Hydro line o-rings, NOS Toro vs new

[Petes Horse 20]

Thought I would share an experiment brought on by boredom and waiting for parts/payday. I found some new very old oem Toro backup o-rings and wanted to compare them to my new o-rings.

Measured them both and found the Toro backups to be 25 thousandths smaller diameter and a lot harder than the new ones. When I put the Toro backup on the new o-ring and

pushed down on them it wanted to roll off and was difficult to keep together. The new backup fit well and was very stable. I could put much more force on them.

The new backup also fit snugly into pump recess while the Toro oem would fall out. I figure the Toro ones may have shrunk over the years.

 

To measure, I used the highly scientific method of picking them up with my caliper then slowly opening it until they fell out

 

Toro #103184

Viton 90 durometer #018 contoured backup

Viton 70 durometer #018 o-ring

 

Toro backup on top of new o-ring

 

New backup on new o-ring

 

Toro backup side view with what looks like an eyelash in the background.

 

New backup side view eyelash removed.

 

[pfrederi 17,887]

Interesting.  Toro didn't make the backer rings (neither did Sundstrand).  Who knows how long ago they bought them and how long they have been sitting on a shelf in some warehouse.

[Sarge 3,463]

I did some comparison of the o-rings for the Sundstrand hydro pump to manifold set I got from @pfrederi and a fresh set from LJ Fluid Power just for the heck of it and satisfy my own curiosity - exactly the same as far as I could measure them . Durometer appears to be the same as well - I cannot detect any difference in them anywhere id/od/thickness . Older rubber parts will shrink and I suspect it's why some of the older units have a tendency to start weeping a bit with age - new seals stops the problem . Same with axles and crankshafts ,ect - they all shrink over time and get brittle . Add a bit of bearing wear - you'll get a leak for no apparent reason . Waiting on a pair of seals and needle bearings for the D's hydro pump trunnion shafts for the swash plate - this pump decided to leak after I changed the housing gasket , ugh .

 

I'm surprised some of these parts aren't more specific or proprietary - that's a good thing . I doubt Sundstrand or WH or Toro made their own and I'm sure as long as they aren't some cheap import replacement good quality rings/backers in the correct size should be fine .

 

Sarge

[pfrederi 17,887]

The backer rings I got from McMaster actually had a cure batch# and  a packing date.  August 2014.  I bought them in November 2015.  I wonder if there is a shelf life?

[Sarge 3,463]

I'd bet if you called McMaster and asked a tech - they'd get an answer for you quickly . I'm still amazed every time I use their tech line service - those folks are dedicated to getting whatever answer you want without question and never go that wanting to argue with you about your concerns - I really love that company and have yet to get anything from them that wasn't top quality at a fair price . Wish everyone did business like McMaster , it would make this stuff so much easier .

 

Have you tried their phone app ? First time I've seen a store app that actually works excellent - it should be an example to the rest of them .

 

Sarge