1966 230 C

sandersen · May 19, 2014, 09:30:47 PM

I have a quick question for the TJ guys... I'm rebuilding my winch brake cylinder and have all the new packing and o-ring in place. I put the shaft, gland, and piston back together but it won't fit back into the can...at least without tearing up the new blue packing which protrudes about a 32nd or even 64th around. I applied some grease and a little force but it's going to tear up the new packing If I drive it down into the can...and then it's gotta go by the snap ring groove too. Has anyone else run into this? It seems the new aftermarket packing is a tad larger in circumference. I thought about throwing the whole thing in the freezer to contract it (like when you're installing new bearings), but I'm afraid of cracking the plastic packing. Any tips or insights would be great. Thanks.

dixmont · May 19, 2014, 10:28:03 PM

you need to throw 1 or 2 pieces of the v packing away. the center ones compare it to thickness of your old one, if you dont it will not go together

sandersen · May 19, 2014, 10:35:25 PM

Thanks...but just toss the blue v-packing uh? That would make the whole thing drop right in for sure...but I assumed it was necessary...maybe not though. ??

Neilo · May 20, 2014, 12:15:02 AM

Sounds to me like the packing is on upside down. The pressure comes from the rod side in the brake cylinder.

The hard bit is getting the gland over the thread of the rod. Probably have to cover the thread.

Neilo

Neilo · May 20, 2014, 12:17:39 AM

Remember to put plenty of grease on the top of the piston too. It is the only thing that lubricates the upper cylinder.

sandersen · May 20, 2014, 12:59:43 PM

Okay thanks...I'll double check the packing...it does seem to be working against the cylinder as I try to drive it down...the actual V part of the packing is facing the opening of the can...not the best for sliding it in...it just wants to turn up the edges of the packing...it would make sense to flip it. I'll check that. Thanks a ton.

redneck · May 20, 2014, 06:59:08 PM

exact same thing happened to me last summer. I ruined one packing trying to install it, then the second packing I took to a retired machinist and had him install it and he had same issue, so he put the cylinder on his lathe and shave a little off the inside wall to make a better fit.
My cylinder is the older type with the hole through the top of the cylinder instead of having the ears welded to the top and the hole through them. Maybe these older brake cylinders have a little thicker wall inside then the newer ones

sandersen · May 20, 2014, 07:28:03 PM

Interesting...and thanks for the input. Mine has the ears welded to it with the holes drilled through them for the pin. When i get a chance I'm going to check on Neilo's tip that the packing maybe upside down...but i thought I was careful when assembling everything but you know how that goes. The open part of the V is facing into the cylinder so when it's pushed down the lip of the packing is wanting to peel back up. I was tempted to take a razor knife and shave off some of the packing around the piston but that didn't seem right. Thanks again.

Neilo · May 20, 2014, 10:29:06 PM

From what you describe, the v packing is certainly on upside down.

BHC · May 21, 2014, 06:23:00 AM

when i was working in the shop rebuilding hydraulic cylinders lots of times we would take 1 piece of the packing out,( Old style ring packing) sometimes i think the kits come with extra pieces and at other times the materiel that they now are making the packing out of is different than 30 years ago, so the old guys said. Yes we did machine alot of the pistons to take the new packing kits as well, but not always. Which piece, to remove? On a 2 way ram the center piece of packing is not the one that going to hold the pressure it not u shaped but help the other rings by holding space which makes them expand out, maybe putting the old piece in would do this for you? if it is any good.
I do not remember, one for a TJ winch but assume this is a 2 or 3 pieces piston? in which case a shim may be missing or needed between the pieces which may be making the packing expand to much as well, some kits did come with these shims. just make sure if you do this you have room in the tube. Lots of lock tight on the bolts holding the piston to the ram.
At times we would use a thin piece of tin and hose clamps like a ring compressor on a piston around the packing, other times we had thin tin formed in a cup shape that went into the tube to cover threads, so not to damage the packing. lots of grease and some big hammers at times.

sandersen · May 21, 2014, 11:40:53 AM

Thanks a ton guys, that's very helpful...per Neilo's advice, I turned the packing over last night and will try to tap the piston down into the cylinder again tonight...I compared my set up with the old packing assembly and I set it up the same way it came off...but the actual material is different with the new packing. It seems like harder plastic versus the old softer almost rubber stuff. Covering the top of the cylinder with grease is not something I would have thought of either. Thanks again...