Dump truck cylinder leaking only at bottom of travel.

[lennyzx11]

A quick update with no progress to date. I haven’t gotten that pin on the cap side loose yet. I’m going to use heat this weekend and if no good then I think I’ll disconnect the barrel end and pull the barrel off the rod.
I switched the hoses around and tried it but the exact same thing happened.
I’m thinking the first seal under the cap is bad to cause this.

 

[Have tractor did travel]

My dump trailer has almost same symptoms. If it's been sitting for a week, then, when raised, oil gushes from the top of the cylinder.
My repairs frequently go like yours. So the way I'm handling this is to replenish the hydraulic fluid when it gets low. I think you lose more fluid than do I, so that option may not be available to you.
Isn't life fun ?

 

[deereman75]

Typically on dump cylinders they get a groove worn in the chrome in the fully retracted position from all the pounding around experienced while the truck or trailer is driving. The fact that it isn't leaking otherwise points to this rather than bad seals. It's not the seal itself causing the damage, but rather the steel on either side of the seal groove.

The only fix is a new rod/tube section. I make LOTS of new sections for the big multi stage telescopic cylinders on gravel trucks. I'd say that at least half the dump cylinders that come in for seals need new tubes/rods as well.

 

[lennyzx11]

Typically on dump cylinders they get a groove worn in the chrome in the fully retracted position from all the pounding around experienced while the truck or trailer is driving. The fact that it isn't leaking otherwise points to this rather than bad seals. It's not the seal itself causing the damage, but rather the steel on either side of the seal groove.

The only fix is a new rod/tube section. I make LOTS of new sections for the big multi stage telescopic cylinders on gravel trucks. I'd say that at least half the dump cylinders that come in for seals need new tubes/rods as well.

Hmm… I never thought of that. It was mentioned here of the possibility of a bent rod but it measured true and straight when extended and I laid a straight edge on it.
I could see the gland hitting a spot way down inside at the bottom of the barrel causing this.

What puzzles me is the fluid doesn’t come out under pressure from the cap end but is a steady pouring type stream in the last 8 or so inches of retraction and no more even when deadheaded either way. I can stop the travel in those areas and the leak stops holding the bed up for hours without creeping down.

Another symptom is when extending and going up, the rod shows a heavy cover of oil like the outermost wiper seal didn’t scrape it off tightly.
It seems to be “overfilling” the cap end when the rod is retracting like it’s getting more return oil to that end than volume of the cylinder can hold.
I think I’ll pull the valve and make sure the return into the tank is clear.

 

[bindian]

Typically on dump cylinders they get a groove worn in the chrome in the fully retracted position from all the pounding around experienced while the truck or trailer is driving. The fact that it isn't leaking otherwise points to this rather than bad seals. It's not the seal itself causing the damage, but rather the steel on either side of the seal groove.

The only fix is a new rod/tube section. I make LOTS of new sections for the big multi stage telescopic cylinders on gravel trucks. I'd say that at least half the dump cylinders that come in for seals need new tubes/rods as well.

Agreed, as I mentioned in post #6, but in not as much detail. It is wear from being bounced around in the same spot over and over and over.
hugs, Brandi

 

[BravoXray]

So, lennyzx11, did your get the leak problem solved?

Inquiring mind want to know.

 

[Eretansal]

Have you tried going to a car repair shop? Whenever I go on a long trip, I check my car at the local car repair shop. I always want to ensure everything is alright with the car before starting the trip, and the chances that something can happen with the car are low. I will never forget my trip to Losaltosresort.com. I had to drive one thousand miles, and on half the trip, I started having problems with the gearbox. Luckily I was able to repair it ASAP, otherwise, I wouldn't arrive on time at the hotel to check-in.

 

[ROUSTABOUT]

After you get that pin out, put a grease fitting on the cylinder part. Put it easy to get to. Even though the pin isn't a pivot point, the grease will keep it easy to remove. A lot of equipment has grease fittings in those type situations. I've used a porta power on those pins, and a coaxing torch. One of those impact slag guns, air needle scaler is the official name, will get it loose, or really help. Don't mushroom it, only makes it worse. Slather pin in grease when you re install it.

 

[Leejohn]

try a air chisel with a flat end.

 

[wdchyd]

Lenny, you’re probably heading down that road to just cut the pins and deal with the pieces. Pulling the barrel off the rod is going to be some tough sledding, it will be a bear to work on under the truck body to do it right.