Howling noise coming from front end of '86 911
 

Drove a REALLY NICE '86 911 yesterday...no smoke, engine was strong, interior is near perfect, and (for a change) ALL options seemed to work. The car has 89K on it, and no visible oil leaks...all gauges read good. I took it for a fairly good drive on a local highway with little traffic. When I returned as I pulled off the ramp from the highway into the business district, the front end started, quite literally, howling. THIS WA OCCURING WITHOUT ME APPLYING THE BRAKES! This wasn't the typical "woo-woo-woo" sound I would expect from a bad bearing, but rather a constant, and quite loud "woooooooooooooooooooooo". I tapped on the brake pedal and it would go away...at least briefly. I didn't really have time to see if it would vary with steering (besides that, the roads were pretty much straight).

My suspicion is that it's a sticking caliper that's barely touching the rotor...hence the sound that can go away with a slight touch of the brakes and the lack of the "woo-woo-woo" sound of a bad bearing, but others seem to be suggesting this could be a bearing problem. I'm going to look at the car again this weekend, and I'd like to get any input from anyone that can help me isolate this problem before I go there. DON'T LET ME BIAS YOUR OPINIONS WITH MY OWN...WHAT ELSE COULD POSSIBLY CAUSE SUCH A NOISE?

Thanks in Advance,

Bill Wagner

[This message has been edited by Bill Wagner (edited 11-29-2000).]

Really sounds like a stuck brake caliper. Mine did the same, only above a certain speed.
First ~65 mph, then 50, and one week later the caliper was completely frozen. Couldn't move the car by hand any more.

Careful, these things are EXPENSIVE unless you can do the repair on your own. But I don't know about a repair kit for an '86.
(Maybe its another time for Warren to reply...)

Hope this helps

Jens

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Was the air conditioning on? Maybe the blower motor in front that moves air across the front condensor is going bad...
regards,
jlex.

A sticking caliper results in serious pulling of the car to one side! I've had one. Generally, if you pull out the pads, you can always fit a C-clamp in there and force the piston to move. This essentially freed my right front caliper.
A new one isn't much really...just a couple of hundred bucks for an 84 maybe more for 86 dunno

Anyway if your car didn't pull at all, then it ain't a stuck caliper. These guys have the real opinions but the fact that applying the brakes changes the sound could easy be a function of a change in stress on the bearings and not necessarily suggest that the howling is emanating from the brakes themselves.

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Kurt B
1984 911 Carrera Cabriolet
75 914 1.8


[This message has been edited by Kurt B (edited 11-30-2000).]

Maybe I should clarify that I mean sticking caliper and not frozen caliper. The car didn't pull one way or another, but on the other hand I didn't do anything to stress the brakes either.

Any recommendations for tests that will help me isolate this on Saturday when I take it out again?

Bill,
I am having a similar noise from my 78. I am going to disassemble and check for a stuck caliper this weekend. I would be interested in what you have found out.




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78 911SC

I had a sticking caliper on the RF of my 84 when I first bought it. I made the dealer rebuild both calipers with factory rebuild kits before accepting the car. I know the noise, and I'd bet that's what it is. Ask the seller to credit you the cost of some new calipers and for your first upgrade....

good luck, sounds like an otherwise nice car.
I don't think such a common and inexpensive problem should be any reason to pass up a good example, assuming the price was right.

FYI, I paid $14,500 for my 84 3.2 coupe in 1999. It was a sunroof coupe, with full leather, sunroof, forged wheels, and some other oddities. It had 99k and was in great shape with some stone chips, etc. But otherwise it was very clean and it included the brake rebuilds, a two year warranty at no cost to me, and a new turn signal switch (they always seem to need replacing!) Your potential buy sounds as nice, with lower miles and two years newer, so keep an eye on the price.

Dave

Dave, you got a sweet deal!

I have never experienced brake howl. Stuck caliper or no stuck caliper. They make a scratchy noise if they're dragging, and of course they can squeal too, but there is no brake howling in my experience. My bet is wheel bearing.

With the wheel off the ground (important jack test), spin the front wheels. Bearing noise is a faint rumbling rattling. It will not be smooth, but rather like there is grit in the bearing.

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'83 SC

BILL,
I HAVE THE SAME PROBLEM ON MY 87 TARGA,PASSANGER SIDE FRONT.HAD THE ROTOR TURNED, WORKED FOR 200-500 MILES, ITS BACK AGAIN. I DID SOME DIGGING AND WAS TOLD THAT THE RUBBER BRAKE LINES HAVE A TENDANCY TO COLLAPSE AND WEAKEN WITH AGE.I AM ORDERING ALL NEW OEM RUBBER LINES......

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Thanks for the posts, guys, but I (unfortunately) took the liberty of posting this very same post at a local Porsche site. Unfortunately, I told the readers where the car was, and one of them, who was apparently also looking at the car, thought he'd better jump, and he did! I KNEW I should have put a deposit on it!

In any case, from the info I've received from all the places I've posted this the consensus seems to be either a sticking caliper that's barely touching the brake disk when it sticks or a bad bearing. I've heard a lot of opinions both ways.

I'll never know...the search goes on!

Thanks,

Bill Wagner

(DAMN that car looked good!!)

Bill, Next time make a conditional offer subject to an inspection by a local Porsche dealer to determine the true problem. These normally cost about $ 100.00. You can use the cost to repair as leverage to bail out of the deal or to re-negotiate. At least you would have the car off the market if the seller will agree. If the seller refuses to allow an inspection - move on!

Huey581
86' Cab

Although it's too late for this car, this may help.
I've had two incidents where a piece of road debris wedges between the rotor and the tin shield on the back of the wheel assembly. It can mimic a partly locked pad if the friction is great enough. It can also cause a great squeal without any noticeable difference in handling. Reversing direction may dislodge it or removing the wheel and poking around will find it.