Cylinder repair Ford backhoe

[loopman]

Hello,
I was hoping someone may be able to advise me on the best way to remove the end cap off of a boom cylinder on a Ford 4500 backhoe? I have read about 'gland nut tools' but the job seems a little too large for one of these? Caps are around 6" across and have several recesses to take a special tool. I have heard Stilsons mentioned also, but would rather not burr up the surface too much. Judging by the leak, these have not been serviced for many years so it may take a bit of effort removing them. Oh, and this will be my first go a resealing a ram, wish me luck (happy to hear any and all advice!) Cheers.


Also, how does one obtain seals for these, I can find no model or part number on the cylinders, and I'm not even sure what the backhoe model is. Do I just take the disassembled ram into the local hydraulic shop, or will they need numbers??

 

[TractorTech]

Last question first. The model of the backhoe should be on a metal plate on the LH side, looking forward, of the tower frame. It will be a 19-... number to indicate exactly what size it is and what extras are on it. The 'basic' model, however, is a 755 series. This is the number to get you to the parts book on the New Holland website. Most any NH dealer can get the parts, but the parts are pretty standard.
It looks like it is leaking at the rod from your picture. Before you go and disassemble and repack, loosen the inner nut and slide it down the rod. If there are any shims under it, remove one or two, tighten the nut back and check for leaks. If there are no shims left under the nut, then you will have to repack.
A Stilson or pipe wrench will work without marring the gland nut too much. What is used is an adjustable notch-type spanner for lack of better name.

 

[LD1]

Sorry I cant help with the disassembly, other than try a large pipewrench???? And maybe a little heat if you are replacing seals anyway.

As to the model, it is either going to be a 750, 753, or 755. Those are 10', 13', and 15, hoes. It could be any one of those on a 4500, but I think the most common was the 755.

You can go here New Holland Parts - Best diagrams, pricing and service! And in the model search, just type 755. Then scroll near the bottom and you will see 755 series backhoe attachment. Select that and you can get an exploded diagram of all of the cylinders. It appears to be either the Crowd or Lift cylinder though. The bucket cylinder had a different cap.

Just make sure you know weather its the 750, 753, or 755. Because they all had different cylinder sizes. 3.5" for the 750, 4" for the 753 and 4.5" cylinders for the 755.

 

[LD1]

Sorry I cant help with the disassembly, other than try a large pipewrench???? And maybe a little heat if you are replacing seals anyway.

As to the model, it is either going to be a 750, 753, or 755. Those are 10', 13', and 15, hoes. It could be any one of those on a 4500, but I think the most common was the 755.

You can go here New Holland Parts - Best diagrams, pricing and service! And in the model search, just type 755. Then scroll near the bottom and you will see 755 series backhoe attachment. Select that and you can get an exploded diagram of all of the cylinders. It appears to be either the Crowd or Lift cylinder though. The bucket cylinder had a different cap.

Just make sure you know weather its the 750, 753, or 755. Because they all had different cylinder sizes. 3.5" for the 750, 4" for the 753 and 4.5" cylinders for the 755.

 

[loopman]

Hi TractorTech - thanks for the fast reply!

It's all starting to make sense, the only tag I could find was "19-454" which didn't make sense with the backhoe models (753 or 755), know it does thanks to your help.
I shall indeed have a look for the shims as you suggest, not being familiar with their use however I must ask, why would they be there? Do they just provide a protection buffer between the turning force of tightening the cap and the seal, or do they perform some other function?
Thanks!

 

[loopman]

LD1, thank you for the link, with that gem I have managed to find the parts diagram for my aged backhoe, it shall have a new lease of life very soon!
Appreciate it very much.
Cheers.

(P.S. You were correct, it is the crowd cylinder in the picture, though the lift cylinder needs the same treatment)

 

[TractorTech]

You can look up the 19-454 on the online parts book and it shows you the sections relevant to that unit. Being that it is a side-shift backhoe, not very common in the U.S., it makes it a 752. I think that is a 10' hoe in the 755 series.
By removing the shims under the packing nut and tightening the nut, you are squeezing the packing cups tighter, hopefully sealing the leak. Sometimes it works, but if the chevron packing has torn, then it doesn't stop it.

 

[loopman]

A preliminary update for anyway following this thread. A large pair of Stilsons (pipe wrench) with the added advantage of a four foot length of water pipe on the end made short work of undoing the end caps. All went pretty straight forward once I positioned the loader and backhoe so that the weight was off the rams and they wouldn't fall after removing the pins. Only had two issues so far:-
1. couldn't physically pull the crowd cylinder out even with the hoses disconnected. Ended up reinstalling hoses and pushing it out using the hydraulics (a bit messy though!)
2. cannot push the lift ram in to clear the mounting point for removal (all hoses are disconnected). Has about 6" of travel left but will not budge. Unless I work something out all I can think of is to wait until I reassemble the other rams, then use the hydraulics again to shift this one?
Will disassemble the piston seals in the next couple of days and take into the local hydraulic shop for matching, will keep you all updated.

(Starting to worry about how hard it might be to get those big rams back into the cylinders after new seals are on -??)

Cheers.

 

[LD1]

A large prybar and/or large soft faced mallet helps when trying to move the rods in and out

 

[loopman]

Job done!

Replaced gland seals only due to cost (stabilizer leg seal kits were $490 per cylinder! - I had expected < $100). All went well (extra leverage needed here and there) and all back together. Old girl is running well with no leaks and should last me for a few years (very low usage on the farm - just handy to have)

All the piston seals looked okay other than some slight imperfections in the Lift cylinder, I'll keep an eye on it and see how it goes for a few hours. What would be the indication of piston seals leaking? - low 'strength' from the cylinder, slow movement etc ???

Anyway, another job attempted and lessons learned, and of course the final sense of accomplishment at the end after doing something not tried before - now to put it to good use and get that shed sight leveled so I have somewhere warm and dry to work on these machines