XM757 steering

[cranetruck]

The other day I put the front axles on blocks, removed the wheels/tires and started to exercise the steering.
Turning the steering wheel was still kind of tough and I'm wondering about the "sealed for life" joints, perhaps a dozed or so in this mechanism.

These kind of joints must be used in the general automotive industy and what is the long term experience with them, as in not used for a long time? Any experts out there?

 

[Recovry4x4]

Bjorn, any way it could have been drag from the power steering? It wasn't running was it?

 

[cranetruck]

Not running, just cold turning. Yes, the power stering cylinder would offer resistance, but it's kind of a rubbery toughness, the steering wheel tend to turn back a bit for each movement.

 

[Elwenil]

I'd think you could drill the cap on those joints and install a Zerk fitting and grease them. I've done it with other automotive joints in the past such as ball joints and tie rod ends, even U joints. I didn't have a snazzy drawing of the joint either, lol. Judging by the pic, there should be no problem drilling and tapping the cap on those. You could also dig around and see if there is another common application for a similar joint that you could replace them with. Looks like it would be a big pain since most of the joints are made into the links though so some welding with someone who knows what they are doing would be a given. If you go that route, get to a NAPA with the shaft length and taper diameter and see what can be dug up. I'd try the greasing option first though. At the worst you may end up with a useless hole to be plugged in the joint cap.

 

[rdixiemiller]

Bjorn
You are fighting the power steering cylinder, it will give you that funny "rubbery" feeling.
I would drill and tap holes in the top cap of the tie rod ends and install grease fittings. Those "sealed for life" joints weren't all they were supposed to be when they first came out. Remember, sealed for "life" of what? A 40 yr old truck? Or the tie rod end?
I would probably tear down one of the sealed brake assemblies too, just for kicks. I would hate to have to repair one on the road somewhere without knowing what was in there.

 

[cranetruck]

Thanks for the come-back. Not sure if grease will get where it would be needed around the ball, though.
Perhaps just a lot of exercise is the cure.
If it's permanently lubed and sealed, the lubricant should still be there, right?

 

[Elwenil]

Not necessarily. there are a lot of "sealed for life" joints and such in the auto industry that last less then 30K miles because they loose the lube. If the boot has gotten damaged at some point, or had gotten hard with age, I'd be suspicious.

 

[cranetruck]

This is what a joint looks like now. The "seal" doesn't appear to be present or perhaps the drawing is conceptual.

If the seal is there, high pressure grease could permanently displace it.

Robert, I'll test it again with the engine running, got most of the parts for the fuel system now so it shouldn't be too long.

 

[ida34]

Bjorn,
I would not mess with them unless they are giving you a specific problem. If they are then I would replace with a greaseable tie rod end. I know this would be problematic at best with alot of fabrication involved. Are any of them loose or are do they give you concern based on the resistance in the steering? Maybe disconnect the tie rods and check them by hand to see if they are binding. I would not drill and tap the tie rod ends. If they were not designed to be greased then you might end up damaging them by pumping the grease in.

 

[rmgill]

I dunno Bjorn, looks like private Snuffy took it apart and didn't put the seal back on.

 

[cranetruck]

For the next several months, everything MV related also becomes weather related, cold rain, freezing rain,
snow and cold weather in general will take the fun out of it.

First step will be to take one of the joints apart and check the movement of the ball-stud. I don't want to drill the cap.
Perhaps exercising it will get it loosened up, if in fact it's frozen...
I rather take my time on something like this than go for a "quick fix".

Here is a description of the joint (image above from the SAE paper): "...the design, featuring Delrin in combination with a woven cotton fabric
impregnated with a dry lubricant. The rod ends are protected from dirt entry by the use of a polyurethane seal."
The polyurethane seals are all gone for whatever reason, but the "dry lubricant" should still be present.? The truck only has like 3,000 miles on the odo....

 

[cranetruck]

Checking the joints for stiffness. The joint at the drag link ends are very hard to move, the one closest to the camera did not move at all. With the mechanical advantage afforded by the length of the drag link itself, the joint at the idler arm end could be moved.
When I tried to turn (=steer) the wheels, freed up with the linkage removed, they too were very hard to turn indicating that the tie rod ends are pretty much frozen too.

Wonder if "exercise" alone will get them loosend up....

 

[Elwenil]

You could try that, or the lack of lubrication could cause them to self destruct in short order. A potential steering linkage failure on a truck that big could be a problem no one wants. Luckily they will only do about 45 MPH, lol.

 

[ida34]

Bjorn,
Based on your above statements, my vote is to replace them. Some things you can get away with limping through. Steering and Brakes are not among those things.

 

[rdixiemiller]

If you have one that is frozen, drill it and grease it. You aren't out anything but a little time. I drilled and greased many, many tie rod ends when I was turning wrenches in the late '70 s and early '80 s. The top cap is just sheet metal, easy to work with. You would be surprised how much water would come out of those "sealed" joints.
You can also replace them. Pull one loose and get the measurements. You may find a common deuce or 5 ton end that can be purchased from Saturn cheaply.

 

[jasonjc]

The 3000 mile is not the proplem its the 40year of bad wheather rain snow sun salt. I dont think that truck has been inside since it left the factory. I'll bet the seals have been gone a long time letting moister get into those joints that cotton will hold water just as good as it did the dry lube. And we all know what happens when moister is it contact with steel for a long time.

 

[JDToumanian]

Delrin is a very slippery plastic, with many similarities to Teflon (both are made by DuPont) except Delrin is harder and less subject to deformation under pressure. If those joints have Delrin inserts in them, then as long as they are not sloppy or rusted solid I would think they are okay.

They're obviously very different from a traditional ball rod end... personally I would not add grease since they were never designed to have grease in them - they were designed to run dry. It's possible, (and this is pure speculation on my part), that there was a technical bulletin issued at some point instructing that the rubber seals be cut off because they trapped moisture which could cause rust rather that allowing the joint to dry out. This possibility occured to me because I think it's very odd that ALL the seals are missing.

Regards,
Jon

 

[cranetruck]

Jon, good arguments! I know for fact that this kind of seal will not keep moisture out, just dirt from accumulating, maybe ice.
I "exrecized" the drag link for less than 5 minutes and it now drops after I release it. It takes over one minute to drop 12 inches, but it is an improvement.
I will not try to inject grease, again I like your arguments Jon.

 

[cranetruck]

Exercised the drag link some more (image above) and it now drops in about 20 seconds. If they all loosen up like that, I should be in good shape.

 

[Recovry4x4]

Sounds like its really coming together Bjorn. Can't wait to get a ride in it. As I said before, I rode in Tom Bauers and it was pretty neat.