t2d2

iTrader: (8)

^ They're for the power steering. One goes to the small barb on the air intake tube, alongside the big barb for the IAC bypass. The other one goes to the front of the intake manifold, on the bigger of the two small barbs (driver's side).

Some people remove those hoses, which I believe are only for speed-sensitive power steering adjustments, to avoid PS leaks on the alternator, and cap the pump off down below. Why the P.O. would have left the hoses lying around, if so, is the question.

dricacho

So should I cap both hoses off for now?

t2d2

iTrader: (8)

I wouldn't think capping the hoses would do anything if they've been that way with the car running. I would see if they come out freely or if they're still hooked up to something, then go from there.

Do you have the intake tube and manifold barbs exposed, or have they been capped?

dricacho

I've tried tugging on the hoses but no go, it's connected somewhere. Next time I have the car up on lifts, I'll look around from under the car.

t2d2

iTrader: (8)

You quoted but ignored/overlooked the most important bit above...

dricacho

I will check this when I get home from work. I did notice something capped off on the manifold.

dricacho

I found the ones that were capped off.




This one have been broken off before. Does it matter which hose goes to what?

t2d2

iTrader: (8)

Bingo! So, you know what the hoses are for and where they went. And you don't have any vacuum leaks as a result of them being disconnected. Now the only mystery is whether they were properly capped off down below at the power steering pump. You might be able to see it from above with the air intake tube removed. I was able to work semi-blindly on it at one point when I was replacing all the old vacuum hoses. I hated how much force was exerted on that little intake hose barb by it and the super stiff IAC bypass hose, and wanted more supple hoses on there before my barbs broke like yours.

Does anyone know what happens to the PS pump when the two hoses are left exposed like that? Does it simply default to minimum or maximum power assist?

I would guess it matters which hose goes where, if restoring the system to full functionality, but other than routing the longer one the further distance, I'm not sure what you would base it on. I might be able to trace mine back down below by feel, but it's easy to get mixed up that way.

Ali SC3

iTrader: (10)

its ok to leave the pump switch open if its not broken but if it is it will leak some, so cap off the switch on the pump with vac caps or use one small vac line and connect it to both barbs, it will just be a little cleaner.

dricacho

Is this pump switch accessible from the top? I was looking for it when I had the air filter box out.

Ali SC3

iTrader: (10)

I dont have a sc400, its on the side of the power steering pump, just follow those 2 hoses. if those 2 hoses are connected to that still you can just cut and connect those 2 hoses together.

dricacho

Did some googling and found out that the hoses are connected this air control valve which is on the lower side of the PS pump. This is a common source of leaks. Some have replaced the valve with a bolt to plug it up and disconnect the vacuum sources, like the one on this video => .

I'll be addressing this the next time I get the car on the lifts.

Ali SC3

iTrader: (10)

yes, the bolt is the permanent replacement. this will take care of the future leak issue.
since its a sc400, I would mention the alternator shield as well, since you will be right there.
the power steering is located right above the alternator on sc400's (that I know) and when they leak they can ruin the alternator over time.
So if you are removing that plug and likely dropping PS fluid, at least cover the alternator when doing it if not installing the shield aka plastic bleach jug cut in half with 3 holes for screws.

dricacho

Great idea! It seems like most japanese cars have the p/s pump located on top of the alternator, my Z32's alternator is also below the p/s pump. It's such a poor location for the alternator as it's more exposed to the elements as well.

Ali SC3

iTrader: (10)

I would have to agree that it is a poor placement choice. it was at least better on the 2jz they put it on the bottom but on the other side than the power steering pump.
Both however are poor placement on trucks (they often get swapped into toyota pickups and 4runners as well), as the first large pool of water you try and get across you would learn that you are likely to soak that alternator hanging out there on the bottom of the motor and it shut off and well not good things generally speaking would occur from there.

I always liked how the mk3 supra 7mgte placed it high up on the motor, you would have to be waist deep in water to have that motor shut off on you and was quite popular and easy to swap in trucks and 4runners. on the other hand though, its really not aesthetically pleasing to be staring at an alternator all the time =) so I take them moving it to lower placement on the newer motors as an overall good thing, cause we rarely drive through a small lake of water generally speaking. its about the only argument that can be made for a 7m in a truck but those motors are known to start bottom end knocking sooner or later.

back on topic though everyone I have known who has owned a sc400 has had to change the alternator at some point from the PS leak, so might as well prevent it.