qws

Ok guys, some of you already know and some don't. My 84 is far from stock. 388, cam'd, HSR.
Over the past year I've gotten the AC going again in it. However it is affecting the Power Steering when turned on. You feel the vibration in the steering wheel.

About a week ago I blew one of the Orings on the high pressure side of the PS pump. I ended up just replacing it with a new AC Delco pump and AC Delco HP line. I've noticed after bleeding the pump and rack fluid that when the AC is off I have a nice steady flow of fluid in the reservoir. When I turn the AC on it becomes and earthquake in there, splashing all over and bubbles. And once again you get the vibration in the steering wheel
Any thoughts as to whats causing this?

aklim

Question. Do you have enough RPM that you aren't lugging the engine when the AC is engaged? The IAC should turn the idle up a little, IIRC. That or your compressor is causing hesitation or going out the door would be a guess.

JackDidley

Belt slipping ?

qws

To answer your questions

RPM does jump up when turning on the AC, 150 to 200 RPM
I hope the compressor isn't on its way out, it was new last year, but anything is possible

The belt was just replaced a month ago. It doesn't appear to have any slippage. Now I do use a undersize pulley on the crank only. All smog equipment has been removed. I use a 81.5 in 6 groove belt

JackDidley

Very odd. I have my idle at 725 Ac off and 775, AC on. Underdrive pully and the motor is stock except for a ZZ4 cam.

qws

I'll have to double check the RPM settings. It was tuned into the ecm and can't really remember exactly. I do know when AC is off I'm around 850-900

Maybe it is the compressor, Just seems to be pulling a heck of a load when on. its only a rebuilt cardone. I was looking on Rock Auto and see that the four seasons compressor comes with a LTR4 compressor vs others that are listed as R4. Not sure of the difference but may look into what that difference is.

aklim

I don't remember mine either but on the scanner, it will list "command idle", "desired idle" or something similar, IIRC.

Tom400CFI

In the belt's path, where is the tensioner pulley?

Hot Rod Roy

You undersized pulley makes the ps pump and ac compressor act like your idle is like about 500 rpm or so, since your belt speed is reduced because of the undersized pulley. I'll bet your problem would go away if you had the correct sized crankshaft pulley.

WVZR-1

I wonder if "tinkering" with the orifice in the flow control valve could maybe influence your situation. It might be something to consider. Maybe a call to TurnOne and explain your observation. Orifice diameter is often modified on Saginaw pumps. There should be many good reads.

Since your pump is already a reman maybe the flow control valve actually isn't correct.

HRR's pulley suggestion certainly might influence the observation in that it's going to speed-up the pump but maybe "tinkering" with the orifice can accomplish the same thing.

qws

Interesting.

To answer TOM, the belt tensioner is between AC and Alternator.

Turn One rebuilt the rack about 2 years ago and its certainly worth a call to them. I'll get in touch with them today and see what they say.

As far as the crank pulley, I'll have to see if I still even have it anymore. If I do it only takes a few min's to change out and at least try it.

I googled this as well and it seems to be common with small cars. Couldn't find anything yet on a C4

Tom400CFI

Is the PS 'before' the AC? IOW, if you were attached to the belt, and you left the crank hub, would you go around the PS pulley before you got to the AC?

qws

The belt goes up from crank pulley and outer edges hits the water pump and power steering. So going cw it would be water pump,ac tensioner across to alternator ps then back to crank pulley.

I called turn one. They don't feel it's the under sized crank pulley since I should feel the vibration when AC is off as well. They feel it's more of a chassis vibration coming from the AC compressor clutch. Maybe out of balance, bad bearings, etc. So maybe I should look into that

Tom400CFI

Copy that. That pretty much blows my theory. I was thinking the pulses from the AC pump could be 'jerking' the belt and thus affecting power steering. I don't think that's the case though.

Could you have your wife turn the wheel while you watch the AC pulley, PS pulley, and tensioner pulley to see if you can SEE what is going on?

JackDidley

I just remembered something. A few years ago, if I turned on the AC, the belt would slip. I was sure it was a compressor issue as that was the only time it squealed. Turned out, a bolt was missing from the PS mounting bracket and the load from the AC just tweaked the whole PS pump bracket when it kicked on. Maybe you have a similar thing going on.

qws

I had a few mins earlier today to take a look at it. I did check all the mounting bolts,brackets on both AC and Power Steering. Nice and tight and all hardware is in place (good call and worth a look)

Started it up and checked the belt seemed to run fairly smooth around all the pulleys, Turned on AC, RPM jumped up 50 RPM, then took another look. I think I saw some fluttering in the belt between the tensioner and Alternator. Its a bit of a longer run since the Air Pump was removed several years ago. I took the old bracket went to the store and got a small pulley to put on it.. threw it on and the flutter is gone. Not sure if this is really working yet or not but for 10 bucks its worth a shot. I just don't like how close the pulley is to the water pump pulley, but its not touching.

The screwdriver shows the new pulley

qws

So I test drove it... ahhhh a little better but not great. You feel it most when sitting at an intersection and it makes the exhaust clang as well when on. I've never have gotten the AC exactly where I want on this thing so I'm on a mission at this point. The compressor seems to be putting a ton of load on the car when on, so I'm a bit tempted to try another one to see if there is a difference.

aklim

Pretty stupid question but have you turned the AC compressor by hand? Not the pulley section which is energized but the compressor section? Not sure if there is a way to see if the clutch is engaging properly or just jumping around? Just some dumb ideas I am tossing out right now.

qws

No I haven't. I've watched it while on and appears to be fully engaging. Runs consist and smooth

qws

Ok, so I ended up removing that pulley... the sound and vibration got worse. After playing around with this I do believe the problem lies between the tensioner and Alt. If you watch the video that belt is fluttering pretty bad. I tried the next smaller belt and it won't fit. So my next thought is some time of a "guide" to hold the belt down midway. I'll have to come up with a way to do that and see what happens.