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How to Solve and Prevent Hydraulic Problems

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How to Solve and Prevent Hydraulic Problems How to Solve and Prevent Hydraulic Problems Brendan Casey How to Solve and Prevent Hydraulic Problems 2 Copyright © Brendan Casey 2005, 2007 All rights reserved. No part of this electronic book may be reproduced or transmitted in any form or by any means, electronic, mechanical, photocopying, and recording or otherwise, without the prior, written permission of the publisher. The contents of this book reflect the author’s views acquired through his experience in the field under discussion. The information in this book is distributed on an “As is” basis, without warranty. Every effort was made to render this book free from error and omission. However, the author, publisher, editor, their employees or agents disclaim liability for any injury, loss, or damage to any person or body or organization acting or refraining from action as a result of material in this book, whether or not such injury loss or damage is in any way due to any negligent act or omission, breach of duty, or default on the part of the author, publisher, editor or their employees or agents. First published in 2005 by HydraulicSupermarket.com PO Box 1029 West Perth WA 6872 Australia Email: [email protected] Web: http://www.hydraulicsupermarket.com/books Copyright © Brendan Casey - www.HydraulicSupermaket.com How to Solve and Prevent Hydraulic Problems 3 Table of Contents Introduction........................................................................................................................ 5 Anatomy of a hydraulic pump failure............................................................................. 7 Hydraulic cylinder failure caused by the 'diesel effect'............................................. 10 Hydraulic ram leak caused by operator error............................................................. 12 Hydraulic pump and motor case drains - filter with caution..................................... 14 The value of the humble hydraulic symbol................................................................. 16 Compression and decompression of hydraulic fluid................................................. 18 Hydraulic cylinder rods turn black................................................................................ 21 Determining hydraulic pump condition using volumetric efficiency........................ 22 Solving hydraulic system overheating problems....................................................... 24 Hydraulic cylinders - checking rod straightness ........................................................ 26 Hydraulic pump life cut short by particle contamination........................................... 27 Hydraulic press failure illustrates the importance of scheduling change-outs...... 28 Hydraulic motors - how dry starts damage them....................................................... 30 Hydraulic valve failure caused by cavitation .............................................................. 31 Hydraulic hose failure costs and prevention .............................................................. 32 Hydraulic system troubleshooting - check the easy things first .............................. 34 Proactive maintenance for hydraulic cylinders .......................................................... 35 Hydraulic fitting selection the key to leak-free hydraulic plumbing......................... 36 Converting 37-degree hydraulic fittings into zero-leak connections....................... 38 Hydraulic filters that do more harm than good - Part 1 ............................................ 39 Hydraulic filters that do more harm than good - Part 2 ............................................ 40 Hydraulic filters that do more harm than good - Part 3 ............................................ 41 Hydraulic pump control problem highlights the value of testing ............................. 42 Adding hydraulic oil - without the dirt .......................................................................... 45 Hydraulic fluid - getting the viscosity right .................................................................. 46 High hydraulic fluid temperature - how it causes premature failures..................... 48 Biodegradable hydraulic fluid - its application and use ............................................ 49 Hydrostatic transmissions - making sense of case drain flow Part 1..................... 50 Hydrostatic transmissions - making sense of case drain flow Part 2..................... 52 Copyright © Brendan Casey - www.HydraulicSupermaket.com How to Solve and Prevent Hydraulic Problems 4 Hydrostatic transmissions - making sense of case drain flow Part 3..................... 54 Temperature shock of hydraulic components and how to avoid it ......................... 56 Configuring mobile hydraulic valves using power beyond....................................... 58 The true cost of hydraulic oil leaks .............................................................................. 61 Hydraulic system oil types and manufacturers' recommendations ........................ 63 Which hydraulic oil?....................................................................................................... 65 Reducing noise emission from hydraulic systems .................................................... 67 Hydraulic repair using aftermarket hydraulic parts ................................................... 69 Dealing with water in hydraulic fluid ............................................................................ 71 Hydraulic troubleshooting basics................................................................................. 73 Dealing with air contamination of hydraulic fluid ....................................................... 75 Understanding hydraulic load sensing control........................................................... 77 Flushing hydraulic systems........................................................................................... 79 The anatomy of hydraulic vane pump failure............................................................. 82 Pressure intensification in hydraulic cylinders........................................................... 85 Testing Hydraulic Cylinders.......................................................................................... 87 Reducing hydraulic cylinder repair costs.................................................................... 89 Dealing with bent hydraulic cylinder rods................................................................... 91 Understanding Hydrostatic Balance............................................................................ 93 Hydraulic filter condition monitoring ............................................................................ 95 How to avoid hydraulic troubleshooting mistakes..................................................... 97 Power saving with hydraulic load sensing control..................................................... 99 Dealing with hydraulic and pneumatic leaks............................................................ 102 Sourcing aftermarket hydraulic components ........................................................... 104 Nailing hydraulic logic element leakage ................................................................... 106 Putting the brake on water hammer in hydraulics................................................... 109 Priority number one in hydraulics maintenance ...................................................... 111 Make sure YOU know the 'animal' you're dealing with .......................................... 113 Solving hydraulic cylinder squeal............................................................................... 114 Storing hydraulic cylinders - safely............................................................................ 116 Storing hydraulic cylinders - Part 2............................................................................ 118 Copyright © Brendan Casey - www.HydraulicSupermaket.com How to Solve and Prevent Hydraulic Problems 5 Introduction I've spent the better part of 16 years working in and running hydraulic repair shops i.e. rebuilding hydraulic components. During this time I kept seeing the same pattern: Failed hydraulic component comes into shop along with concerned customer who wants to know why it has failed after a relatively short time in service. Based on what I saw after tear-down, I would explain the cause of failure - for example, high contamination levels, wrong oil viscosity, high temperature operation, cavitation, faulty circuit protection devices and so on. Customer leaves thousands of dollars poorer with rebuilt component and a hard-learned lesson on hydraulic equipment maintenance. For as long as there are hydraulic equipment owners, mechanics and maintenance people out there who believe that hydraulics don't require any special kind of attention, this cycle will continue. In an effort to bridge the knowledge gap on what needs to be done to get maximum life from hydraulic components, I have written Insider Secrets to Hydraulics and it's sequel, Preventing Hydraulic Failures. Over the past 30 years, the performance, sophistication and operating pressures of hydraulic equipment have increased significantly. This is particularly true in the case of mobile hydraulic equipment. As a result, modern hydraulic equipment is not only more expensive to fix when it breaks, proactive maintenance is imperative to maximize service life and minimize operating costs. It's not realistic to expect (as many equipment owners do)
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