Undercoating U-joints

[Brad S.]

Wondering if spraying the knuckles & joints/crosses with undercoating would help or hurt???
Since I've got the front shafts out and the joints are ok, thought this might protect them....
I suppose a person could ask this about any of the driveline joints???

 

[joshofalltrade]

i would advise against it. for one, any material that gets on the joint itself may mess with the seals that hold the grease in, and the zerk fitting that allows you to lube it. anything on the rest of the shaft will have a chance of throwing the shaft out of balance enough to cause issues with vibration, which may cause more issues.

 

[IDIoit]

i wouldnt. it may work this round, but id think it would be a PITA replacing them in the future

 

[mblaney]

When you say 'undercoating' I assume you mean a rustproofing? Like Krown? I wouldn't use rocker guard (drying rubber stuff) but I definitely blast everything steel (except brakes) with rustproofing.

If you are thinking of the rubber stuff (or the old waxy rustproofing) then I say no. You will never get a good enough job to keep moisture out, creating a perfect environment for corrosion. If you have all of your parts new on a bench then I see no problem with finishing them (paint, etc) but to coat an assembly with moving parts won't work. Just blast it with rustproofing. My truck has only ever seen hydraulic fluid for rustproofing and it has no rust. Hydraulic fluid does not have detergents so it won't harm seals, etc.

 

[madpogue]

Sounds like a job for Fluid Film.

 

[Brad S.]

Thanks all, I was thinking more along the lines of actual rubberized spray.
BUT the anti rust spray sound little more "workable".

 

[icanfixall]

Why not just pump in more grease often. Wipe off the grease that comes out. Do this monthly and it will keep the joints water free. Depending on how many rivers you cross you may need to grease more often.

 

[mblaney]

Sounds like a job for Fluid Film.

I just bought a 5 gallon pail of Fluid Film; was too late to use before this winter but I look forward to the spring!

 

[dunk]

I've painted joints before after assembling a two piece shaft. Just partial incidental coverage though from painting the shafts. No harm, but I wouldn't undercoat. I'd imagine that could damage the seals. Just grease them periodically if greasable. Wouldn't hurt to spray the outside with WD40 now and again when under the truck greasing things. I tend to knock off dirt/rust off things and spray with rust converter or WD40 when I'm under the truck. Little by little it helps it from rusting away. My ujoint failures have usually been from torque though, they don't last long enough to rust

 

[madpogue]

Why not just pump in more grease often. Wipe off the grease that comes out. Do this monthly and it will keep the joints water free. Depending on how many rivers you cross you may need to grease more often.

Grease INSIDE the joint won't do a single thing for rust OUTSIDE the joint.

 

[79jasper]

Something is wrong if your u joints are rusting out that bad.
Like cheap u joints.

Sent from my SM-T537R4 using Tapatalk

 

[Brad S.]

I wouldn't say they are rusting out, just looking to prevent problems.
I've had enough engine oil leaking down over the last 10-11 years to help with rust, etc.(engine rebuild should fix the oil leak)
The first time I did this project, taking out the front carrier, the inside passenger side joint was bad and needed to be replaced.
Now I'm trying to stop the oil from leaking out of the front differential= shafts out, thought I could "treat" the whole joint with something...
I try to get a pic of them and post it.

 

[IDIoit]

replacing the seals are a PITA, but will solve the leakage

 

[Dieselcrawler]

I just paint them .

 

[Brad S.]

I just paint them .

Someone mention this above and something came to mind.
The flip cards with a picture drawn on each page/card. Maybe I could draw smiley faces on cups of the joints, then as they spin around...???