Corroded hydraulic cylinder aluminium gland nuts suggestions

[Bki26]

The tilt cylinder on the bobcat 763 g series has suddenly started dripping a lot more so worth a rebuild if I can figure out what seal kit (machine serial is 512451150) and the lift cylinders will need done shortly as well.

The tilt cylinder thankfully hasn't fully corroded yet so the pin holes are still usable however it seems to be solid as even after peening the thread area it snapped one of the pins and I didn't even have full body weight on it! Think I'm gonna drill 2 extra pin holes but for the larger pins and maybe blowtorch if I can't shift it.

The lift cylinders are almost completely gone so I'm really not sure how to get the one with no holes off but might be able to just get the one with 1 hole left. My first idea was melting but don't want to damage the rod do next was perhaps gallium to eat the aluminium away or try and drill some pin holes almost against the rod and try using a concrete breaker to hit it round as don't have an air hammer.

 

[Kram]

3" sweedish pipe wrench?

as don't have an air hammer.

Good excuse to get one!

 

[tom2207]

wire brush , bit of heat , oxy acet ,,, then a Swedish nut lathe [or pipe wrench ],,, it will clean up and be grand

 

[Bki26]

3" sweedish pipe wrench?


Good excuse to get one!

The corrosion has caused the lift cylinder glands to taper otherwise I'd use the 36" pipe wrench, I might be able to use the grinder to get it square however there's not much material so it probably won't work. I'm not sure there's enough material between the rod and cylinder threads to drill into the gland for new pin holes so I might be better off fully retracting the rod so if I scratch it wouldn't be a big issue and drilling multiple times to weaken the gland for removal.

As for the tilt since I've still got most of the gland and pin holes I think I can get it with the spanner so gonna try drilling for larger pins first then add heat if still nothing.

 

[tom2207]

The corrosion has caused the lift cylinder glands to taper otherwise I'd use the 36" pipe wrench, I might be able to use the grinder to get it square however there's not much material so it probably won't work. I'm not sure there's enough material between the rod and cylinder threads to drill into the gland for new pin holes so I might be better off fully retracting the rod so if I scratch it wouldn't be a big issue and drilling multiple times to weaken the gland for removal.

As for the tilt since I've still got most of the gland and pin holes I think I can get it with the spanner so gonna try drilling for larger pins first then add heat if still nothing.

you will probably strip threads without heat .

 

[zzr1200]

Looking at the state of the gland nuts and condition of the chrome on the rods, I'd consider removing the cylinders as complete units, fully extending the rams.

Then cutting the rods as close to the cylinder gland nut, then pushing the rod/seal carrier inside the cylinder tube and machining out the gland nut, and the rod eye off the piston rod.

If your lucky you could/maybe save the cylinder tubes (you may have to replace them), make new gland nuts and refit the rod end eyes to new rods.

I'd suggest steel or cast gland nuts, the cost will still be cheaper than new bobcat parts.....

 

[Bki26]

you will probably strip threads without heat .

Gonna replace the lift glands as £30 each so not worried about them but tilt is £130+ so will give it some heat.

Looking at the state of the gland nuts and condition of the chrome on the rods, I'd consider removing the cylinders as complete units, fully extending the rams.

Then cutting the rods as close to the cylinder gland nut, then pushing the rod/seal carrier inside the cylinder tube and machining out the gland nut, and the rod eye off the piston rod.

If your lucky you could/maybe save the cylinder tubes (you may have to replace them), make new gland nuts and refit the rod end eyes to new rods.

I'd suggest steel or cast gland nuts, the cost will still be cheaper than new bobcat parts.....

The time, effort and currently not owned tools required it would be cheaper and easier to just replace the whole lift cylinder for both side so definitely not going that route lol.

The chrome isn't that bad it's mostly mud/dirt streaks you're seeing in the pics so I want to ideally only damage the gland during removal since that's what I'll replace.

 

[zzr1200]

Gonna replace the lift glands as £30 each so not worried about them but tilt is £130+ so will give it some heat.



The time, effort and currently not owned tools required it would be cheaper and easier to just replace the whole lift cylinder for both side so definitely not going that route lol.

The chrome isn't that bad it's mostly mud/dirt streaks you're seeing in the pics so I want to ideally only damage the gland during removal since that's what I'll replace.

I can understand the wish to unscrew the glands and save time possibly.

Gland nuts at £30.00 a pop is a good price if available.

However having worked for Access Platform/Plant companies as a service engineer for many years, l wish you very good luck with those glands.

 

[Gareth J]

Ah, this is the brush painted boat anchor from a while back isn't it .... Before investing time and energy dismantling those bits, might be worth removing them entirely and chipping back the rust on the whole rams, especially around the pipe unions. Might be that there are areas that are really thinned and not really fit for service anyway. The alloy glands will be horrible to remove the way that salt water corrodes it siezed but probably doable with lots of heat.

 

[m_c]

I'll be honest, and say going by the level of corrosion, those are likely not going to unscrew cleanly regardless of what you do.
I'd still give it a try by drilling deeper/new holes and with some heat, but the issue will likely be they'll need that much heat to break the corrosion, that you end up melting the alu so you end up with a galled mess if it does unscrew.

I'd try and get a new gland nut first (or at least a decent photo/diagram), so you know where the seal (between the nut and the tube/cylinder) sits, and then work on the basis it's going to need destructive removal.
Then I'd probably go for drilling lots of holes, followed by die grinder/chisel/screwdriver/<insert whatever metal destruction tool will fit> to get the gland into two parts, which will then hopefully allow some wiggle on the rod to push it to the side to give a bit better access for cutting the outer remains enough to get it out.

Also wrap the rod with a few wraps of black tape to try and give some impact protection from when a tool inevitably slips!

 

[Kram]

With enough heat, those nuts should come off with a pipe wrench.

If not, remove and soak ends in strong hot caustic for a day or two.

 

[roofman]

You would be supprised how little money can buy a pair of generic double acting rams...looking at that its going to destroy the fine thread on the way out..i have been known to be wrong though.

 

[zzr1200]

You would be supprised how little money can buy a pair of generic double acting rams...looking at that its going to destroy the fine thread on the way out..i have been known to be wrong though.

Agree, I've used these before good quality at sensible prices, select rod end type, input rod diameter, and stroke length

Looking at your current cylinder conditions it would be worth it..... and the elbow for the painted pipe union pictured "Looks interesting" to say the least...

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[Bki26]

I think I will be able to get it eventually with brute force heat and soaking in lye to eat it away over a couple days or I might just drill most of it out then blowtorch the rest. Everything else on the cylinder is fine it's just needing new seals as don't think they've been changed in the decades of use.

 

[Bki26]

It looks like they're not that fine thread so might get lucky https://ebay.us/m/WBADx9

 

[zzr1200]

It looks like they're not that fine thread so might get lucky https://ebay.us/m/WBADx9

£230.00 incl postage, plus import taxes + VAT each = Expensive...

How many gland nuts do you need, 3 or 4???

 

[m_c]

It looks like they're not that fine thread so might get lucky https://ebay.us/m/WBADx9

The extra O-ring at the top might mean the threads aren't that corroded, so probably worth putting a bit extra effort in to trying to unscrew it.

If you're not in any immediate rush to dismantle it, it could be worth giving a soak with some decent penetrating oil and a bit gentle heat a few times over a couple of weeks to give it the best chance of moving.

 

[Melvyn Best]

Sodium hydroxide dissolves aluminium

 

[Gareth J]

It's probably worth speaking to a place that makes rams from scratch, if you have one reasonably locally, and asking what it'll cost to make one - obviously your first phone call is unlikely to result in "ah, the bobcat x421 lift ram, that'll be £445 per side, sir" but they'll be able to tell you the critical measurements they do need to quote accurately.

And then seeing if you can find any being broken up.

I mean, it's probably never going to be worth putting new ones on, but at least you'll have a baseline and you might be pleasantly surprised. There's a lot of work to be saved there.

 

[Bki26]

£230.00 incl postage, plus import taxes + VAT each = Expensive...

How many gland nuts do you need, 3 or 4???

Lol I'm not buying from him I can get 2 on aliexpress for £40 delivered I was just using it to show what the head should look like on the red heavily corroded lift cylinders.

As @m_c says I should be able to remove them as the oring looks to still be hidden by what's left of the rim so should have kept the threads sealed I just need to somehow get a grip so might grind down the corroded aluminium enough to get the 36" stillson on some "flats" and brute force it after heat since the expansion rates are different enough to hopefully pop any corrosion.

It's probably worth speaking to a place that makes rams from scratch, if you have one reasonably locally, and asking what it'll cost to make one - obviously your first phone call is unlikely to result in "ah, the bobcat x421 lift ram, that'll be £445 per side, sir" but they'll be able to tell you the critical measurements they do need to quote accurately.

And then seeing if you can find any being broken up.

I mean, it's probably never going to be worth putting new ones on, but at least you'll have a baseline and you might be pleasantly surprised. There's a lot of work to be saved there.

New are like £300+ each so if I can get the head off and replace the seals then that's like £100 max which would definitely be preferable. The cylinder is 1.5" rod 2.25" bore 27.88" stroke so in metric that's 38/57/708mm which means I could potentially get away with a 40mm rod 60mm bore 700mm stroke cylinder and that's £300 delivered for 2 from hydraulic megastore for example.