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pdecheine
Joined: 02 Dec 2009 Posts: 29 Location: United States
1966 Catalina
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Posted: Fri Sep 25, 2015 7:16 am Post subject: 66 Catalina Brakes |
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My 66 Catalina has developed an unusual problem. When I apply the brakes normally they work fine. When I apply lots of pressure the left front makes a loud scraping noise. I removed the drum, everything is in place, there is no scoring on the shoes or the drum. I sanded the shoes and the drum, the noise is still there and now it pulls to the left. The brakes were completely redone last fall. |
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Larry Site Admin
Joined: 01 Jun 2006 Posts: 4774
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Posted: Fri Sep 25, 2015 10:56 am Post subject: Brake Problem |
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The good news is that there is no damage. However, something is certainly amiss.
As far as a scraping noise, I've had shoes that made noise for no apparent reason, but it is usually an indication of something not being right. I would like to suggest that perhaps too much pressure is being put onto the left side; almost anything will squawk if that's happening.
With the pulling to the left when braking hard, it could be from two causes. Perhaps the left side is activating too soon (wheel cylinder partially extended already when the brake is applied). Or just the opposite, the right side lagging. Either way, it would cause an unequal braking and a subsequent pulling. Too much on the left, perhaps a noise too.
If you haven't checked our 1966 Service Manual On-Line, give it a look-see. Perhaps it will give some ideas. I would also lift the front end (both sides) and do some wheel spinning, do some brake applications (soft and hard) and see if there is any change to how the wheels spin AFTER the brake applications. Maybe one (left) will drag when you then spin it.
If the auto adjusters aren't working (did the '66 have them?), I would crank both side nice and tight and then back them off equally leaving just a little dragging sound. Then test again while in the air, and also on a test drive to see if one side gets tighter then the other.
Sanding the shoes and drum probably just made a sticking problem stick (bite in) even better, thus a pulling; but it was a good thing to do. Don't forget to sort of sand/file the edges of the shoes a bit too. They usually have a bit of a champher, but perhaps with some wear they are straight now. And an excessive pushing (back to the wheel cylinder theory) might be forcing them towards a previously "unused" portion of the drum (usually pretty rusty and bumpy).
Bottom line, I'm sort of inclined to think of a wheel cylinder not performing properly. Please keep us posted. _________________ PontiacRegistry.com... building the single largest source of Pontiac information, services, and entertainment in the world! |
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pdecheine
Joined: 02 Dec 2009 Posts: 29 Location: United States
1966 Catalina
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Posted: Fri Sep 25, 2015 5:46 pm Post subject: |
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Thank you Larry, you have given me some great suggestions! |
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pdecheine
Joined: 02 Dec 2009 Posts: 29 Location: United States
1966 Catalina
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Posted: Sat Sep 26, 2015 7:18 am Post subject: |
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I just manually adjusted the self adjusters on the front brakes as you suggested. The pulling has stopped, yay! I did also get both wheels spinning and then applied the brakes, both sides released so I think I will drive it for awhile to see if the noise disappears as mysteriously as it appeared. Last summer I replaced the entire brake system, lines, master and slave cylinders, shoes, hardware, and had the drums turned (they were new 15 years ago). long story short, after I finished the rebuild, there were some major problems with overheating and grabbing I couldn't solve so I took the car to a brake "expert" Randy's Brakes. He charged me $500 to fix all of the mistakes I supposedly made. The problems were still there. I took it back twice and when Randy decided it was time to throw wrong parts at the problem at my expense, I gave up.
That's when I looked at the shop manual you have on this site. I found that the shop manual says absolutely no bonded shoes are to be used or the brakes will grab and overheat. I replaced the bonded shoes with riveted, organic shoes and the brakes were fine. It seems the folks at OPGI aren't really knowledgeable about what they are selling. They sent me the wrong brake lines twice (I finally had them custom bent locally) open boxes with wrong parts inside, the wrong hoses for the front, and of course the "premium" brake shoes were bonded, semi metallic and totally wrong for this car.
I really appreciate having you and this site as a resource for information! |
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Larry Site Admin
Joined: 01 Jun 2006 Posts: 4774
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Posted: Sat Sep 26, 2015 10:51 am Post subject: Brake Issues |
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Wow! It's good to be right, or at least on the right track. I mentioned the tightening of the shoes, but probably, also, should have mentioned that perhaps the self-adjusters just weren't self-adjusting right. That can happen. Remember, you need to do a few nice firm reverse back-up and brake applications to make the adjusters work (ratchet/adjust).
Sometime you might want to take the adjusters apart and make sure they are nice and clean where they turn on themselves. A little WD40 won't hurt, but don't use any permanent lubricant... brakes and oil/grease not a good combination. Also check that the adjusting links are being nice and tight against the adjuster "star" wheel.
You might also check that the "teeth" on the adjusters are nice and sharp. They can get worn down and rounded with age. That will keep them from ratcheting with the moving arm link sometimes. A sharp flat file to the "V" of the teeth works a lot cheaper than new adjusters too.
I would enjoy it now, and know that you are on the right track to tackle it again if it begins to pull again.
Learning can be expensive... just be glad you don't have a "old car student loan" to pay off. Well, there still are the credit cards. I know some darn good mechanics up here if you need.
BTW, I'm just up the road from you. And while I may not know everything, please be welcome to call me with any questions or just ideas to trace a problem. I can even come down and check it out for you too... I drink Miller! _________________ PontiacRegistry.com... building the single largest source of Pontiac information, services, and entertainment in the world! |
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vncruiser
Joined: 06 Mar 2017 Posts: 5
1966 Grand Prix
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Posted: Tue Apr 04, 2017 10:02 pm Post subject: |
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Where do you find the online service manual? I have a 66 Grand Prix. Put bonded shoes on it from Auto Zone and the car won't stop at all. Stopped better with worn out and cracked shoes... _________________ Drive like hell. You'll get there faster.... |
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pdecheine
Joined: 02 Dec 2009 Posts: 29 Location: United States
1966 Catalina
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Posted: Wed Apr 05, 2017 9:39 am Post subject: |
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Larry was able to provide me with a service manual on a flash drive. As you may have already discovered, it is necessary to manually operate the adjusters until you feel resistance when you're spinning the wheel. After that they will wear in and they will self adjust every time you back up and step on the brakes. I do recommend that you switch over to organic riveted brake shoes. The shop manual was very specific about not using bonded brake shoes and the modern bonded brake shoes are semi metallic. |
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Larry Site Admin
Joined: 01 Jun 2006 Posts: 4774
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Posted: Thu Apr 06, 2017 11:13 am Post subject: Brake Material |
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Sadly "Generous Motors" kept getting more and more greedy with royalty payments, so we basically had to tell them to "put it where the sun don't shine." If you need a manual I will put it on a flash drive for not much more than the cost of the drive and postage. Drop me a note.
This problem with brake shoe material is getting out of hand. I never heard of bonded shoes causing this much of a problem though. Did you try really roughing up the surfaces with coarse sand paper?
Also, "back in the old days" we used to take our drums into the parts store and they would "arch the shoes" to your drums. Today I guess they just hope the shoes will eventually wear their way into the drum shape/size. But that leaves the possibility of high spots on the shoes that really cuts down on the surface area making contact.
If it's the bonding, or the material, I don't know, but certainly the good old "organic" material was best back then for those cars, and I'm sure the same would be best now. Check with some place like NAPA. They seem to be the last still around with old information. As another thought, check a speed shop. They may be all about exotic materials, but perhaps have answers for the older cars.
Check with these people at Brake and Equipment Warehouse
455 Harrison Street NE, Minneapolis, MN 55413
800-233-4053 / 612-378-3141
http://www.brakeplace.com
They also give our members a discount. You may have to remind them depending on who you speak to.
Keep us posted on what you learn so we can help others. _________________ PontiacRegistry.com... building the single largest source of Pontiac information, services, and entertainment in the world! |
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