Trouble installing cylinder seals

Hi, I am currently doing some long overdue maintenance and repairs on an inherited 235C Cat excavator 1974.
I've replaced most of the seals in the bucket cylinder but cracked the buffer seal trying to install it. The seals were about 20% the price of Cat seals, Blumaq brand.
It's 4-3/4 ID and 5-3/4 OD and 7/32 thick.
Seal was about 80f and I used the standard fold technique to push it into the cylinder gland end. It cracked long before I got it into position, I tried again with a new seal and heated it in oil to about 250f and it cracked as soon as I deformed it just a little.
I'm unsure if it was my technique or the cheap seal quality that caused my troubles.

Also I installed the wiper seal about a month ago and it was sitting on the table in the shop for a few weeks, looked at it recently and there were several cracks straight through it!
It seems like the urethane was really brittle and shrunk and cracked.. You could break off little pieces like it was some hard chocolate...
I think ill order new wipers and buffer seals for the bucket and boom cylinders to replace these questionable ones, I was thinking from Hercules seals. I hoped the wipers would remain in good shape maybe for a decade, even exposed to the elements as they are. A couple weeks in a shop seems like it was defective, it had a light coating of grease on it as well. That made me think the buffer seals were similar, as the appear to be made from the same material.
For now I'm finishing up line boring the bucket and welding up some bad wear.
I've line bored the horrible boom pins and want to reseal the cylinders before it goes together in the spring.

Thanks for any thoughts anyone has on this!
Gerry

With that kind of luck with the seals, you prolly should replace the piston seals with Hercules.
Bulldog is another good quality brand.
Where did you buy those seals ? Blumaq headquarters are in Spain.

I got them from global parts zone.
Some of the seals were CTP brand. I ordered Hercules ones to replace all the Blumaq ones I have.
I set all of them on the shelf out of the bag to see if any will shrink as the first one did.
Thanks, it's good to know Hercules and Bulldog are good. Also closer shipping to me.

I think you will have much better luck with the hurcules seals at least they were defective before you put it all together

Yes, I feel lucky to have found my mistake before they were assembled on the machine.
This cylinder must weigh about 1000lbs, it is not fun to deal with.
The old wiper seals were cracked apart as well. There are marks from the cylinder being apart before, so not original. The seal on the cylinder stop had just a few crumbs left of it.
Hopefully it will hold up now and be of use to me or someone for years to come.
The seal I heated in oil I was flexing excessively afterwards and it doesn't seem to crack at all now.
Being that it will live in not as hot oil, I feel it would not have held up long even if I got it in there.

do you have a hydraulic shop near you ,maybe see if they will install it

I dont think he had installation errors just bad materials those bigger seals are easy to put in you could tie a new buffer in a knot and not break it it if was made properly

I do regularly use a local hydraulic shop for some work related stuff. Also I rebuild one specific style of small hydraulic cylinders regularly at work.
Never had trouble with installing a seal before that I can think of.

Here's a picture that wiper that cracked just sitting on the table. I painted it since then and never bothered to tape it off since it's coming out

OldIronCanuck said:

Here's a picture that wiper that cracked just sitting on the table. I painted it since then and never bothered to tape it off since it's coming out

Click to expand...

Had to go back and reread your first post!

That wiper seal looks like something I might expect to see on a 25 year old machine that has never been rebuilt!

Only good thing is it happened before you put the cylinder on and started working machine in some nasty gritty material. If it happend then you might have had major hydraulic problems before you saw it!