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Braingears
Expert
Date registered: Apr 2006
Location: St Petersburg, FL
Vehicle(s): G320 & ML320
Posts: 1450
| High Velocity Grease
Several weeks ago, I replaced the CV-Joints on the short shaft between the transmission and the transfer case. The transfer case (and the entire truck for that matter) was shaking like hell while accelerating. After I replaced the shaft / joints, everything was smooth again. Whenever I replace parts (especially if another shop does it), I always ask for the dead parts back! When the drive-shaft shop replaced the joints, they commented that it appeared that the grease was "washed out". Tonight, I put on my dirty shirt, and inspected the older CV-Joints. I was shocked to find that all of the grease was actually in there (throughout the entire CV-Joint). It was all dried up and very hard, almost flaky. I could not feel any true lubricating properties left in the mass that was formally grease. I could not smell any burnt smell either. It started to make me think. If the grease was still grease, I probably would not have had to replace the CV-Joints. It has also made be think about all of the other bearings and joints (especially the propeller shafts, and CV-Joints in the front axle). Anything that builds up with heat and has this type of constant velocity is going to be subject to the same issues. What specific grease holds up best in these conditions? Is synthetic best? Does one hold up better against water intrusion? Should I use a different grease for each of the different components?
Wheel Bearings, Knuckles, UV-Joints, CV-Joints, etc.... On parts like CV-Joints; should we inject newer grease from time-to-time to prevent stuff like this happening? I know I've asked a lot of questions... do any of you have any good recommendations? |
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Braingears
Expert
Date registered: Apr 2006
Location: St Petersburg, FL
Vehicle(s): G320 & ML320
Posts: 1450
| RE: High Velocity Grease
Here is a picture of one of the ends...
 (CVJoint.JPG)
Attachments
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 CVJoint.JPG (123KB - 1 downloads)
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: High Velocity Grease
C/V's usually are set up with a Moly based grease I believe. When I did my swivel balls and wheel bearings I used Redline full synthetic C/V grease thinking that if there is cross contamination the grease in there will work for all of the purposes; lubricating the C/Vs, the king pin bearings, lubricating the wheel bearings and keeping the water out of the housing. There are a number of other products out there and some pretty interesting industrial greases that are capable of a wide range of applications. I think Dave Gomes used a type of boat trailer wheel bearing grease in his swivel balls to keep out the water and that makes a lot of sense.
I have used Hydrotex MTP Ultra in some things and I think it is pretty great stuff but I don't know if it will live in a C/V joint. In the prop shafts I use two diffferent greases because the guns have different tips. I use a Valvoline moly based wheel bearing grease in one of them and Redline grease in the other. I don't mix the grease and kind of look at it as a long term experiment to see what if any difference there is on bearing life.
I have just replaced a C/V shaft on one the TD's because the boot failed after 370,000 miles. Original C/V's with the factor grease. The C/V didn't fail, the boot did and it was less expensive to replace the entire shaft than the labor and parts would have been to repace the boot! I guess that some factory fill grease can last an incredibly long time and keep a C/V alive. There are those who run C/V's in the G housing without a boot.
Has anyone injected extra grease into the C/V boot with a needle from time to time to freshen up the goo?
-Dai |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: High Velocity Grease
Chuck,
I didn't see the photo and I think you posted it as I was writing the response to your first post. It looks to me like there must have been some moisture that invaded the C/V because there is rust present. A joint that is well sealed will not have rust inside. I bet moisture caused the failure by mixing with the grease and destroying it's lubricating ability. I have seen this with sealed type bearings on farm machinery. Water gets in and compromises the grease. I really think that C/V was killed by moisture based on the photo. My opinion.
-Dai
Edited by dai 2/26/2007 1:51 AM
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Braingears
Expert
Date registered: Apr 2006
Location: St Petersburg, FL
Vehicle(s): G320 & ML320
Posts: 1450
| Re: High Velocity Grease
The boxes have been sitting open on the front porch for the past week. Here in Florida, we have quite a bit of humidity, plus it's rained several time too. I will open the other one and see if it has the same symptoms. When I first looked at them, there was no signs of rust.
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| RE: High Velocity Grease
Hi Chuck.
When I recentlly re-did my front axle, I, too, used Redline RedMoly all around, including the swivel ball. Waste of money, you say to put 800 gms of expensive grease in the swivel housing? Perhaps, but when I found the last CV Boot was breeched,,,,, it is now worth every penny!! No mixing and matching for me.
Redline seems to be the ideal material for CV's, bearings, etc., with high temperature, high pressure, and water repelling qualities.
My .02 |
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J.R.
Elite Veteran
Date registered: Apr 2006
Location: Southern Maryland
Vehicle(s): 00 G500, 09 911 4S, 11 Cayenne S, 86 280GE (sold)
Posts: 828
| Re: High Velocity Grease
One of the better articles on rebuilding a CV Joint using Redline Grease and presuming the parts are still in good shape. Enjoy.
http://www.gmcmotorhome.com/tech/axle/index.html
I learned a neat trick when I installed new CV-Joints in my 86 a few years ago. The gent who was helping me had been around the shop a while. Before we inserted the shaft into the CV, he took all of the grease and squeezed it out carefully on to the top of the CV. Then he covered it in a plastic bag. A second person (me) held the bag around the outside of the CV has he gently massaged all of the grease into the CV. A beautiful thing, cheap, simple, mostly clean and there was no doubt that the grease got into all of the little/important places.
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Bruce
Veteran
Date registered: May 2006
Location: Flagstaff, AZ
Vehicle(s): 230GE, 300TD, 200D
Posts: 191
| Re: High Velocity Grease
dai - 2/25/2007 10:39 PM
I have just replaced a C/V shaft on one the TD's because the boot failed after 370,000 miles. Original C/V's with the factor grease. The C/V didn't fail, the boot did
Has anyone injected extra grease into the C/V boot with a needle from time to time to freshen up the goo?
-Dai
Dai,
The 123 cars rear axles CV boots are filled with an oil from the factory rather than "grease". It's about like 30w oil. I dont know what the actual formulation is, but it is thin like oil. You may have noticed when the boot failed that the undercarraige was wet like someone sprayed oil all over under there.
Bruce |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: High Velocity Grease
Bruce, I didn't notice that detail! This was the first failure I had with one of these and happened when my wife and her mother were up on Mount Hood as the snow was falling and heard the thump, thump, thump, of the boot leaving the half shaft. (She actually described it as fumpfumpfump). When she called me they had noticed an unpleasant smell of somthing cooking on the exhaust. How did you discover that it is oil and not grease? When the TD made it home there was no oil left to notice. May be filling the boot with MT-90 and sealing it up might be the best lube?
Redline grease is around $7 to $8 around here. I use it on everything except farm implements greased daily. For that high service stuff where I go through a case of grease during the growing season I like Cheveron Professional EP GL-2. It works great. I personally think the Redline grease is reasonably priced as are the gear oils. The parts they are protecting are expensive, really expensive. $32 bucks worth of grease for over 100,000 miles of service in the front end of a G seems pretty reasonable to me. That's .00032 per mile. I'm keeping track.
Great tip J.R.
-Dai
Edited by dai 2/28/2007 11:35 PM
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Braingears
Expert
Date registered: Apr 2006
Location: St Petersburg, FL
Vehicle(s): G320 & ML320
Posts: 1450
| Re: High Velocity Grease
I guess I know what I'm going to be replacing in my Grease Gun...
Now I just have to find where to purchase it... |
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| Red Line Source
Braingears - 3/1/2007 12:06 AM
I guess I know what I'm going to be replacing in my Grease Gun...
Now I just have to find where to purchase it...
I get mine here:
http://www.myoilshop.com/AutoPrds.html?
She's $2 per tube cheaper than buying direct from Redline. |
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Bruce
Veteran
Date registered: May 2006
Location: Flagstaff, AZ
Vehicle(s): 230GE, 300TD, 200D
Posts: 191
| Re: High Velocity Grease
dai - 2/28/2007 8:32 PM
How did you discover that it is oil and not grease? When the TD made it home there was no oil left to notice.
-Dai
Dai,
I had a CV joint fail on one of the cars a few years ago. The boot was intact, but the joint was making a noise. I removed the axle and when I started to remove the boot, I had a big mess - oil spilling all over. I did not expect that.
By the way, I've been thru about 3 boot failures over the years and they always seem to be the inner joint. Just curious, was your failure an inner joint?
Bruce |
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| Re: High Velocity Grease
Whats needed for lubrication is oil. Grease is oil mixed with a "soap" to maintain a higher viscosity. Many times grease is more practical than oil (Ranger Rover knuckle housings are filled with oil rather than grease - one of the reasons they tend to leak, since oil is difficult to seal off).
So whenever its feasible, oil can be used to lubricate CV joints. But since it is easier to seal off grease, many CV boots are filled with grease. Even when a CV boot breaks, lubrication is not immediately lost. Also, its more difficult to contaminate grease with water than oil with water. Given the intended use of the G - grease was the right engineering decision.
http://en.wikipedia.org/wiki/Grease_(lubricant)
On a side note, when adding grease to the knuckles - make sure that you add the same grease (same in the sense that it has the same base/soap). Mixing two different base greases can lead to catastrophical failures. http://72.14.253.104/search?q=cache:frABlpSuchUJ:motorcare.com.au/w...
Maybe its time now for the engineers to improve the durability of CV boots.
Edited by 4x4abc 3/1/2007 1:32 PM
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: High Velocity Grease
Bruce, yes it was the inner joint next to the diff. Probably has more flexing there than at the other end over time. Might also have more heat exposure transfered from the diff than at the wheel?
Harald, I can't really complain about a boot failure on a vehicle in its 24th year of service with 370, 000+ miles on the chassis. I don't begrudge money spent repairing these machines. The 460 G and the 123 TDs don't let you down and warn you before something is going to break. PK and Mina made it back fine and they were a long way from home. Very safe, reliable transport.
Part of the reason that I decided to use the Redline red moly synthetic grease throughout the swivel ball assembly was to avoid the mixed grease base problem. Keep the king pin bearings, wheel bearings, swivel housing and the C/V all compatable.
Cheers,
-Dai |
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