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Deschodt's Avatar
 
Join Date: Oct 2004
Location: CA
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Please help me with my clonker !

I have this 83 that has started to clonk... It's annoying and I think it's a sign of something loose that should not be, but I can't figure out what...

It all started when a past mechanic replaced the pads in the rear and did a handbrake adjustment... The car would not move backwards easily anymore, like the brakes were still on, but if you drove forward a few inches, it released and then you could back up normally... Then we did torsion bars, bushings etc, and that made a lot of noises more obvious.. I tracked them all down except for the damn clonk, which I suspect comes from the rear brakes/handbrake mechanism area, as a left over of that "handbrake lockup while reversing" issue...

When the car experiences initial acceleration from a standstill (not even hard, just the little jerk of motion to get it going), something goes "clonk" back there. Forward AND reverse. Engine on/off (but then you need a slope), in gear or neutral. It sometimes also does it in motion but generally at low speeds..

I put her on a lift, looked at the suspension, sway bar attachments, nope...
I'm thinking (wild ass guess) that maybe something in the handbrake mechanism moves - is there a drum shoe in there ?

Please shoot any idea you have, it's not just the sound that gets me, it's the idea something is tearing itself apart... Thanks !

Old 05-12-2009, 05:24 AM
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Have you checked your CV joints?
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79 911SC RoW
"Tornadoes come out of frikkin nowhere. One minute everything is all sunshine and puppies the next thing you know you've got flying cows".- Stomachmonkey
Old 05-12-2009, 05:41 AM
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Brake Pads seating themselves? Mine tend to click now and again (after rebuilding the calipers)...
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1985.1 944 NA

Past: 84 RoW Coupe, 86 Carrera, 95 993, 80 SC, 73.5 T
Old 05-12-2009, 05:51 AM
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I have not checked the CV joints... Boots look a little tired but leak free. Is there something specific I can do to check them without tearing them apart ?

Brake pads seating ? I thought so too initially but it's been 3 months and a couple track days now ! Thanks - keep'em coming !

Last edited by Deschodt; 05-12-2009 at 06:23 AM..
Old 05-12-2009, 05:54 AM
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My pads still seat themselves over a year later. Tend to do it most when I roll backwards and hit the brakes.
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1985.1 944 NA

Past: 84 RoW Coupe, 86 Carrera, 95 993, 80 SC, 73.5 T
Old 05-12-2009, 06:03 AM
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Jack the back end up and spin your tires listen for any unusual noises. Grab the axle shaft and wiggle it. If there's any play in the joints its probably time for a replacement.
This may also (spinning your wheels) tell you if the noise is coming from the brakes.
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79 911SC RoW
"Tornadoes come out of frikkin nowhere. One minute everything is all sunshine and puppies the next thing you know you've got flying cows".- Stomachmonkey
Old 05-12-2009, 06:13 AM
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A clunk sounds like something heavy.

CV joints, or Caliper body not tightened down enough would be my first thoughts.

Could be loose pads.
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Old 05-12-2009, 06:34 AM
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Okay, armed with your advice I went and looked.... I could not make it clonk on the lift by spinning the wheel in both directions, though it rubbed quite a bit on the brakes - back to that in a second... The left rear wheel was a little loose axially (grabbing the tire from top and bottom and push-pulling). That made a noise that could be my "clonk" - who knows... Wasn't the wheel... The damn disc was loose!!!



Those screws in red were loose enough to be tightened with my finger nails (well, almost, that might have hurt). One of them took 3 turns of the screwdriver to seat in ! Ugh... How does that happen? Do they work themselves loose over time ? Is there a torque value for these ? Loctite required ? I just went medieval with the biggest screwdriver I could find... The other 3 wheels/discs were tight !

I'll test drive in the morning, too tired now (wife's LR3 got a flat tonight, and raising 6000 lbs on a jack is good enough exercise for the day).

One more Q: Is it normal for the rear wheels to rub on the brake pads like mine does... With the weight of the wheel on, it's not too bad, wheel off it's pretty hard to move the disc by pushing on the studs. Definite SHHHHH.... is there a number of turns a wheel should complete when you spin it by hand? Just ballpark... Seems the pads are rubbing too much, but I don't know brakes much so I could be wrong...

Thx !!!

Last edited by Deschodt; 05-15-2009 at 05:12 PM..
Old 05-15-2009, 05:10 PM
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You need to remove those rotors and check the e-brake against diagrams. Something is amiss inside.
Old 05-15-2009, 05:13 PM
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Quote:
Originally Posted by milt View Post
You need to remove those rotors and check the e-brake against diagrams. Something is amiss inside.
Based on the rubbing, you mean ?

Also I wanted to ask, with the E-brake on, the wheels will spin a tiny bit back and forth, and that clonks too... Normal ? I don't think that is a problem though, I hope the disc/rotor was it !

Last edited by Deschodt; 05-15-2009 at 05:31 PM..
Old 05-15-2009, 05:23 PM
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1980 911 SC
 
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What milt said.

Take them apart and start looking for parts that are loose, missing, or worn. If the wheel "will spin a tiny bit back and forth" then something is loose. It is probably the break shoes themselves, their mounting post, or the little "butterfly" adjusters. There is nothing in there that is difficult to analyze or fix.

Replacing all of the small hardware peices in there is a lot cheaper than not having your car STOP when you want it to.
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Old 05-15-2009, 06:42 PM
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Those screws don't mean much. The wheel and the lug nuts tend to keep the disc flush to the hub.

I agree with the old guy posting above....loose junk under all that mess....

The good thing doing this? Y'all learn how this stuff works.....
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Old 05-15-2009, 07:57 PM
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Don't forget to consider wheel bearings - that was the eventual cause of my clunking...

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Old 05-15-2009, 08:45 PM
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