pnutbailey

I have an '86 Iroc. At the end of last summer I replaced the a/c compressor , dryer , etc... This year when I try to use my a/c , it works fine either in park , or driving. But, if you come to a stop ( redlight ) the car gets a vibration through the brake pedal and gear shift ( not saying this is the problem , that is just where you can REALLY feel the vibration ) and makes a really odd sound. The belt is as tight as I can get it. The compressor is new , the bracket isn't bent , WTF..

BLUETA

The belt is not tight enough. Be sure to look at the top bolt on the bracket. I'll bet it is at the end of the slot. You think you have pulled the belt really tight, but you just ran out of room. Try a shorter belt and get it really tight. Then after a few days, you may have to retighten again after the belt streaches.

ZZ28ZZ

Mine does that too at idle with A/C on. I switched from a Cross Fire to a TPI. There was an extra support for the upper A/C bracket that bolted to the Cross Fire intake manifold. The TPI manifold didn't have a place to attach the support. Didn't see any good places to attach a custom support bracket either. For now, I just raised my idle speed a little (on the chip) and the vibration is much less noticeable.

tom3

Been fighting this for a while on my truck, vibration just above idle and right at 60 mph, just my luck. Put in a new (not a rebuild) compressor with R134 and correct oil. Noise/vibrationi still there. Really at a loss what causes this. Next step might be a new belt tensioner. Sure is an expensive noise. If you get yours figured out be sure and post.

pnutbailey

I have a new compressor on my iroc. When I get my vibration is with the car in gear and stopped (foot on the brake) the vibration stops when in park or while driving. Sometimes when i am slowing down for a red light the rpm's drop and the car seems like it almost stalls. Again, only with the a/c on. Just put a smaller belt on it and the vibration lessened , but not to any great degree.

Vader

Does the compressor have "the brace"?

pnutbailey

no, it does not. Although i bet that would almost solve my problem. what year car is that pic from? Also thanks to everyone who took the time to try and help.

KITT1983

iTrader: (3)

Do you know where I could get that brace?

sofakingdom

iTrader: (1)

Junkyard

Not hard to make a suitable substitute, as well

battman

iTrader: (2)

I've had two cars have that exhibit this problem, both were TPI serpentine belt systems.

The first car had headers, no bracket bracing on either side, it vibrated like crazy at certain RPM's

The second car has headers and all the support brackets on both sides, still vibrates but not quite as bad.

The only thing I can attribute the vibration to is both cars have the A.I.R. pump removed and use and alternate belt routing. The long run of belt from the AC compressor to the crank shaft is causing the vibration, I can see it in the belt.

My next step is get an A.I.R. delete pulley and run the stock routing to see if it fixes it.

paulo57509

There's another brace that can be added to reduce the vibration. There was a TSB back in the day regarding compressor vibration that listed the P/N's for the "fix".

I believe that pre-'87 TPI cars did not have this added brace.



At the time I found the TSB, the parts were available from the dealership.

I can see if I can dig up the TSB is anyone is interested.

KITT1983

iTrader: (3)

please do

paulo57509

TSB 86-179 references an inertia ring that is installed onto the compressor.

I think this acts similar to a crankshaft damper. I forgot about this one. IIRC, there was a good reason I had for not installing this. Probably because it was NLA at the dealership.

TSB 88-409-1B and 89-408-1B references the brace and hardware.

Both of these TSB's are essentially identical.

Edit: Forgot to add Figure 1 to TSB's 8x-409-1B.

KITT1983

iTrader: (3)

thank you

turboguard

So I'm also having this problem, I took a video to demonstrate:


Would tightening the belt solve this issue, or could the clutch also need service?

paulo57509

Tightening the belt should help. But don't overtighten it because it'll strain the compressor and water pump bearings.

Try loosening both the PS and AC belts. Re-tighten the PS belt first and then do the AC belt.

KITT1983

iTrader: (3)

bump

1987L69

https://gbodyforum.com/threads/flopp...5/#post-477311 I know its for a Monte Carlo SS but it will work on ours, I did it on my 87 SS Monte and I am going to do it to my Z28 here soon
http://www.montecarloss.com/communit...Number=1027488

KITT1983

iTrader: (3)

i have v belts i don't think that will work

1987L69

those are V belts, I just put a mod like that on my 84 Z28 and it works great

paulo57509

When my friend installed a ZZ3 in his '68 El Camino he had a terrible a/c belt vibration (very long distance between the W/P and compressor).

He took the entire belt idler assembly off a VW Jetta and fab'ed up his own brackets as in the previous post.

1987L69

It works great!

stahrman0612

Mine is doing the exact same thing as yours. It's normal until I turn on the AC. I've tried tightening it without over tightening, but still jumps around like yours in the video? My mechanic said it was normal on these year cars?? Maybe to a certain extent, but I don't think this much moving is normal??? If you find a way to fix it, be sure to post your solution. Thanks!!

KITT1983

iTrader: (3)

any updates

KITT1983

iTrader: (3)

https://nemigaparts.com/cat_spares/e...f/09/mf09-013/

just bought. GM PART NUMBER "10046001" after searching forever

stahrman0612

Did it fix the problem?

KITT1983

iTrader: (3)

the part just arrived

KITT1983

iTrader: (3)

yes

KITT1983

iTrader: (3)

yes

Chevy86 IROC-Z

iTrader: (17)

I had and still have that issue but not really bad before putting a pulley on the upper AC bracket. Still vibrates but not as bad. I will be extending the pulley though with a thingy-ma-jig that I made.

Chevy86 IROC-Z

iTrader: (17)

Update on my vibration. I was missing a nut behind the PS Pump. No more vibration!!! Granted that I have an 86 TPI. But the stud behind the pump had no nut. The stud protruded behind one of the brackets. All good now.

sofakingdom

iTrader: (1)

Yup, that would certainly make a difference.