Ford 3000 power steering fluid bubbling foaming

[FordnMassey]

Hi,

I have a 1967 UK built Ford 3000 with power steering of the type with external hydraulic rams on the drag links. Recently it started to get bubbles in the PS fluid that turns the fluid to foam and sprays out the breather hole in the cap. PS system works fine otherwise, doesn't lose fluid and isn't noisy.

Things I've done so far:

Replaced the rubber hoses that join the PS pump to the external reservoir.
Checked the connection of the intake pipe on the pump is tight.
Replaced the filter in the reservoir.
Turned the steering lock to lock around 20 times with the engine off, until the bubbles stop.
Inspected for leaks and found none
On restarting the engine, the bubbles return immediately and within 30 seconds the oil goes foamy and the reservoir overflows.
Did this last test with filter in and out and get the same result.

I am thinking that the pump intake side of the system is the most likely cause of the issue as the suction side can pull air in. Possibilities I can think of:

Blockage in the pump intake line from reservoir, causing high vacuum and oil entry? (I haven't yet pulled this down)
Issue with pump seals on suction side, if any such seals exist? (I'm wanting advice before I do a rebuild)

Has anyone seen this before and have any ideas?

Thanks in advance.

FordnMassey

 

[Tinhack]

I'm wondering if you have a cracked or loose steering column. Or the suction line from the column is loose. That's the only place air can get into the system. The suction line is the one in the center of PS canister.

 

[TractorTech]

You also could be getting air in on the oil seal of the pump.

 

[FordnMassey]

Hi,

Thanks for replies.

Thanks Tinhack, there's nothing to see indicating a crack or loose steering column. Correct me if I'm wrong, but the return line from the column to the reservoir is not under suction, as the oil would still be being pushed back towards the reservoir.

Again, correct me if I'm wrong, as this will decide what I'll try next. As I see it, suction is the only way new air can be added to the system and suction only occurs between the uptake pipe where it starts at the reservoir through to the point where the oil passes thru the meshed gears in the pump. Everywhere else is pressurised, surely? If this statement is correct, then I guess as TractorTech suggests, looking at the seal in the pump is the next step. It could be having air sucked past it without ever leaking oil, or without me being able to see it leaking oil as it drops into the engine sump. Does that seem like good logic? I don't like tearing down 55 year old parts unless I'm pretty sure it's needed, otherwise I might do more harm than good.

So last question is, does anyone have a parts number listing for a seal kit on old style power steering pump with separate reservoir?

Thanks again for your help.

FordnMassey

 

[Egon]

Did you check fluid for water?

 

[TractorTech]

Hi,

Thanks for replies.

Thanks Tinhack, there's nothing to see indicating a crack or loose steering column. Correct me if I'm wrong, but the return line from the column to the reservoir is not under suction, as the oil would still be being pushed back towards the reservoir.

Again, correct me if I'm wrong, as this will decide what I'll try next. As I see it, suction is the only way new air can be added to the system and suction only occurs between the uptake pipe where it starts at the reservoir through to the point where the oil passes thru the meshed gears in the pump. Everywhere else is pressurised, surely? If this statement is correct, then I guess as TractorTech suggests, looking at the seal in the pump is the next step. It could be having air sucked past it without ever leaking oil, or without me being able to see it leaking oil as it drops into the engine sump. Does that seem like good logic? I don't like tearing down 55 year old parts unless I'm pretty sure it's needed, otherwise I might do more harm than good.

So last question is, does anyone have a parts number listing for a seal kit on old style power steering pump with separate reservoir?

Thanks again for your help.

FordnMassey

The pump seal kit is DHPN3A674A. It runs about $45. from New Holland. Aftermarket kits happen to be more money!

 

[FordnMassey]

Thanks Tractortech and Egon. Fluid returns to clear once the bubbles settle out, so I think it's clear of water.
Thanks for the part number, I have found it on eBay, tho postage to Australia is slow.
I'll post what the outcome is of the rebuild, for future reference by other people.

 

[Tinhack]

Thanks Tinhack, there's nothing to see indicating a crack or loose steering column. Correct me if I'm wrong, but the return line from the column to the reservoir is not under suction, as the oil would still be being pushed back towards the reservoir.

There is suction inside the canister. That's what draws the fluid through the filter. The return line just dumps into the canister through ports in the internal sleeve. There should be a spring behind a washer on that sleeve that pushes the filter against the pump inlet. If the reservoir is low on fluid or you are missing the spring or washer, it could suck air there through any hose breach. But I will defer to a bad seal in the pump.

 

[FordnMassey]

Hi,
I put the rebuild kit through the pump and problem solved. I did no other work on the pump. The problem will have been the shaft seal. Interestingly the kit I received contained 3 seals, none of which were the same thickness as the original, but I installed one and it worked.
For anyone using this information in the future, the rebuild is easy. The hardest part is cleaning the exterior. Total time around 6 hours.
Also for future users of this thread, the reservoir on these "pump separate to reservoir" units is most certainly not under vacuum. I can now run the tractor and use the power steering with the lid off the reservoir without any bubbling issues, so there is no vacuum in the reservoir cannister. If you have bubbling, it's not a leaky reservoir cannister.
Thanks for everyone's help.

 

[TractorTech]

Hi,
I put the rebuild kit through the pump and problem solved. I did no other work on the pump. The problem will have been the shaft seal. Interestingly the kit I received contained 3 seals, none of which were the same thickness as the original, but I installed one and it worked.
For anyone using this information in the future, the rebuild is easy. The hardest part is cleaning the exterior. Total time around 6 hours.
Also for future users of this thread, the reservoir on these "pump separate to reservoir" units is most certainly not under vacuum. I can now run the tractor and use the power steering with the lid off the reservoir without any bubbling issues, so there is no vacuum in the reservoir cannister. If you have bubbling, it's not a leaky reservoir cannister.
Thanks for everyone's help.

That’s good to hear. In some cases, there can be two thin seals installed back to back with the spring side facing out. As long as your new seal has a good surface to ride on to make a seal, it is fine.