Modify single acting cylinder to double acting - can it be done?

[mickeyw]

Hi All,

I have a 1987 Renault 68-12 with an MX front end loader. The main cylinders are only single acting, which limits certain tasks.

For instance, if I could put some down force on the bucket things like scraping yard would be a whole lot easier, hence me contemplating double acting cylinders, and wondering whether anyone has altered their S-A cylinders to D-A.

I understand the difference in function and operation, but I'm not so familiar with the internal design of cylinders.

Might it be possible to dismantle a cylinder and add another port to feed to the other side of the piston, thus making it D-A.

I appreciate I'd need to change the service valve to D-A as well.

I know the easy option would be to buy new cylinders, but it would be preferable to avoid that expense when I have my own engineering facilities.

Thanks in advance.

 

[bcp]

Some single acting cylinders use the rod for a piston, so there is no oil space to use on the rod side.

Bruce

 

[4570Man]

Some single acting cylinders use the rod for a piston, so there is no oil space to use on the rod side.

Bruce

That looks like what he has.

 

[ptsg]

Hello,

While it's possible to convert the cylinder, it'll take a lot of work and expense. Which I don't think it's worth it versus getting a pair of double acting cylinders of a place like Flowfit, Steerforth or others. They aren't that expensive.

A single acting cylinder, like the ones you have, doesn't have a piston. Instead, they use a bigger rod with a simple clip on the end to prevent the rod from coming out. The fluid will push the rod out. Even if a piston was added, the surface area on the rod side would be so little that you would barely have any downforce at all.

This means, you would need a machining shop or hydraulic shop to machine a piston and most likely another smaller diameter rod, which would then need an entire new gland. Times two.

I've been in your situation in the past with smaller cylinders. Had a hydraulic shop converting them to double acting and ended up costing much more than just buy new cylinders.

More recently, when I built my loader, I just made the entire cylinders my self. Ended up costing me about 60€ per cylinder, including all the materials, seals, etc.

 

[LD1]

That looks like what he has.

Agree.

There isnt a piston or piston seals.....so converting wouldnt work.

The only seals in those cylinders are the gland seals. And drilling another port would would simply displace the rod and still make the cylinder extend.

New generic cylinders are in order here.

 

[mickeyw]

Hello,

While it's possible to convert the cylinder, it'll take a lot of work and expense. Which I don't think it's worth it versus getting a pair of double acting cylinders of a place like Flowfit, Steerforth or others. They aren't that expensive.

A single acting cylinder, like the ones you have, doesn't have a piston. Instead, they use a bigger rod with a simple clip on the end to prevent the rod from coming out. The fluid will push the rod out. Even if a piston was added, the surface area on the rod side would be so little that you would barely have any downforce at all.

This means, you would need a machining shop or hydraulic shop to machine a piston and most likely another smaller diameter rod, which would then need an entire new gland. Times two.

I've been in your situation in the past with smaller cylinders. Had a hydraulic shop converting them to double acting and ended up costing much more than just buy new cylinders.

More recently, when I built my loader, I just made the entire cylinders my self. Ended up costing me about 60€ per cylinder, including all the materials, seals, etc.

Hi Pedro, thanks for answering and putting that so clearly.

I should have realised the significance of the rod diameter and what I was suggesting myself really. Always good to have someone help with the thought process though.
I have no concerns (other than a time shortage) to do any machining and welding myself. It's always good to be able to look at something useful and say to yourself 'I made that'

It sounds like your cylinder builds worked out pretty reasonable in material costs.
I have bought quite a bit of gear from Flowfit over recent years, including the parts for my log splitter build, but they are more expensive than they used to be. I'll have to have a measure up and get some prices.