SC Grinding when stopping, But it's not the Brakes???

pcaconc1 · 06-07-2004, 06:10 AM

My 83 SC with 112K makes a grinding sound when stopping. Both myself and a 30 year Porsche mechanic have examined and agreed it is not the brakes. It looks like it may be somewhere in the drivetrain; bearings, trans, ????

More Background; 2K on complete engine trans rebuild, lowered aprox 1in, low mile AVS Intermediates, new brakes and rotors... starts, runs, brakes, shifts, turns, better than new... but what is this grinding noise, help.

chrisp · 06-07-2004, 07:05 AM

So you can glide to a stop without depressing the brakes and it still makes the noise?

How about rolling to a stop with clutch in versus clutch out (I know you can't glide to a stop with clutch out but you can get close)?

GrindingGears · 06-07-2004, 07:41 AM

bearings would be my guess if your certain it's not the brakes.

didn't your wrench repack the bearings when he did the brakes?

welcome to the bulletin board

Purrybonker · 06-08-2004, 08:13 AM

Chuckle, chuckle - I'm wringing my hands over the same kinda problem, except that mine is making more of a moan or groan than a grinding noise.

Brakes just redone - front bearing races replaced/bearings repacked. I was convinced the noise would be history, but remains after this work. Bearings are nicely snug - no hanging calipers - wheels all spin loosely.

Yet, pretty consistently I have a slight groan as the car rolls to a stop (brakes or no) or begins to roll away from a stop.

Strange, this car may be haunted...

Ken

chrisp · 06-08-2004, 08:22 AM

Possible front end groaning coming from the bushings as the front end load changes and suspension travels while coming to a start or pulling away?

Just a thought.....

IROC · IROC's Garage

Quote:

Originally posted by Purrybonker
Yet, pretty consistently I have a slight groan as the car rolls to a stop (brakes or no) or begins to roll away from a stop.

Strange, this car may be haunted...

Ken

My car does this and has ever since I started using Pagid orange pads. Even with two different sets of calipers up front (mine groans in the front), it still does it.

I attribute it to the pads vibrating a little in the caliper at low speeds. I don't lose any sleep over it.

Mike

Purrybonker · 06-08-2004, 01:43 PM

Thanks for the comment Mike - misery loves company. That's an excellent diagnosis and about the only thing left in the bag of possible excuses - I've ruled out suspension because it happens at such low speeds. That only leaves brakes and bearings. I'm just suprised to see the problem persist with new pads and the bearing repack.

Although I would like nothing better than to throw a few bills at new calipers - I think I'll do like you and give up losing sleep over it.

Par911 · 06-08-2004, 02:20 PM

Welcome to the board pcaconc1. It sounds like it is a wheel bearing or CV boot problem. Is the noise coming from the front or the back? If your CV boots are dry then they will make a grinding/moaning noise. Try checking the CV's and if that checks out, then maybe it's time for new wheel bearings as others suggested. Also register on the local board, www.dorkiphus.com ,for announcements of local events and engine drops

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LFogelson · LFogelson's Garage

I had the exact problem on my '82SC. It was the right rear bearing. Before fixing it would only make noise when coasting and go away with acceleration. Eventually the noise changed from grinding to a loud groan...obvious bearing. I let it go for too long, when the bearing was finally changed the hub was grooved. I needed a replacement that I bought used from a wrecker.

pcaconc1 · 07-06-2004, 03:28 PM

I like the vibrating caliper theory... That way I only have to deal with the embarassment of coming to stops like I'm dragging my front spoiler. As for the bearing theory... would you notice that when cornering or any other transtional load, or faulty road surface??? because that was the way it was with my 928GT... that more like a clunk-clunk-clunk; this sounds more like I'm dragging plastic on the road... sort of a curr-r-r-r-r like it's gargling mouth wash???

And thanks for the welcome.

pgsandiego · 07-06-2004, 05:16 PM

I had a simular problem last year with a daily driver. Id get a grinding noise just as I was coming to a stop. Turns out a CV joint had a pinhole leak and was dripping grease on a brake pad. Had to replace the CV boot and brake pad (cant get grease out of a pad). Check your pad for contaminents and CV joints for leaks.

Easily ruled out if you get grinding while coasting to a stop (no brakes).

Good luck!