Delta Vee

Either way, if the fine folks at Delta Vee came up with the solution it means that the same solution is accessible to anyone else - with some research. Seals can't just be fabricated with chewing gum and a pair of pliers: unless Delta Vee has a hidden ISO 9002 facility in the back of their shop they are using an off-the-shelf application.

 

Well, you don't need to be ISO to do good work but that's an entirely different topic. It's possible, and likely, they have worked with a vendor that specializes in seal manufacturing and that vendor produces seals for them, to their specifications, and only sells to them.

So, "off the shelf" is probably not meaning a standard, stocked part.

 

OK! You guys fight it out and decide who gets to deconstruct my blown out shock. I only have 1.

Sounds like PSI is not interested.

Laserguru is donating his time. Does he have the tools and knowledge to take this apart? Once the seal is out it can't be destroyed so that is can be copied, sourced, or remanufactured. Thanks for volunteering!

DRocks and I have history but he does quality work and probably has what it takes to get this apart and could probably make it or source it. Finally, he has the infrastructure to sell it or make it available for sale.

So whatever the community wants I'll do. We could even have Laser take it apart and DR figure out how to make it. I love it when the braintrust beats these problems.

 

Well, my name says a lot actually. I'm a PhD laser physicist who runs a R&D firm in very high energy lasers for the DoD. We have plenty of resources in the labs.
I, can't, however promise anything like an infrastructure that could do downstream shock rebuilds or source parts. Our overhead and G&A, all gov't audited and approved yields some very commercially non-competitive pricing. Your tax dollars hard at work.....

If DRocks wants to lead and play, it may be a more straightforward path for the community. I will be willing to assist at any turn.

 

OK PM me your addy and I will send the shock to you next week.

 

Guys, while the topic is interesting to me, we don't have the resources at this time. Too many other projects in development at this time.

Thanks for the confidence.

 

Gets shipped to Eric this week.

 

What are the requirements/specs for the seals? Our prototype and cryogenics labs use plenty of them, some with operational requirements up to 30,000 psi. Most are COTS as well.

 

Wade, when I get it and get a chance to do teardown, I'll cheerfully be in touch. I'm expecting an older seal compound (like a chlorinated PTFE) that can be superseded by something newer. We'll have to see about the physical config.

Does anyone in this loop have any ideas about this failure mode? Besides leaking, do there tend to be damaged shock rods? Particular wear patterns? I understand that the system (including accumulators) used Dexron IV or better. Is that correct? Data, gentlemen....all you got.

 

Failure mode for the 550 Maranello shocks is leakage, however for the 456 (someone correct me if I'm wrong) it's leakage, as well as occasional bursting of the shock. body itself, but I'll let someone else chime in on the cause of the bursting as I'm certainly not an authority on the 456 system.

There's usually some light scoring of the shock rods themselves, but it's usually polished out by the shock rebuilder.

 

Thanks. I'm aware that failure of the accumulators leads to hydrolock in the rear shocks and the bursting of the shock body. Usually noticed by the rear suspension becoming really hard and unforgiving. I haven't experienced it and also understand that periodic replacement of the accumulators (essentially a half fluid filled, half nitrogen filled separated bladder design) is a seriously recommended maintenance procedure. Another place where the cross-referenced parts list is absolutely invaluable.

So for the 456 fronts and the 550s, this is essentially an issue of a crappy seal material? Breaks down from the fluid? Poor tolerances on the part design and fabrication? I get once you have leakage you're equally likely to get foreign material intrusion and scoring.

Thanks for the info. Always good to get as much input and failure modes as possible when doing FMA.

 

I think you mean actuator seal.

 

I will surely keep everyone informed as the project progresses.

 

Dear God, man! Next you'll want statistical analysis on a sample of 1.

 

I'm guessing this is a combination problem, not just a bad seal but a bad design etc.

 

So, in the leaking seal failure analysis world (aerospace at least), the first suspicion always rests on the gland design. If that isn't done properly based on the loading of the seal both static and dynamic, you're sure to get deformations of the seal shape. Second suspicion is poor material selection such as an incompatibility of the seal material and the working fluid. One would think this isn't all that tough to do with all the data available from both seal and hydraulic fluid manufacturers but it's amazing how often it happens. Third is the surface finishes, contaminations, etc. We'll see.....

 

Don't forget quality control and parts not manufactured within specification.