Register free!

The Green Industry's Resource Center



Reply
 
Thread Tools   Display Modes
  #21  
Old 07-08-2013, 09:57 AM
kman91 kman91 is offline
LawnSite Member
 
Join Date: Jun 2013
Location: Houston
Posts: 23
Here are the pictures from my pump. It looks like somehow something got in the system and took out the cylinder block by getting caught in between it and the valve plate.

Has anyone seen this kind of failure before?
Attached Images
   
Reply With Quote
  #22  
Old 07-08-2013, 10:55 AM
BigFish's Avatar
BigFish BigFish is offline
LawnSite Bronze Member
 
Join Date: Jul 2008
Location: chesapeake, va
Posts: 1,656
Not that big of a groove. You might wanna pull all the valves and fittings outta the head and check 'em for broken springs etc. Looks like that had to be a fairly large chunk at one time.
__________________
" But let me tell you something ,folks: You can't fix stupid! There's not a pill you can take, there's not a class you can go to. Stupid is forever!"

......AMF!
Reply With Quote
  #23  
Old 07-08-2013, 11:23 AM
kman91 kman91 is offline
LawnSite Member
 
Join Date: Jun 2013
Location: Houston
Posts: 23
That's a good idea BigFish. I did pull the springs and pistons, and the pistons look perfect, but I didn't think of checking the springs.

>Looks like that had to be a fairly large chunk at one time.

That's what I was thinking. How could something that big get through the filter? I would suspect it would have to have broken off something already in line before the pump, or in the pump itself, but I see no other damage to anything other than damage to the bearings caused by the metal shavings.

It looks like it was caused very quickly, since there's no real wear on the valve plate between the openings in the same area, only some minor galling. Whatever it was, it got chewed up pretty quickly after it did the damage.

For some reason, in the piston bore, around the springs is the only place I could find any metal shavings. I guess that's the only place they got stuck.
Reply With Quote
  #24  
Old 07-08-2013, 01:24 PM
BigFish's Avatar
BigFish BigFish is offline
LawnSite Bronze Member
 
Join Date: Jul 2008
Location: chesapeake, va
Posts: 1,656
Naw, man, I'm talkin' about the pump end cap/head assy Check that out as above.
__________________
" But let me tell you something ,folks: You can't fix stupid! There's not a pill you can take, there's not a class you can go to. Stupid is forever!"

......AMF!
Reply With Quote
  #25  
Old 07-08-2013, 01:44 PM
piston slapper's Avatar
piston slapper piston slapper is offline
LawnSite Platinum Member
 
Join Date: Mar 2010
Location: Tampa Fl
Posts: 4,027
That's a bunch of damage...
Looks like the pump cavitated at one time causing extreme friction and heat to the valve plate...
The valve plate warped and made contact with the cylinder..there is usually a layer of fluid between them..even under pressure..
A piece of the valve plate wore into the cylinder block...look closely at the slits in the plate..the hot pressurized fluid did the rest..
1200 psi is normal between the valve plate and the cylinder block...at around 300 degrees..
Any leaks between them will act like a mini pressure washer ...blasting away more and more metal until it fails..
The metal residue in the hydrotank is all that's left of the missing metal...
__________________
If You Have All The Answers...Except The One You Need...You're Not Trying Hard Enough...
Do The Work
Reply With Quote
  #26  
Old 07-09-2013, 12:12 AM
kman91 kman91 is offline
LawnSite Member
 
Join Date: Jun 2013
Location: Houston
Posts: 23
Thanks BigFish, that's a good suggestion. I'll do that.

Piston Slapper, I'm not sure I can imagine what you're talking about, but it's an interesting theory. I wonder what would have caused the cavitation. Filter neglect?

How's the best way to flush the system?

Thanks guys, you've been a BIG help!
Reply With Quote
  #27  
Old 07-09-2013, 09:20 AM
piston slapper's Avatar
piston slapper piston slapper is offline
LawnSite Platinum Member
 
Join Date: Mar 2010
Location: Tampa Fl
Posts: 4,027
[QUOTE=kman91;4811226
Piston Slapper, I'm not sure I can imagine what you're talking about, but it's an interesting theory. I wonder what would have caused the cavitation. Filter neglect?![/QUOTE]

Heres a pic of a cylinder block with over 500 hours..just like new...
Notice the spaces between the piston ports..
Attached Images
 
__________________
If You Have All The Answers...Except The One You Need...You're Not Trying Hard Enough...
Do The Work
Reply With Quote
  #28  
Old 07-09-2013, 09:47 AM
piston slapper's Avatar
piston slapper piston slapper is offline
LawnSite Platinum Member
 
Join Date: Mar 2010
Location: Tampa Fl
Posts: 4,027
If you look at the damaged cylinder block...you will notice the voids between the ports are tapered..
If they were caused by a piece of metal..they would be consistant...not tapered..
The tapering of the grooves is caused by hydralic fluid screaming thru the breach between the ports..

A closer look at the slits in the valve plate shows only 1 damaged slit..the piece that initially contacted the cylinder block..
If the pump had ingested a piece of metal...all the slits would be hogged out...

The pump might not have been purged correctly when installed...causing this long term failure...
THIS DIDNT HAPPEN IN ONE DAY...
__________________
If You Have All The Answers...Except The One You Need...You're Not Trying Hard Enough...
Do The Work
Reply With Quote
  #29  
Old 07-09-2013, 10:39 AM
kman91 kman91 is offline
LawnSite Member
 
Join Date: Jun 2013
Location: Houston
Posts: 23
I see what you mean, but how did the oil blast away metal? If the oil got past about 500 degrees F, it would start to vaporize. This is far below the melting point of any of the metals involved.

By purging, you mean working out the air bubbles? From what I can tell from the Hydro Gear manual, you just have to run it for a little bit to work out the bubbles. If this is true, surely they would have worked themselves out, right?
Reply With Quote
  #30  
Old 07-09-2013, 10:55 AM
piston slapper's Avatar
piston slapper piston slapper is offline
LawnSite Platinum Member
 
Join Date: Mar 2010
Location: Tampa Fl
Posts: 4,027
Quote:
Originally Posted by kman91 View Post
I see what you mean, but how did the oil blast away metal? If the oil got past about 500 degrees F, it would start to vaporize. This is far below the melting point of any of the metals involved.

By purging, you mean working out the air bubbles? From what I can tell from the Hydro Gear manual, you just have to run it for a little bit to work out the bubbles. If this is true, surely they would have worked themselves out, right?
Hydralic pressure will blast a hole thru steel over time..like a mini blowtorch..

If the pump was started dry..irreparable damage occurs in less than 10 seconds..
__________________
If You Have All The Answers...Except The One You Need...You're Not Trying Hard Enough...
Do The Work
Reply With Quote
Reply

Tags
exmark , hydraulic , lazer z , pump , wheel motor

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump





Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©1998 - 2012, LawnSite.comô - Moose River Media
All times are GMT -4. The time now is 06:27 AM.

Page generated in 0.11523 seconds with 10 queries