M1123 A2 Power Steering return line blowing off

[mgieselman]

My M1123 A2 power steering return line from the bottom port of the oil cooler has blown off twice now.

Somehow I think the low pressure side is getting pressurized.

Any pointers on where to start troubleshooting?

 

[Dieselmeister]

Follow the return line hand over hand and see if it is kinked or squished anywhere.

 

[Thunderbirds]

Take a look if it is near the steering arms/pitman arms, so when you steer it could pull it off. Do you have a hose clamp on it? Pictures could help us help you diagnose...

 

[Mogman]

The return circuit does get pressurized by the Cadillac valve to turn the fan off, your clamps must be able to withstand at least 100 PSI
It is possible the Cadillac valve is creating too much back pressure also.

 

[Mogman]

Because it is the same connection I would suspect an issue with that connection.
I would start by replacing that piece of line and clamps.

 

[TOBASH]

Agree with Mogman.

New line that is 2” longer. New clamps. Make sure you route the hose properly some nothing catches on it.

I suspect the inside of that hose has been ripped up from pulling off several times and the inner diameter is too wide. I also suspect this happened before so they cut the hose down and put it on with the same hose clamp. That means the line is probably short.

 

[mgieselman]

Thanks for all of the replies.

I’ll have new 3/8” 300psi Gates hose delivered tomorrow and will replace the existing hose.

The hose goes from the bottom barb to the low pressure side of the steering gearbox.

Answers to other questions:
1) I traced the hose and it’s not kinked anywhere.
2) Both ends of the hose had clamps on them and they were tight.
3) It didn’t appear that the steering linkage could pull off the hose.
4) Attaching some likely not helpful pictures.

I’ll post an update after I install the new hose and clamps, refill, bleed and test.

 

[HoveringHMMWV]

The fluid in that 2nd pic looks “frothy”.

 

[mgieselman]

The fluid in that 2nd pic looks “frothy”.

Yeah I started the truck with the filter off and it “aerated” the fluid, I waited for it to degass before continuing.

 

[Dieselmeister]

Check the hose from the top barb going to the cadillac valve. Make sure it is clear. Disconnect the hose at the cadillac valve, and blow air through the cooler and the top hose. If that is clear, and your new hose blows off, then you know that the problem is either the cadillac valve, or the line from the valve back to the reservoir.

 

[mgieselman]

Check the hose from the top barb going to the cadillac valve. Make sure it is clear. Disconnect the hose at the cadillac valve, and blow air through the cooler and the top hose. If that is clear, and your new hose blows off, then you know that the problem is either the cadillac valve, or the line from the valve back to the reservoir.

The parts TM shows the top bard going to the steering box and bottom to the cadillac valve, my truck was plumbed opposite.

Assuming it doesn’t matter since the cooler isn’t directional.

 

[Dieselmeister]

The parts TM shows the top bard going to the steering box and bottom to the cadillac valve, my truck was plumbed opposite.

Assuming it doesn’t matter since the cooler isn’t directional.

View attachment 925709

Correct. It's nondirectional. I usually use the bottom as inlet, that way, any air will get pushed out easier, although at the flowrate I doubt it will matter.

 

[Hummer Guy]

Cheap hose clamp and hose can cause that, I had the same issue until I use the Norma hose clamps