lube jobs

[lakewoodpaul]

My older WCC service guide, states [in the lube instructions] to use a hand operated grease gun only. I bet the service garages use air when they do a lube job. Anyone know the logic behind that recomendation?

[edgray]

Quote:

Originally Posted by lakewoodpaul My older WCC service guide, states [in the lube instructions] to use a hand operated grease gun only. I bet the service garages use air when they do a lube job. Anyone know the logic behind that recomendation?

Both of guns, one a lever pump and one pneumatic powered, are operated by hand.

To answer your question, no.

I see no logic as to why the motive force for the grease would make any difference to the end result. Ed

[JoeT]

My Freightliner Chassis Manual says to use a hand-type grease gun or a high-pressure gun with a low-pressure adapter to lube the U-joints. Otherwise the U-joints may not receive enough lubricant.

[DriVer]

I have a Lincoln one hand grease gun and let me assure you there's plenty of pressure to hit any of the 13 fittings on the chassis.

Best thing about the lube job I did today - ALL the driveshaft Zerk fittings were facing toward 6 o'clock!

Model 1133
Same as 1132 with 18" whip hose and coupler.


Works great and it's less filling!
.

[Beagle RC Air]

Quote:

Originally Posted by lakewoodpaul My older WCC service guide, states [in the lube instructions] to use a hand operated grease gun only. I bet the service garages use air when they do a lube job. Anyone know the logic behind that recomendation?

Well, I guess I can take a shot at this. A U-joint seal can be blown out by using an air powered grease gun due to the high pressure it puts into the grease channel. Once a seal is blown out (one of four) then all the lube will take the line of least resistance an go towards the blown out seal, starving the other three sides of the universal joint. Happens all the time with 'Jack in the Box' mechanics/lubemen.
I just replaced both U-joints with new Spicer joints because two of the caps showed no signs of getting grease, it all went to the blown out seal cap. Turns out the joints were still good, but at 80k it seemed like good move to replace both.
On some sealed front suspension parts the same problem can happen. Just need to apply enough grease till the boot fills. Air grease guns are ok in the hands of skilled and caring lubeman, but how many of those do I know?
Beagle

[donhoward49]

Quote:

Originally Posted by Beagle RC Air Well, I guess I can take a shot at this. A U-joint seal can be blown out by using an air powered grease gun due to the high pressure it puts into the grease channel. Once a seal is blown out (one of four) then all the lube will take the line of least resistance an go towards the blown out seal, starving the other three sides of the universal joint. Happens all the time with 'Jack in the Box' mechanics/lubemen. I just replaced both U-joints with new Spicer joints because two of the caps showed no signs of getting grease, it all went to the blown out seal cap. Turns out the joints were still good, but at 80k it seemed like good move to replace both. On some sealed front suspension parts the same problem can happen. Just need to apply enough grease till the boot fills. Air grease guns are ok in the hands of skilled and caring lubeman, but how many of those do I know? Beagle

I hope u are still monitoring this post. How do i tell that the u joints are getting grease without blowing the seal??
Still learning after all thees years..

[DriVer]

Quote:

Originally Posted by donhoward49 I hope u are still monitoring this post. How do i tell that the u joints are getting grease without blowing the seal??

I use a single hand operated Lincoln grease gun. "My" guideline is when the U-Joint spits, that's usually enough grease and I stop.

[ottffss]

Quote:

Originally Posted by Beagle RC Air ... Just need to apply enough grease till the boot fills. Air grease guns are ok in the hands of skilled and caring lubeman, but how many of those do I know? Beagle

And that be the story. With a "powered" gun be it air or electric folks have a strange tendency to just blow grease until the cows come home, the seals split and things are left worse than before with grease spewing all over the place and more importantly, a split wide open seal waiting to bleed the rest of the grease and then ingest road nastiness like dirt.

Secondarily, some of the pneumatic guns are also extreme pressure guns that will damage grease limiting Zerks often found on IFS carrier bearings.

How much grease?
In general, just enough to see the seal expand. No more.

On a grease limiter Zerk just until the limiter plunger raises and stops the flow.

Note on the following I use the term "spit" and not "spew" deliberately.

U-Joint - add until all FOUR seals just start to spit, if you have a dual Zerk U then switch to the other Zerk as soon as one seal spits to finish off the rest.

On a drive shaft slip joint - until it spits from the breather in the center of the yoke. On a main drive shaft a nice clean trick is to pump just less than what you think it'll take (you learn this over time, my K2 will consume 3/4+ tube on that joint alone) and then lower the RV ALL the way. Raise it again and see if it spit. If not shoot some more and lower again. Repeat until it just starts to bleed. This way you won't fling grease all over the place when you roll. Another trick I have heard, never tried as I do the above, is to wrap a layer of Saran Wrap around the yoke. Not sure how well that will really work. I prefer to just not add so much that it will sling by doing the previous method.

My K2 will take about 1.25 to 1.5 tubes of grease with every grease job which I do around 10k miles. Why? I drag lots of light around with the gun. It is a perfect opportunity to do a thorough, detailed chassis inspection to find impending issues that I can then take care of on MY schedule, not a roadside breakdown schedule.

[sdennislee]

Can't add a thing to the 2 posts by Beagle and ottffss. They nailed it for you.

[LEMO]

Just wanted to add my 2 cents, and give a big word of thanks to DriVer and others who add their knowledge to these posts. I bought a used 05 Southwind last year. We I bought it the previous owner showed me the service records which indicated regular service to it's curreent 16,000 miles. After 3,000 miles more I again had the coach services at a different shop near my home. After finding out about the number of zerks, I crawled under and checked things out. I found that all the steering zerks, were well lubed, BUT none of the Zerks on Drive Shafts, had ever been greased. I now have my own grease gun like DriVers' above and do my own service. Thanks guys, nobody need a u joint to go while on the road.
LEMO

[lakewoodpaul]

Quote:

Originally Posted by edgray Both of guns, one a lever pump and one pneumatic powered, are operated by hand. To answer your question, no. I see no logiemotive force for the c as to why the difference to the grease would make any nd result. Ed

That is my point you can apply a whole lot of force on a hand operated lever action grease gun and you can also apply an adjustable amount of air pressure to an air operated grease gun. As far as as adding " JUST ENOUGH GREASE TO FILL THE BOOT", if the boot is full and the seal is intact why bother to grease again 3000 mi later? I thought you grease again to remove old grease with all kinds of contaminants and ground up metals out of the part your greasing.

[Mike Canter]

Ottffss, you are not exactly correct on U-joint lubrication. According to the Dana Spicer Driveshaft Service Manual DSSM3264 just filling with grease until a little grease starts to spit out of the seals will result in an early U-Joint failure. Those grease seals on the U-Joints are designed to expand to let the old grease purge out that may contain grit out of the joint. You will NOT damage the seals doing this. Dana Spicer also shows pictures of using an air operated grease gun to accomplish this. It is real important to pump new grease into those U-Joints until all the old grease is purged out. Like I said failure to do this will result in an early failure of the u-joint bearings. The other important thing is to have the grease purging out of all four grease cups on that U-joint. If it does not purge out of one cup then you should place a piece of wood against the driveshaft and use a mallet or a hammer against the wood to knock the driveshaft towards the cup that did not purge so that you open up the clearance around the seal to allow it to purge. If you cannot get all four seals to purge then the driveshaft should be removed and the problem fixed.

As far as greasing the front steering joints all my boots are open on one end and the idea is to also pump grease into those boots until all the old grease is purged out. My boots as well as many other MH are like this and you cannot hurt those open boots with a pneumatic grease gun. I do agree that if those boots are sealed then you should not use a pneumatic grease gun but you need to check and see what boots you have.

[dieselclacker]

"My K2 will take about 1.25 to 1.5 tubes of grease with every grease job which I do around 10k miles. Why? I drag lots of light around with the gun. It is a perfect opportunity to do a thorough, detailed chassis inspection to find impending issues that I can then take care of on MY schedule, not a roadside breakdown schedule."





Just curious, what is a K2 chassis, and how many grease zerks does it have?

Dieselclacker

[ottffss]

Quote:

Originally Posted by Mike Canter ...Those grease seals on the U-Joints are designed to expand to let the old grease purge out that may contain grit out of the joint. You will NOT damage the seals doing this....... The other important thing is to have the grease purging out of all four grease cups on that U-joint.

Mike (almost) totally agree - the U-joint cup seal are about the only seals where that is true. Meaning - in this joint only - you can blow grease to the cows come home without seal damage.

However, to be very clear, the reason for "purging" the U-Joint as you suggest (and as stated in DSSM3264) is to eliminate grease incompatibility issues - not just to clear the U-Joint for the fun of it. Getting all 4 cups to spit flushes plenty out. Per DSSM3264 "Make sure fresh grease is evident at all four universal joint bearing seals" is NOT emptying a cartridge thru the joint. As I lube with the exact same product every time there is never a grease incompatibility issue. YMMV

The 4 cup spit, as previously mentioned, is exceedingly important as is using both Zerks if installed.