Cylinder reseal, can't get cylinder started back in tube

Doug580l · Jul 2, 2020

I am resealing one of the stabilizer cylinders on a 580sl. I cannot get the cylinder started back in the tube without ruining the piston seal. I have ruined 2 seals already. I am doing my best to keep it square and not hit it too hard with a dead blow hammer once I can't get it to move by hand. It seems to me that the seal has too much slack or freeplay in it and keeps slipping out of place and tearing. I am using Bulldog brand seal kit. I am not very experienced at rebuilding hydraulic cylinders but I have successfully done 4 so far. Is there a certain method to getting it in or should I order that seal directly from a case dealer? I am extremely frustrated at the moment, any help is appreciated.

Thanks,
Doug

Welder Dave · Jul 2, 2020

Some have mentioned using a piston ring compressor or even wrapping shim stock around the seal and putting hose clamps on for awhile to contract the seals as much as possible. There's some info in the archives if you look.

Doug580l · Jul 2, 2020

Thanks for the reply.
I tried searching for some info but haven't had any luck yet.

The piston ring compressor isn't working because the problem occurs where the taper in the tube is, just past the threads, about 1.75" into the tube and the piston ring compressor gets pushed off before that. I had to look up what shim stock is, sounds like that has a chance to work. Any recommendation on the thickness, I assume the thinner the better. Grainger has some that is .001" thick and 6" wide. Can't imagine that has enough strength, maybe the .003"?

Thanks,
Doug

funwithfuel · Jul 2, 2020

I'd go with the .003 over .001 there should be
.008" available, that's what I've used in the past. Less like paper, more like a tapered ring compressor with lots and lots of lube.

Tinkerer · Jul 2, 2020

Welcome to the club Doug !
I had a similar experience not long ago. I finally took my cylinder a professional.
The last half of my last post in this thread says it all.
https://www.heavyequipmentforums.com/threads/purchased-my-last-bulldog-seal-kit.81148/

Doug580l · Jul 2, 2020

funwithfuel said:
I'd go with the .003 over .001 there should be
.008" available, that's what I've used in the past. Less like paper, more like a tapered ring compressor with lots and lots of lube.

Thanks, I ordered the shim stock in a couple sizes.

I have the piston ring compressor on it now and I will put it in a plastic bag in the morning and let it soak in some ice-water for about an hour and try it again. If it doesn't work I'll wait for the shim stock.

Doug

Junkyard · Jul 2, 2020

Do you have a vacuum pump? Like for AC? You can adapt it to the cylinder fittings and it’ll help a bunch pulling it in. Even sometimes will help draw the seals past the area that’s giving you fits. Are you using any lube or oil?

funwithfuel · Jul 2, 2020

Always learning, I never thought of that but it makes perfect sense

Doug580l · Jul 2, 2020

Tinkerer said:
Welcome to the club Doug !
I had a similar experience not long ago. I finally took my cylinder a professional.
The last half of my last post in this thread says it all.
https://www.heavyequipmentforums.com/threads/purchased-my-last-bulldog-seal-kit.81148/

I don't feel so bad now.

Really hope I don't have to bring it to a hydraulic shop. Closest one is about 60 miles away. Probably a better option than driving the backhoe into the pond like I was considering earlier.

I like the way you used the engine hoist to hold the cylinder, wish I thought of that. At first I left the cylinder on the machine. When that didn't go well I put it in my vice and was standing on my workbench.

I just rebuilt my 2 swing cylinders a few weeks ago and that went great so naturally I assumed I knew what I was doing. Should of known better.

Doug

Doug580l · Jul 2, 2020

Junkyard said:
Do you have a vacuum pump? Like for AC? You can adapt it to the cylinder fittings and it’ll help a bunch pulling it in. Even sometimes will help draw the seals past the area that’s giving you fits. Are you using any lube or oil?

Yes I do, great idea! Using hydraulic oil and grease.

Doug

DMiller · Jul 2, 2020

Have wrapped Aluminum Flashing around WELL LUBED seals, then installed hose clamps as see on Turbo boots to pull down tight and then drive the piston back into the bore, had good luck with that.

Junkyard · Jul 2, 2020

funwithfuel said:
Always learning, I never thought of that but it makes perfect sense

I can’t take credit for that discovery. A fellow HEF member told me that, Mikebramel. Works like a charm.

jimg984 · Jul 2, 2020

make sure disconnect the hoses on cylinder could be causing back pressure

Tinkerer · Jul 2, 2020

Doug580l said:
Probably a better option than driving the backhoe into the pond like I was considering earlier.
Doug

OMGosh ! Thanks for my laugh of the day !!
In all the years I have been resealing hydraulic cylinders, I never thought I would be taking one to a shop to get it back together.
Oddly that particular one had been done before with no problems.
I even heated the barrel with a heat gun and the dam piston still wouldn't go in.

NH575E · Jul 3, 2020

I had the same problem with the first one I did. I actually had my son in law hold mine straight as I backed my other tractor into it and forced it in. It shaved a little off the yellow band seal but went together and works fine to this day.

When I did my other side I clamped the seal with a hose clamp and put it in the freezer for a while. I took it out and put the piston on the rod just before I was ready to put it back together and it slid in without any resistance. That side is also working fine.

Both of my stabilizer cylinders will leak down sometimes and other times they stay up. I am talking over a period of days. Neither leak down as you watch and sometimes they stay up for weeks without moving. I guess that is in the valves.

DMiller · Jul 3, 2020

There is a Pilot control block for the Stabilizers, so they must be pressured down or up, the small parts inside tend to erode or contaminate pretty easily.

Nige · Jul 3, 2020

Doug580l said:
I am resealing one of the stabilizer cylinders on a 580sl. I cannot get the cylinder started back in the tube without ruining the piston seal. I am using Bulldog brand seal kit.

IIRC that particular brand of seal kits does not have a particularly good reputation. I seem to recall comments in this same backhoe loaders forum that various posters had experienced issues with them. I can't be more specific than that though, maybe someone else can shed some light.? So in effect what I'm saying is that it might not be anything you are doing wrong, it might be the seal.

NH575E · Jul 3, 2020

On my first attempt at repacking a stabilizer I used a factory kit. I saw no difference in the factory kit and aftermarket kit I used on the second stabilizer other than price. I'm sure the difference in getting the piston back in had to do with method rather than parts.

Not saying inferior parts can't be found but so far the aftermarket kits I've purchased looked and worked fine.

Doug580l · Jul 3, 2020

Got it back together this morning!

I left the piston ring compressor on overnight and put the piston end in a cooler filled with ice for several hours this morning, used plenty of grease and the damn thing slid right in without a lot of effort. Didn't even need the hammer. It was easy to notice that the seal was not loose like before. Thanks so much to everyone for the help. Hopefully I'll remember this and all the other tips when I do the next cylinder.

Doug

Welder Dave · Jul 3, 2020

Great you got it back together.

Cylinder reseal, can't get cylinder started back in tube

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