Power steering high pressure side hose ID size?

[Superdawg]

I am always looking for ways to boost the steering assist on my 2004. 5. I purchased the following two hoses from the dealer:

pump to hydroboost: mopar # 5212 2339 AC



hydroboost to gear: mopar #6816 4575 AA



I was under the impression the high pressure side is 1/4" ID. I have a 3/16" rod and it makes it through straight section of the hyroboost to gear hose with a little resistance.



When I tried to send it through the pump to hydroboost hose, it only passes through about 7", about 1" away from the heavy metal vibration thingy that is glued to the hose. It does go a few inches farther with serious effort, then stops. See pic.



I tried it with the one that is in my truck now and it goes though, about 1 foot in, but has some restriction.

I am going to take this hose back to the dealer and try another. I may just take this one and have a hydraulic hose company just make a new one that is at least 1/4" in diameter.



What say you? Could this possible restriction lessen the power in my steering?



thanks,

Tom

 

[Bob4x4]

Pressure will not be affected by the size of the hose. Flow may be but so slight I doubt you could measure it. That hose has an insert,I would not be poking anything in it that could possibly damage it.

 

[Superdawg]

Bob,
Point taken about possibly damaging the insert. Looking at the big picture though, any restriction in pressure or more likely flow, is bound to result in being harder to turn the wheel.
Any suggestions as to a custom hose manufacturer near Hunt Bch or Orange County, CA area?

 

[Bob4x4]

I used to use these guys http://www.hose-man.com/lamirada.html but its been a while

 

[Superdawg]

Update: I cut open the hose that goes from the ps pump to the hydroboost. The rubber hose is 3/8 ID with a plastic restrictor line that is about 1/8" ID. It flops around in there. It is secured to the fitting on the pump side and stops about 7" from the metal fitting at the other end. That is what my 3/16" rod was apparently hitting. From talking to a BMW mechanic friend of mine, he believed the restrictor line, loose on one end, acts as a type of accumulator, restricting flow and softening the pressure spikes in the system.
That being said, I went ahead and had a hose made. Using the power steering pump to hydroboost hose, I had an AN-6 fitting braised to the metal line and another AN-6 fitting braised to the metric fitting on the hydroboost side. They put a 3/8" ID hose with a 1/4" ID plastic hose insert for a restrictor inside, attached to the AN fittings on both sides. This way, I can have another hose made with AN-6 fittings and replace it easily and for a low cost.
Metro Fluid Connectors in Fullerton, CA did the work.
Results: More response at the wheel. A little less effort to turn left/right and quicker return to center after the turns. I think I felt a little more vibration through the steering wheel but now, after a couple weeks, I can't tell. The brakes seem fine.

 

[seafish]

Thanks for taking the time to update.

So would you consider running a 3/8" id hose with no restricting liner at all??

 

[Superdawg]

The metal lines and the hydroboost appear to be about 1/4 ID so I don't think going to 3/8 ID with no restrictor is going to help.

 

[Bob4x4]

The teflon liner is not designed to be a restriction as far as I know. Hydraulic lines are sized to flow a known quanity under a known pressure without building excessive heat. I am sure there is a hydraulic engineer on tdr that could explain the whys and why nots. I don't see how a teflon lined hose could be considered an accumulator as my understanding is the liner with the reinforcement layers around it will not expand to any degree. The liner will protect the outer layers from chemical break down.

 

[Superdawg]

Bob,
I would have though the teflon was a protective liner too but this application is different. That teflon liner flops around inside the 3/8 ID rubber hose. It was attached to the fitting on the pump side of the hose. On the the hydroboost side, the teflon liner stopped about 7" short of the other fitting and just flopped around in there. The fluid would be able to flow through the teflon hose and back, between the teflon liner and the inside of the 3/8" hose. This is what my BMW mechanic friend thinks acts as an accumulator, softening the pressure spikes. He may be wrong.

 

[Bob4x4]

When the liner comes loose the hose has failed. It will be noisey.

 

[Superdawg]

I checked two brand new hoses from the dealer, both liners ended about 7" from the hydroboost side fitting. mopar # 5212 2339 AC

 

[Superdawg]

I thought I would give an update on my experiments with the high pressure PS hose from the pump to the gearbox.

Original complaint: Not enough steering assist, annoying slight pull to the right, more than I thought it should for road crown.

Between the newer OEM pump and hydroboost, I had a custom hose made with a 1/4" ID restrictor (OEM has about 1/8" ID). This gave me increased steering assist which was good. The bad, some angry noises from hydroboost on hard braking. I also modded the PS reservoir cap for additional venting.

Over New Years, I towed the trailer up to Yosemite. All good until I started climbing the rolling hills out of Fresno. Between climbing and turning right/left pulling 10k, the PS pump started to cavitate. I pulled over and gave a rest (several times) to let the air bubbles work out of the system. We continued on into Yosemite where I had the garage mechanic look it over. Yup, you probably cavitated the pump. Could be due to higher flow custom PS pump, allowing more fluid flowing too fast. Steering now needs more effort and has more play.

I limped it home after our vacation, removed the 1/4" ID hose and put the stock one back in. I replaced the pump with another OEM pump. I took out the Redhead rebuilt power steering gear and replaced it with the latest PS gear (the big one) from Mopar. I had the new Mopar one on the shelf for a while. I had installed it before but it never seemed to have enough assist to make it work well. Too hard to steer right/left. I also put a stock vented PS res cap back on. Apparently, there is about 7 lbs pressure before it releases. Some think the slight pressure keeps the bubbles down in the reservoir.

Now, I was all back to stock parts, the latest and greatest Mopar had to offer. The darndest thing, it steered better than ever. Not perfect, but better than it ever was before. That annoying pull to the right was gone. Apparently, I was able to cobble together the right combo of parts that seemed to work well, something I was not able to do before. Go figure, what the factory designed, whooda thunk that?

Now the newer Mopar steering gear has a slow leak out of the front of the box where the input shaft comes in. Oh well. Past warranty.