Does anyone know the sizes of the ‘O’ rings that go on the power steering pump where the pressure hose connects?

A week ago I replaced the high pressure hose because it was leaking between the hose and hose joiner. When I took the old hose off the pump I noticed the top ‘O’ ring had a couple of small cracks in it and the bottom one (at least I think it was originally an ‘O’ ring, may have been some sort of rubber washer) was a squashed piece of black gunk. I tried just replacing the hose but this didn't work as the old 'O' rings didn't seal.


Being late at night and needing the car the next day I hunted through my box of plumbing bits and found a couple of ‘O’ rings that I thought would do the job. Fix-a-tap No. 9 for the top and No.10 for the bottom.

All seamed fine for a week, until tonight when a couple of minutes from home the steering started making very loud grinding noises. I got the car home and lifted the bonnet to see the remains of my fresh new power steering fluid being pumped out around the high pressure hose nut.

I guess ant the end of the day ‘O’ rings aint ‘O’ rings.

What size and type of ‘O’ rings do I need to put here.

Is there anything else apart from 'O' rings (and my own stupidity) that might cause this?

Thanks heaps.

do you have the old ones? i went to a power steering joint and he gave me a few assorted O rings for nothing. Might be easier?

:oopssign:, knew I shouldn't have put the bins out last week.

Found the original ‘O’ ring, I hadn’t thrown it out as I thought. Went to SCA today and got a couple of packets of assorted size ‘O’ rings today that looked liked they had just about the right one.

Tried three different size rings. Tightened the nut as per the manual (Mitsubishi) 20 – 27 Nm. Bled the system of air as described in the manual with the wheels up in the air, turn side to side 3 times on starter motor only. Repeated the procedure again to be on the safe side. Reconnected the coil and started the engine. Every thing fine. No leaks, no noise, fluid level correct.

Then disaster strikes each time. I lower car to ground, start car, check for leaks, no leaks. I then start to drive the car and turn wheel. Within seconds the steering system is again making horrible noises. There of fluid squirting (almost 2 meters) out of the top of the hose around the nut again.

I undo it all and check the ‘O’ rings. One of them had a grove all the way around it, but the other two I tried both looked OK. Could I have damaged the top of the pump by simply changing the high pressure hose?

Help and advice required

Does anyone have any ideas? Has this happened to anyone else? If so, how was it fixed?

At the moment I am not game to try to drive this to the end of the driveway, except to spay the commodore down the end of the road in power steering fluid as I drive past.

Either the hose is split near the nut, or there is damage in the pump spigot or hose coupling. Have you got the washer on? Cracks or splits may be hard to find as they only open up under pressure.

Spigot to body torque = 59 Nm
Nut holding hose on = 24 Nm

The hose is not split

The pressure will build up when you are turning the wheels on the ground thus a normal o ring will not hold up

You need to get the correct o rings from mits, these, like many o rings on Mitsu's are a unique size, slightly too large and they will catch when you install them, slightly too small (the diameter of the rubber used is also vital) and they will leak

They are around 10 bucks for the pair at mits, is your safest and best way to fix this once and for all

Also when you assemble use a smear of rubber greese on the o rings to ensure they slip into place and do not pinch

Thanks for the advice. Ill get onto mits and get the genuine ones.

While I am replacing these 'o' rings is there anything else I should be checking / replacing at the same time?

When I replace the pressure hose (kelpro hps050) there was a piece of paper mentioning a supplied 'o' ring at the bottom, but none was supplied so I just stuck a generic one in there. I didn't find any leaks. Should this be there and if so should I change it for a mits genuine one?