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Discussion Starter #1
Today a very good friend, and very long time AROC US Alfisti in San Diego, asked me to look at her Giulia Spider Veloce. She believed the left rear brake was locked. I jacked both rear wheels up; each would spin by hand, with the usual amount of shoe / drum drag. We lowered the car, she selected reverse, and the car backed up normally about four or five feet, then the right rear abruptly locked up and slid on the smooth garage floor. In first gear the car went forward normally.
What should we looking to fix? Thanks for all insights.
 

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Did the right rear wheel lock after the bake pedal was applied when the car was going in reverse?

Did the wheel catch while turning backwards when off the ground?

Are the brake cylinders moving freely in their positions on the backing plate?

Were the brakes shoes recently shod?

More info is needed to give you a place to start.

Frank La Sala
 

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Discussion Starter #3
Thank you Frank,

Q. Did the right rear wheel lock after the bake pedal was applied when the car was going in reverse?
A. It locked with no brake pedal applied, just gas pedal and torque through the drive line.

Q. Did the wheel catch while turning backwards when off the ground?
A. Good thought, I'm not sure I rotated in reverse direction, only forward while off ground. Rotating by hand forward it was tight (but didn't catch) for 1/2 to 1/3 of the revolution, but I could turn it by hand. Tomorrow, I'll try reverse direction.

Q. Are the brake cylinders moving freely in their positions on the backing plate?
A. I will check this also.

Q. Were the brakes shoes recently shod?
A. No, it's probably been many years since brakes were done, and the car has not driven very many miles in the last four years.
 

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I'd suspect the some or all of the brake lining has come off the shoe and is binding. It's easy enough to pull the drum off and check. I'm interested to know what happened.

Mike Hollinger
 

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I had this identical situation happen with my Giulietta sprint. When backing up the right rear brake would lock up. When applying the brakes while driving forward the same brake would lock up and the car would skid on that locked wheel. Upon inspecting that brake I found that the lining in one shoe had separated from the shoe for about three inches. I backed off the adjuster mechanism slightly and the problem hasn't reoccured. I still need to get the shoes relined. Dennie
 

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Can also happen even without lining separation if the springs, etc. that hold the shoe in place let go; each shoe can in theory bind in its "servo" direction.
Andrew
 

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Dennie & Brad

Best get those brakes sorted now, if a lining separates from the shoe completely, the rotational action of the drum can force it up-n-over the opposite brake shoe which would effectively lock up that drum solid, in fact it could jam it up so hard that you could potentially have to cut the drum off the car...

Plus nothing like a rear brake lock-up at any speed to make your day *very* exciting - also these things tend to happen in traffic & your car is then effectively immobilised somewhere on the road in the path of those dithering drivers in SUV's

A friend out here had a crown wheel bolt come loose in his old '61 Spider, caught on the innards, broke the bolt, the rotational action of the diff carried the broken bolt 1/3rd of the way around the crown wheel & effectively sheared the heads off 1/3rd of the crown wheel bolts which then dropped into the innards & jammed up everything inside the casing & he slid to a halt on the freeway with the rear end locked up solid. The little Spider had to be winched onto a low-loader by brute force. From 60mph to a dead stop in 2 long rubber stripes - at least it stopped in a straight line, if you jam up one back wheel, it'll try & change lanes on you.

Pull the drum & fix it quickly, whatever you do will be cheaper than the alternative.

If you need / want brake rebuild info, just shout, I've got some stuff I wrote up years ago on 2 & 3 shoe brakes - just send me a PM

Ciao
Greig
 

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Discussion Starter #8
Yesterday I visited the garage where the Spider is kept and did some follow up. The drum came off with the usual amount of resistance. The linings have no separation, and around 50-70% remaining good material with very even wear. Return springs all in good shape, no seal or cylinder leakage. There was a LOT of brake lining dust everywhere, much of it gummy, and caked onto the brake lining in uneven clumps. I scrubbed and vacuum cleaned everywhere I could reach with a brush. Then with a cloth dampened with a bit of brake cleaning solvent, I wiped the shoe surfaces until I could see clean, gray lining material. With the drum reassembled, it rotates both directions as it should. I've not heard the owners drive test, but will let you all know the result. We will monitor the condition carefully for the first several miles.
This car belongs to a wonderful lady, Glenna Garrett. Some of you know her as former Secretary of AROC US.
 

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Greig, thank you immensely for that information re; brake lining separation. I hadn't thought that one through and was driving the car. I once had a differential pinion bearing seize up at freeway speeds and the wheels didn't lock up but there was a noise that I never want to hear again. Thank you, Dennie
 

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I'm guessing the car worked fine before Pat passed away some years ago and since then Glenna probably hasn't driven it much if any. So assuming everything worked before, and it probably did and assuming the brake and rear axle seals are still working It's probably something simple. It always is. My guess is the sliding feature of the rear cylinder is dried up and needs a dab of grease... and check to make sure the parking brake cables are limp. Catastrophic failures like brake linings falling off or bolt shearing usually don't apply to cars that have just been sitting.. lack of lube from static parts where it should be or dried out seals is usually the first place to start looking IMHO. Oh, I would bleed the brakes and flush them out to take that out of the mix, just as a general good thing to do.
 

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Discussion Starter #11
Thanks Rick, you've assessed the situation perfectly. Parking brake cables are slack. I'll lube the cyl slides, and bleed the system. When I first posted this, I was puzzled by how abruptly the wheel locked up. Glenna is interested in getting the car sorted, and in use again.
 
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