Seed asked about changing the Chevron seals on the PM drive cylinder.

I will start this by offering my 2 cents.

First thing is to look at why the seal is leaking.

Without putting any part of you in the water box inspect the rod for chrome damage. A mirror under the rod sitting on the water box floor will help you to see the bottom of the rod. DO NOT have any part of you in the water box with the engine running.

There are several things that can take out the Chevron seals. Chrome damage, Slurry hardened on the top of the rod will get run through the seals when you pressure out the unit or just plain wear. If it is just wear you might need to change the guide bands as well but this requires removing the cylinder. You can change the chevron seals but they will not last a long time IF the guide bands are worn.

With that said to replace the Chevron seals.

Push the piston “mud cup” into the material cylinder till the dog bone is flush with the water box. With the truck OFF remove the dog bone and adapter flange from the end of the rod. Ensure to replace all stainless wire to the bolts for lock purposes when going back together. NO Tie wire must be Stainless.

Clean all the material from the rod. With the manual cycle valve retract the rod all the way. Don’t use the remote.

Remove the Socked head “Allen bolts” from the flange that holds the wiper seal and remove the flange. If any of the bolts are loose or damaged on any of the parts  replace them.

With a pick remove the old seals.

Reinstall the new seals 1 at a time in order. Presoak the seals in clean Hyd oil.

Use a blunt screwdriver or I used a old tooth brush with the end ground off to look like a flat spade to push the seals in 1 at a time making sure to seat then fully in and not trapping air under them I would use the flat part of the screwdriver to reach outside the seal to burp the trapped air behind the seal.

Install the new wiper seal in the flange and reinstall the flange. I will need to check on the torque, look in your manual at the parts pages there should be a note for torque speck otherwise send me your serial number and I can check for you.

Install the Adapter flange on the end of the rod Make sure you tighten and loctite Blue or stainless wire the bolts. Same with the dog bone then test. Only use the Blue Loctite on the adapter bolts.

Ensure to replace the water box cover.

And running the water at the level you described is a good practice.

If you have any questions please contact PMA CSG 1 800 890 0269

Or myself  360 600 5695

Or ask on the post either way.

Have fun

Thanks for the drill I will be giving you a call when the deal goes down! What is the estimated time for a rookie? I have done the mud cups and dog bone before.

Honestly it will depend on how long it takes to get the bolts out of the adapter from the dog bone flange to the rod. They are loctited in and can be a bear. Use a good quality socket and you might need a LITTLE bit of heat. not enough to damage the chrome rod

Good question, and advice. Thanks. Yeah, mine and most i've seen leak a Little oil. Mines not excessive but getting close (little oil in the water). My trailer pump also. Anyway, the scary part for me is getting all of those "Allen Screws" out. I wonder if they make an side air ratchet with an impact? Or maybe a impact with a swivel extension?

B-alto

Good questions.

The ring of Allen bolts should be wire tied and shouldn’t be that hard to get out.

The bolts holding the Dog bone adapter should have been locktited in and might require a Little heat. Not so much to damage the chrome. Heat the head of the bolt just enough to brake the loctite bond.

A friend of mine tells me he uses his ½ inch pistol style impact gun.

Next is there are some generations that can be removed from the water box, others like Thom-katts and some enterprise units will need to remove the cylinder.

One quick way to tell if the cylinder needs to be removed is to look at the bolts.

If the end is held on with Socket head screws, AKA Allen bolts you should be ok to do them from the water box

If the gland has Hex bolts, Standard bolts the cylinder will need to be removed, the flange will be under the water box housing.

If you e-mail me I can send a drawing to show this.

woodsa@putzam.com

or contact PMA CSG 800 890 0269

When you take out your old seals note the direction they come out or look in your parts book it will show you.  From experience I left a young lad to change diff seals with specific directions to only get a call asking why the flange wouldn't seat properly. When we re- replaced them not only had he put them in backwards but also had got them out of order.  Those seals come taped together for a reason, they are in order.  If in doubt once again look at your parts book it will show you.  Also be clean,clean,clean I know that sounds like a gimme but you would be surprised.  Alan, we took an old robertson screwdriver and welded a screw on the end to remove the old seals,  I know with your traveling that would make it tough, honestly officer its only a screwdriver, as the rubber gloves are going on, and cough please. It might be something you could use locally. 

Granddad well said.....Cough/Snap :)