In Hydraulics they say that getting two or more cylinders to move at the same time and at the same speed is one of the hardest things to do.
We had a call from a customer who recently purchased a full hydraulic kit including a 12 Volt DC hydraulic power pack with push button pendant control as well as hydraulic cylinders or rams, do it yourself D.I.Y High Pressure Hydraulic Hoses and Hose Fittings, he was in the final stages of completing his Hydraulic Motor Home Canopy. He installed and set up two Hydraulic cylinders to open up a hinged frame for a canvas canopy on the motor home but he could not get the canopy to move smoothly or evenly as the cylinders would not extended at the same time or speed.
The cylinders were exactly the same size, same bore, same stroke, same rod diameter and had a single in and out supply split with Tee fittings to supply both cylinders.
Australian Made Hydraulic Cylinders from 1.5" to 5" bore with up to 48" stroke.
Fact No 1 Hydraulic oil under pressure will always take the path of least resistance.
If one of the cylinders has more load or one had tighter seals or one had a meter more hose or even one more hydraulic fitting the cylinder circuit with least resistance, least friction or least load or work to do will always move first.
Even if the the 2 cylinders are physically connected to a strong a rigid frame like those on a skip bin track or compactor one cylinder will always move before the other eventually causing jams or at the least creating twisting forces.
As most of the work and Plumbing on the hydraulic motor home canopy had been completed we recommended a Cartridge type Hydraulic Flow Divider / Combiner, these items have errors of between 5% and 15% at dividing and combining hydraulic oil flows. These errors were considered acceptable by the client.
A Cartridge Flow Divider will divide a single hydraulic flow into 2 almost identical flows. It will also works in reverse to combine 2 divided flows into one combined flow.
If more accuracy is required to move hydraulic cylinders in unison then we would recommend a Gear Flow Divider, this type of flow divider uses two or more accurately machined gears to mechanically split or combine flow, an error of 5% or less is achievable all be it at a little more cost compared to a cartridge style flow divider.
2 way gear flow divider with built in differential pressure relief valves
The Most accurate way to move two or more cylinders at the same time is with specially manufactured Phasing Cylinders.
Last Christmas the Owner of a 12 metre Mustang Cruiser pleasure boat complained to us that the hydraulic cylinders lifting the floor over his boat's engine room were not lifting evenly, after investigation we discovered that the installation had Phasing Cylinders.
Phasing Cylinders by design are manufactured to move at the same time and speed, BUT ONLY if they have been correctly set up and installed and only if the hydraulic seals are in perfect condition
This synchronized movement is accomplished in the following way.
As a Double acting cylinder is extended the oil on the rod side of the cylinder is displaced, if you take the displaced oil and send into another smaller bore cylinder with the same stroke designed to take all the oil displaced from the first cylinder you will get them to move at the same time and speed.
Take 2 minutes to look at our You Tube Video showing what we found on strip down and how we bench tested and finally got the engine room cover to move up and down smoothly.
Remember the boat's engine room cover has two phasing cylinders.
We Raise the floor by extending both cylinders but by sending pressurized hydraulic oil only into the bottom of the first Larger Cylinder.
We lower the floor by retracting Both cylinders by sending oil only into the top of the second Smaller Cylinder. Our 2 min video.
Cheers Everyone
From the team at Mobile Hose Fixers & Hydraulics Hydraulic Hose Repairs and a whole lot more.
1. Clean the cylinder in wash bay to
remove oil, grease and dirt.
Before commencing disassembly have your mobile phone or digital camera ready and take a picture each step as a part or component is removed.
2. Set up cylinder to be clamped in the floor
vice, with the exception of small convertible type cylinders DO NOT clamp cylinders
on a bench mounted vise. Try and clamp the cylinder on the flat part of the
clevis, if this is not possible use an appropriate sized rod or pin and clamp
the pin in the vise and place end of barrel onto the pin.
3. Finally Level up and support gland nut
/ rod end of the cylinder on sturdy blocks of wood.
4. Whenever possible try and remove
excess oil from both sides of barrel by extending and retracting the rod,
collect all waste oil in suitable containers and empty into waste oil drum for
future collection by approved registered waste collection company.
5. Place oil container underneath gland nut to
collect oil from cylinder when dismantled. Important
this is one of the most important and potentially time consuming steps so
preparation, selection of the most appropriate tools and attention to detail is
paramount.
6. Identify style of gland nut and use
appropriate tool to remove gland nut from cylinder. Check for locking tabs or
grub screws on gland nut, e.g. Yanmar
has locking tabs , JCB cylinders have
grub screws.
7. Most
cylinder gland nuts are threaded into the barrel and need to be unscrewed
counter clock wise (caution) threaded gland nuts can be extremely tight so some
care as well as perseverance is required.
Typical Screw in Gland Nut
Removed Screw in Gland Nut. This Gland Nut is Damaged.
8. At this stage take a couple of
Minutes to Check for Grease nipples lubricating the rod and barrel clevis pins.
Always remove and clean out grease points to ensure that grease can get to the
pins as sometimes hardened bushes rotate in a dry swivel connection and the
grease way gets blocked, Always replace grease nipples with new ones.
9. Remove rod assembly from barrel and collect any oil that comes out in oil tray.
10. Remove barrel from vice and set up
rod in vice. Before attempting removal of piston take a picture with your phone or tablet so you can check which orientation to put it back together.
11. Check for grub screws or scotch keys in piston
or nut retaining piston, screws may be under seals.
Identify style of piston or
piston nut and use appropriate tool to remove piston from rod. Take picture of seals position and location on
gland and piston so you know which way to put them back in.
12. Once gland nut and piston is removed from rod
start to remove seals from both gland nut and piston carefully as you will need
samples to measure up and order.(DO NOT BREAK ANY) Keep all old seals in a plastic bag to show
customer what has been removed and replaced. Don’t assume just because 2 cylinders look
identical that they have the same seals. (Speaking from experience)
13. Once all seals wear bands and or bushes are
removed use telescopic gauges (internal caliper ) to check bore of barrel in several
locations. (check three places at bottom of barrel, three places in middle and
three places at end of barrel.)
14. Also measure rod and put a straight edge on a rod to
check for any damage. (Damage consists of rust marks, dents, scratches, plating
removed.) If either part has imperfections (scratches/
dings) then repair or replace. If not possible then order new cylinder.
15. SEAL, WEAR BAND AND
GLACIER BUSH MEASURING (if the clearance is more than 0.04mm between glacier
bush and rod, will have to machine or press out the glacier bush) After seal removal, search ‘grid for seals” in MHF folder, if
cant be found look on Job card wall.
16. Measure seal and wear band grooves metal to metal only. Draw
& label sizes on grid paper. Put your name, date & job on grid paper Scan & email with order number. Don’t fax.
17. Measure up seals and seal grooves then order a
new set from either manufacturer of cylinder or from reputable seal supplier. (Ensure parts
removed are correct for the job). Compare dimensions with part numbers and with
sizing of components.
18. Check all components for dimensions before re assembly. Put gland nut and piston in lathe and use
emery paper to clean all rust and marks from both (Make sure to clean all
surfaces, especially where seals sit).
19. If applicable put parts in wire wheel to
remove any imperfections. Once all clean re install seals in both gland
nut and piston. If using one piece Teflon seals hold seals
tight to piston with piston ring compressor or a hose clamp and piston assembly
in a plastic bag and then into freezer for 20 mins this will shrink Teflon
seals and make them easier to install. Oil up and install gland nut on rod, lock
tight piston on if held on by nut.(Remember to put
piston in the correct orientation, to prevent damaging piston seals. CHECK
PICTURES YOU HAVE TAKEN WHEN PULLED APART)
20. Oil up barrel and install rod assembly into
barrel and tighten gland nut. Put cylinder on test bench and pressure test
in both directions, retract rod all the way in and plug the piston side of the
cylinder. Pump oil into the rod side and check for bypass. If all ok then clean up, put Mobile Hose
Fixers sticker on the cylinder and bill customer for professional job.(Remember
to also bill clean up time after job is finished)
We have been offering a hydraulic cylinder reseal and rebuild services for about 9 years now and we thought we would write about a couple of particularly interesting jobs we started to work on in our new larger heavy equipment Hydraulics Workshop in Nerang, Gold Coast Australia last week.
Our Nerang Workshop Manager Denis with Our Biggest
Hydraulic Cylinder Reseal To Date
a 3,000 mm Stroke 250 mm Bore Monster weighing in at 2300 kg.
Also this week one of our clients who business has grown incredibly rapidly, recently purchased mobile compactor for his document destruction business. We gave its hydraulics systems and hardware a health check and prescribed overhauled Hydraulic Pumps and we also rebuilt some of the numerous compactor hydraulic cylinders with new rods and seals.
Hydraulic Cylinders or Hydraulic Rams are found on great majority of equipment.
On earth moving equipment they are designed to be STRONG and to work in the worst conditions imaginable, that is, in dirt, rocks, dust and mud and at pressures up to 270 BAR (4000 PSI). So most cylinders will only come apart if you are equipped with all the special and necessary tools required to literally force these components apart.
Typical Cross Section of Hydraulic Ram or Cylinder.
This particular cylinder below is off a 7 ton Kobelco excavator, it has completed about 4000 hours of work, it has a 100 mm Bore, 850 mm Stroke and 55mm Rod diameter.
Generally there are 2 parts where a large Force is required to dismantle a Hydraulic cylinder.
1. Unscrewing the Gland nut on the end of the cylinder. These usually come apart .... eventually with the use of a correctly sized "C" spanner (or Pinned Cam tool) and a long bar for leverage.
The exception are some Yanmar Cylinders that are made to such close tolerances that the threads usually seize or bind up after a turn or two, .... then... liberal amounts of heat (enough heat to usually melt the seals!) and lots force are required to unscrew them.
Gland Nuts usually screw onto the end of a cylinder's Barrel and are then done up very tightly.
2. Unscrewing the nut that holds the Piston onto the Piston Rod.
These nuts are usually done up extremely tight as the piston is the component that has very large forces acting on it in alternating directions of each in/out cycle of the cylinder.
Piston Nut Assembly these Strong Steel Pistons usually screw on to the end of the Cylinder''s Hardened Chromed Rod .
On the Kobelco cylinder despite all our efforts (including heat) we could not undo the nut. The 300 KG steel bench was flexing and creaking under the strain! We could apply more force but we knew the bench could not handle it and would flip or tip over under the high torque we would need to apply.
Bolting the bench to the floor was not an option as its construction was designed for high weight and it was on wheels so large twisting forces were not an option.
Time was now a critical factor as the customer was picking up the cylinder the next day, So we quickly bolted a 2 meter long steel beam to the concrete floor and then bolted a 200 mm steel vise to it.
We still use this floor beam and 200mm vise to dismantle some of the
smaller cylinders that come through our doors with great success.
We then tried again and our floor mounted beam and vice worked a treat!
By our calculations we applied around 4500 NM (3300 foot pounds) of torque to the nut before it came loose. To put it into comparison the typical torque spec to properly seat a crankshaft balancer on the Chev LS1 V8 engine is 330 NM (240 foot pounds) of torque.
Denis Checking out next acquisition a massive Hydraulic Cylinder Breakout Bench
Cheers and all the best for 2019 !
From the team at Mobile Hose Fixers & Hydraulics,
"Living and Working the Dream" on the sunny Gold Coast, Australia.
Removing Repairing and or replacing a damaged Hydraulic Hose is not generally very difficult. That being said there are quite a few important steps to ensure the final outcome is a success.
With a little bit of planing, preparation and using the comprehensive guidelines below you and your machine's hydraulic system will be back up and operating in the shortest possible time and or with the least effect to your wallet or bank balance.
For 13 lucky years my team and I have removed manufactured and installed over 50,000 hose assemblies.
If you are looking to join the hydraulic hose replacement industry and earn some good Money in the process this blog is a good first introduction on the basics of what we do, why we do it and how we do it.
It has been put together by the team at Mobile Hose Fixers & Hydraulics as both a guide and a reference to assist you to carry out your hydraulic hose repair work safely and efficiently.
Before you start you must make a through review of the surroundings and situation, identify the hose AS WELL as any other spare or replacement parts necessary to fulfill the requirements of the application.
It is imperative that you observe and obey all safety requirements before, during and after work has been carried out.
You are required under the Workplace Health and Safety Act to notify the owner or operator of any unsafe conditions or possible premature failure of hoses or associated fittings.
Care must be taken to avoid oil spills. Appropriate caps and plugs must be fitted and drip trays used in order to minimise spills. When spills occur, it is necessary to use rags or oil absorbing materials such as pads and granules to ensure that the oil is removed.
Note: In Australia and most other parts of the world It is an offence against environmental legislation to allow oil to be introduced into the storm water drainage system. Under no circumstances may spilled oil be flushed or dumped into gutters or storm water drains. Take all spilled and waste oil away with you for proper disposal or collection by a registered waste organisation.
Although this is a comprehensive blog that outlines most procedures and gives practical advice on hose making. You may still, however, come across unusual situations requiring creative solutions.
Use your initiative to resolve these situations, Above all you must always follow safety procedures, and ensure that all checks are carried out under normal working conditions.
Contents.
Safety First ALWAYS ( P.P.E)
Pressure Force and Gravity
Prepare to get Dirty (oily hands or neoprene gloves)
Finding the Damaged Hose (trace the leak to the source 😉)
Understand the Mechanics (what does the hose do?)
Make the machine safe
Protection from the Elements sun wind rain
Tools more Tools Special Tools and Techniques
Get to it. Perseverance and Resilience.
It's OK to Swear (it helps release stress and tension)
Colored cable ties Plugs and Caps (keeping it all Organised and Clean)
Secret tricks to help remove the old hose and replace the new hose (rope and wire and tape are your friend)
Once the Hose is out (now what are your Options?)
Store Bought OEM, After Market, or D.I.Y.
Store
D.I.Y
STAMPED and APPS to help you identify what you require.
Reusable fittings advantages and Disadvantages.
D.I.Y Video, Hydraulic Hose Assembly with Reusable fittings.
Hose types and Basic Identification
All our new team members get quickly introduced, trained and then relentlessly questioned and tested on the acronym S.T.A.M.P.E.D. why, because we feel we have proved it thousands of times over that questions asked and answers received based on these 7 letters result in a more effective, durable and safer hydraulic hose repair.
We have completed over 50,000 High Pressure Hydraulic Hose Repairs, and we have found that starting your questions based on this 7 letter acronym will help even the most inexperienced team member pinpoint with much better accuracy just what hose type and construction will be most suited for the application.
From Top Left Fabric Braid up to 500 PSI (35 Bar)
Single Wire Braid up to 2000 PSI (135 Bar)
Multiple Wire Braid up to 4000 PSI (270 Bar)
Multiple Spiral Wire Wrap up to 6000 PSI (410 Bar)
Read on to find out how you can get your self out of trouble and back working with the right hose most ideally suited for you and your machine's requirements.
So when you contact us expect to be asked a few important questions using the Acronym S.T.A.M.P.E.Dand then, based on your answers, we will formulate the best, quickest and most economical solution for you.
Our solutions or options may include.
Sending one of our Mobile Service Technicians out to do the job for you.
Arrange for you bring the hose or even the entire machine to our Gold Coast service center.
Us packing and sending you the parts or the completed hose assembly you need along with instructions to Do It Yourself (DIY).
S.T.A.M.P.E.D stands for
S = Size
T = Temperature
A = Application
M = Media
P = Pressure
E = Ends
D = Delivery
S = Size, The size or more importantly the Hose Inside Diameter. Generally you will need to replace the original hose with one of the same inside diameter. On long runs of pressure wash hose for example we may recommend the next larger size available to maintain original design flow and pressure drop.
Three (3 ) Hose Samples each with a different inside diameter From top to bottom 1/4" (6.5 mm) 1/2" 12.7 mm and 1" (25.4 mm)
T = Temperature, For most Australian operating conditions it is sun and heat rather than cold that causes damage and deterioration in hydraulic hoses. The operating temperature is important in selecting suitable materials of Construction. Normal hydraulic hose will typically run around 60 to 75 degrees Celsius, transmission and power steering hoses may operate up to and around 120 degrees Celsius. Truck air brake compressor hoses may reach 150 degreesCelsius or more
Four (4) Hose samples with their Maximum Continuous Working Temperature
From Top to Bottom, Synthetic Fiber Reinforced Nylon 70 C°,Steel Reinforced Synthetic Rubber 120 C°,Steel Reinforced High Temp Synthetic Rubber 160 C° Stainless Steel Reinforced (PTFE ) Teflon 260 C°.
A = Application. How, Where and How often is the hose being used. Will it be exposed to the elements, sun, Heat, Wind, Rain, Snow and Ice. Abrasive environments such as those found Earth moving equipment, Aggressive chemicals, not just those found in paint or industrial chemical factories, Believe it or not the salt in sea / ocean water can be classified as an aggressive chemical environment because salt when mixed with water and the oxygen in air can deteriorate most materials quite quickly.
Sea Lift, This Machine Drives down a boat ramp and into the sea and positions itself under large twin hulled boats, it then raises up levels out and brings the boat up onto the shore for repairs and maintenance, it may do this task multiple times a day.
M = Media, What type of fluid is going to be flowing through your high pressure Hydraulic Hose? Water, Oil, Gas, Chemicals with what PH Acid or Basic? P = Pressure, The normal Operating Pressure is very important in ensuring the correct hose is selected for strength and durability. Generally we work with an industry recommended Burst to Working Pressure safety factor of 4 to 1. For example a 1/4 inch inside diameter 2 wire braided hose will have a working pressure of 5600 PSI (380 Bar) and have a Minimum Burst Pressure of 22,400 PSI (1520 Bar)
4 Hose Samples with different materials of construction & Working Pressure Ratings. From Right to Left (small to large). 3/8" bore hose Synthetic Fiber reinforced hose SAE 100R6 pressure 34 BAR (500 PSI) 1/2" bore hose with 1 layer of braided steel wire SAE 100R1, working pressure 136 BAR (2000 PSI) 1/2" bore hose with 2 layers braided steel wire SAE 100R2, working pressure 275 BAR (4040 PSI) 3/4" bore hose 4 layers spiral wound steel wire SAE 100R15 ,working pressure 400 BAR (6000 PSI)
E = Ends,
What connections are on each end of the hose. This is Very Important and can vary quite a lot depending on intended application, working environment, how it is positioned and sometimes more importantly on the machine's country of manufacturer or intended country of origin.
Six 1/4" Hose Fittings from Left to Right
14 mm Metric Male,
9/16" JIC Male,
1/4" BSPT Male,
1/4" BSPP Female Straight,
1/4" BSPP Female 45° Elbow,
1/4" BSPP Female 90° Elbow.
D = Delivery, How are you or we going to get your hydraulic hose repaired and leak sorted, and what tests and or special safety procedures will we or you carry out before, during and after final installation and commissioning for example ?
Do we come to you?
will you take the hose off and bring to us?
Will you or can you bring the whole machine to us? or
Will we assemble and pack and send the parts to you ready to assemble and install?
The Story is nearly always the same. The phone call from the stressed customer is nearly always the same,
I had just one
more load to take to the land fill site or
more meter of trench to back fill or
more driveway to blast clean or
car or boat to rinse off... and I was done!
"But then I noticed Oil or Water leaking and pooling on the ground, or worst yet hot Oil was spraying and making a mess of my engine bay or even worse yet pouring on to my customer's newly cured concrete driveway and freshly painted house wall !?
Sometimes the hydraulic hose leak is small and the oil seeps into the ground unnoticed until your machine starts to shudder and loose power or just stops, moving, digging or grinding altogether. What The ! you think to yourself !?!
Repairs to Excavator with a Pulverizer, (a concrete crushing attachment) on a demolition site.
With 50,000 High Pressure Hydraulic Hose Repairs completed over the last 12 years There are a couple of ways to get you back to work. The best and safest way is to call us at Mobile Hose Fixers & Hydraulics (07) 5571 6155
Need Hydraulic Hose Repairs click here However, having a mobile High Pressure Hydraulic Hose Repairs technician visit you is not always possible, practical or economical.
The quickest and most cost effective way to repair or replace a hydraulic hose will require you to have some mechanical knowledge and aptitude and to be capable of safely finding and removing the damaged or leaking Hydraulic Hose.
You will also have invested in some minor insurance such as a handful of D.I.Y Reusable Hose Fittings , Hydraulic Hose and some tools such as spanners or wrenches and preferably (but not essential) a vise or vice mounted to a solid bench or other heavy object. If you want some Guidance and insight on how you can manufacture new high pressure hydraulic hose assemblies with basic tools and without expensiveequipment? Then watch this informative 12 minute video to get an idea what is required to complete a Do It Yourself D.I.Y Hydraulic Hose Repair Assembly using Reusable Field Fit Hydraulic Hose Fittings.
Typical Field Fit Reusable, a Hydraulic Hose Repair fitting used for Hydraulic Hose Repairs and Do It Yourself DIY hose Assemblies. These two (2) piece fittings screw onto the hose in a certain sequence and once assembled are rated to work safely up to the full pressure rating of the hose.
For a complete store overview and everything hydraulic, including, hose, fittings, valves, motors and cylinders. But first please read below to fully familiarize your self and or refresh your memory on the process and parts required. If you get stuck or need assistance use the contact us page to phone us or send a message. Click here to contact us
