Cat d6d recoil spring cylinder leaking

[mlaird37]

D6d 4x04494. The cylinder inside my recoil spring is leaking grease when we tighten the tracks. Is there a way to repair this without having to cut the spring and install a new one.

 

[pittsburgh cat man]

You probably have a seal blown in track adjuster you need to unbolt the yoke where you put grease in slide yoke ahead (probably have to break the track) pull the piston out (some have a threaded hole in the piston)

 

[HATCHEQUIP]

Those pieces on each side of the spring you dont mess with for the seal replacement and you want to get those bolts back in there before you break that track. If your track doesnt have alligator links you might be able to just pull it off the idler after slacking the track so you dont have to remove master pin with a BFH

 

[Nige]

Those pieces on each side of the spring you dont mess with for the seal replacement and you want to get those bolts back in there before you break that track.

Absolutely. If the recoil spring stops let go the spring will exit its location at something approaching the speed of sound and proceed to kill everyone in the immediate vicinity. They are not known as Death Springs for nothing.

 

[pittsburgh cat man]

If you look at pictures sure looks like it’s welded

 

[Nige]

You’re right. Even welded those stops still give me fits.

 

[HATCHEQUIP]

Looks like he's drilling on a bolt but that weld looks cracked away from the bracket, it definitely needs attention.

 

[Welder Dave]

It does look like a very poor weld that broke. I'd put another weld on it then fix the bolt hole. Then you could cut the weld if you had to.

 

[Old Magnet]

You need to get a service manual. Procedure is well defined there.

Remove the four bolts and nut that holds the cylinder to the yoke
Slack off or split the track.
Pull the front idler and yoke forward
Remove the bolt and washer retainer at the end of the spring through bolt and crank the nut to release the pressure on the spring stops.
Remove the hydraulic adjuster from the front pilot of the recoil spring.

 

[mlaird37]

You probably have a seal blown in track adjuster you need to unbolt the yoke where you put grease in slide yoke ahead (probably have to break the track) pull the piston out (some have a threaded hole in the piston)

The grease is coming out the barrel on the inside as seen in the pics. Mechanic telling me I have to cut the spring and replace the cylinder and the barrel and replacing the track tensioner seals would not fix this. Is that correct or is he mistaken

 

[pittsburgh cat man]

The piston inside the cylinder where the grease fitting and relief let me ask you this the big bolt that goes through spring how far can you pull it towards sprocket second can you look through the spring and see if pilot is still in one piece

 

[John C.]

To explain the recoil system that you are working with, that spring has a through bolt that has a cylinder at the idler end and the bolt goes through the center of the spring to a big thick plate at the other end and that plate has a hole in it that the bolt goes through and is held in place by a big nut. A new spring has to be compressed in a big press. The cylinder and bolt are put inside the spring and the plate is set on the bottom and the press compresses the spring until the bolt is protruding through the plate. The big nut is then threaded onto the bolt. The spring has a specified total length that it has to be compressed to and the nut is turned until it will hold that length. The whole spring is then loaded into the track frame. The nut fits into a hole at the back of the track frame next to the sprocket. The usual failure in the system is that the large bolt breaks at the threads on the nut and now all the tension is on that stop bracket that you see in your photo. Before you do anything at this point you need to look for that big nut just in front of the sprocket. If it isn't there, you are in trouble and yes the spring will have to be cut to relieve the tension. You will have to cut at least two of the rings on the spring. The tension on the spring is the weight of the tractor. That nut can also still be there and the rod could still be broken so really at this point you need someone who knows what they are doing to provide facts as to what you have. That stop bracket might just be broken because of the age of the machine. More than likely though its broke because the through rod is broken.

 

[mlaird37]

Mechanic says there is a pin hole from rust in the pilot housing that the grease is coming out of.

 

[Old Magnet]

In that case the spring assembly has to come out. Proceed as though you are going to remove the cylinder but now with tension off the stops go ahead and remove the stops. Take the whole assembly to your Cat dealer that will have the tooling to release the spring tension. Replace the pilot and reinstall.
Here's a generic picture of whats going on in the adjuster.

If the spring bolt is broken then you will have to resort to cutting coils to release the tension.

 

[pittsburgh cat man]

As long as it’s intact and bolt isn’t broken thru I would put seal and wear bands in it the pilot has nothing to do with the grease that pushes the idler out it just holds the cylinder the grease is contained between the piston and the end of yoke shaft when you pump grease in it forces the piston again the end of center bolt and the cylinder pushes the idler out you do realize any grease that makes it into the pilot will be forced out the hole where the center bolt goes

 

[Old Magnet]

OK, agreed, if the pistons seals are working there shouldn't be any grease in the pilot chamber.

 

[.RC.]

Who the hell would weld that part on. Do not forget that part also has a dowel. I would be pulling it all apart and fixing it properly. IF the centre rod is in good order, tighten it up to compress the spring and remove it and fix it properly.