Stinky Posted March 12, 2021 Report Share Posted March 12, 2021 I'm working on a Hyundai Tucson...yeah I know. I have 2 Qs that are just to broaden my knowledge base, and they really won't make me any smarter. But, I knew that youse guys are pretty sharp and would know these answers. It is my wife's car. It has no PS at low rpm. I am also chasing a leak. I changed the pump and that didn't seem to help, but I have a leak, so who knows. This is mostly just gee-whiz info. The Qs...I take the hose to Napa looking for an aluminum heat protection wrap around to line. They have none...I'll rig something up. I ask the parts guy about this, my line has a coiled, flexible steel thing inside the rubber hose coming off the pump. At the center coupling on the hose, about 3/8" OD (fits inside the hose, and maybe 1/4", probably smaller, ID) and goes about 10" in each direction, from the coupling. https://www.rockauto.com/en/moreinfo.php?pk=765700... I thought that it was so it wouldn't get kinked. Before he finds out, fully, what I am talking about he said that it would bump the pressure way up...Yeah, but the pump should have a relief valve, so it couldn't go to high. The clerk looks up my hose, in his system, and then says that it is an oriface tube, to drop the line pressure so that it won't blow the line off the fittings. Sounds like nonsense to me...or else it would blow the line off the 1st fitting on the pump. I was looking for some return line. He sold me some AT cooler hose which it rated for 300# psi. I just did a "Pull the return hose flush on it." (you pull the hose and pump it till it is dry, fill the reservoir and do it until the PS fluid comes out clear red, like the stuff you are pouring in to the res) and it doesn;t have a lot of pressure on it...oh, it has spring-clip hose clamps on it. I doubt that those can hold 50#. So, Q#2, what sort of pressure would the PS system operate on? The clerk said that they use a dif hose for when they make PS pressure-side hoses. He also said that the lines have to be crimped on, as a clamp won't hold them...I've seen clamps used on systems where guys added AC to an old car and there is a shi# load of pressure there. Q#3...I know I said only 2Qs, but would it work w/o an orifice tube in it? Quote Link to comment
EDM620 Posted March 13, 2021 Report Share Posted March 13, 2021 2 things - the pressure line really needs to be crimped but the return line isn't under much pressure so hose clamp is ok. Anyone who uses hose clamps on AC lines needs a smack upside the head. Freon is an Ozone depleater (means it readily reacts with ozone = O3) and is really bad for the atmosphere. Newer freons aren't as bad as the old shit, but the stuff is supposed to be sucked out and put into a pressurized can then disposed of at a haz-mat facility. Don't matter if it's from your fridge or your car, it's bad shit. So bad there are laws about it's disposal - ask a HVAC guy. Quote Link to comment
datzenmike Posted March 13, 2021 Report Share Posted March 13, 2021 The return line isn't under pressure because the end is open and just dumps the returning fluid into the reservoir. If it was pinched it would back up and get pull pressure from the pump. Usually the return line is also a larger diameter. Pressure on the 720 pump for example is 1,100 to 1,200 PSI at idle. The pump has a built in regulator. A spring that the pressure pushes against opening a needle valve that sends the excess fluid right back to the inlet of the pump. Loss of PS at idle? Belt tight? Belt slipping? Correct idle? Does it have variable ratio steering and how is it done on the Tucson? Quote Link to comment
Rick-rat Posted March 13, 2021 Report Share Posted March 13, 2021 EDM, what does freon have to do with PS (power steering)? Quote Link to comment
Stinky Posted March 13, 2021 Author Report Share Posted March 13, 2021 That is a lot more pressure than I figured. Idle is correct and a new belt. Variable ratio...doubt it, it is Rack & Pinion, but I don't know. Gonna pull the rack tomorrow...I hope. Quote Link to comment
EDM620 Posted March 14, 2021 Report Share Posted March 14, 2021 On 3/12/2021 at 7:38 PM, Rick-rat said: EDM, what does freon have to do with PS (power steering)? Just in regards to the mention of "clamps used on systems where guys added AC to an old car" that's all. 1 Quote Link to comment
Stoffregen Motorsports Posted March 14, 2021 Report Share Posted March 14, 2021 If the fluid smells burnt, it could mean that there is a block in the system somewhere, causing your low RPM problem. Try a complete system flush. This can be done with a gallon of fresh fluid and a five gallon bucket, but can be messy and possibly even dangerous. You need two people for this method. Hoses are fluid specific and I buy PS return hose in bulk. Fuel line will break down rapidly with the heat and detergent properties of PS fluid, but there is one hose that I use for both. Generic EFI push-lok hose works for PS return, auto trans cooler lines and fuel. Custom pressure hoses can be made at a specialty shop or by using adapter fittings and AN hose ends. I use Aeroquip high pressure AQP hose and re-usable hose ends. They are pricey, but look good and work great, and are easy to use. https://www.summitracing.com/search/product-line/aeroquip-reusable-hose-ends/part-type/hose-ends/hose-style/aeroquip-aqp-high-pressure https://www.summitracing.com/search/product-line/aeroquip-reusable-hose-ends/part-type/hose-ends/hose-style/aeroquip-aqp-high-pressure I don't like the blue hose, so I wrap it in heat shrink. There is another brand of hose that is black, but I can't remember the name. Quote Link to comment
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