replacing hydraulic hoses

[cod 116]

When one is replacing the hydraulic hoses for the lift cylinder, is it possible to use teflon tape on the male fittings?  I have to hoses that connect to the lift control and both have small leaks.  I'm using the replacement Toro hoses so they "should" be correct but I'm puzzled as they have a tapered thread and when I put them on I made sure they were tight.  While I don't have a problem taking everything apart again to fix the leak ( as practice makes prefect ), I'd like to get it right so any pointers would be greatly appreciated.

 

Thanks

[cheesegrader 433]

I'm no expert, but I have been told NOT to use teflon tape on hydraulic fittings.  It can break free, circulate in the system, and damage the pump.

On my tractors, hydraulic leaks have been from bad O-rings, and from leaks in the swivel section on older hoses.  Tape wouldn't help either one of these problems.

[MalMac 1,328]

I second that, no tape. Check your o-rings and replace. Make sure you do not over tighten. It smashes the o-ring and causes tiny tears.

[brandonozz 168]

Teflon shouldn't get into the system if installed on the male threads ....but if you ever remove that fitting the tape will be in the female threads and could get pushed into the hydraulic system when you reinstall the fitting again .....and teflon is not good in oil service. It can degrade in oil service, get gummy and the fitting can become loose. As mentioned above, find the real problem and put in new "O" rings and lubricate the rings before installing to help prevent damage to the o ring.

Edited September 7, 2013 by brandonozz

[Jeff-C175 7,195]

 

they have a tapered thread

 

They do?  You sure?

[cod 116]

 

 

they have a tapered thread

 

They do?  You sure?

 

Another reason to take pictures...

 

Actually Jeff I thought they were but prehaps they were straight threads.  What I found with the new hoses was that there were a couple of fittings on the hoses that were rigid, so you had to turn the complete hose to get them into the female thread.  A couple of the fittings had an O-ring, a flat washer and a nut above the male threads that you can tighten once the hose is installed.  I'm almost positive that the hoses that go into the lift control were rigid with an O-ring so I wiped the O-ring with tranny oil, hand tightened the hose and then used a wrench to snug it up.  I do not think I over torqued the fitting but I didn't have any torque specs for the hoses to use as a reference.

 

The fittings on the tranny, lift cylinder and the back of the lift control are dry so at least I got those correct.  Other than the weeping fitting the only other hassle was trying to get the hoses routed through the opening in the side plate as it's too small IMO.  After I ordered the new hoses,  I found another thread :

 

 

that I wish I had found sooner as it looks cleaner and the small hose diameter would make it easier to rout the lines.

[varosd 1,185]

Cod:

         check out this hyperlink. under the Thread Identification tabs....it shows the proper tightening of ORB/JIC etc fittings.

 

http://www.surpluscenter.com/techhelp.asp?catname=hydraulic

[Jeff-C175 7,195]

 

After I ordered the new hoses,  I found another thread :

 

That's exactly what I did a few months ago, my thread is here:

 

 

If I could have gotten the hoses from Toro for mine, I don't think I would have looked any further either.

 

I do have to say in hindsight though, that installing the fittings to the hoses was sorta time consuming, but in the end the results are perfect.  No problem routing the smaller hoses through the opening.  It did take a couple tries at positioning the adapter fittings so everything lined up but all in all not too bad a job.  All dry as a bone now.  No more having to add oil to the tranny every time I mow or wipe down the top of the deck when finished.

[Jeff-C175 7,195]

Just looked at the file that Don posted, thanks Don!

 

I know Cod's job is done, this might benefit future readers though.

 

This section on installation instruction though seems to differ from my experience, but I might be misunderstanding what it says...

 

 

Recommended SAE O-Ring Adjustable Stud Assembly Instructions

STEP 1: Follow steps 1 and 2 from the foregoing
instructions, then proceed to the following steps below.

STEP 2: Looking at fitting from end with nut/washer/o-ring
assembly, turn nut clockwise as far as possible by
hand.

STEP 3: Using wrench, turn fitting into port until the
washer touches thread nearest wrench pad.

STEP 4: Back off fitting counterclockwise not exceeding
one revolution until it is oriented in the correct position.

STEP 5: Place wrench on the wrench pad of fitting to
prevent fitting from turning, and torque nut to the value
shown in the following table.

 

In my thread above, post #29, I described seepage problems when I followed the above instruction.  It MAY be because the chamfer on the WH cylinder/valve/tranny was larger or deeper than 'standard', or they used 'fatter' O-rings.

 

I found that the only way I could get them to seal properly was to follow the procedure I described in my thread, which is different than in the PDF file.  That is, I had to run the locknut down until the O-ring JUST TOUCHED the last thread of the part that threads into the device.  I believe that what was happening on my installation was that the O-ring was not being compressed enough to seal the area of the chamfer because it was being pushed down into the void between the un-threaded part of the adapter, and the threads on the cylinder/valve/tranny... 

 

I hope this makes some sense to someone!  Hard to describe with words.

[cod 116]

 

I hope this makes some sense to someone!  Hard to describe with words.

 

 

Jeff,

 

Trying to describe what ones trying to fix is half the battle as well you know.  Having only owned my 418 since May, finding this website and the wealth of info is fantastic and it's been a real help when I'm trying to tame the red beast by cleaning up 26 years wear and tear.  So thanks for the tips for both the electrical and hydraulic fixes.

 

Cod

[Jeff-C175 7,195]

Hi Cod,  You're welcome, I like to help when I can!

 

I've sorta been doing the same thing this year 'refreshing' stuff on my 175 that I've let go for too long.  Early this year I thought I would pop for a new machine, but after seeing the prices of something that actually might hold a candle to my old-timer I decided to invest a little time and money and she should be good for another 30 years.  I think she'll outlive me, that's for sure!