Maximum Hydraulic Pressures

[blown formula]

I know we have some experts here so here we go!

What is the maximum pressures developed or used in the three hydraulic system of boats?

Trim (Bravo w/ Prestolite pump)-?

Steering w/Mercruiser Power steering pump w/Latham steering?

K-Planes with Mercruiser tab pump?

I am building some replacement lines & need to know the pressures involved.
Thanks!

[rbtnt]

I think the power steering is 1200 psi.

[Roger 1]

I think the power steering is 1200 psi. I don`t know why, but for some reason Mercruiser decided to pur 600 psi hose on mine! That lasted for a while but ruptured while I was out on Lake Michigan. I took it off and had a local Hydraulic repair shop make a good one to replace it with.

[Gary Anderson]

Never really worried about it. -4 and -6 S/S lines are rated at 1500psi or above. Never blew one.
I do know my aftermarket steering rating from the relief valve was 1100 psi.
Gary

[Cord]

I belive the k-plane and trim system are around 600psi.

[blown formula]

Thanks Guys, That is about what I thought the pressures were. I just hated to have hoses built & like above, have one burst where it is secured UNDER the engines!. I now feel I can avoid that with certainty.

Trim I/O cylinder and trim tabs are 400 PSI. When replacing the tab hoses last year I could not find any in the 400 to 600 psi range. The rating jumped from 250 to 1200 or 1500.

From Boston Rubber I learned that hose burst pressue is 4 times the working pressure. So the 250 psi hose had an unstated 1000 psi burst pressure. Using 250 psi hose at 400 was at less than 50% burst of burst. With those margins I felt 250 was a safe way to go.

[blown formula]

With the known pressures now, has anyone ever built there own hoses using Earls or JIC type fittings???
Is this practical?

[Mbam]

For stock Mercruiswer stuff the steering is 1200 PSI on the high side, 100 PSI on the return. Oildyne pump is set at 2200-2600 PSI high side (up on drive, down on tab- blue wire hot) and 400-600 PSI on the low side. The older Prestolite pump was higher.

The Bennet type tabs have a much lower working pressure, not sure what it is.

I don't like stainless hose for steering as 1 nick in the braid and the pressure capacity is gone, and as far as I know the stainless/teflon hose is the only one with the proper rating, the regular stuff with anodized fittings is not rated that high.

For steering you want a hose with an SAE rating, I can't remember the number but your favorite hose supplier will know, 100R rings a bell.

[ALFSTER]

use any SAE R1 hose its rated at 2200 psi working psi and 8000 burst psi,its also coast gaurd approved for hydraulic use