unpredictable brakes - Team Camaro Tech
Brakes, Suspension & Steering Conversion questions, Steering & Handling

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post #1 of 13 (permalink) Old Aug 10th, 17, 11:45 AM Thread Starter
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Phil McCullough
 
Join Date: Jun 2007
Location: rural, Urbana, Ohio
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unpredictable brakes

I need help! I got my 67 SS/RS drive-able and refitted a year ago but don't drive it much, though I intended to, because the brakes are less than satisfactory often pulling severely to the left sometimes wanting to skid the left front tire. The condition lessens as the brakes warm up. The brake system is all new, no sign of contamination and have been bled several times. I suspect that I may have mismatched some components? This is a power drum brake system that I tried to duplicate the original with. The Booster is new bought separately from the master cylinder the MC looks like the original but has a slightly larger bore (disc brake maybe?) the rectangular splitter looks and mounts just under the MC and appears to work OK. The lines are stainless and not kinked. The system is filled with silicon fluid (new stuff to me!) I am not a complete novice but am unsure what to look for to correct these brakes. I have considered switching to front disc brakes but hate too just yet as this is a numbers matching in the family since new car.???
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post #2 of 13 (permalink) Old Aug 10th, 17, 12:17 PM
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Kevin
 
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Re: unpredictable brakes

I was in the same situation with my car after completely rebuilding my manual drum brake system. All new parts and bled the system. Long story short the problem was twofold, one was the front end alignment was way off( toe out) after I rebuilt that also. And second was the brakes were not adjusted tight enough. Need to move the brake adjuster on each wheel till there is noticeable drag when spinning the tire while jacked up, mine were too far backed off and all the shoes were not contacting the drums at the same time.

Don't know if that is any help to you but it is what the issues were for me.
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post #3 of 13 (permalink) Old Aug 10th, 17, 02:12 PM
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Dave
 
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Re: unpredictable brakes

Like Kevin said above, brake issues; especially pulling, are due to front end parts and bad brake adjustment. The hydraulics assuming the seal is still good is seldom an issue, which is why the factory uses hydraulics instead of rods and bell cranks like those used on horse drawn wagons and early cars.

Worn tie rods and the rest of the steering components are the usual suspects. But if you have a bad (rusted solid) self adjuster, or din't adjust your brakes shoes when new shoes were installed, it will also cause problems.

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post #4 of 13 (permalink) Old Aug 11th, 17, 09:03 AM Thread Starter
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Phil McCullough
 
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Re: unpredictable brakes

My front end parts are mostly new replaced anything worn except except gear box which does have a bit of wear. Front end alignment done by man with 50 years experience and has latest equipment available. Front end dropped about 2" via springs everything else as original except new. wear seems to be even on shoes except for more wear on left front. I haven't tried backing off the left wheel brake adjustment a bit yet as that didn't seem a good idea. Sorry to say that I haven't given this problem as much attention as I should have and am fishing for something I could have missed?
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post #5 of 13 (permalink) Old Aug 11th, 17, 09:10 AM
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Dave
 
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Re: unpredictable brakes

Are both shoes the same color?

If there is one set wearing faster than the other I might suspect mismatched shoe material (one organic, the other metallic, or ceramic). Difference if material will affect wear rate and friction coefficient.

Or it could be one was adjusted too tight and the other was too loose.

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post #6 of 13 (permalink) Old Aug 11th, 17, 09:21 AM
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George
 
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Re: unpredictable brakes

Be sure you don't have the incorrect self adjuster on the right front, as it could be backing off instead of tightening (incorrect thread), just one thing to check. FWIW
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post #7 of 13 (permalink) Old Aug 11th, 17, 09:31 AM Thread Starter
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Phil McCullough
 
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Re: unpredictable brakes

I need to investigate further, as I recall all the shoes were same color and were bought as a set from NAPA. Drums resurfaced new hardware. It's as suggested probably something simple. I'm 78 and been laid up a while and currently have a tractor in the way (another rebuild project) but will move it today so I can get on the Camaro issue! Pmac
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post #8 of 13 (permalink) Old Aug 11th, 17, 11:52 AM
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David Pozzi
 
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Re: unpredictable brakes

The drum brakes can be fixed, but I have to say, the best thing I ever did was put front disc brakes on my 67 Camaro. Drums will never work as evenly as discs, and the drum brakes on a Camaro are tiny for the job they have to do.
Brake shoes have a Primary (short) and Secondary (long) shoe. Make sure the Primary shoe is in front, it pushes the secondary shoe into the drum, so the front shoes are acting like force generators forcing the Secondary shoe into the drum. The shoes should have edge marking to identify them: "pri" and "sec". If the shoes were installed reversed, the brakes will grab, so check the left front first.


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post #9 of 13 (permalink) Old Aug 11th, 17, 12:35 PM
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Re: unpredictable brakes

If you are concerned over the numbers matching, you could always upgrade and hang on to the old parts if you sell it. I drove with four wheel drum brakes for four years, and it was absolutely miserable. And that was AFTER we rebuilt all four wheel cylinders, and replaced all the springs. Its archaic technology, and a safety issue. I upgraded to a set of stock power front discs, and they are Amazing!
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post #10 of 13 (permalink) Old Aug 12th, 17, 07:24 PM Thread Starter
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Phil McCullough
 
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Re: unpredictable brakes

I have 14" wheels, what are the limitations as far as period correct front power discs are concerned? I think I have a disc brake MC, I'm thinking at the time of rebuild I had to settle on a MC with a larger bore to match the appearance of the original. Is it best to just get a "kit"? My stuff now does all the right things except pull left. Like I said I will investigate further on that as soon as I can but gathering parts is an option, druther be safe than 100% original looking!
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post #11 of 13 (permalink) Old Aug 13th, 17, 08:02 AM
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Al
 
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Re: unpredictable brakes

Phil, Check to be sure you don't have both primary shoes on one side and both secondary shoes on the other side. I've seen this done. Also check installation per David's post. After that adjust both sides to have equal drag. Also as mentioned above be sure the self-adjusters didn't get switched side to side. There are some 14" wheels that will clear disc brakes. If you have the original drum brake wheels they will not clear disc's. Check the wheel forum.

Al

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post #12 of 13 (permalink) Old Aug 13th, 17, 08:48 AM
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Rick
 
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Re: unpredictable brakes

A disc brake master cylinder usually has a bigger front reservoir. I put front disc on with 14" steel wheels and your choices are limited. I just used parts made for original equipment. I got Delco rotors on Amazon, Raybestos calipers w/ pads on eBay, etc. it was really very easy.

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post #13 of 13 (permalink) Old Aug 14th, 17, 08:32 AM Thread Starter
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Phil McCullough
 
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Re: unpredictable brakes

Recon I need to expand my horizons a bit, act younger, learn better networking and parts swapping, all things I enjoyed at a younger time when it was an absolute necessity. The original lasted many years though less than desirable by todays standards. I don't race anymore though I enjoy watching and like the feel of a solid performing car but an unmodified 67 convertible will never be like the cars of today, so if I can get to drive right I will further evaluate modifications to make it "better".
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