

You are way farther north in the cold, so the 75w90 should be good.

Charlie

macdoe · #15 09-09-2012, 02:59 PM

Quote:

Originally Posted by charmalu

Iam using the Amsoil 80w90 in all my vehicles differentials, and in the Datsun`s 5 spd trans.

You are way farther north in the cold, so the 75w90 should be good.

Charlie

Good news... Yes, I thought the synthetic would help with the colder weather this coming winter, I had it in my Mustang years ago as well as their ATF for the 5 speed. I could shift that thing with my little finger.
Thanks